318 96 overheated a couple days ago! Need help...

[Leo]

Hi gang. I'm new and I been reading quite alot in the garage section of this forum. Great info BTW. Anyhow, I was wondering if anyone here can possibly help me. Here's my situation. What I noticed thus far, the coolant stays cool inside the radiator. The right main hose attached to the radiator becomes warm, but the left hose, which appears to be the one leading the coolant from the engine into the radiator, is always cold. Now, to me, there seems to be no circulation of coolant. So, I'm thinking is the 'waterpump'. However, I removed waterpump, pump looks ok. I don't see any visible damage, wear or tear. There's no flippers. It's black, plastic & round. I noticed also a drip, a slight leak coming from behind the engine. Coolant is dripping. I also checked thermostat. Removed Therm. from housing and dunk it in boiling water. It works. When 318 overheated, there's a hiss and smoke clearly from behind the engine, I see a couple large hoses there. The only problem I can't get to them. Is too cramp in there. I'm afraid I may have to take it to the shop eventually. So, if there's a raptured hose behind the engine, could this be the only problem? Or did a failing (thermostat/waterpump) caused the rapture? Also checked radiator for leaks, seems to be ok.

Leo

[bmw///m3///]

if you water pump has plastic propellars replace it anyways.

[Leo]

I just had some more time playing around with the engine. I noticed the cooling fan is not rotating, even when the temp. gauge is at the half level. It turns out, the thermostat was shut and thus the coolant was not circulating. I placed back the housing without the thermostat and coolant is freely circulating about, when with the thermostat in place, it fails to circulate. So, I'm thinking replacing this unit. The waterpump is, from what I gathered, in excellent condition. I know the impellers are plastic, but the piece is very solid. So, now I'm scratching my head as to why the cooling fan is not rotating? Anyone care to elaborate? I'm a little stump on this one, and on top of that, I bought my 318ti without a manual. I wish I had one!

[bmw///m3///]

ive heard of this before. it may be the fan switch that is bad(or maybe thermostatre switch or something related?). Search on bimmerforums.com

I think I already saw this problem on there. But anyways post your problem on there and you should get an answer soon.

good luck///

[BMWDRIFTER]

make sure you bleed the air out by opening the screw beside the radiator cap. you may have air trap in the system.

[mickd]

Sounds to me like a stuck thermostat, coolant is not circulating through the radiator. I don't understand, you said that you checked it by heating it in water. You should find out the temp it opens at, might be opening at too high of temperature causing the engine to overheat or you are shutting off the engine before it gets to hot to open (good thing). I don't know off hand the temp of the ti thermostat but I would verify it opens at the correct temp. I have never worked on things relating to the fan, If the temp sensor for the fan is at the lower part of the radiator like it is on the water cooled VW's I had owned, the fan won't come on with a stuck thermostat because there is no coolant flow to the radiator, thus, the temp sensor stays in unheated coolant. The coolant leaking might just be from the overflow when it got hot. Check all your hoses and clamps. I would just replace the thermostat.

[Leo]

It was a stuck thermostast. Thus water was not circulating.

Plastic unit behind the engine that connects to hose was busted. A VIC Gasket kit was installed by mechanic. I could not get behind the engine, and I decided to turn my vehicle to a shop. Total cost repair bill, 484.99 $124.13 for parts, and $350.00 for labor. Well, it runs like a dream again.

Leo