Headgasket, waterpump or thermostat??

[brad1]

Hi all
Ive seen threads on this countless times, but never any outcome. Basically a couple of weeks ago, my temperature light started beeping and flashing red, i thought, weird, and the coolany was very low, hardly anything in there, so i topped it up with antifreeze and a little more water. And a few days later it started flashing again and was low So i topped it up again and it has been continuos up until now. The past few days its been going very low. For instance the other night, i filled it up as it started flashing red, then drove about 20 miles home. Came out for work in the morning, started the car, and guess what, it started flashing again f*** sake i thought, bloody car. And since then its had to be topped up daily from near enough empty to the max line. Its got no white crap/sludge etc on the oil cap. The oil level is the same and no white stuff in there as i checked the dipstick and all seems fine. Changed the coolant cap and no luck. The car temperatures still seem normal, no change in them, doesnt overheat or anything. The only symptoms im getting to work from as the coolant pipes are full of pressure once after a hard drive, when driven sensibly with no hard accelerating, them dont seem to fill with pressure. But after a hard drive, i release the coolant tank cap and theres loads of pressure and sounds like a keetle boiling when undoing it. Also it seems to fill with like froth from a bear. Anyone ever been to a nightclub foam party, its coming back into the coolant tank like that Also the coolant hasnt changed colour, no grey colour etc. Im lost. Anyone please help as i just want to get rid of my car as its doing my bloody head in

 

[andycupra]

have you checked for a leak? as thats what id put my money on.

 

[brad1]

Forgot to put aswell, checked everywhere and no leaks. Remember aswell, that if there was a leak, no pressure would build up. Im at a lost end

 

[andycupra]

well its going somewhere!

the amounts you are talking you would know if the head gasket was letting it through the exhaust, it doesnt appear to be in the oil..

Re pressure, it could be that any leak is not evident when hot, or the pressure could be building up and then forcing a leak.

If there is no leak, where is it going?
have you looked at pipes from underneath? removed the undertray etc?

does having the heating on increase consumption?

 

[brad1]

Its like you drive the car and the water is getting hot and turning into foam etc and its pressurising, they its leaking out of the overflow on the header tank, but what would cause it to do this??

 

[MJ]

I too am getting a little tired of seeing all these"oh no my head gaskets f*cked, but its not, oh wait, it is, oh wait... no its not threads"- which never yield any outcome!?!

If there are bubbles coming through the return pipe then this signifies that air is getting drawn into the system. I've always believed that vag built tdi head gaskets are pretty reliable BUT there failure is not unheard of. Brad what you should do is have a cross contamination test done - this will check the coolant for contamination from exhaust gas chemicles:

http://cgi.ebay.co.uk/Universal-cyl...iagnostic_Tools_Equipment?hash=item518f3908ef

This way you will know for sure if the gasket, head or block is allowing for exhaust gas to enter the coolant system thus massively increasing the pressure - which results in the coolant being spewwed out.

 

[barnsley]

is this a 150 engine that runs a egr cooler

 

[MJ]

No a 110 tdi none pd

 

[platofan]

Put tissue under the overflow on the expansion tank and take it for a high spped boot, if the tissue gets wet/or goes pink (blue if you don't use g12) then the coolant is getting displaced by gasses leaking from the cylinder in coolant channels as the pressure of the exhaust gasses are greater than the pressure in the coolant system.

As for the sniff test, make sure the engine is fully up to temp and revving when they test it because I had one done on a cold-ish engine which would not be hot enough to make the gasket blow or for any cracks in the head to show up.

I've got the exact same problem and everyone says the pd's are bulletproof etc but some have got to fail.

Apparently the block should be ok if it's only an exhaust gas leak but you won't know if the gasket is bowing or there is a crack/warping until the head comes off. (...so Seat tell me). I've read of people just having a bad HG though and curing the problem with a HG and bolt change.

About £400-£600 for a HG change i've been told or there's engines on ebay that come fully fitted for about £1k but i' not sure on a 2nd hand engine as I need to keep my mapped ecu and I don't know the history of a 2nd hand engine.

 

[joshpmc]

i had exactly the same problem as you for about a month. Had it pressurtested and came back ok had a sniff test done and came back ok. checked for leaks but there was none changed the cap and no luck. I was then told by awesome gti that it could be a crack in the cylinder head. I bought another cylinder head and gasket set, had the new (but used if you get me) head skimmed and i have spent the last 2 days fitting it. Finally got it on today andwill be putting the rest of the car back together tomorrow so will let you know how i get on. I am also going to have my old cylinder head pressure tested as wen i took the old gasket off it looked like that was the prblem and not the cylinder head. Oh and i drove my car like this for week or two until eventually it smoked badly so i called it a day and stopped using it. I would suggest u only use the car wen u need to until u find out the problem!!
Send me a pm if you need anymore info, my car is a tdi 110 asv engine!!

 

[platofan]

Hopefully it was just your HG...or at worst the head.

I haven't read much about there being cracks in the blocks but I really don't know how common a cracked block is.

 

[brad1]

Right, it seems my fans aint kicking it, and the climate control isnt working, i press the bottom left climate button and it doesnt stay on, i did hear it wont work below a certain temperature, but not sure if this is true or not. Im not sure if these two are related?? Would the fans not kicking in cause the coolant to boil up and pressurise, even in this cold weather?? My needle for the temperature gauge seems fine, stays at 90, doesnt go over at all even when the coolant is boiling

 

[MJ]

The fan control units probably buggered, that or one of the wires to it has broken. Your A/C will not work below 4 degrees, if you press the button the snow flake will appear then disappear straight away.

 

[brad1]

MJ, would the fans not working cause this problem mate, or could it be the thermostat?? How much are thermostats by the way??

 

[MJ]

Thermostats are about £7

No this would not cause the problem, if the fans were not working it would only cause issues when the engine is at idle with the car at standstill like when your stuck in traffic because the fans act as the cold air flow.

Diesels run cold anyway, if i had the fans on in my leon from start-up then the temp gauge would not move, the only time it would begin to warm up was after a drive however when it was cold it built up no pressure in the tank.

You could leave your car running from cold one morning and wait 20-30mins then remove the cap to see how much pressure has built up - alot signifies a problem, like exhaust pressure entering the system.

 

[bondwithme]

K-seal fixed it

HI,

I had a similar problem on my tdi asv engine so decided after a lot of research to try k-seal and it worked perfectly chances are it is only a small crack / leak. Now most on this forum would cringe BUT k-seal was designed for the rover k series engine that used to suffer with hg failure, it is safe to use on any petrol or diesel just google and read!!

Hope this helps oh by the way change the thermosat first just to be sure the temp guages are very very inaccurate I have 90 on my gauge but a digitat thermominter showed a temp of 70 in the ex tank.

To check for heat distribution buy a non contact infra red thermomiter from ebay very very useful


Hope this helps