Alot of pressure in cooling system

colinR32 · 21-05-15, 09:47 PM

So i have a B3 audi 80 1.8 auto(slow i know, but i like her)
I have done a head gasket on her a few months back along with new radiator and thermostat. Now when sitting in traffic or anywhere to that matter for a little
Period of time the pressure in the cooling system is unreal and causing coolant pipes to burst/pop off, now this only happens when stationary as for every other aspect of the car is perfect runs and drives spot on, alot of real warm heat from heaters ect but this pressure is my only problem, anyone any ideas??

Regards colin

John. · 21-05-15, 11:54 PM

Header tank cap not releasing pressure when it should?.....get a new cap and take it from there.

Hanuman · 22-05-15, 12:51 AM

Low speed cooling- fan not working.

My V8 did something very similar, which turned out to be the viscous coupling on the engine driven fan, so in slow traffic, it very quickly cooked up. A side effect was it also heated the transmission fluid up which is cooled through a side element in the rad, causing some hard shifting, and even a gearbox limp home of sorts.

If there is no viscous fan, then there should be some other method of cooling which isn't kicking in.

fourringsrus · 22-05-15, 05:53 PM

Had similar with a straight six BMW a while back, head was actually cracked

jamiecoysh · 22-05-15, 09:07 PM

I agree head is cracked internally just had the same problem with my 2.0e

Sandro · 22-05-15, 11:06 PM

head cracked or head gasket gone

msh · 22-05-15, 11:10 PM

When there's a pressure in system due to blown gasket, usually there also are problems with heater, which here aren't present...

Does temp gauge work? How high does it point when engine is warm? When it's straight vertical, it's showing 100 degrees. Also, does coolant fan kicks in in any time?

colinR32 · 23-05-15, 08:15 AM

well folks thanks alot for all responses, but after doing a late one last night i have finally got to the problem, it turns out the fan isnt kicking in at the temp it should, i have bridged the fan so that when the egine is running it is on constantly and hey presto the pressure has gone.

22-05-15, 12:51 AM	#3
Hanuman Trickster Classic Audi Club Member Join Date: May 2009 Location: Heckling from the cheap seats, Phnom Penh, KoW Posts: 7,025	Low speed cooling- fan not working. My V8 did something very similar, which turned out to be the viscous coupling on the engine driven fan, so in slow traffic, it very quickly cooked up. A side effect was it also heated the transmission fluid up which is cooled through a side element in the rad, causing some hard shifting, and even a gearbox limp home of sorts. If there is no viscous fan, then there should be some other method of cooling which isn't kicking in. __________________ I wish they would keep the damned Chinese away now that I can go home, so that I can enjoy Fish amok and a draught Angkor Last edited by Hanuman; 22-05-15 at 12:56 AM. Reason: Spilleng- how it gets closed from cooled is anyone's guess!

23-05-15, 08:15 AM	#8
colinR32 Grown up member Classic Audi Club Member Join Date: Nov 2012 Location: Ayr Posts: 75	well folks thanks alot for all responses, but after doing a late one last night i have finally got to the problem, it turns out the fan isnt kicking in at the temp it should, i have bridged the fan so that when the egine is running it is on constantly and hey presto the pressure has gone. __________________ ITS A VAG THING, YOU JUST WOULDNT UNDERSTAND

21-05-15, 11:54 PM	#2
John. 4 ring whore! Classic Audi Club Member Join Date: Mar 2011 Location: Scottish Borders. Posts: 7,539	Header tank cap not releasing pressure when it should?.....get a new cap and take it from there.

22-05-15, 05:53 PM	#4
fourringsrus Grown up member Join Date: Feb 2011 Location: Ashford Kent Posts: 468	Had similar with a straight six BMW a while back, head was actually cracked

22-05-15, 09:07 PM	#5
jamiecoysh Grown up member Join Date: May 2013 Location: Torquay, Devon Posts: 119	I agree head is cracked internally just had the same problem with my 2.0e

22-05-15, 11:06 PM	#6
Sandro Grown up member Join Date: Feb 2011 Location: Chelmsford Posts: 651	head cracked or head gasket gone

22-05-15, 11:10 PM	#7
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	When there's a pressure in system due to blown gasket, usually there also are problems with heater, which here aren't present... Does temp gauge work? How high does it point when engine is warm? When it's straight vertical, it's showing 100 degrees. Also, does coolant fan kicks in in any time?