head gasket failure

[raf_gti]

I'm fairly certain the HG on my 205 has gone, there was a lovely puff of white smoke when driving along and now there is a little bit of mayo in the filler

My question is, what actually causes the gasket to go? The engine was rebuilt ~10K ago and has been treated to regular, quality oil, it is also never thrashed but is well used.

Could there be bigger problems ahead or will a new gasket hopefully be sufficient?

ta!

[Steve_D]

The head and possibly the top of the block may not be flat.
If the head was not skimmed last time it was rebuilt then this may be why the gasket failed again.
When you strip it have the head inspected for warp and flatness. If required have it skimmed.

Steve

[raf_gti]

thanks for the reply

tbh as I've taken the car off the road straight away I'm hoping the head will not have warped, how do I check myself? Will it be visually obvious or does it have to go on some sort of rig?

[Sam_68]

You have to remove the head to check whether it's warped. It's usually visually obvious if you lay a steel rule across it (lengthways, crossways and diagonally); any gap at all between the steel rule and the face of the head means it's warped.

If the engine was only rebuilt 10K miles ago, question you might have to ask yourself is 'was it torqued up correctly?'.

Edited by Sam_68 on Saturday 7th March 14:03

[stevieturbo]

raf_gti said:

I'm fairly certain the HG on my 205 has gone, there was a lovely puff of white smoke when driving along and now there is a little bit of mayo in the filler

My question is, what actually causes the gasket to go? The engine was rebuilt ~10K ago and has been treated to regular, quality oil, it is also never thrashed but is well used.

Could there be bigger problems ahead or will a new gasket hopefully be sufficient?

ta!

But are there actually any real symptoms or indications of HG failure ?

One puff of smoke, and a little bit of mayo means nothing.

[Sam_68]

stevieturbo said:

One puff of smoke, and a little bit of mayo means nothing.

At the very least do a chemical test on the coolant and compression test the cylinders, before you start taking cylinder heads off.

Has there been any sign of overheating?

[Marf]

Yeah you want to be sure that its gone, get a garage to do a sniffer test and do a compression test yourself.

Is it actually losing water? In the current weather conditions a little bit mayo can just be as a result of condensation from short journeys.

When the headgasket went on my Charade Turbo as a result of some dodgy ignition numbers in my mapping, I had no white smoke, no mayo, no loss of water, just a few almost unnoticable bubbles in the expansion tank in the 10 seconds after shut down.

Garage confirmed with a sniffer test, took the head off myself and there was a miniscule blow on one of the waterways, not even 1mm across.

Edited by Marf on Saturday 7th March 15:15

[raf_gti]

The puff of smoke was fairly large then a had a nice plume afterwards, think of the effect you get in Forza when the car is knackered!

I'm off into Halfords to get a compression tester and will also have the sniff test carried out as well.

The mayo to me is too much of a coincidence coming at the same time as the smoke, I would be very surprised if they weren't linked.

There was no signs of overheating beforehand and coolant levels were fine, I stuck the car in the car in the garage and havn't had a chance to check since.

[Sam_68]

I have to say that whenever I've suffered a head gasket failure bad enough to plume steam from the exhaust (and I've had a few, over the years), the temperature has always shot straight off the scale.

I'd be interested to know how you get on.

Edited by Sam_68 on Saturday 7th March 18:03

[trackdemon]

Pretty common problem on the TU engine - I've just had to change the h/g on my 306 (1.4 petrol), albeit at 120k miles. Good news is its a pretty straightforward job to do yourself and not too expensive on parts.... if it does need it don't skimp on a head skim & you may as well replace water pump + cambelt at the same time.

I'd be suspicious about the quality of rebuild if the h/g has gone just 10k miles later (assuming it hasn't been overheated).

[raf_gti]

trackdemon said:

Pretty common problem on the TU engine - I've just had to change the h/g on my 306 (1.4 petrol), albeit at 120k miles. Good news is its a pretty straightforward job to do yourself and not too expensive on parts.... if it does need it don't skimp on a head skim & you may as well replace water pump + cambelt at the same time.

I'd be suspicious about the quality of rebuild if the h/g has gone just 10k miles later (assuming it hasn't been overheated).

Rebuild was from a reputable company (DES) so I'm fairly confident on that front, hopefully it is just a case of bad luck!

Is HG failure simply down to the fact that the gasket has failed or it the symptom of something worse?

[Sam_68]

They do just randomly fail sometimes, but other possible causes include:

• Overheating
• Warped head (which can in turn be caused by overheating)
• Incorrectly torqued cylinder head bolts.

If you've not noticed any overheating and the head is checked and skimmed before refitting, there should be no real reason for the problem to recur.

Some engines are more prone to HGF than others, though (ask any Imp or K-series Elise owner!), and from what Trackdemon say, the Pug TU sounds like it's one of them (though I have no personal knowledge of this engine).

What's the correct torquing procedure after a rebuild on the TU? Some engines should be re-torqued after the first 500 miles or whatever, following head gasket replacement, though it's becoming less prevalent now that stretch bolts are so commonplace.

[Mr2Mike]

Sam_68 said:

and from what Trackdemon say, the Pug TU sounds like it's one of them

IME they aren't that bad, possibly a bit more prone to HGF than average, but not in the same league as the K series and Fiat Fire engines for example.

[thong]

Mr2Mike said:

Sam_68 said:

and from what Trackdemon say, the Pug TU sounds like it's one of them

IME they aren't that bad, possibly a bit more prone to HGF than average, but not in the same league as the K series and Fiat Fire engines for example.

Mike i agree worked with this engine many years back it its not know for head gasket failure, you always get mayo build up in these motors so dont worry about it,compression testing is a waste of time realy as this normaly shows ok,chemical test first then leak down test.

[trackdemon]

HG failure is most commonly caused by overheating (resulting in a warped head), but it can also be just age (mine wasn't overheated but had done 122k miles).... If the head bolts/torquing procedure were suspect I'd expect it to go sooner than 10k miles

The TU is a little more prone to h/g than most engines (just check pug forums!) but as mentioned its not in the same league as k-series, renault 1.4 etc.... Its just one of those things.

First symptoms on mine were mayo on the radiator cap, then misfiring (which I thought was coilpack on its way out!) and eventually losing oil (which of course was ending up in the cooling system!).

[raf_gti]

trackdemon said:

HG failure is most commonly caused by overheating (resulting in a warped head), but it can also be just age (mine wasn't overheated but had done 122k miles).... If the head bolts/torquing procedure were suspect I'd expect it to go sooner than 10k miles


First symptoms on mine were mayo on the radiator cap, then misfiring (which I thought was coilpack on its way out!) and eventually losing oil (which of course was ending up in the cooling system!).

Oh yeah I forgot to mention, since that last oil change about 800 miles ago the oil is down by 'half' on the dipstick and she is taking an age to settle into a decent idle, much changed from before my puff of smoke! I've just had a nose in the coolant tank and whilst it does not appear any water has been lost it does look rather cloudy although not massively so.

A pressure test reveals 120, 80, 120, 160 psi so something is definately wrong I would say. On cylinder two the sprak plug is very dry looking whereas the other cylinders plugs are all the same, slightly oily with a sooty end.

Arse!

[That Daddy]

thong said:

Mr2Mike said:

Sam_68 said:

and from what Trackdemon say, the Pug TU sounds like it's one of them

IME they aren't that bad, possibly a bit more prone to HGF than average, but not in the same league as the K series and Fiat Fire engines for example.

Mike i agree worked with this engine many years back it its not know for head gasket failure, you always get mayo build up in these motors so dont worry about it,compression testing is a waste of time realy as this normaly shows ok,chemical test first then leak down test.

The TU is known for Headgasket failure in fact it normally shows early signs off this by allowing oil into the cooling system and if left unchecked causes overheating with obvious consequences,the seal on the gasket around the oil feed between the block and the head to the cam gear fails allowing the above so not really your average headgasket failure but failure none the less,and in my experience not caused by overheating but old age,if caught early the head sometimes avoids needing facing too,i will say its a cracking little motor though and knew of a TU fitted to a BX Citroen covering over 200k with a careful owner many years back