Possible Head Gasket Failure

[russgregg]

Hi there, i'm looking for some advice on my mk1. I've been noticing some smoke when cold and happened to check the oil today and found some white sludge on the underside of the filler cap. Are the head gaskets prone to going on these engines or do blocks/heads have a habit of cracking? The engine only has 85K and still seem to be running as it should although the car has done very little in the past 2 years as it's been sorned while i've been doing some bodywork.

I did a compression test this afternoon and the cylinders are ranging from 155 to 165 psi. If anybody has any suggestions as to likely causes please let me know.

[Lauren]

If you do a lot of short journeys you will get some 'mayo' on the underside of the filler cap. If it's been sitting for a while this might explain it to some extent.

I take it that it's not overheating or using coolant?

head gaskets can go, blocks don't crack.

[Rossyboy99]

mate this time of year the smoke is thick from the hot air hitting cold, if its mayo on the filler cap but none in the header tank or on the bottom of the dip stick you'll be ok also check your coolent level for a week mark the tank, if its going down rapidly you might have an issue, hows your temp gauge, sounds like the time of year matey so panick over and compression is good.

[krista-mr2]

i had the same symptoms and yes it was my head gasket..i had mayo in my cap but none on the dipstick.

[boyzdad]

Head gaskets can fail in 3 ways that I am aware of (well that I have had experience of!).

1:Cylinder to water way, this can be out to water, check for bubbles in coolant when reving the engine OR water in to the engine as it cools down, this can be small, hard to turn over, to alot, engine is jammed by water (this can damage pistons)

2:Cylinder to oil, the oil level increases, and you get white mayo etc.

3:Both 1+2

When you checked the compression, were any of the plugs extra clean? This can be caused as the engine "steam cleans" them.

As you have gone this far, simply remove the inlet cam cover, it's only 6 nuts (ok, a few more for the accel linkage). And have a look inside, if it all mankey (proper mankey, not just a bit round the lid)..... it's the headgasket, I am guessing that it is probably just the time of year.

One last thing, check the breather pipe between the inlet cam cover and manifold is not blocked.

Hope this helps.

[russgregg]

Thanks for all the advice folks, i'll get take a look under the cam covers then just keep an eye on it for a while. Appreciate the help!!

[mr2mk1chick]

I'm hoping that its not your HG, bit more like damp etc for short journeys in winter.

There is also a 'sniff test' you can get done, to see if any combustion gasses are found in the coolant system. The tester is placed on the coolant filler neck and if there are any gas bubbles the test liquid changes colour or something like.

[System-G]

With the engine cold, stick your finger into the oil filler neck and rummage around. If your finger comes out with mayo, remove the cam cover and check for severity.

The only definitive way of identifying HG failure if (there are no obvious signs) is a sniff test which can be done at most garages.

[crazylegs]

with these engines it is almost never that you get a water to oil failure. the mayo will just be the damp.( i will now be proved wrong )

[jon_st205]

Head gaskets can fail in 3 ways that I am aware of (well that I have had experience of!).

1:Cylinder to water way, this can be out to water, check for bubbles in coolant when reving the engine OR water in to the engine as it cools down, this can be small, hard to turn over, to alot, engine is jammed by water (this can damage pistons)

2:Cylinder to oil, the oil level increases, and you get white mayo etc.

3:Both 1+2

4. Failure between two cylinders - which is quite common on 4A's. Diagnosed with similarly-low compression on two cyl's. Of course not the problem of the OP though.

Jon

[Karl_T]

I wouldn't want to promote the sniff test as definitive or 100% reliable. It's a dodgy one to do on a car with an expansion bottle with little air gap. You just don't get enough gas to change the indicator, even when the gasket has gone. I had a fail and the sniff test said all was well.

Karl_T

[boyzdad]

Ignore this one was trying to learn how to do quotes!

[boyzdad]

Messed it up, tried to edit it, and ended up making this one! Maybe I should just quit while I am sort of ahead

4. Failure between two cylinders - which is quite common on 4A's. Diagnosed with similarly-low compression on two cyl's. Of course not the problem of the OP though.

Jon

And that one

[PW@Woodsport]

Basically id ignore every single post on this thread,im serious,a sniff test is not 100% conclusive,and a compression test is even worse.I used to advocate the sniff test myself too years ago but it has proven to give inconclusive results.None of these methods work with any certainty.

These days the only way to be 100% sure is with a special tool we made for testing head gasket breaches.Its a spark plug that has been drilled out and the ceramic stem cut off,so basically its the threaded part,the nut part and a big hole through the centre.Then we got a 10mm steel tube about 8" long,welded that to the spark plug and then welded an airline end onto the tube.... so the new tool screws into the spark plug hole and with the engine rotated to TDC on whatever cylinder you wish to test (99.9% of the time its cylinder 4 on a mk1 thats gone) ,then supply 70psi of air to that cylinder and take the cap off the coolant filler point.

If there is even the slightest breach in the gasket the compressed air will get forced through it and fine bubbles will appear at the coolant neck.You can clamp the airline to watch them fade away or increase the pressure to watch them become more regular.... it really is a bombproof method of diagnosing it and we have tried every method!

Repeat the test on the other 3 cylinders...i guarantee you it will tell you one way or the other if its breached ,compression tests don't work because there is sometimes a 10% variation between the cylinders anyway.... and 10% might just be a hairline breach.

Hope that helps

[boyzdad]

Basically id ignore every single post on this thread,im serious etc

Paul tbh, I find that comment, at best a bit harsh.

russgregg's question wasn't "how can I 100% tell if my head gasket has failed".

He said he had found some white sludge on the underside of the filler cap and finished up by asking " If anybody has any suggestions as to likely causes please let me know."

The reply from Rossyboy99 didn't even mention head gaskets!

I did put forward my own personal experience of head gasket faliures, but also added "I am guessing that it is probably just the time of year. "

While I am confident that you find your method of finding faulty head gaskets to be spot on, to simply brush everyone else's opinion/experience aside, is, in my opinion, pretty arrogant.

Did we really ALL post post information/advise that should be ignored? There are some very experienced members on this forum I for one am always ready to listen to other ideas, including air pressure head gasket testing

[PW@Woodsport]

I didn't reply to the mayo issue,thats present on all cars...i was referring to the HG testing methods that we know do not work 100%.I was offering a bulletproof way for him to find out if it had gone or not and you have taken my "Basically id ignore every single post on this thread" line too literally..... that was simply in response to the HG tests.

You just highlighted a problem with internet forums,unless you actually know the person posting its hard to gauge their attitude.... arrogant no,to the point and factual,yes.

I could have worded that better,and if you took offence i apologise.

[Rossyboy99]

pw please explain further this innvention

you state that you will see air bubbles in the header tank indicating a possible breach of the gasket either way?

you also state 100% acurate yes?

why then have you not appeared on the dragons den in order to make your fotune my friend, i'll give you 5p for 90% of the business!

[mr2mk1chick]

I didn't reply to the mayo issue,thats present on all cars...i was referring to the HG testing methods that we know do not work 100%.I was offering a bulletproof way for him to find out if it had gone or not and you have taken my "Basically id ignore every single post on this thread" line too literally..... that was simply in response to the HG tests.

You just highlighted a problem with internet forums,unless you actually know the person posting its hard to gauge their attitude.... arrogant no,to the point and factual,yes.

I could have worded that better,and if you took offence i apologise.

Well your method could be used if all the other useful tests come up as negative, despite HG faliure 'signs' if someone was to be that unlucky.
I guess with most faliures the other techniques are usually adequate. Esp as we all don't have a PW 'special tool'

Karl - the sniff test is done at the filler neck, so the expansion bottle can be excluded from the equation i think...

[boyzdad]

Thanks Paul, I wasn't especially offended, just more surprised.

I know you are always very helpful on the forums, and I have only heard good things about you.


nuff said

[PW@Woodsport]

lol @ dragons den ,tell you what i will do,i will take a pic of this SST i made and put it on this thread tonight,then you will be able to copy it and make one yourself.

It 100% will confirm or deny a water jacket to cylinder gasket breach every single time,not really rocket science we just thought how we could totally rule out the ifs,buts and maybes of other tests once and for all,and this way really works.Compression tests and sniff tests are far from conclusive.

I will even go a step further,for those that dont have a PW SST as jo put it,drop me a pm,give me some beer tokens and i will make one for you,can't help any more than that really!