cooling system header tank - Page 2

vag80 · 21-02-09, 05:32 PM

If the rad and hose cool to touch when car up to temp then you do have an air lock

ChrisG · 21-02-09, 05:33 PM

OK so I've just spent another hour plus trying to sort this out....... argh !
It still this :
start up, withing athree or four minutes the guage is halfway up the scale and within a couple more minutes is way up, almost at the top.
At this point the heater will blow hot air .
the pipes are warm from head to pump ( smallish diameter)
ditto pump to head
large dia pipe from head to top of rad is warm at head end but cool halfway along
pipe inlet/outlet on thermostat is cold
large dia pipe from rad to thermostat is cold
pipe between rad and header bottle is cold
rad is cold
even after more time these last five are still cold

Is there air trapped around the thermostat area ??
Should I just drain the whole system and refill slowly??
I shall tax it next week so will be able to move car to house ( currently SORN and in lock up for winter) where I have a better water supply than 4 pint milk cartons I have to keep taking to the garage !!

Any further help/suggestions will be gratefully received........thanks

mikes2 · 21-02-09, 10:11 PM

is the return hose from the heater matrix getting warm ?

this hose feeds the thermostat which sends the water to the radiator.

It sounds like the thermostat is not opening to allow the water to go to the radiator. If this happens the fan will not come on.

It may be the heater matrix is blocked and not returning the water round the system

ChrisG · 08-03-09, 03:48 PM

OK, last part of the saga!
It looks as if there were several things that went wrong together.
Thanks to vag80 and mikes2 for their help comments and particularly vag80 who arrived at my door and went about three hours later having largely sorted it it out.
There was an air lock -- not sure where but it was BIG.
Bit disconcerting to see vag80 pulling off the various cooling heater hoses with the motor running. In fact there was little ( virtually no ) water from several of them. He reckons the pump is also weak.
Anyway once the water was flowing reasonably from all hoses..... on to the next bit.
The dash light was then flashing ( low water /overheating).
vag80 suggested the sender could be the culprit:
the sender had broken.... at the same time.... it was oK when I started but not afterwards.... honestly!
Ordered a new one from the Dealer ( seems to be an Audi only part)
Part came in , looked very different, but went with it, cut off the old connector they said and here are two new spade connectors to put on....
Light stopped flashing BUT the guage didn't work
Mikes2 checked out part numbers and sent me a link to an obsolete parts organisation and a VW dealer in Kirkaldy happened to have the original sender in stock and at half the price Audi wanted.
Big THANKS to Mike.....
http://www.partspool.com

car is now working properly, as far as cooling is concerned and I'm now moving on to changing the power steering fluid and arb bushes....

21-02-09, 10:11 PM	#13
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	is the return hose from the heater matrix getting warm ? this hose feeds the thermostat which sends the water to the radiator. It sounds like the thermostat is not opening to allow the water to go to the radiator. If this happens the fan will not come on. It may be the heater matrix is blocked and not returning the water round the system __________________ 1991 90 quattro 20v sport 1991 90 quattro

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21-02-09, 05:32 PM	#11
vag80 Senior Member Classic Audi Club Member Join Date: Oct 2008 Location: Bracknell Posts: 1,967	If the rad and hose cool to touch when car up to temp then you do have an air lock

21-02-09, 05:33 PM	#12
ChrisG Senior Member Classic Audi Club Member Join Date: Dec 2007 Location: Bracknell, Berks. Posts: 1,465	OK so I've just spent another hour plus trying to sort this out....... argh ! It still this : start up, withing athree or four minutes the guage is halfway up the scale and within a couple more minutes is way up, almost at the top. At this point the heater will blow hot air . the pipes are warm from head to pump ( smallish diameter) ditto pump to head large dia pipe from head to top of rad is warm at head end but cool halfway along pipe inlet/outlet on thermostat is cold large dia pipe from rad to thermostat is cold pipe between rad and header bottle is cold rad is cold even after more time these last five are still cold Is there air trapped around the thermostat area ?? Should I just drain the whole system and refill slowly?? I shall tax it next week so will be able to move car to house ( currently SORN and in lock up for winter) where I have a better water supply than 4 pint milk cartons I have to keep taking to the garage !! Any further help/suggestions will be gratefully received........thanks

08-03-09, 03:48 PM	#14
ChrisG Senior Member Classic Audi Club Member Join Date: Dec 2007 Location: Bracknell, Berks. Posts: 1,465	OK, last part of the saga! It looks as if there were several things that went wrong together. Thanks to vag80 and mikes2 for their help comments and particularly vag80 who arrived at my door and went about three hours later having largely sorted it it out. There was an air lock -- not sure where but it was BIG. Bit disconcerting to see vag80 pulling off the various cooling heater hoses with the motor running. In fact there was little ( virtually no ) water from several of them. He reckons the pump is also weak. Anyway once the water was flowing reasonably from all hoses..... on to the next bit. The dash light was then flashing ( low water /overheating). vag80 suggested the sender could be the culprit: the sender had broken.... at the same time.... it was oK when I started but not afterwards.... honestly! Ordered a new one from the Dealer ( seems to be an Audi only part) Part came in , looked very different, but went with it, cut off the old connector they said and here are two new spade connectors to put on.... Light stopped flashing BUT the guage didn't work Mikes2 checked out part numbers and sent me a link to an obsolete parts organisation and a VW dealer in Kirkaldy happened to have the original sender in stock and at half the price Audi wanted. Big THANKS to Mike..... http://www.partspool.com car is now working properly, as far as cooling is concerned and I'm now moving on to changing the power steering fluid and arb bushes....