High Pressure In Coolant System (Head Gasket Issues??)

[Telephonewire]

2011 Seat Ibiza FR 2.0 TDI (Engine Code CFHD) - 60k Miles

Had this car for about 8 months now, already fitted new timing belt and water pump about 4 months ago as it developed a water pump leak.

Fitted a Bluespark tuning box about 3 months ago which has lifted the power to around 175BHP.

Several weeks back the coolant warning light came on. Upon inspection the coolant level had dropped to virtually zero in the header tank. Upon carefully releasing the coolant reservoir cap the coolant level came all the way back up and beyond the 'normal level' mark. I then tightening up the coolant cap again and carried on with the journey and the same thing happened about 15 minutes later.

Upon further investigation it doesn't look like I am losing any coolant, the system just getting pressurised and forcing the coolant out of the header tank and into the coolant pipes expanding them like balloons to take up the volume.

I have also noticed the coolant colour going from the bright fluorescent pint to more of a dirty pink / brownish colour suggesting to me that exhaust gasses are contaminating the coolant.

There is no sign of any oil in the coolant and no sign of any coolant in the oil.

Another test I performed was to release any pressure in the coolant system by opening the coolant cap up first thing in the morning. Then start the car up from cold and drive a few hundred meters up the road and then open the header tank cap again. This resulted in lots of pressure in the header tank even though the coolant itself was still virtually cold. Hence it's nothing to do with overheating problems etc.

I spoke with Darkside Developments (who were very helpful) who suggested what I am experiencing could be "head lift" (as opposed to head gasket failure). Caused by the head bolts stretched by the additional power I was running. I was rather surprised by this as adding +35 BHP to a 141 BHP diesel, in my opinion, wasn't "excessive".

Rather than having the engine stripped down, head skimmed, new gasket, head bolts etc. I thought I would try swapping the head bolts to upgraded versions (12.9 vs Std 10.9) to see if this would cure the problem. I had read on another forum that some people had reported that swapping the head bolts had cured their similar problems.

Unfortunately having just fitted the new upgraded head bolts this weekend it has not fixed the problem!!

I am wondering what my next step should be now?? Now some people have said that once the head gasket seal has been broken (even if the head gasket itself has not failed) simply putting new head bolts in won't fix the problem. So this suggests it could and probably still is a head gasket issue which continues to allow exhaust gases into the cooling system and hence my only solution is to have the engine stripped down and head skimmed and new head gasket etc.

Before I go down this route I was wondering if there are any other routes by which exhaust gases can enter the cooling system? Could it be possible via a failed EGR vale or oil cooler or indeed anything else??

I am reluctant just to give it to a garage for fault finding as I can do that myself. I am happy to give the car to a garage to remove and skim head etc. and do the job once I am sure of what the problem is.

I like about 8 miles south of Cambridge if anyone knows of any reputable local(ish) VAG independents??

Any comments welcome!!

 

[SEAT Rule]

Hello there,

it does sound like cylinder combustion fumes are possibly entering into cooling system,
you don't always have oil / water mixing it depends where it's gone.
Most diesels have high compression so any weakness in the head gasket, or cylinder head or cylinder liner will show up more once the engine is up to running temperature.

Your best bet is to check your coolant level once the engine has cooled down, as that will show you the true level.
I wouldn't of thought adding 34 BHP would do any damage, but depends how healthy your engine was when you added more power to it. Regarding Darkside Developments they do know their stuff when it comes to diesel engines, they've got really good reviews.

Are you getting excessive pressure in your coolant hoses, or are they getting really hot as these can be first signs of head gasket failure.

What does your temperature gauge read when you're having problems, if it's reading 95°C to 100°C when you're driving then you've definitely got a problem.

I'd be inclined to get a compression test done on all 4 cylinders.
Also are the top hose and bottom hose similar temperature, if not then possibly thermostat is stuck closed, but then your engine would overheat might even bubble up in expansion reservoir.

Regarding the EGR valve that's just to recirculate the exhaust fumes from exhaust manifold to inlet manifold, it's a way of helping to reduce the exhaust pollutants, as the engine reburn's the exhaust fumes at full throttle.

Also if your oil cooler had gone you'd more then likely get oil in the coolant, if it's a tubular type that fits between oil filter and oil filter housing.

Hope this helps
Si