GTti probs

Hello,
I don't speak German, so I'll do in English..

I own a red 1988 GTti with almost 40.000km and I do have some problems.

1)Cold start everything fine, but when restarting the engine with a warm engine after 5 minutes, I have to do a restart. The engine isn't smooth and when stopping at a red traffic light,the rpm meter drops till 2-300 rpm. He is not falling out. After 5 more minutes everything is stabilising but the engine stays bumpy..

2)When I put the GTti in my garage and cut the engine off, in the majority of the times I hear bubbles strokes in the coolant system. More precisely in the top hose from the radiator top to the thermostat. In this top hose the pressure is strong..

The engine was never overheated (during my ownership) and the coolant level stays perfectly normal. No bubbles in the expansion tank and no white smoke, oil substance perfect. I have checked a couple days ago for CO in the coolant system with a small device from WURTH, everything fine and perfect.

I have changed temp sensor (green) and thermostat but no changes at all.
I've been changing the trim pot (air/fuel-mix), idle screw but no major difference.
In the past the previous owner fitted a new radiator when bringing the GTti back into traffic, cause the car stood still for several years.

Can you give me another advice upon this subject?
Thanks in advance!

[JapanTurbo]

hi

I think you have some air in the coolig system (the reason for the rough idle)
you had to bleed the cooling system properly, best with removing the water temp sensor behind the dizzy (12 mm spanner)

Maybe your head gasket is already gone..

georg

The mechanic responsible of this big garage also thought it was headgasket, but after the test (3 times) he was firm. Absolutely no head gasket, cause this test is bullitproof according to him.
Can it be the waterpump?

[62/1]

Hello,

sometimes the breech of the water-cooler is to old and damaged - there is a valve in it.

Rene

What is a breech

[Nightfly]

Breech : Closed way, like a cork or a stopper...

[62/1]

ok, perhaps radiator cap is better *gg*

Rene

[Brummkreisel]

what 62/1 and nightfly mean is the seal in´side the Radiatorcap. The seal will turn older with the time and then it happens that some hot coolingwater come out..

[62/1]

not really,

the problem is not the seal, its the valve. This valve opens if to much pressure is in the cooling circuit, and if cooling fluid is missing in the circuit. Without pressure (cold, not running engine) water can get from cooling fluid reservoir through the cap into the cooling circuit.

If this valve inside the cap is old and damaged, it did not close. In this case, the cooling circuit cant set up pressure. Without pressure water boils at 100 degree celsius. With pressure its at +/- 120.
If the cap is not working perfekt, you can often hear a sound like an old coffee machine out of the cooling reservoir.

Rene

Yes its indeed the sound of an old coffee machine!!
But, the level in the expansion tank with a cold engine is at full level and with a warm engine 2 or 3 centimeters above..so I think the valve works fine no?