Head Gasket Problems or something simpler
Discussion
Hi All,
Could really use some advice, it's a bit of a complicated story so I'll try and keep it breif. My family bought me a car back in June as a birthday present, a 2010 Mercedes W169 A160 Blue efficiency. It looked absolutely mint and had full merc service history. The idler roller pulley was on it's way out (common problem) so I took it to Sevan motors in shepherds Bush as he is very experienced with the A/B class and the idiosyncratic flat sandwich engine that most mechanics would despise you for bringing to them (seriously it's all a nightmare!). He told me to take it back and get a refund ASAP as it was rusted so badly he couldn't even take it apart and put it back together without it falling apart. Air con condenser was shot too. So I returned the car and got a refund no problems.
I got another W169, a 2009 A150 with less miles and more options, cat c from a rear impact that had been well repaired and passed inspection. After the last experience I THOROUGHLY checked this car over leaving nothing to chance and it seemed perfect. There were two intermittent ECU errors I noticed on my ELM scanner P007A Charge air temperature sensor and also another related to the charge air temp sensor. Not a difficult job to replace or clean. I logged the codes and saved them, cleared them and they never re appeared. Few days later I start the car, it's struggling to maintain idle. Scan shows a misfire on cylinder 3. I check everything thoroughly and to my horror a huge amount of foamy mayonnaise has worked its way up the oil filler cap which wasn't present when I inspected the car. There is a little puffing from the oil filler and the oil smelled of petrol so bad my eyes were burning. Oil temps were high, the last car might get to 96/97 degrees under hard driving, this thing was getting to just over 100. So I'm thinking the head gasket is gone and I'm screwed. Thing is there's no overheating, no loss of oil or coolant, no smoke from the exhaust and I did an exhaust gas test of the coolant system and no gases were present....
A few days later I start it up, the idle is lumpy it can barely rev up or maintain a steady rpm. I'm thinking the worst
I believe the car was basically an old lady's shopping chariot and had suffered many many short journeys and cold starts/trips. I used a metric f*ton of Redex and and redex advanced and subjected the motor to a Italian tuneup that even an Italian might consider abuse! Since then no misfire, no error codes or ECU lights and a pretty smooth drive. I didn't want to drive to get a oil change/spark plug replacement on this fuel contaminated oil to so siphoned about 2 litres (out of 4.7) and replenished with fresh oil which immediately improved engine NVH and much lower oil temps. The oil I got out looked old and in bad shape.
So here's the big question, is my Head gasket going or gone? OR has this poor car been running rich due to the intake temp sensor, suffering deposits and buildups and potentially blocked injectors from miss daisy, and therefore excessive fuel and misfires have contaminated the system. Could a bloody good service be all I need for some happy motoring or are these ominous signs that something big is going to happen soon? A worn piston ring is also a possibility I've considered.
Any advice appreciated, I've never seen a car that seems like it's either head gasket problems or just a case of Doris driving around with clogged injectors and an ecu running rich. Engine is sweet as a nut, probably more powerful than the last one, though shorter gearing helps. No terrible sounds, knocks, leaks. No loss of oil or coolant either!
Any advice appreciated, I'm stuck with her now so whatever happens be it a head gasket replacement then that will have to happen. If a good service, new plugs/injectors/coil pack will remedy the situation id be bloody relieved.
Could really use some advice, it's a bit of a complicated story so I'll try and keep it breif. My family bought me a car back in June as a birthday present, a 2010 Mercedes W169 A160 Blue efficiency. It looked absolutely mint and had full merc service history. The idler roller pulley was on it's way out (common problem) so I took it to Sevan motors in shepherds Bush as he is very experienced with the A/B class and the idiosyncratic flat sandwich engine that most mechanics would despise you for bringing to them (seriously it's all a nightmare!). He told me to take it back and get a refund ASAP as it was rusted so badly he couldn't even take it apart and put it back together without it falling apart. Air con condenser was shot too. So I returned the car and got a refund no problems.
I got another W169, a 2009 A150 with less miles and more options, cat c from a rear impact that had been well repaired and passed inspection. After the last experience I THOROUGHLY checked this car over leaving nothing to chance and it seemed perfect. There were two intermittent ECU errors I noticed on my ELM scanner P007A Charge air temperature sensor and also another related to the charge air temp sensor. Not a difficult job to replace or clean. I logged the codes and saved them, cleared them and they never re appeared. Few days later I start the car, it's struggling to maintain idle. Scan shows a misfire on cylinder 3. I check everything thoroughly and to my horror a huge amount of foamy mayonnaise has worked its way up the oil filler cap which wasn't present when I inspected the car. There is a little puffing from the oil filler and the oil smelled of petrol so bad my eyes were burning. Oil temps were high, the last car might get to 96/97 degrees under hard driving, this thing was getting to just over 100. So I'm thinking the head gasket is gone and I'm screwed. Thing is there's no overheating, no loss of oil or coolant, no smoke from the exhaust and I did an exhaust gas test of the coolant system and no gases were present....
A few days later I start it up, the idle is lumpy it can barely rev up or maintain a steady rpm. I'm thinking the worst
I believe the car was basically an old lady's shopping chariot and had suffered many many short journeys and cold starts/trips. I used a metric f*ton of Redex and and redex advanced and subjected the motor to a Italian tuneup that even an Italian might consider abuse! Since then no misfire, no error codes or ECU lights and a pretty smooth drive. I didn't want to drive to get a oil change/spark plug replacement on this fuel contaminated oil to so siphoned about 2 litres (out of 4.7) and replenished with fresh oil which immediately improved engine NVH and much lower oil temps. The oil I got out looked old and in bad shape.
So here's the big question, is my Head gasket going or gone? OR has this poor car been running rich due to the intake temp sensor, suffering deposits and buildups and potentially blocked injectors from miss daisy, and therefore excessive fuel and misfires have contaminated the system. Could a bloody good service be all I need for some happy motoring or are these ominous signs that something big is going to happen soon? A worn piston ring is also a possibility I've considered.
Any advice appreciated, I've never seen a car that seems like it's either head gasket problems or just a case of Doris driving around with clogged injectors and an ecu running rich. Engine is sweet as a nut, probably more powerful than the last one, though shorter gearing helps. No terrible sounds, knocks, leaks. No loss of oil or coolant either!
Any advice appreciated, I'm stuck with her now so whatever happens be it a head gasket replacement then that will have to happen. If a good service, new plugs/injectors/coil pack will remedy the situation id be bloody relieved.
There's no reason to jump to any conclusions. A misfire and fault codes tells you there's something not running right and you want to get that diagnosed and fixed ASAP. In particular a sustained misfire can overheat and destroy a cat quite quickly which can be an expensive repair even if the original problem turns out to be minor.
As far as HGF and so on, you would get a compression test, leakdown test and block test done before reaching any conclusions about that. If you have a reliable mechanic I suggest you get the car to them and ask them to diagnose it.
As far as HGF and so on, you would get a compression test, leakdown test and block test done before reaching any conclusions about that. If you have a reliable mechanic I suggest you get the car to them and ask them to diagnose it.
GreenV8S said:
There's no reason to jump to any conclusions. A misfire and fault codes tells you there's something not running right and you want to get that diagnosed and fixed ASAP. In particular a sustained misfire can overheat and destroy a cat quite quickly which can be an expensive repair even if the original problem turns out to be minor.
As far as HGF and so on, you would get a compression test, leakdown test and block test done before reaching any conclusions about that. If you have a reliable mechanic I suggest you get the car to them and ask them to diagnose it.
Im desperately not trying to jump to conclusions, the misfire has never been recorded again and neither has the charge air sensor fault. I have continually scanned and interrogated the ECU and it's never re-appeared.if the misfire continued I'd have it towed as I'm aware of what unburned fuel can do to a catalyst.As far as HGF and so on, you would get a compression test, leakdown test and block test done before reaching any conclusions about that. If you have a reliable mechanic I suggest you get the car to them and ask them to diagnose it.
I completely agree with what you suggest and if it were any other car it would already be done, but the engine in the A class is a absolute bloody nightmare. Two of the spark plugs are not too bad to reach for checking and for compression testing but the rear two need Chinese acrobats to access. You can't even get to them from underneath because Mercedes in their wisdom placed the rear spark plugs directly next to the exhaust manifold (just what a high comp engine needs
)Im just wondering if it's feasible that lack of use, sedentary driving and poor servicing could be the cause of this issue. Would a HG leak not cause some more serious problems than what I've experienced? The lack of any leaks or contamination is surely a good sign? I might have gone from an A160 to an A150 but that's just the badging they went with from 2010. It's the same engine and it feels every bit as powerful, if not more so than the previous one. If there was any compression loss surely there would be a performance dip?
Is it feasible that all that mayo appeared because the car had finally had a bloody good run and it was evaporating up the filler neck? No foam or.contaminatiln on the dipstick either.
I will probably pay for the specialist to.do what you've advised, there's no point spending money on a full service to end up with fouled plugs.and.fuel contaminated oil again.Just wondering if a clogged PCV valve might also cause or influence these problems?
Yes all that could be the perfect normal result of a car that hasn't been serviced because it was hard to service and the owner couldn't be bothered.
Or it could be the result of some problem your scanner isn't detecting.
If it was HGF then driving it hard would probably have made that worse, not better. It's still a possibility but the evidence for that is weak.
Or it could be the result of some problem your scanner isn't detecting.
If it was HGF then driving it hard would probably have made that worse, not better. It's still a possibility but the evidence for that is weak.
GreenV8S said:
Yes all that could be the perfect normal result of a car that hasn't been serviced because it was hard to service and the owner couldn't be bothered.
Or it could be the result of some problem your scanner isn't detecting.
If it was HGF then driving it hard would probably have made that worse, not better. It's still a possibility but the evidence for that is weak.
Yes I will try and find someone more local with access to the Mercedes STAR diagnostics system as it shows a LOT more info (any local ph'ers to Bedfordshire with STAR that could help for a good fee would be appreciated) Or it could be the result of some problem your scanner isn't detecting.
If it was HGF then driving it hard would probably have made that worse, not better. It's still a possibility but the evidence for that is weak.
Oil filter, oil change and air filter can be done by anyone. Though you have to remove the ECU to get to the air filter, nice one Mercedes
. Plugs COULD be done by a local mechanic but he'd probably never want to speak to you again.The A class and 1st gen B class are the only front mid engined front wheel drive cars i can think off the top of my head. It has its advantages, massive interior room, good handling, crash protection etc but it's a car that seemed to be designed to cause mechanics to have mental breakdowns! Engine and subframe needs to be lowered for a lot of typical jobs
thought thankfully not plugs.Sevan in London is a master and it's no wonder he dedicated himself to the sandwich floor cars but it's a trek for me and I don't like driving in London very much.
I guess I could always get Halfords to do it, the quoted price IS the quoted price and there's YouTube videos that show you how to do it all easily that someone with the correct tools could easily follow. I just don't have the tools or experience
I've attached an image of the M266 engine for anyone who can't understand why this is the biggest PITA
Hi All,
I'm asking for a bit more help if anyone experienced can advise me on what they think I should do.
The car is being serviced next week, Oil and oil filter, spark plugs and air filter. I also got a can of carb cleaner seeing as the mechanic has to take the throttle body and PCV etc off to get access to the motor.
The engine is running pretty great, good fuel economy, no CEL errors and no fault codes or not at least any an ELM scanner can detect.
When idling there's the odd "pulse" every now and again, I guess very much like how a 3 pot feels when idling. If you try and "hold" a steady rpm there will be a difficulty in maintaining it, usually dipping down by 100RPM or so in little bursts. My mechanic knowledge is limited but I know coil pack problems can be similar but this will occur ANYWHERE in the rev range .
What's confusing even more is fuel economy is excellent. I don't have a Dyno but I used GPS to confirm that the car can accelerate at the rate the manufacturer claims. I don't have a private road to do 109mph but I feel it would achieve it easily. There are no error logs at all, why the P007A & D errors miraculously fixed themselves is a mystery. I know that sometimes an ecu has to see quite a variance to throw an error code but surely it must know that it's poorly?
I think either servicing the car will fix the problems or I'll end up ruining 5 litres of very expensive oil and fouling brand new plugs if I don't get to the bottom of what's causing this problem. I have got myself some basic socket sets and torx sockets as well as a multimeter to try and see if I can pinpoint the problem because if I can then it would be so easy to fix while the service is being carried out. Is there a surefire way or at least a good indication on how to tell apart the symptoms of a fouled plug, blocked or weak fuel injector or a busted coil pack?
I'm asking for a bit more help if anyone experienced can advise me on what they think I should do.
The car is being serviced next week, Oil and oil filter, spark plugs and air filter. I also got a can of carb cleaner seeing as the mechanic has to take the throttle body and PCV etc off to get access to the motor.
The engine is running pretty great, good fuel economy, no CEL errors and no fault codes or not at least any an ELM scanner can detect.
When idling there's the odd "pulse" every now and again, I guess very much like how a 3 pot feels when idling. If you try and "hold" a steady rpm there will be a difficulty in maintaining it, usually dipping down by 100RPM or so in little bursts. My mechanic knowledge is limited but I know coil pack problems can be similar but this will occur ANYWHERE in the rev range .
What's confusing even more is fuel economy is excellent. I don't have a Dyno but I used GPS to confirm that the car can accelerate at the rate the manufacturer claims. I don't have a private road to do 109mph but I feel it would achieve it easily. There are no error logs at all, why the P007A & D errors miraculously fixed themselves is a mystery. I know that sometimes an ecu has to see quite a variance to throw an error code but surely it must know that it's poorly?
I think either servicing the car will fix the problems or I'll end up ruining 5 litres of very expensive oil and fouling brand new plugs if I don't get to the bottom of what's causing this problem. I have got myself some basic socket sets and torx sockets as well as a multimeter to try and see if I can pinpoint the problem because if I can then it would be so easy to fix while the service is being carried out. Is there a surefire way or at least a good indication on how to tell apart the symptoms of a fouled plug, blocked or weak fuel injector or a busted coil pack?
Just thought I'd upload a few videos of it might help as I'm desperate to get this motor running well. If anyone has two cents on this I'd appreciate it!
One is of the oil filler neck that seems to let out a fair bit of gases, some people I've shown this have told me that it's normal for older motors to suffer a fair bit of blow by and that it's not too excessive especially if there is another issue going on such as poor maintenance and old spark plugs. The absence of any exhaust gas problems from the tailpipe, coolant reservoir and lack of any emissions control issues leads me to believe this might not be too bad?
https://streamable.com/pycf3w
The second video shows the ever so slightly unstable idle speed and how trying to maintain 2k rpm or similar results in these dips and drops. I might have been wrong in my last post, it may hold higher rpm's okay 2k is where it's very apparent and also a bit at idle.
https://streamable.com/wblqd1
It's getting serviced on Saturday and I know that new spark plugs and cleaning of the throttle body/PCV and Charge air cooler might eliminate these issues. If however it turns out to be something else I could end up ruining new plugs and oil 😑
I used torque and my elm scanner, still not a single error thrown up. I then decided to run a continuous scan and absolutely everything stayed in the green, no misfires or anything detected even if I held it at 2k and experienced the rpm dips. Given how the coils are coming off during the service and they are about £20 would it be worth getting a spare before Saturday? I'm wondering if there's not an error code for a misfire because it's simply a poor burn rather than a total misfire?
Are there any parameters I could be looking at in torque with the scanner to narrow down this problem? I did notice one parameter R THR (relative throttle position?) would fluctuate along with the rpm dips, as if I had let off the throttle a bit despite holding it steady.
One is of the oil filler neck that seems to let out a fair bit of gases, some people I've shown this have told me that it's normal for older motors to suffer a fair bit of blow by and that it's not too excessive especially if there is another issue going on such as poor maintenance and old spark plugs. The absence of any exhaust gas problems from the tailpipe, coolant reservoir and lack of any emissions control issues leads me to believe this might not be too bad?
https://streamable.com/pycf3w
The second video shows the ever so slightly unstable idle speed and how trying to maintain 2k rpm or similar results in these dips and drops. I might have been wrong in my last post, it may hold higher rpm's okay 2k is where it's very apparent and also a bit at idle.
https://streamable.com/wblqd1
It's getting serviced on Saturday and I know that new spark plugs and cleaning of the throttle body/PCV and Charge air cooler might eliminate these issues. If however it turns out to be something else I could end up ruining new plugs and oil 😑
I used torque and my elm scanner, still not a single error thrown up. I then decided to run a continuous scan and absolutely everything stayed in the green, no misfires or anything detected even if I held it at 2k and experienced the rpm dips. Given how the coils are coming off during the service and they are about £20 would it be worth getting a spare before Saturday? I'm wondering if there's not an error code for a misfire because it's simply a poor burn rather than a total misfire?
Are there any parameters I could be looking at in torque with the scanner to narrow down this problem? I did notice one parameter R THR (relative throttle position?) would fluctuate along with the rpm dips, as if I had let off the throttle a bit despite holding it steady.
Who is doing the service?
You said "It's getting serviced on Saturday and I know that new spark plugs and cleaning of the throttle body/PCV and Charge air cooler might eliminate these issues. If however it turns out to be something else I could end up ruining new plugs and oil"
You said in an earlier post "Sevan in London is a master and it's no wonder he dedicated himself to the sandwich floor cars but it's a trek for me and I don't like driving in London very much."
I suggest you would save yourself a lot on worry and stress plus the costly parts cannon approach of buying parts to replace parts that may not be the problem if you just take the car to him.
You said "It's getting serviced on Saturday and I know that new spark plugs and cleaning of the throttle body/PCV and Charge air cooler might eliminate these issues. If however it turns out to be something else I could end up ruining new plugs and oil"
You said in an earlier post "Sevan in London is a master and it's no wonder he dedicated himself to the sandwich floor cars but it's a trek for me and I don't like driving in London very much."
I suggest you would save yourself a lot on worry and stress plus the costly parts cannon approach of buying parts to replace parts that may not be the problem if you just take the car to him.
paintman said:
Who is doing the service?
You said "It's getting serviced on Saturday and I know that new spark plugs and cleaning of the throttle body/PCV and Charge air cooler might eliminate these issues. If however it turns out to be something else I could end up ruining new plugs and oil"
You said in an earlier post "Sevan in London is a master and it's no wonder he dedicated himself to the sandwich floor cars but it's a trek for me and I don't like driving in London very much."
I suggest you would save yourself a lot on worry and stress plus the costly parts cannon approach of buying parts to replace parts that may not be the problem if you just take the car to him.
Service is being done by a local friend, very qualified and services classics, modern Porsches etc. I made 100% sure he is comfortable with the A class and he is. I would go to Sevan in a heartbeat but we really are talking mates rates on this local service. Thing is I don't even think this is something worth troubling Sevan with. Imagine for a second this isn't an A class and it's a Toyota Corolla or a Honda Civic, if you saw those problems what do you think would be the cause?You said "It's getting serviced on Saturday and I know that new spark plugs and cleaning of the throttle body/PCV and Charge air cooler might eliminate these issues. If however it turns out to be something else I could end up ruining new plugs and oil"
You said in an earlier post "Sevan in London is a master and it's no wonder he dedicated himself to the sandwich floor cars but it's a trek for me and I don't like driving in London very much."
I suggest you would save yourself a lot on worry and stress plus the costly parts cannon approach of buying parts to replace parts that may not be the problem if you just take the car to him.
I just wanted to update my post following the service and successfully fixing the vehicle, it might help someone with similar problems or with a W169. I don't have a bad head gasket thankfully.
The friend I had helping is studying at uni for a degree in Marine engines and was very experienced.
Reason for poor idle and inability to hold lower rpm's was mainly two reasons, the heat shields that cover the plugs and also deliver the electricity to them had grease used in a previous service, it had gone seriously manky and would probably prevent good electrical contact with the plug. Secondly the plugs themselves, probably changed all of once by his estimation in the cars 90+ thousand mile life. They were awful and totally worn out.
Smell of oil in petrol is kind of a non issue, the oil drained from the sump had no irregularities, didn't even look too bad (though 2 litres had been siphoned and replaced by me last week to be on the safe side). It had no smell of petrol. Could be the evaporative purge solenoid is a bit slow at doing it's job, didn't even know what they were. I would probably need STAR to see what it's up to in more detail. I cleaned what I could as it's disconnected during the procedure followed.
We followed this guide to remove everything up on top of the engine: https://youtu.be/dBkBi23GHt8. The front of the car was raised to make work easier. Not that they were particularly dirty but the throttle body/PCV were cleaned as was the VLIM housing/runner pipes.
Engine starts better, idles smoothly and settles down to idle quicker. MPG is up. Probably has a little more poke on offer but nothing night and day.
I guess the moral of the story, if you have a W169 or want to buy one....yes the plugs are a pain in the backside to do but they really should not be neglected. I guess they are more likely to be neglected than on other cars because of the access issues, but the fact they are located next to the exhaust manifold and use heat shields mean they will wear quicker than on most cars if anything and need MORE regular changes. Another joy of W169 ownership 👍 And it is a joy the baby Benz is back to how she should be!
The friend I had helping is studying at uni for a degree in Marine engines and was very experienced.
Reason for poor idle and inability to hold lower rpm's was mainly two reasons, the heat shields that cover the plugs and also deliver the electricity to them had grease used in a previous service, it had gone seriously manky and would probably prevent good electrical contact with the plug. Secondly the plugs themselves, probably changed all of once by his estimation in the cars 90+ thousand mile life. They were awful and totally worn out.
Smell of oil in petrol is kind of a non issue, the oil drained from the sump had no irregularities, didn't even look too bad (though 2 litres had been siphoned and replaced by me last week to be on the safe side). It had no smell of petrol. Could be the evaporative purge solenoid is a bit slow at doing it's job, didn't even know what they were. I would probably need STAR to see what it's up to in more detail. I cleaned what I could as it's disconnected during the procedure followed.
We followed this guide to remove everything up on top of the engine: https://youtu.be/dBkBi23GHt8. The front of the car was raised to make work easier. Not that they were particularly dirty but the throttle body/PCV were cleaned as was the VLIM housing/runner pipes.
Engine starts better, idles smoothly and settles down to idle quicker. MPG is up. Probably has a little more poke on offer but nothing night and day.
I guess the moral of the story, if you have a W169 or want to buy one....yes the plugs are a pain in the backside to do but they really should not be neglected. I guess they are more likely to be neglected than on other cars because of the access issues, but the fact they are located next to the exhaust manifold and use heat shields mean they will wear quicker than on most cars if anything and need MORE regular changes. Another joy of W169 ownership 👍 And it is a joy the baby Benz is back to how she should be!
Jaz2000 said:
Now that it is running well my advice would be to send an oil sample off for analysis, this will show if there is any water, fuel or trace elements of different metals in the oil. You will then know if you have a healthy engine.
I actually had that thought when doing the job then got so distracted pouring it back into the new oil container for the mechanic to go dispose of I totally forgot 😅. It's a really good shout though and one I'll endeavour to actually remember in the future. One thing I learned that is good, on the Mercedes W169 A class mayonnaise up the filler neck is literally normal. It's a very long path to travel so on short journeys plenty of condensation occurs. I've since been to a local friend who has DAS/XENTRY or whatever it's called. EVAP purge solenoid is working okay and lots of other modules. He could see one of the fuel injectors is lagging a bit and that turned out to be the odd ticking I was hearing which was confirmed with a stethoscope. I've run some tanks containing Redex, Redex advanced injector cleaner, STP and now liqui Moly Jectron in order to see if I can get it sorted without having to go through that whole pigging process again 😅 My baby Mercedes has run more kerosene than a 747 🤣 It's not a huge issue and not causing any misfires, errors or problems driving it's just I can "feel" it now and then. I will change the injectors though if it comes to it. Been focusing on the cosmetic at the moment and upgrading a lot of the interior exterior to avantgarde spec.
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