Water Pump

[ya5]

Hi..

How can you tell if a waterpump has gone bad...??

Also is it true that there is some kind of seal on the spindle / shaft of the pump that if it goes bad it will suck air into the system when car is running with out losing any water ... as this is something a few people have said could be causing airlock problem im getting ... I had a new water pump less than a year ago ...

Car is 316 1997 ...

Thanks

[BrazBimmer]

I don't believe that a spoiled seal can live with the coolant at the same level.
Even if dynamically the situation you mention were true there wold be coolant loss with the engine off. (there is pressure in the circuit)
What are your symptoms ?
Jorge

[Headnsouth]

Water pumps seals will leak if they are going bad but also the bearing usually makes noise. Why do you think you have an air lock?

[ya5]

Well, so far I had head gasket changed about 2 months ago and everything was fine until a week ago when there was alot of pressure in the cooling system.. and it blew the radiator.. so assume air is getting into somehow..


So far Ive changed the radiator and thermostat and both have not made a difference.. checked all hoses all seems fine .. dont seem to be losing any water either... if I leave it idling for like 3-5 min it gets alot of pressure in teh system, the pipes go rock hard... also the heaters seem to blow hotter when the car is under load ??

Any Ideas..

Thanks for replies so far ...

[Headnsouth]

it sounds like you head gasket job is not sealing. Combustion gases are getting into the cooling side from the sounds of it.
Look at your dipstick does it have a creamy looking foam on it or the oil cap?
Its not overheating is it?

[Tefal]

did u bleed the cooling system correctly after the work?

[ya5]

there is no mixing of oil and water as far as I can see.. and yes it was bled properly after the head gasket was done....

But when bleeding it now it constantly has bubbles streaming through so it near enough impossible to bleed when car is running and heaters are set to hot ...

only worried as when the system is under pressure the fan doesnt kick in so it could over heat....

[Tefal]

bleed it with the engine off. http://www.pelicanparts.com/bmw/techarticles/E36-Coolant_Flush/E36-Coolant-Flush.htm

[ya5]

ok thanks for replies guys ...

Ive now last night completely bled the system with the car getting up to temp and heaters on full hot and I know there is no air in there now.. and have left it to cool down over night. so now I gonna top up if it needs some and put rad cap back on and see what happens..

I will try that Tefal if this doesnt work... will report back later

Thanks ..

[Joshs325is]

Speaking of the radiator cap, has it been changed?

[ya5]

Well I drove the car for about 5 miles and can say that the PROBLEM still persists...

All pipes are rock hard again.. the heaters are working perfectly too...

Ive now parked up and letting it cool down and every 20min or so just loosen the rad cap slightly to let so pressure out without spilling any coolant... so once car is cool and everything I will see if any coolant has been lost..

Im really stuck here have tried everything now...

And yes I have got a brand new rad cap from BMW fitted ..

Thanks

[smcgee]

there is no mixing of oil and water as far as I can see.. and yes it was bled properly after the head gasket was done....

But when bleeding it now it constantly has bubbles streaming through so it near enough impossible to bleed when car is running and heaters are set to hot ...

only worried as when the system is under pressure the fan doesnt kick in so it could over heat....

You need a block tester. It is $20 at Autozone. Do a search for it at their website. It fits in the neck of the expansion tank. You fill it with a solution that changes color if combustion gases are entering your cooling system. I used one to diagnose my blown head gasket after my car overheated from a failed water pump.

When you had your head gasket replaced did you have your cylinder head checked out for cracks or warping?

[ya5]

OK will try that block tester .. have had a look round for one but will hunt one down tomorrow...

Yh I did have the head pressure tested and skimmed... all is fine with the head as far as I know ...

Im just running outta of ideas now ...

Thanks

[rkrug]

You may want to do a compression test on the cylinders .. If one is low you know you have issues .