Hello,
I am new to this group. I did some search regarding the topic but some questions remain unanswered.
I have a '84 944 which I bought in 1998. I had not driven it for few months. Last week I took it out and soon realized that the engine overheats. The temperature was reaching the end mark. I decided to change the thermostat but when I took out the hose at the water pump I noticed that there is no thermostat! I connected the hose back , refilled the cooling system and bled the air out. Now, only whenthe engine idles for a while, the symptoms are:

- The engine overheats
- The radiator is cold all around, hence the cooling fans do not come on
- Upper radiator hose very hot and pressurized.
- The coolant starts pouring out of the expansion tank's hose by the cap
- And, seemingly, coolant drips out of crank shaft area around the big pulley.

What could be causing all this? I am guessing the water pump is not functioning properly but I am not sure what causes the leak in the crank case area. Does the water pump turn using a belt? What is he best way to test the water pump?
Since the engine reached the max temperature mark a few times, how can I tell if this has caused any warp?

Any suggestion would be appriciated.
Thanks.

 

It's most lightly to be the water pump, it's located at the front of the engine and is ran of ether the cam belt or the balance shaft belt.
To get at it you will have to remove the air box, then remove the front timing covers and you should see it's pully right in the centre with a bit sticking out in the centre of the pully. If you start the engine at this stage with the cover off you may be able to see where the leak is comming from, Note take care not to get too close to the exposed belts as you could injure your self badly.
The water pump assembaly has a prety big casing and will need a lot of removals of pulleys and belts around it, so not a small job.

I would also check the engine oil for discoloration (a creamy color), as if you ran the engine for a long thim whilst overheating the head gasket may have blown. Fingers crossed it didn't.

Good luck, hope it works out...

 

I have never seen a waterpump fail in that the impeller becomes seperated from the pulley, which would be the only way it "couldn't work." Not to say that it isn't possible, I have just never seen it. The leak is probably from the pump though, so you are going to need to replace it anyway.

Could be a clogged radiator, bad oil cooler, etc. I would start with what you know is bad (waterpump leak), and go from there.

 

I have seen this accure in a sence once on a Jaguar XJ8 which use a plastic impeller which the blades physicaly wore down to the point where it couldn't circulate the coolant around the engine causing it to over heat. Usualy its the impeller shaft that becomes worn and leaks coolant out the side of the shaft. This is most evadent when the engine is ran from cold before heat expantion of normal running temperatures.
The main problem with having a coolant leak in a pressurised cooling system is not so much the leaking out of coolant but the fact that coolant can get out then air can get in thus a loss of pressure which resulting in a drop in the boiling point. As we know that the reasion for pressurising the system is to raise the boiling point so that the engine can run to a higher opperating temprature thus a more efficient engine.

 

Thank you all so much for the reply. I will take the cover off to check the pump and its belt. I did check the oil and no creamy stuff in it s no sign of coolant leak into the oil.
Thanks again.

 

I forgot to mention although you may have checked that there is also no cream in the cooling system also.

 

Hello,

I opened the cover in front of the engine and noticed that when the engine is running water pump is not turning even though the belt turns around it.(it slips). It seems that the water pump is seized.What can cause this? I guess I need to replace the water pump. What else should I change while replacing the water pump?

Thank you.

[IMG]local://upfiles/3882/2FF8E3CCDE1B4781910B7F11909729C1.jpg[/IMG]

[IMG]local://upfiles/3882/BFDC8FF0EBCE405BB32EB9CE3A03949F.jpg[/IMG]

 

My god that's extreme, you should change the belts as it may be scored due to it slipping on the pully. Before you remove the belts how is the belt tention, is it loose? How's the tentioner? I would not start that engine again until you repair it.

 

In the pics you posted I dont see any oil, so I would replace the pump, belts and all the pullys. If the car sat long enough for the water pump to freeze, you may have issues with the bearings in the pullys too. This is an area you dont want to take chances with. If there is oil leaking from any of the front seals I would replace them also, but you might want to dothem anyway "while your there". Like Anthon33 said dont start it again till its fixed or it could get real expensive real fast.

 

check this one, http://www.aa1car.com/library/overheat.htm
Engine overheating problem might be from radiator cap and the pressure it holds. If the radiator cap does not hold pressure correctly then coolant could boil and therefore the engine would overheat. Another reason might be caused by thermostat failures; it is recommendable that you check. And coolant leaks such as those from the porsche radiator, the hoses, the water pump, the freeze plugs or any others. Also, problems in the water pump could be the cause and therefore you should check it and replace it in case it is needed.