motor

BACR · 06-26-2007, 11:55 AM

Car: 318i 1996

From about 1000 miles ago the water has been boiling over the radiator filler cap every time i stop the engine of the car. I took the car to bmw and they said it was the radiator that needed replacing.

I replaced the radiator today but it has the same problem, it boiled over after you stop the car.

2 garages have said its not the head gasket. And about 2000 miles ago I had the thermostat changed as it was giving incorrect readouts (1 miute it would be fine then it would say the engine was dead cold).

Please help!

ARMAN · 06-26-2007, 01:08 PM

what about temperature sensors, are they working? they are pretty cheap to buy. Is water pump ok?
is fan working? it should work all the time when engine is working + it runs faster when engine is too hot(you can hear it working louder). It can be disfunctional fan pulley http://www.realoem.com/bmw/showparts...44&hg=11&fg=35 try to get another used one to try or you need to buy a new one.
From the discussion on our local bmw forum it can be fan which need to be replaced or water pump but you need to try it yourself

Take it to some smaller bmw garage where people know e36 not original bmw service they are killer expensive. also ask local guys on your local bmw(e36) forums.

I hope you dont fill the water back when the engine is still hot(I saw people do that :shock

or the head will crack 8)

ZfrkS62 · 06-26-2007, 11:11 PM

I'll be willing to bet your water pump has disintegrated. The water pump impellers in that era were made of a plastic composite. As it ages, it becomes brittle and breaks apart, typically where it is pressed onto the stainless steel shaft that connects it to the water pump pulley. At first it expands off the shaft, but eventually just breaks apart. Don't worry about the pieces that move through the cooling jackets. If they're small enough to get in, they're too small to do any harm.

The new pump impellers are stainless steel and a lot more reliable.

They're fairly easy to do, but i would let a shop do it. Mainly because you have you use two 10mm bolts (rather long ones) to push the pump out. The M44 motor is extremely temperamental about having the pump come out straight. If it isn't pulled out evenly, it'll get stuck, then you'll be fucked. And whatever you do, don't pull it by hand, let it fall out. 9 times out of 10, it'll suddenly come free and you'll jam the threads for the fan clutch right through your new radiator.

BACR · 06-27-2007, 02:35 AM

the temperature sensors are working, but the fan hardly ever comes on, only when i switch the aircon on.

I shall check the fan and water pump.

BACR · 06-27-2007, 02:44 AM

however if it was the water pump wouldn't the engine overheat when you drive it? because mine does not overheat atall.

ZfrkS62 · 06-28-2007, 01:25 AM

simple test:

top off your coolant tank and leave the cap off.

Start the car and watch the top of the fill neck. You may have to rev the engine to see it, but there should be a stream of coolant coming out of a small hole below the where the radiator cap threads are.

I'm pretty sure the 318 has the overflow tube like the others. If you don't see the stream, it's going to be the water pump.

I suppose your aux fan could be a source of the trouble if it wasn't kicking on with the AC, but your fan clutch should be able to handle it.

Grab the fan blades and spin them (with the engine off of course) if there is no resistance and the thing just spins, you need a fan clutch.

The sensors are pretty resilient. So you can stop worrying about them.