Water pump or head gasket broke?

[platofan]

Hi

I've had my 130tdi for a week and it's already causing me grief.

Firstly I have a coolant leak in the expansion tank, I see it dripping from underneath when I top up the coolant past the MIN level so I suppose that needs replacing.

Temp has seemed fine but the car has done 107k and it's giving me a whoosh of air even hours after it has had the engine turned off so there's pressure shooting out when I open the expansion tank lid.

Now i'm just wondering if this points to a broken water pump or a head gasket? Because the car is new to me I don't know if it has a coolant leak but when I got it I had to add about 1.5l of coolant to it to bring it up to the MIN marker - but whether this was a case of a leak into the engine or a leak of steam out of the expansion tank I don't know.

Are there any definitive tests I can have done or should I just get the pump/belt and headgasket changed?

Thanks

Btw I have no creamy oil cap. Looks like a months wages are about to say godbye though.

 

[platofan]

Is there an overflow on these reservoirs, if so where?

Just turned the engine on and left if with the cap off for a few mins and the seems to be the tiniest bubbles but I don't know if they're from the return pipe or coming up from underneath?

I'll keep an eye on the levels until I get a new reservoir.

Thanks

 

[Viking]

That stream of bubbles is pointing to an ingress of air somewhere, and the only place that can come from really is the head gasket.

However, I'm puzzled by your explanation. You say it leaks coolant when you top it up past the minimum mark, but then say it holds pressure overnight. One of those is incorrect surely as a water leak would be an air leak aswell.

 

[platofan]

Well I think there's a slight split under the header tank and when I top it up so much it leaks out the bottom until it gets to the min mark....that's why I wondered if there was an overflow.

Also it holds pressure even when cold, just went out and got the hiss when I took the expansion cap off. 20 hours I deliberately left it for and still it's got pressure in there.

Maybe I should get the new reservoir, eliminate the leak and see if the hissing/coolant loss stops?

 

[Viking]

See that's the puzzle. If you top it up and it leaks water out straight away, then there's no way it'll hold air pressure.

Anyway, change the bottle (and cap) first, then see what happens.

 

[meltonlad]

i had the same mate. have a read through this.

http://www.seatcupra.net/forums/showthread.php?t=233967

 

[platofan]

Right I removed the tank today and there is no leak, it was the overflow - hence why there is still pressure in the system when cold. My bad, thanks for the link to the thread though. Interesting read.

My problem now is narrowed down to pressure staying in the system.

Temp doesn't rise above 90.

Is there anything else this could be apart from a headgasket failure?

Thanks

 

[MJ]

The temp fault could be down to: faulty temp sensor, faulty dash pod, there are many possibilities mate.

A head gasket to go on a pd is extremely rare though, people often see certain signs of a HG leak and instantly assume that it is at fault when 99% of the time its something different causing it.

It could be that the water pump has gone or that the fans are not kicking in because the temp sensor is telling the ecu that the coolant is still cold - this would raise the real coolant temp and create alot of built up pressure which would eventually be released through the overflow on the header tank.

90 degrees is the normal working temp, no more no less - apart from the initial warm up period.

 

[platofan]

Thanks, might replace that.

Would it cause the pressure to stay in the system for over 24 hours of not being driven though?

Cheers

 

[meltonlad]

mate have you done the secret climate control temp setting ?? that if you got climate ?

 

[MJ]

there is a pressure release on the coolant cap which is there to allow excess pressure to escape, might be worth trying another cap from a scrap vehicle to see if it still holds. Does the car run rough or loose coolant?

 

[platofan]

I do have climate control.

I need to wait to see if i'm losing coolant but the car runs fine, i'm just worried about the pressure blowing something up!

 

[meltonlad]

try this then... you need setting 51 just in case the temp gauge is wrong...

http://www.wak-tt.com/tt/climatecontcodes.htm

 

[platofan]

Thanks, i'll try that tomorrow. I'll also try a new rad cap if a new one may release pressure.

 

[platofan]

The climate control diagnostics show around 54 degrees so I don't know if something is wrong there. The gauge showed 90. I don't know what figures to be expecting though lol. It's not overheating at least.

Went to Seat and the man swore that it would probably be the water pump as he said these engines rarely blow a gasket. Fair enough, but I didn't think that could cause the pressure build-up i'm getting.

 

[Viking]

Is there coolant circulating through the header bottle? If so then the water pump is working. This small stream of bubbles leads me to think that the head gasket is passing combustion gas (very high pressure) into the coolant waterways (relatively low pressure) and that's what is pressurising the coolant.

 

[meltonlad]

it could !!!! i had major pressure build up and it was due to my water pump being fooked...

 

[platofan]

Thanks for the replies.

The tank is pouring coolant back into the reservoir so it does look like it is circulating.

I think I should maybe get an 'exhaust gas in coolant' test done then hopefully that'll confirm what I think. Headgasket.

Cheers

 

[Nazlfc]

Any ideas

Thanks for the replies.

The tank is pouring coolant back into the reservoir so it does look like it is circulating.

I think I should maybe get an 'exhaust gas in coolant' test done then hopefully that'll confirm what I think. Headgasket.

Cheers

Hi Platofan,

Any joys on identifying the problem. Reading your thread it seems that I have the same issues. On mine I also don't get any heat through the climate control even set to HI. Also I get bubbles in the expansion tank (even when cold) and also have pressure in the expansion tank even after opening when it is stone cold 48 hrs later.

Let us know how you get on. Hopefully for both our skaes it is not a HG.

Cheers

 

[platofan]

Hi

I messed about with the thermostat and the heating seems to heat up now after a min of the engine running. I'll put a new stat in tomorrow. if that doesn't work i'll rplace the coolant sensor.

Had a sniff and pressure test done. They came back fine which actually annoys me because i'm still getting the 'hiss' with a cold engine. I've been told it's normal but I know it shouldn't be!

I still don't know if i'm losing water as I haven't done a long enough run to get it so hot that it turns to gas.

No temp problems either so I guess i'll just have to wait until it's defo the HG as i'm not up for paying £400+ for something that doesn't need doing.