how to tell if head gasket is gone?
Discussion
foolishly bought my first car last month, not knowing anything and in a rush. too many problems with it, head gasket gone, crack on the head, starter motor dead..you get the drift.
canceling insurance is too expensive so im just putting another car on the policy and getting rid of this one.
so as i started looking for an new car, i was told that if there is yellow gunk on the oil cap (like my car) then the head gasket is gone. but im also aware that it could just be a condensed mixture of oil and water (or something along those lines)
my question is how do i tell the difference, if an oil cap has gunk on it, whether its perfectly normal or a blown head gasket.
5 of the cars ive gone to see already all had this yellow gunk in them.
thanks
canceling insurance is too expensive so im just putting another car on the policy and getting rid of this one.
so as i started looking for an new car, i was told that if there is yellow gunk on the oil cap (like my car) then the head gasket is gone. but im also aware that it could just be a condensed mixture of oil and water (or something along those lines)
my question is how do i tell the difference, if an oil cap has gunk on it, whether its perfectly normal or a blown head gasket.
5 of the cars ive gone to see already all had this yellow gunk in them.
thanks
Buy a compression tester. You can run the car with the expansion cap off and smell the coolant for exhaust gases, or see if it starts bubbling. Excessive white smoke out the back that doesn't clear is another sign. Sometimes though they don't show up, which is where testing the compression helps. You're not necessarily looking for high figures, just that it's the same across the cylinders +/- 10%
In a lot of cases, a head can be skimmed, new gasket put on and you're away. Might be worth getting a quote for repair. In some cases a scrapper engine can be a way out for an existing car
In a lot of cases, a head can be skimmed, new gasket put on and you're away. Might be worth getting a quote for repair. In some cases a scrapper engine can be a way out for an existing car
Gawri20 said:
my question is how do i tell the difference, if an oil cap has gunk on it, whether its perfectly normal or a blown head gasket.
Apparently this is 'normal' in some engines like Renaults (as seen on a Twingo I went to see with the missus recently). I'd still avoid anything with that mayo round the filler cap though. No no no no. What is with the head skimming? Stupid old wives tales!
In short, with such a small amount of time spent with the car, you can't bee 100% sure of anything. If you can be there on the first start of the day, with the engine stone cold, run it for a bit then allow it to cool completely is the only way you can carry out a proper investigative test of the head gasket. If there's no pressure in the coolant from cold, and it's at the correct level that's good. If it get up to temp and the cooling fan runs for a bit then turns off, that's good. If there's no sign of leaks when the engine's hot and there's no tell-tale rusty marks around the coolant cap, this is encouraging.If the oil is clear or black but not cloudy, that's good, too. If it fires evenly and doesn't misfire from the off that's a good sign as well.
Gunk under the oil cap can mean nothing more than a lot of recent short journeys.
Simply researching what engines have common failures is a waste of time as you find any number of reports of any engine lunching its head gasket; the reasons are just too common for it to blow. Across cylinders, from a cylinder to a water channel, from a water channel to a oil way. A water way to outside. A compression test won't always tell you anything. A test for combustion gases in the coolant won't either.
In short, other than borrowing the car for a week, the best you can do is try to run it from cold, go on a decent drive, let it idle and get hot and try your luck. Sorry to sound negative, but that's the way I'm afraid.
And don't let anyone tell you a head needs skimming just becasue the gasket had failed or it's over heated. Only if there's physical pitting or damage to the mating surface does a head ever need skimming. I've been fed this rubbish for years.
In short, with such a small amount of time spent with the car, you can't bee 100% sure of anything. If you can be there on the first start of the day, with the engine stone cold, run it for a bit then allow it to cool completely is the only way you can carry out a proper investigative test of the head gasket. If there's no pressure in the coolant from cold, and it's at the correct level that's good. If it get up to temp and the cooling fan runs for a bit then turns off, that's good. If there's no sign of leaks when the engine's hot and there's no tell-tale rusty marks around the coolant cap, this is encouraging.If the oil is clear or black but not cloudy, that's good, too. If it fires evenly and doesn't misfire from the off that's a good sign as well.
Gunk under the oil cap can mean nothing more than a lot of recent short journeys.
Simply researching what engines have common failures is a waste of time as you find any number of reports of any engine lunching its head gasket; the reasons are just too common for it to blow. Across cylinders, from a cylinder to a water channel, from a water channel to a oil way. A water way to outside. A compression test won't always tell you anything. A test for combustion gases in the coolant won't either.
In short, other than borrowing the car for a week, the best you can do is try to run it from cold, go on a decent drive, let it idle and get hot and try your luck. Sorry to sound negative, but that's the way I'm afraid.
And don't let anyone tell you a head needs skimming just becasue the gasket had failed or it's over heated. Only if there's physical pitting or damage to the mating surface does a head ever need skimming. I've been fed this rubbish for years.
RWD cossie wil said:
Have a look at the front of the bonnet, if it says "Rover" , then I would suggest that the head gasket has gone.
Best way I have found is to get the engine nice an warm... Top the header tank to the top and with it running watch for bubbles... if you have combustion going into the water it usually shows up as a steady stream of bubbles of air coming to the surface.
As buzzer says but also remove oil filler cap, if it looks like egg mayo then the gasket has gone.
Compression testers are cheap enough and would go some of the way to confirming it but you don't say if it's a high miler with service or bought off a 99 year old that never took it over 30
Compression testers are cheap enough and would go some of the way to confirming it but you don't say if it's a high miler with service or bought off a 99 year old that never took it over 30
RWD cossie wil said:
Have a look at the front of the bonnet, if it says "Rover" , then I would suggest that the head gasket has gone.
Splendid non-advice. Yeah ... get an MG ... be alright then.... 
Astra Dan's advice is good and covers most aspects.
Note to OP, under given circumstances, any car can have issues with a cylinder head gasket, even so called superior German product.
Whatever car it is, suggest you take it to someone who really knows about the make of car you have. If any professional immediately diagnoses a damaged cylinder head gasket simply on a "they all do that, well known fact" basis, find someone who is better equipped to diagnose what the problem is with your car.
Under certain conditions such as weather, driving styles and distances, combined with various grades of oil, I have known the oil filler to be completely solid with the so called 'mayo'. So much so you could stand a spoon up in it!
There was nothing wrong with the cylinder head gasket. The lady owner only used it for short journeys of 2-3 miles. In cold, damp weather those were ideal conditions for the build up of that oil-condensation mix which can be as a result of damaged cylinder head gaskets.
Removal of the 'mayo' from that oil filler tube with the spoon and regular longer journeys during cold weather to allow the engine to fully warm did the trick. That hotter running burns off any condensation and avoids any further 'mayo' build up.
Oil in the header tank is NOT a sure sign of a damaged cylinder head gasket. Many professionals have been sold a dummy with that one. It could be there because during a previous repair replacing a damaged cylinder head gasket, the cooling system was NOT flushed and cleaned thoroughly of oil from the previous problem.
It is a very complex issue and it is rare that any two cars behave exactly the same. Make a list of all like likely suspects and systematically work through it with various tests to identify the cause. You may or may not have anything to worry about.
.
Edited by MGJohn on Monday 23 April 23:36
Unfortunately, as has been said (in amongst the other guff) you can't easily tell as short trips can produce the mayo. Happened on my Corrado recently.. topped up the oil and was alarmed to see some mayo but I had been doing short trips in colder weather. Just took it on a 1000 mile road trip last week and the filler cap was mercifully still clean.
What you can do though is check for clean coolant.. not everyone is regimented about changing coolant so it could be grotty anyway, but there should be no oil in it! The engine should run nice and smooth, with no lumpiness or misfiring, and ideally let it get properly up to temperature. If you can take it for a drive and come to a stop and let it sit idling for a few minutes and make sure it's still running smooth. Without getting the coolant checked or going down the route of compression checks and stuff there is no easy way to know the HG is in tact!
What you can do though is check for clean coolant.. not everyone is regimented about changing coolant so it could be grotty anyway, but there should be no oil in it! The engine should run nice and smooth, with no lumpiness or misfiring, and ideally let it get properly up to temperature. If you can take it for a drive and come to a stop and let it sit idling for a few minutes and make sure it's still running smooth. Without getting the coolant checked or going down the route of compression checks and stuff there is no easy way to know the HG is in tact!
Finally something relevant to my work 
A few things:
1) You'll smell burning glycol (sweet smell) - this isn't always there but if you smell it whilst driving, it's a good indicator to get that f
ker looked at.
2) Water temp rising - the water at the thermostat should be around 90C for Europe, so if it's gone above that it's another reasonable indicator that something is up (although it could mean you might have a cavitated pump or a leak somewhere in the system. This happens because as exhaust gases leak in to the cooling system, its efficiency decreases (air/exhaust gas is a worse thermal conductor than water-glycol).
3) Start to lose power - this is more of an alternative to #2. Modern engines derate above certain temps - usually between 110-120C.
4) White smoke from the exhaust - self-explanatory as this is water that's gotten in to the exhaust
A few things:
1) You'll smell burning glycol (sweet smell) - this isn't always there but if you smell it whilst driving, it's a good indicator to get that f
ker looked at.2) Water temp rising - the water at the thermostat should be around 90C for Europe, so if it's gone above that it's another reasonable indicator that something is up (although it could mean you might have a cavitated pump or a leak somewhere in the system. This happens because as exhaust gases leak in to the cooling system, its efficiency decreases (air/exhaust gas is a worse thermal conductor than water-glycol).
3) Start to lose power - this is more of an alternative to #2. Modern engines derate above certain temps - usually between 110-120C.
4) White smoke from the exhaust - self-explanatory as this is water that's gotten in to the exhaust
Mr2Mike said:
Carrot said:
This.
I have yet to meet a standard rover owner (including one of my own) that has not had at least one failure in its miserable life.
Then I guess you haven't met that many Rover owners.I have yet to meet a standard rover owner (including one of my own) that has not had at least one failure in its miserable life.
I cant think of any other car that has such problems with Head Gasket failure...
Pig Skill said:
A HGF can occur between cylinders and they suffer lost compression. There could be no damage to the gasket between oil and water galleries and therefore no mayo.
If you have been stung once then get a pro inspection on anything you are ready to buy
This ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^If you have been stung once then get a pro inspection on anything you are ready to buy
buzzer said:
Mr2Mike said:
Carrot said:
This.
I have yet to meet a standard rover owner (including one of my own) that has not had at least one failure in its miserable life.
Then I guess you haven't met that many Rover owners.I have yet to meet a standard rover owner (including one of my own) that has not had at least one failure in its miserable life.
I cant think of any other car that has such problems with Head Gasket failure...
My Rover gasket has been OK for 4 years and 30,000 miles so far. On a 15 year old car.
I know a sample size of one is statistically insignificant, but as long as that one gasket is the one in my car then I really don't care what happens to all the others.
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