Audi suspect head gasket failure,but somethig doesnt seem right..

[willster]

my car was in at Stafford Audi yesterday and had cambelt ,pump belt,waterpump,tensioners and auxiluary belts done.
I asked if the tech could road test my car and suggest his opinion of the possible power loss. They said it was of combination of the head gasket failing slightly(he did a block/vacum test) and the coolant temp sensor. Although ive had no coolant loss or sludge in coolant or white stuff around oil filler cap .The only thing i have had is a little whisp of white smoke on coldstarting that smells acrid and isnt like staem more like cigareete smoke that hangs in the air in whisps. and a little more of the white smoke when flooring it.
As for the coolant temp sensor this never behaves erratically through the dial or brings any dash lights up etc. so i dont understand how they think this needs replacing or how they think its connected to power loss??! Mabye im missing the point here but ive never heard this temp sensor being associated with power loss although the woman from Audi assured me it controlled fuelling or something and could explain the hesitation in my cars power? Please help ,Audi want over£900 for headgasket and coolant temp sensor. Is it necessary and how likely is it to fix my problem?? Thanks Will

[nutter1980]

Hi m8, from the sounds of if , I had the exact same problem.

I had the smelly white smoke too, and the power loss, In my case whenever it happended I pop the bonnet open and uplug and re plug in the maf sensor cable afew times and the power loss dissapears.

Not saying that this is your problem, but sound similar.
I also read on the TDi club forum that the connectors on pre 2003 audis are prone to moisture and corrosion, they can also send mixed signals to the ECU about how much air/fuel the engine receives.

When I had this problem, my MAF sensor was replaced, I limped to the garage, as soon as the sensor was replaced the probem went for about 5 weeks, then it reappeared, It then dawned on me that the first think the mechanic did was clean the wired connector (not the one on the senor) with some electrical spray. My car is in audi stockport today having a new connector fitted.

Also read this , it basicly expains about the dodgy connectors.

http://forums.tdiclub.com/showthread.php?t=77582&highlight=cage+mod

[willster]

cheers nutter your a ledgend! that is an exciting discovery for me, im off to get the cleaning spray and silicone insulating compound. could be a cheap fix for me i hope.mine has had new MAF so i can rule out the unit itself. really appreciate your advice and will let you know how it goes.

[nutter1980]

Willster,

Make sure you get the right stuff, I got mine from CPC.

Its called Dow Corning 4

Look for my post on that link I sent you its one of the last ones, it has the link to the data sheet and the product.

Let me know your findings

[Crasher]

They changed the timing belt on a car they knew had a faulty head gasket!

[willster]

They changed the timing belt on a car they knew had a faulty head gasket!
i guess they must have changed it first before they started poking around with the power hesitation problem. why, is this bad? gasket cant be leaking much atall as my coolant level has stayed constant,could i get away with leaving it for a while till it develops and i start losing coolant or oil? :confused:

[willster]

Willster,

Make sure you get the right stuff, I got mine from CPC.

Its called Dow Corning 4

Look for my post on that link I sent you its one of the last ones, it has the link to the data sheet and the product.

Let me know your findings
cheers nutter i searched for it on the web and found a supplier,i have two 100ml tubes coming monday. so i guess i just squirt it in the end of the connector?!

[onzarob]

If the head gasket has gone then thats allot of labour you could of saved if you had it done when the cambelt etc was done :(

not sure how a vacuum test will indicate slight head gasket failure, I would change the temp sensor and see if it improves as the white wisp may just be down to condensation, do you drive short journeys allot?

[willster]

not really usually at least 20 mins motorway, thanks i will try changing the sensor when i find it! think im just going to forget about the headgasket until it produces more noticeable and definate signs.is this safe to leave or might it cost me even more in the long run? yeah that would have been better if they noticed it before doing the cambelt.

[a8 tech]

if this is a pd engine you cant do a cylinder leakage test only a combustion test which isnt that acurate on diesels.I have never fitted a head gasket on a pd engine for failure since the engine was launched.Post your engine type and code

[nutter1980]

cheers nutter i searched for it on the web and found a supplier,i have two 100ml tubes coming monday. so i guess i just squirt it in the end of the connector?!

2 tubes !! lol , 1 tube would do about 100 cars lol , never mind.
Look at the link I sent you , there is a picture guide how to add the gung.

[adamss24]

Hi was the car's engine ever overheated ? I doubt that you have a head gasket problem on a V6 tdi, it could be that the coolant temp sensor is duff and the ECU injects more fuel at idle/start-up and retards timing slightly to compensate for cold weather ! Its the fuel consumption that bad ? Also faulty airmass meters (MAF) are common troughout the range... I suspect that the timing was a little off as well.

[willster]

if this is a pd engine you cant do a cylinder leakage test only a combustion test which isnt that acurate on diesels.I have never fitted a head gasket on a pd engine for failure since the engine was launched.Post your engine type and code

Engine is AKE 052509 really appreciate your help ,its 01 A4 2.5tdi (180bhp)
i did think it was a hasty and brutal diagnsis from Audi.

[willster]

Hi was the car's engine ever overheated ? I doubt that you have a head gasket problem on a V6 tdi, it could be that the coolant temp sensor is duff and the ECU injects more fuel at idle/start-up and retards timing slightly to compensate for cold weather ! Its the fuel consumption that bad ? Also faulty airmass meters (MAF) are common troughout the range... I suspect that the timing was a little off as well.


certainly hasnt overheated since ive had it, but it had had 5 owners before me and no service history! so its definately possible! i usualy get around 35mpg driving very sensibly , i tend not to hammer it as the power just isnt there right off the bat ,takes a second or two to kick in. Appreciate your diagnosis,it sounds like that could be the case. I will change the temp sensor for sure. I thought of all the places i could take my car Audi would be the most knowledgable and straight with me but it seems possibly not!! cheers , Will

[willster]

Thanks nutter i will look at the guide, you think thats funny , i came very close to buying the kilo tub!! guess im just enthusiastic to sort my sick car out! thanks pal

[a8 tech]

ok,this engine suffers from sticky turbo vaines but headgasket failure would not be at the top of my list for your symptoms,and again head gasket failure is uncommon and only severe overheating would affect the power.A quick way of testing the airmass would be to disconnect it and try it,but i would make sure the turbo rod is moving freely under vacuum pressure

[willster]

Thanks A8 you have put my mind at rest a little, i will try and figure out the turbo test or else take it to a turbo specialist .Is my engine a PD? so its not possible to check for a leaking head gasket on this engine with a block test? just i want to ring Audi and quizz them a little over it, .I just bought new airmass and have tried disconncting but made it worse, am going to try that electrical insulating compound as a member on here told me the sensor connector ends can really benifit from a lick of this stuff! who knows if it will work but at this stage i will try anything, especially if its cheap! cheers again for your help.

[Crasher]

No, it isn't PD-it is VEP.

[willster]

Thanks crasher think i might have enough ammunition to quizz Audi.

[willster]

just thought id let you know how i got on with the electrical insulating problem, it does seem to have perked up a bit since a applied the stuff, although i changed the coolant temp sensor at same time so its hard to say which has worked! definately worth doing though considering the results some people have had. Checking the CAT is my next port of call. think il be able to take it off but not sure what to look for to determine if its bust!? any ideas?