Discussion
Ron, being a sparks you probably realise that by joining the 2 wires that lead the otter switch, you eliminate the switch and the fan(s) should work constantly. If they do, just replace the otter switch - a bit fiddly in situ, involves removing the light pod (not sure it can be reached from underneath). There should be a rubber seal that the switch fits into, all held in place in the tank by a nasty spring clip contraption.
Hi Ron...Even though i have a manual fan switch that keeps me on my toes shyte happens...
I actually found the electric seal that goes on the rad collar before the hose and has a groove in it for the sensor wire to run along so that it doesn't leak...You can have that if you want...If you go the probe option..I had it on Delilah and as long as you calibrate it to when the thermostat has been open for a few degrees then it should be fine..Those types of switches need to go the hot side of the engine which is from rad to engine...Otherwise your fan may be on all the time and the thermostat will struggle to open fully.
I actually had two control units from Kenlowe which for a man of your calibre could wire in although i may of slung em...Ill have a look.
There is also a coupling thermostatic switch which the RR use which is the same OD as the hose ID.
http://www.ebay.co.uk/itm/35MM-HOSE-ADAPTOR-RANGE-...
But this is a pre-set temp.
As said if you want the seal and the control unit...(If i still have it) its yours...
Cheers
Ziga
I actually found the electric seal that goes on the rad collar before the hose and has a groove in it for the sensor wire to run along so that it doesn't leak...You can have that if you want...If you go the probe option..I had it on Delilah and as long as you calibrate it to when the thermostat has been open for a few degrees then it should be fine..Those types of switches need to go the hot side of the engine which is from rad to engine...Otherwise your fan may be on all the time and the thermostat will struggle to open fully.
I actually had two control units from Kenlowe which for a man of your calibre could wire in although i may of slung em...Ill have a look.
There is also a coupling thermostatic switch which the RR use which is the same OD as the hose ID.
http://www.ebay.co.uk/itm/35MM-HOSE-ADAPTOR-RANGE-...
But this is a pre-set temp.
As said if you want the seal and the control unit...(If i still have it) its yours...
Cheers
Ziga
Hi all
Thanks for the offer of the bits zig but I'm sorted. New adjustable stat ordered
Will have a tinker tonight to get everything prepared and check its not a fan issue rather than the otter switch
Not going to replace the otter switch as
A access is crap
B dont want to disturb it and risk inducing a leak
C want some adjustability to fine tune it
Will report back once I'm up and running again
Thanks for the offer of the bits zig but I'm sorted. New adjustable stat ordered
Will have a tinker tonight to get everything prepared and check its not a fan issue rather than the otter switch
Not going to replace the otter switch as
A access is crap
B dont want to disturb it and risk inducing a leak
C want some adjustability to fine tune it
Will report back once I'm up and running again
Evening all
Well my woes continue
New adjustable fan stat arrived and fitted. All seemed well set it to 40 deg ran engine up and fan kicked in set to 50 deg and after a few moments fan kicked in again, reset to 85deg (82deg thermostat fitted) and time for a run. Unfortunately the temp rose and rose so pulled over to let it cool- fan was running but cut out quite quickly even though gauge was showing 95 deg??
Then whole sitting waiting for the engine to cool- bang-the temp gauge went off the scale as if id flicked a switch
Even turning off the ignition or pulling off the connector to the sender didn't affect it - after a couple of mins I turned the ignition on and off and it immediately dropped to 90 degrees ???
All a bit odd
Onwards and upwards
The engines still overheating
Not sure if I can trust the temp gauge
Not sure if the new fan stat is working correctly or accurate
Possibly got 2 different temps going on - one temp at top hose (where fan stat is) and another at the engine itself (possibly a stuck /faulty engine Stat ??)
Next plan of attack
Might remove/replace engine stat to remove it from equation
Borrow my company's laser thermometer so I can get an accurate measurement of the engine/top hose /radiator temperatures
Next episode to follow shortly.....
Ron
Well my woes continue
New adjustable fan stat arrived and fitted. All seemed well set it to 40 deg ran engine up and fan kicked in set to 50 deg and after a few moments fan kicked in again, reset to 85deg (82deg thermostat fitted) and time for a run. Unfortunately the temp rose and rose so pulled over to let it cool- fan was running but cut out quite quickly even though gauge was showing 95 deg??
Then whole sitting waiting for the engine to cool- bang-the temp gauge went off the scale as if id flicked a switch
Even turning off the ignition or pulling off the connector to the sender didn't affect it - after a couple of mins I turned the ignition on and off and it immediately dropped to 90 degrees ???
All a bit odd
Onwards and upwards
The engines still overheating
Not sure if I can trust the temp gauge
Not sure if the new fan stat is working correctly or accurate
Possibly got 2 different temps going on - one temp at top hose (where fan stat is) and another at the engine itself (possibly a stuck /faulty engine Stat ??)
Next plan of attack
Might remove/replace engine stat to remove it from equation
Borrow my company's laser thermometer so I can get an accurate measurement of the engine/top hose /radiator temperatures
Next episode to follow shortly.....
Ron
mrzigazaga said:
Hi Ron.
Where did you place the thermo switch/Probe?...
It also sounds like you have a dodgy gauge or sender.
Hi zigWhere did you place the thermo switch/Probe?...
It also sounds like you have a dodgy gauge or sender.
Probe is in top hose as recommended on the instructions that came with it.
My current train of thought is that the engine stat is faulty and not opening therefore not getting water flowing through the rad and overheating. This would also explain the reluctance of the fan to operate correctly as until the engine stat opens the probe in the top hose wont be getting the hot engine coolant flowing over it. Not sure if my hypothesis is correct but its the only ine I've got at the moment !!
Yep sounds like stat ..... I would drain the coolant take the stat out remove top and bottom hoses on the rad run your pressure washer through it and see if any sludge come out allow to drain. Check stat is working using a kettle when her who must be obeyed is not looking! Replace stat or leave it out if you do not mind a bit more fuel on cold start
Re-burp the car and test
Chris
Re-burp the car and test
Chris
Jack Valiant said:
Yep sounds like stat ..... I would drain the coolant take the stat out remove top and bottom hoses on the rad run your pressure washer through it and see if any sludge come out allow to drain. Check stat is working using a kettle when her who must be obeyed is not looking! Replace stat or leave it out if you do not mind a bit more fuel on cold start
Re-burp the car and test
Chris
Cheers Chris Re-burp the car and test
Chris
Was my plan of action next
Going to borrow a laser thermometer to accurately measure all my temps to see how accurate my temp gauge and adjustable fan stat is also.
adam quantrill said:
A good test of the stat before removing is to run the engine on fast idle from cold and feel the top hose, it should be cold for quite a while then suddenly get hot.
Hi AdamOn the way to the fest the temp would rise and fall, now it overheats. Wether it was the stat being temperamental and has now failed altogether I'm not sure. Yesterday when I overheated the top hose was hot but wether 80deg hot ie fan nit kicking in or 100 deg hot ie fan control not calibrated properly I'm not Sure
Basically I've no confidence in any if the cooling system components until I can accurately measure the temperatures in the system to see how accurate everything is and that they're working correctly
Think ill pull the stat - if its being temperamental even testin may not show a fault but if I dont have one fitted it cant be a factor
A rad flush and refill, followed by running the engine up to temp monitoring everything and checking with a laser thermometer should tell me a bit more about what's happening
Cheers Ron
Hi Ron,
Sorry to hear about your on-going issues; they sound horribly familiar to what I went through when I first changed my head gaskets.
Firstly I'd say ignore the temperature gauge going to full scale deflection when you tapped it; I suspect that's an electrical fault and a red herring.
You can check the thermostat without taking the car apart... As Adam says the top hose should be cold after a cold start for a minute or two and then suddenly get hot; and you can confirm if the thermostat is opening fully by checking the bottom hose temperature when the engine has been running for a while - if the bottom hose gets hot then you have a decent flow of coolant through the radiator therefore the thermostat is opening fully (or nearly so).
The temp gauge jumping around when you're driving is almost certainly air in the system; the gauge will probably read high when it's immersed in water and low when the sensor is surrounded by air/vapour - so your problem is air in the system. The car will then expel air/water out of the expansion tank when an air bubble passes through the heads and you get a local hot spot which in turn locally boils the coolant when the air bubble has passed by.
So the question becomes - where is the air coming from? I think you said you burped the system and the car ran OK immediately afterwards, but on the next run from a cold start the car gave problems again. This sounds like the air is getting in when the engine is cooling down and the coolant is contracting - so that implies a leak to the outside. This is exactly what my 350i was doing a while back and it turned out to be perforation on the heater pipes running under the intake manifold - the leak was so slight that it wasn't dripping; when the engine was hot it was boiling off before it had a chance to form a puddle. It could also be a similar leak from any of the hose joints or even on the radiator. I only discovered the leak on my car when I found damp patches after I'd started it from cold and then turned it off before it heated up.
Having said all that I'm also a little confused that you have Elring head gaskets on a 3.5L engine; I thought they were only available for a 3.9L with bigger bores. It may not be a problem anyway depending on the block/head castings and the water jacket positions - I don't know if the positions of the water channels changed when they went to 3.9L; plus there's plenty of bored out 3.5L blocks out there that don't have problems.
Good Luck!
Martin
Sorry to hear about your on-going issues; they sound horribly familiar to what I went through when I first changed my head gaskets.
Firstly I'd say ignore the temperature gauge going to full scale deflection when you tapped it; I suspect that's an electrical fault and a red herring.
You can check the thermostat without taking the car apart... As Adam says the top hose should be cold after a cold start for a minute or two and then suddenly get hot; and you can confirm if the thermostat is opening fully by checking the bottom hose temperature when the engine has been running for a while - if the bottom hose gets hot then you have a decent flow of coolant through the radiator therefore the thermostat is opening fully (or nearly so).
The temp gauge jumping around when you're driving is almost certainly air in the system; the gauge will probably read high when it's immersed in water and low when the sensor is surrounded by air/vapour - so your problem is air in the system. The car will then expel air/water out of the expansion tank when an air bubble passes through the heads and you get a local hot spot which in turn locally boils the coolant when the air bubble has passed by.
So the question becomes - where is the air coming from? I think you said you burped the system and the car ran OK immediately afterwards, but on the next run from a cold start the car gave problems again. This sounds like the air is getting in when the engine is cooling down and the coolant is contracting - so that implies a leak to the outside. This is exactly what my 350i was doing a while back and it turned out to be perforation on the heater pipes running under the intake manifold - the leak was so slight that it wasn't dripping; when the engine was hot it was boiling off before it had a chance to form a puddle. It could also be a similar leak from any of the hose joints or even on the radiator. I only discovered the leak on my car when I found damp patches after I'd started it from cold and then turned it off before it heated up.
Having said all that I'm also a little confused that you have Elring head gaskets on a 3.5L engine; I thought they were only available for a 3.9L with bigger bores. It may not be a problem anyway depending on the block/head castings and the water jacket positions - I don't know if the positions of the water channels changed when they went to 3.9L; plus there's plenty of bored out 3.5L blocks out there that don't have problems.
Good Luck!
Martin
Edited by The Hatter on Wednesday 27th July 10:59
The Hatter said:
The temp gauge jumping around when you're driving is almost certainly air in the system; the gauge will probably read high when it's immersed in water and low when the sensor is surrounded by air/vapour - so your problem is air in the system. The car will then expel air/water out of the expansion tank when an air bubble passes through the heads and you get a local hot spot which in turn locally boils the coolant when the air bubble has passed by.
So the question becomes - where is the air coming from? I think you said you burped the system and the car ran OK immediately afterwards, but on the next run from a cold start the car gave problems again. This sounds like the air is getting in when the engine is cooling down and the coolant is contracting - so that implies a leak to the outside.
This makes a lot of sense...I think the expansion tank you have is not helping as there is no overflow or catch tank so as Martin say's "The car will then expel air/water out of the expansion tank"..If you have no overflow then there is nowhere for the pressure to be released.So the question becomes - where is the air coming from? I think you said you burped the system and the car ran OK immediately afterwards, but on the next run from a cold start the car gave problems again. This sounds like the air is getting in when the engine is cooling down and the coolant is contracting - so that implies a leak to the outside.
And..."This sounds like the air is getting in when the engine is cooling down and the coolant is contracting"...If you do not have a catch tank then there is no supply to replace the expanded coolant, The small catch tank only really holds what it needs once everything has settled down.
I found this out by keeping an eye on my coolant level in the expansion tank and what was in the catch tank after a motorway run compared to when its cooled in the morning, Its around a pint that is expelled on expansion and then drawn back in when cooling/Contacting.
Also check the matrix hoses...Mine has a minor leak that i have noticed on occasion when I drive it in the rain with the roof on and windows up...Just a tiny puff of steam randomly...I know i must sort it as it will get worst!.
If i had known i would of lent you my thermostat laser pointer at the fest...Good luck with it....
Ziga
Ron if your car has the heater on / off switch by the bulkhead disconnect the cable and manually close it and then see if it changes conditions, then you will know if its a heater matrix or associated internal hoses issue ... Martins point about the hidden pipes under the plenum is well made as I have had this issue before. Interestingly on the Serp engines they took these out and routed the heater hoses alongside the drivers side cylinder head! 
If all else fail Ron I have a digital thermometer if you are passing
Chris
If all else fail Ron I have a digital thermometer if you are passing
Chris
Unfortunately the heater valve will close one pipe but not the other - so a heater leak will still happen, although not as strongly.
Look at my recent post on temperature fluctuations - all cured now and it was a head gasket leak. The bubbles accumulate at the top of the engine and cause the stat to operate a bit erratically.
Now it's fixed I have the standard behaviour - goes up to 90 or slightly over on the cruise from cold, then you can see when the stat opens and the temp drops 10 degrees in about 30 seconds, then heads back to 85-90. Also I have a thermocouple on the top hose and that now tracks the temp gauge pretty accurately.
Get the digital thermometer on it - that will tell you if the gauge is accurate or not.
Do the stat tests (the bottom hose one is good - thanks Martin)
Check for coolant loss or burping. If you have a standard 350i layout where the expansion tank overflow goes down a plastic pipe onto the road, remove that pipe and stick on another one into a catch tank. I used to use a small plastic bottle under the expansion tank on my 350i. Then I could monitor coolant loss after a drive and also save money by pouring it back in ;^)
Any signs of gases bubbling out after a run are signs of head gasket issues.
Look at my recent post on temperature fluctuations - all cured now and it was a head gasket leak. The bubbles accumulate at the top of the engine and cause the stat to operate a bit erratically.
Now it's fixed I have the standard behaviour - goes up to 90 or slightly over on the cruise from cold, then you can see when the stat opens and the temp drops 10 degrees in about 30 seconds, then heads back to 85-90. Also I have a thermocouple on the top hose and that now tracks the temp gauge pretty accurately.
Get the digital thermometer on it - that will tell you if the gauge is accurate or not.
Do the stat tests (the bottom hose one is good - thanks Martin)
Check for coolant loss or burping. If you have a standard 350i layout where the expansion tank overflow goes down a plastic pipe onto the road, remove that pipe and stick on another one into a catch tank. I used to use a small plastic bottle under the expansion tank on my 350i. Then I could monitor coolant loss after a drive and also save money by pouring it back in ;^)
Any signs of gases bubbling out after a run are signs of head gasket issues.
Hi all
Martin - think you're right about gauge - seems to be an electrical issue once the engine gets very hot - a bit of a red herring
As for drawing air in via heater tubes - how quickly did this happen ? At the moment mine will over heat on a very short journey 8 miles ish - going from cold it will just get hotter and hotter until I have to pull over to let it cool
Adam - I've not discounted the head gaskets being the culprit - they were the last thing I fiddled with after all - but its odd that the engine is on the point of boiling but the fan doesn't operate until I turn the adjuster down to 75-80 degrees
Not noticed any bubbles in the coolant.
Picking up.the laser thermometer today so hope to pull stat ,flush rad and measure all the temperatures tonight
Thanks for all the advice
Ron
Martin - think you're right about gauge - seems to be an electrical issue once the engine gets very hot - a bit of a red herring
As for drawing air in via heater tubes - how quickly did this happen ? At the moment mine will over heat on a very short journey 8 miles ish - going from cold it will just get hotter and hotter until I have to pull over to let it cool
Adam - I've not discounted the head gaskets being the culprit - they were the last thing I fiddled with after all - but its odd that the engine is on the point of boiling but the fan doesn't operate until I turn the adjuster down to 75-80 degrees
Not noticed any bubbles in the coolant.
Picking up.the laser thermometer today so hope to pull stat ,flush rad and measure all the temperatures tonight
Thanks for all the advice
Ron
I have tell tale stickers on my top and bottom hoses and have the infra red thermometer. The latter was a god send when I was trying to find my issues. I even bypasses the heater thought that will lose a small volume. The stickers are a handy way for me to see all is well. They display a max temp reached.
Main issue was the system losing pressure, evidenced by water brimming up in the expansion bottle and spurting out (no bubbles either). Worst culprit was the swan neck cap not sealing but not obvious, next was an air lock that I solved by fitting a bleed valve when I returned the heater to the circuit (400 heater pipes run a different way to the 350 so not sure if relevant).
My stat was tested in a pan on the stove with a thermometer.
When I replaced the hose to my heater matrix, the old hose virtually pulled off even though the jubilee clip was tight (the clip was just keeping it there and not sealing it), there was some evidence of water weeping past the connection. However it was a b
h of a job but a hand on the connection should be able to feel the damp.
pipe by Jeff, on Flickr
Main issue was the system losing pressure, evidenced by water brimming up in the expansion bottle and spurting out (no bubbles either). Worst culprit was the swan neck cap not sealing but not obvious, next was an air lock that I solved by fitting a bleed valve when I returned the heater to the circuit (400 heater pipes run a different way to the 350 so not sure if relevant).
My stat was tested in a pan on the stove with a thermometer.
When I replaced the hose to my heater matrix, the old hose virtually pulled off even though the jubilee clip was tight (the clip was just keeping it there and not sealing it), there was some evidence of water weeping past the connection. However it was a b
h of a job but a hand on the connection should be able to feel the damp.pipe by Jeff, on FlickrAh, Overheating on an 8 mile journey is unlikely to be a small leak somewhere; it sounds a bit more serious - assuming of course that the temperature gauge is not lying and an infra-red thermometer should tell you that. Your fan not cutting in when the new top hose sensor is set to 85/90 DegC ish is still indicative of air in the system so I still think that's the problem, but whether it's the cause or a symptom I'm not so sure.
I think you said it oveheated in a big way before you did the head gaskets; I hope nothing else was damaged at that time. Did you check the heads for flatness and/or have them skimmed?
Another thought... You can easily check the temperature of the engine using the main sensor that feeds the ECU. Just stop the engine, unplug the ECU temperature sensor and measure the resistance of the sensor on a multimeter. It's not particularly sensitive at high temps but it'll give you a pretty good idea what's going on.
I think you said it oveheated in a big way before you did the head gaskets; I hope nothing else was damaged at that time. Did you check the heads for flatness and/or have them skimmed?
Another thought... You can easily check the temperature of the engine using the main sensor that feeds the ECU. Just stop the engine, unplug the ECU temperature sensor and measure the resistance of the sensor on a multimeter. It's not particularly sensitive at high temps but it'll give you a pretty good idea what's going on.
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