GTI 8V coolant misbehaviour

[jackytwoshoes]

Hi there folks

I've just got myself a rather nice Jetta GTI 8v, pics to follow!

It's coolant system is playing up a bit.

I actually bought it in London and drove it up to Glasgow.. Along the way the coolant was leaking out of the top of the cap on the expansion tank. This would cause the level to go down obviously. Upon squeezing the large pipes by the radiator, they'd make a squeezy hissy sound like there's lots of air in there. Upon topping up the coolant and squeezing those pipes, coolant squirts out of the expanision tank inlet. Is that right? When the engine is running, coolant is constantly trickling into the expansion tank from the inlet, which rises with revs.

I've topped it up a couple of times and it seems like it might be a bit better, but I've only run it for short times compared to the long journey I just did though so it's really hard to tell.. Could it be as simple as a leaky cap? (is that tank pressurised at times?) Did it have a big air lock that might go away with topping it up? (it hadn't been used for a while before I got it)

It doesn't seem to be a headgasket problem as the oil is fresh after 400 miles, no sign of gunk etc!

[Sam]

Water is not meant to squirt from the top cap 
If i were you mate i would drop all the coolant out of her and then fill with water, squeeze about and check for any holes then drain again and fill with 50% mix of g12 ++

After this just keep an eye on her, it does sound like you said as if she has an air block but there is no harm in doing the job properly yourself

[jackytwoshoes]

Agreed!
Should it squirt from the smaller inlet hose into the tank when I squeeze the pipes?

[SoundillusioN]

Hi there folks

I've just got myself a rather nice Jetta GTI 8v, pics to follow!

It's coolant system is playing up a bit.

I actually bought it in London and drove it up to Glasgow.. Along the way the coolant was leaking out of the top of the cap on the expansion tank. This would cause the level to go down obviously. Upon squeezing the large pipes by the radiator, they'd make a squeezy hissy sound like there's lots of air in there. Upon topping up the coolant and squeezing those pipes, coolant squirts out of the expanision tank inlet. Is that right? When the engine is running, coolant is constantly trickling into the expansion tank from the inlet, which rises with revs.

I've topped it up a couple of times and it seems like it might be a bit better, but I've only run it for short times compared to the long journey I just did though so it's really hard to tell.. Could it be as simple as a leaky cap? (is that tank pressurised at times?) Did it have a big air lock that might go away with topping it up? (it hadn't been used for a while before I got it)

It doesn't seem to be a headgasket problem as the oil is fresh after 400 miles, no sign of gunk etc!

The bit I highlighted is correct, this is normal... However if the seal on your cap is duff, you need a new cap as the system is meant to be pressurised and it's not going to work properly if the cap doesn't seal... Other than that, do as caister says.

[jackytwoshoes]

Brilliant, I love it when a problem disappears in one easy step!

[Sam]

As stated, the little pipe is simply an overflow pipe that pushes coolant back into your header tank so that is fine

[jackytwoshoes]

Will definitely flush through a couple of times, it's got a bit of a rusty colour about it at the moment!!!

[Sam]

Will definitely flush through a couple of times, it's got a bit of a rusty colour about it at the moment!!!

Dissconect the coolant pipe at the bottom of the rad where it connects into the water pump and fold it down. This will insure the system it fully drained. Then put a hose pipe in the expansion tank and turn it on at a rate where it is putting in as much water as it been forced out and leave for 5 min. If the water is still brownish take of the top rad pipe and ram the hose in there and leave to flush through as the brown water will be comming from the inside of the rad.

[Ant1981]

It doesn't seem to be a headgasket problem as the oil is fresh after 400 miles, no sign of gunk etc!

That part isn't necessarily true. Headgaskets fail in many ways. Some fail with no signs visible in the oil what so ever. One way they can fail is when the gasket fails between a cylinder and a water channel. This can cause coolant to leak into the cylinder, causing the engine to 'burn off' the coolant, so you'll lose coolant without and visbile leaks. That would also cause air locks and a pressurised cooling system and you'd still see nothing in your oil.

[ramps]

It doesn't seem to be a headgasket problem as the oil is fresh after 400 miles, no sign of gunk etc!

That part isn't necessarily true. Headgaskets fail in many ways. Some fail with no signs visible in the oil what so ever. One way they can fail is when the gasket fails between a cylinder and a water channel. This can cause coolant to leak into the cylinder, causing the engine to 'burn off' the coolant, so you'll lose coolant without and visbile leaks. That would also cause air locks and a pressurised cooling system and you'd still see nothing in your oil.

The man speaks a truth that has happened to me, but there would be a considerable amount of steam out of the exhaust, my backyard looked like a sauna!