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Coolent expansion tank problem
https://forums.tipec.net/viewtopic.php?f=25&t=2663		 Page 1 of 1
Author:  buddha44 [ Tue Feb 24, 2009 12:24 pm ]
Post subject:  Coolent expansion tank problem
Hi Folks,
Am baffled by this one, has anyone got any ideas?.
The coolant expansion tank is filled up to the MAX marker level with antifreeze. after
driving around 300 to 400 km the level has dropped down to MIN. I keep topping up,
the same happens over and over again. I cannot find any leakage what so ever in
the system?. I'm in Sweden and it is around -5 to 0 at the mo with a lot of snow so
I do have the heater on most of the time. The fan works perfectly on the car. No
problems with blowing hot/cold air that can be found on 944's, also the AC works.

Am now thinking of trying "radiator stop leak" to see if that will help?.

I'm a normal working guy and it's costing me an arm and a leg just on antifreeze!
has anyone else experienced this problem?

thanx Warren 944 s2, luv the car more than the missus
Author:  tr7v8 [ Tue Feb 24, 2009 1:23 pm ]
Post subject:  Re: Coolent expansion tank problem
DON'T USE STOP LEAK. It will clog the system up.

Try changing the pressure cap, it could have a weak spring & lifting under pressure. You could also have a weeping hose which is leaking under pressure & then evaporates off so you don't see the leak, get someone to pressurise the cooling system & see what happens.
Final thing could be a slightly weapy head gasket that opens up when running.
Author:  Li Moo Bai [ Tue Feb 24, 2009 2:45 pm ]
Post subject:  Re: Coolent expansion tank problem
Oil cooler is another common source of leaks iirc
Author:  J.J. [ Tue Feb 24, 2009 3:23 pm ]
Post subject:  Re: Coolent expansion tank problem
Agree with Jim Rad weld is for bodgers! You need a pressure check on the system. I had a pin hole in the top hose & didn't spot it until it dumped half the coolent. Head gasket & oil cooler usually have other symptoms but not always at first. Check all your hose clips are tight & that the washer on the temp sensor in the rad' hasn't split. (Been there too!) As well as the condition of all the hoses not forgeting the two heater hoses at the back. The bigger the leak the easier to find. :) (If it's the rad' there not expensive new.)
Author:  hotblack944 [ Tue Feb 24, 2009 5:06 pm ]
Post subject:  Re: Coolent expansion tank problem
Hi Warren,

buddha44 wrote:
the level has dropped down to MIN.

Does it ever go below MIN? Are you aware of the following, taken from the owner's handbook?

Quote:
When the engine is cold, the coolant level should reach the minimum mark on the expansion tank. When the engine is warm, the coolant level will be above the minimum mark.

See page 75 here: http://alordofchaos.com/Documents/944_owners_manual.mht

Unless it goes below MIN, I don't think you have a problem.

One other thing, has the system been bled properly - see further on in owner's manual?
Author:  mymerak [ Tue Feb 24, 2009 5:24 pm ]
Post subject:  Re: Coolent expansion tank problem
Hi

You say you keep topping up the system

Had an identical problem recently.

Discovered a hair line crack in the radiator and only lost coolant when the engine got hot

If that's your problem then I think it has to be a pressure test to find it in all probability
Author:  barks944 [ Tue Feb 24, 2009 8:18 pm ]
Post subject:  Re: Coolent expansion tank problem
hotblack944 wrote:
Hi Warren,

buddha44 wrote:
the level has dropped down to MIN.

Does it ever go below MIN? Are you aware of the following, taken from the owner's handbook?

Quote:
When the engine is cold, the coolant level should reach the minimum mark on the expansion tank. When the engine is warm, the coolant level will be above the minimum mark.

See page 75 here: http://alordofchaos.com/Documents/944_owners_manual.mht

Unless it goes below MIN, I don't think you have a problem.

One other thing, has the system been bled properly - see further on in owner's manual?


That's the result of an expansion of the coolant when its heated, what he is describing is a loss of coolant. Are you sure your supposed to fill it to maximum level when cold as that wouldn't leave much room for coolant expansion. Maybe you should let it stay at minimum and see if it still looses coolant?
Author:  Richy_S [ Tue Feb 24, 2009 9:12 pm ]
Post subject:  Re: Coolent expansion tank problem
Like it says above if the level is not dropping below min dont worry - the coolant is finding its natural level.

If it does fall below min get it pressure tested. I recently had the same problem and it turned out to be the waterpump.

In the process of changing it as below.

Image
Author:  PaulSmith [ Wed Feb 25, 2009 7:48 pm ]
Post subject:  Re: Coolent expansion tank problem
Same here - if it settles at the miminum but does not go below then don't worry.

My S2 has sat at the minimum for the last 10 years. If you put any more in it just gradually spits it out of the overflow pipe..

If it DOES go below the minimum then get it pressure checked for leaks.
Author:  Siggy [ Wed Feb 25, 2009 10:49 pm ]
Post subject:  Re: Coolent expansion tank problem
As he's in Sweden, its probable that the engine never gets too cold, most/all houses or flats have a connector outside to plug the car into and a heater in the engine block.
Author:  frenchy [ Thu Feb 26, 2009 9:29 pm ]
Post subject:  Re: Coolent expansion tank problem
The steel water pipe that runs the length of the engine above the exhaust manifold gets pinholes in it with age, water sprays out under pressure and evaporates with the heat from the exhaust.
Quite a common problem, check it out, and a reasonably cheap fix.
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