GolfGTIforum.co.uk

Model specific boards => Golf mk2 => Topic started by: Donuts on 26 October 2008, 09:33

Title: too much pressure in coolant?? 1.8 digi
Post by: Donuts on 26 October 2008, 09:33
I have a persistent leak from the union of the lower rad hose and the radiator itself. It is intermittent.
Originally I thought that the leak was from the radiator, which I replaced. I have also replaced the header tank and the tank cap. I also replaced the original rad hose clip with a jubilee clip. It still leaks. Hoses get quite hard - maybe head gasket is leaking gas into the system, over-pressurising it. car performs very well. Engine does not consume oil or coolant. No coolant in oil, and no oil in coolant.
What do you reckon? I am thinking of changing the lowere rad hose itself. If it is distorted somehow, it could leak undo pressure and/or heat. Or maybe the head gasket is on its way out. Suggestions very much appreciated!
Title: Re: too much pressure in coolant?? 1.8 digi
Post by: adam_mk2 on 26 October 2008, 09:44
i have the same problem!
Title: Re: too much pressure in coolant?? 1.8 digi
Post by: Diamond Hell on 26 October 2008, 10:06
Take your cars to a garage (or an AA man) who will 'sniff' your coolant for carbon monoxide. 

This will get into the coolant if you have a cracked head or a blown headgasket.
Title: Re: too much pressure in coolant?? 1.8 digi
Post by: DarnPB on 26 October 2008, 12:52
You could just have an airlock that you don't know is there. The pressure may be the same, but if you have a larger volume of air wanting to expand, it has to go somewhere and it will leak at the weekest point.
Title: Re: too much pressure in coolant?? 1.8 digi
Post by: Donuts on 26 October 2008, 13:09
Thanks.
First I will take it for a drive with the coolant tank cap removed and heater full on. Will let it boil over - should sort any airlock.
Then will get the coolant checked for gas from the combustion.
Next on list is a RR wheel bearing. Then need to sort out why there is a rough noise when I depress and release the clutch pedal. It never ends! Nevertheless, its a nice - but expensive- hobby.

I appreciate the help.
Title: Re: too much pressure in coolant?? 1.8 digi
Post by: danny_p on 26 October 2008, 13:34
if there is to much pressure the cap will vent surely
Title: Re: too much pressure in coolant?? 1.8 digi
Post by: Mr Blue on 26 October 2008, 18:58
Ive got the same problem.

yesterday i fitted a mk3 vr6 engine-to-heater matrix pipe that has a bleeder tap built in. So far so good. Bled up quickly too.

Always have alot of air in the matrix. Maybe its time for a new one :rolleyes:
Title: Re: too much pressure in coolant?? 1.8 digi
Post by: Diamond Hell on 26 October 2008, 19:27
Then need to sort out why there is a rough noise when I depress and release the clutch pedal. It never ends! Nevertheless, its a nice - but expensive- hobby.

Sounds like the clutch release bearing is probably on it's way out.

Engine and gearbox split coming up for you.

At least you'll get to know the car inside out - you DID say it was a hobby  :grin:
Title: Re: too much pressure in coolant?? 1.8 digi
Post by: Donuts on 26 October 2008, 21:07
Then need to sort out why there is a rough noise when I depress and release the clutch pedal. It never ends! Nevertheless, its a nice - but expensive- hobby.

Sounds like the clutch release bearing is probably on it's way out.

Engine and gearbox split coming up for you.

At least you'll get to know the car inside out - you DID say it was a hobby  :grin:
:grin:
Turns out that it was low on gear oil. Added 300ml and now its fine!

Title: Re: too much pressure in coolant?? 1.8 digi
Post by: Donuts on 28 October 2008, 18:08
Then need to sort out why there is a rough noise when I depress and release the clutch pedal. It never ends! Nevertheless, its a nice - but expensive- hobby.

Sounds like the clutch release bearing is probably on it's way out.

Engine and gearbox split coming up for you.

At least you'll get to know the car inside out - you DID say it was a hobby  :grin:

The noise is back :sad:
Looks like the bearing will have to be replaced.
Bled any remaining air from the coolant. Think its still over-pressurising. Will get it tested for gas. Looks like the HG will have to be done
 :grin:
Turns out that it was low on gear oil. Added 300ml and now its fine!


Title: Re: too much pressure in coolant?? 1.8 digi
Post by: rubjonny on 29 October 2008, 12:44
no need to split gearbox from engine to do release bearing, its in the end behind the green cap, doable when the engine is still in the car.  Arse about face setup in a MK2!

edit: just to clarify this is on 1.6-1.8 8v/16v engines w/ manual box.  1.0-1.3 and G60 have the release bearing inside the gearbox bellhousing so box off as you say :)
Title: Re: release bearing
Post by: Donuts on 03 November 2008, 14:32
no need to split gearbox from engine to do release bearing, its in the end behind the green cap, doable when the engine is still in the car.  Arse about face setup in a MK2!

edit: just to clarify this is on 1.6-1.8 8v/16v engines w/ manual box.  1.0-1.3 and G60 have the release bearing inside the gearbox bellhousing so box off as you say :)
Thanks for the help.
Is this the correct release bearing? http://www.performance-cafe.com/product_info.php?cPath=7_167&products_id=1293
Title: Re: too much pressure in coolant?? 1.8 digi
Post by: rubjonny on 03 November 2008, 16:12
yep looks like it!  you also need the green end cap, I had a quick look on that site but i coulsnt spot it.  if you're really carefull you might get rthe old one off in a state to be re-used, but they're so cheap it isnt really worth the effort/risk!
Title: Re: too much pressure in coolant?? 1.8 digi
Post by: Donuts on 13 January 2009, 22:29
I have a persistent leak from the union of the lower rad hose and the radiator itself. It is intermittent.
Originally I thought that the leak was from the radiator, which I replaced. I have also replaced the header tank and the tank cap. I also replaced the original rad hose clip with a jubilee clip. It still leaks. Hoses get quite hard - maybe head gasket is leaking gas into the system, over-pressurising it. car performs very well. Engine does not consume oil or coolant. No coolant in oil, and no oil in coolant.
What do you reckon? I am thinking of changing the lowere rad hose itself. If it is distorted somehow, it could leak undo pressure and/or heat. Or maybe the head gasket is on its way out. Suggestions very much appreciated!

I know this is an old thread but I thought that someone might appreciate the update:

I removed the matrix bypass valves...problem solved. There was an airlock in the system