Losing Coolant While Car Is Moving

[My135]

Filled it up and let it sit over night. Checked coolant next day, coolant level was still at maximum position. Then drove car for 6-10 miles, waited 30 minutes for it to cool down and checked the coolant level. The dip stick dropped from its maximum position to minimum.

So coolant is leaking for sure. Did a pressure test, and the pressure hold. No white smoke or obvious sight of coolant fluid on the ground. No temperature warning light too. Oil temperature is normal with coolant in the car, but went up a little with less coolant.

Any suggestion where the coolant could possibly go? Blown head gasket or something else??? Please help and thanks.

[litebulb]

I had a oil leak that would drip hot oil onto my coolant line which would then bleed coolant. I would go from max to min in a month. But yours sounds pretty severe to be a similar case.

[My135]

Any one heard about coolant-oil separator?

[Dackelone]

Originally Posted by My135

Any one heard about coolant-oil separator?

135i's have an external oil cooler. 128i's have a coolant to oil cooler. Also 135i's with automatic trans will have the coolant to oil cooler. Its rare for them to crack and mix. When they do you get a choco milkshake mix.

Oil is under more pressure than coolant - so you will see oil droplets in your coolant res.


Its probably your water pump, though. I would remove the lower engine cover and look for leaks. IF your car has more than 60K miles your over due.

[My135]

I've just replaced the water pump & thermostat 5 months ago (10K Miles). I don't think this is the problem since last time I got a temperature red warning light when it gone bad. Now I got no temperature warning light, just radiator coolant warning light and the oil temperature is creeping up whenever coolant is lost.

[Dackelone]

Originally Posted by My135

I've just replaced the water pump & thermostat 5 months ago (10K Miles). I don't think this is the problem since last time I got a temperature red warning light when it gone bad. Now I got no temperature warning light, just radiator coolant warning light and the oil temperature is creeping up whenever coolant is lost.

Just because its a new part doesn't mean it is a good part. Maybe one of the clamps is loose?

Your gonna need to pull off the lower engine cover, pressurize the cooling system and see whats leaking. You know you have a leak. You just need to find out where.

[mike@x-ph.com]

I was losing coolant too last week, it turns out one of the lines was leaking.

[My135]

It just happened my friend has the same problem. He found out the gasket between the base of the oil filter housing and the engine block was broken; and the coolant escaped into the oil filter housing.

I am going to replace the gasket this weekend and see if this fix my problem.

Please refer to the link below, part#4 is the gasket which I refer to.

http://realoem.com/bmw/showparts.do?...67&hg=11&fg=30

[My135]

If I am right about the problem and the fix, I think a lot of people got overcharged by BMW dealer by claiming they replaced the head gasket which is a much bigger job as compare to this.

[e36addict]

So no leaks on the ground at all? That's strange.. Have you tried to bleed the system? I'd try that first, may have an air pocket.

Key on, engine off, turn fan speed down to 1 notch(slowest) turn both temps up to max(84) ac button off, and hold gas pedal to the floor for 10 seconds. You should hear the water pump start to run. At that point, the process takes about 15min to complete. If the level drops during the process, you have air in the system.

[Pig Farmer]

Originally Posted by My135

I've just replaced the water pump & thermostat 5 months ago (10K Miles). I don't think this is the problem since last time I got a temperature red warning light when it gone bad. Now I got no temperature warning light, just radiator coolant warning light and the oil temperature is creeping up whenever coolant is lost.

Food for thought... Have you recently begun to use your heater? I can't help but wonder if the heater core drained while changing the water pump. If the system wasn't primed properly, the heater core may have been empty. When you turn on the heat, the heater core valve would open and fill the heater core. This would obviously cause the coolant level to drop.