Mk2 Gti 8v (over)heating

3185 Views 18 Replies 5 Participants Last post by PGTi, Jan 17, 2006

PGTi

Discussion Starter · Dec 21, 2005

My Golf, which I only use for the occasional forray, is putting water out the expansion bottle. I took it for a spin today, topped up the expansion bottle before I left and noticed it had spat some coolant out when I got home.

The car did reach operating temperature, I think, but the top hose of the rad was hot while the bottom hose was stone cold. (Meaning the bottom of the rad was cold and the fan switch(new) wouldn't activate),

The water pump has 3 hoses connected
1 was cold (the same one connected to bottom of the rad.

2 others were hot.

Is there any particular blockage which would cause a malfuntion?

There doesn't appear to be any leak on the water pump, and no strange noises, so I assume it's ok.

The Heater blows very hot. Would that rule out the thermostat being dodgy?

PG

1 - 19 of 19 Posts

Geo

· #2 · Dec 21, 2005

I'd say it's the thermostat. It is located where the bottom hose goes into the lh side of the block (as you stand looking at the car) so when it sticks then the bottom hose stays cold.

Easy enough to fit, if the car has pas there's a bit more involved but otherwise it is very easy.

Winger

· #3 · Dec 21, 2005

Thermostat are a little temperamental aren't they? I remember having mine tested before in my old mk2. Perhaps worth replacing.

Hope the problem isn't the head gasket. I'm no mechanic, but if in your situation, would test or replace the thermostat.

Geo

· #4 · Dec 21, 2005 (Edited by Moderator)

Just replace it they are dirt cheap. I did the one in my mk2 and replaced it with a lower temp one.

Although in the cold weather like we have at the moment it could take a long time for it to open anyway so it could be the head gasket unfortunately as Winger says.

It could also be the cap, is there much pressure building up in the coolant hoses?

PGTi

Discussion Starter · #5 · Dec 21, 2005

QUOTE (Geo @ Dec 21 2005, 02:20 PM) <{POST_SNAPBACK}>Just replace it they are dirt cheap. I did the one in my mk2 and replaced it with a lower temp one.

Although in the cold weather like we have at the moment it could take a long time for it to open anyway so it could be the head gasket unfortunately as Winger says.

It could also be the cap, is there much pressure building up in the coolant hoses?

I haven't checked the cap. What kind of pressure should there be?

Car doesn't have PAS.

Geo

· #6 · Dec 21, 2005 (Edited by Moderator)

Should be some pressure but the hoses shouldn't be too hard. If there is no pressure then the cap is most likely fupped.

Too much pressure points to either thermostat or head gasket, and if the thermostat sticks it can lead to head gasket failure.

To replace the thermostat just look under the car where the bottom rad hose joins the engine, there should be a plastic housing with 2 10mm bolts holding it on, the thermostat is in there.

PGTi

Discussion Starter · #7 · Dec 21, 2005

QUOTE (PGTi @ Dec 21 2005, 02:28 PM) <{POST_SNAPBACK}>I haven't checked the cap. What kind of pressure should there be?

Car doesn't have PAS.

Wouldn't Head Gasket trouble result in an oil-water emulsion?

Geo

· #8 · Dec 21, 2005

Only if it is blown between an oil-way and a water-way.

If it's blown between one of the cylinders and a waterway it can result in pressure buildup in the coolant system.

PGTi

Discussion Starter · #9 · Dec 21, 2005

QUOTE (Geo @ Dec 21 2005, 02:36 PM) <{POST_SNAPBACK}>Only if it is blown between an oil-way and a water-way.

If it's blown between one of the cylinders and a waterway it can result in pressure buildup in the coolant system.

OK, thanks.

Baza

· #10 · Dec 21, 2005

Sounds like a stat alright although the rubber seal could be going/gone on the cap of your expansion bottle also. Best to replace both before jumping to any conclusions.

PGTi

Discussion Starter · #11 · Dec 21, 2005

2

QUOTE (Baza @ Dec 21 2005, 03:27 PM) <{POST_SNAPBACK}>Sounds like a stat alright although the rubber seal could be going/gone on the cap of your expansion bottle also. Best to replace both before jumping to any conclusions.

Cap and stat both replaced.

Fooking hell, OEM parts are expensive.

€8.32 for the cap,
€19.38 for the stat,

from Commons Road motors Navan, PLUS VAT

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JMS

· #12 · Dec 21, 2005

2

QUOTE (PGTi @ Dec 21 2005, 09:37 PM) <{POST_SNAPBACK}>Cap and stat both replaced.

Fooking hell, OEM parts are expensive.

€8.32 for the cap,
€19.38 for the stat,

from Commons Road motors Navan, PLUS VAT

The expansion bottle itself is around 40 euro without the cap, and that's from OTTO.

Has your problem been sorted?

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PGTi

Discussion Starter · #13 · Dec 22, 2005

QUOTE (JMS @ Dec 21 2005, 11:48 PM) <{POST_SNAPBACK}>The expansion bottle itself is around 40 euro without the cap, and that's from OTTO.

Has your problem been sorted?

I didn't get a chance to give it a good run, yet. Bottom pipe from rad was heating up so thermostat is now working.

Baza

· #14 · Dec 22, 2005

QUOTE (PGTi @ Dec 22 2005, 09:31 AM) <{POST_SNAPBACK}>I didn't get a chance to give it a good run, yet. Bottom pipe from rad was heating up so thermostat is now working.

Compare the 2 caps before you put it on, make sure the seal is missing/damaged before you replace it, if it looks grand throw in the stat and see how it goes if it runs well bring back the cap.

PGTi

Discussion Starter · #15 · Dec 22, 2005

QUOTE (Baza @ Dec 22 2005, 10:50 AM) <{POST_SNAPBACK}>Compare the 2 caps before you put it on, make sure the seal is missing/damaged before you replace it, if it looks grand throw in the stat and see how it goes if it runs well bring back the cap.

I know the caps are a problem item so I'll keep it. It would nearly cost me the price of it to bring it back.

Isn't VAT a right cunt? Especially when you know others can get the same parts VAT free or even at 13.5%?

JMS

· #16 · Dec 22, 2005

Could do with one of those caps myself, it's slightly leaking but not bad, must change it all the same.

PGTi

Discussion Starter · #17 · Jan 4, 2006

I'll do a George on this one and hope all is well. Took the car for a good run today and it seemed OK. The new expansion cap was definitely needed, there was much more pressure in the cap when I loosened it.

JMS

· #18 · Jan 4, 2006

That's the job!

PGTi

Discussion Starter · #19 · Jan 17, 2006

Never should tempt fate, I guess.

I took the Golf out for a 10 mile run today, felt she wasn't running 100%, popped the bonnet when I got back and, hey presto, she has blown the Head Gasket. Oil and water courses now seem to be one and the same and she was ticking a bit too loud from the head cover area.

So, now, with 170k on the clock, should I go for a simple CH repair, complete overhaul, or replace the engine?

1 - 19 of 19 Posts

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