m20 coolant leak problem

[m30power]

Ok here goes...

1990 325i

Just replaced:
-Radiator
-Fan clutch
-Thermostat
-Bled coolant, changed oil, new air filter, new battery

Car seemed to run fine after doing all this...no overheating anymore! :D

I let it heat up, and took it for a 3 mile spin around the neighborhood...all was good...no coolant leaking.

I drove it 55 miles last night. Stopped for food. And drove it 55 miles home again. The car did not overheat, and I thought it had ran very well the entire time.

-I get out of the car at home and smell coolant. I look under the car and sure enough its leaking...coolant overflow tank is down towards the bottom.
-I check all hoses I had removed when working on the car and no leaks from any of them.
-everything under the AFM and towards the rear of the engine bay is soaked with coolant.

Any ideas to what it could be? Overflow tank is not leaking. I am going to get under the car tomorrow and look around more.

If it was leaking from the head I figure it would have been leaking prior to going on the long drive. Im praying its not the head thats leaking!

[CabrioPunk]

Milkshake oil would note a head leak, where the two are blending. Coolant look oily or oil look like a milkshake?

[m30power]

no not at all the coolant was green before and after me replacing it.

-leak seems to be coming from the area under the throttle body.

[m30power]

when I replaced my oil it looked pretty normal to me too!

[jlevie]

If there is coolant on the front of the engine and you can't find leaks at the hoses, the next logical suspect would be the water pump. A pressure test of the colling system should find the leak pretty quickly.

[m30power]

the leak isnt from the front of the motor...seems to be under the throttle body!

[stumble_t]

Its probably the throttle body gasket on the side

[AnimalE30]

Its probably the throttle body gasket on the side

Yup, mine would only leak when I would rev the car up - took me a while to figure out it was the source of the leak.

[m30power]

whats the best way to replace it?

obviously take it apart. But can anyone help me with the size of the torx screws?

Can I just remove the 4 screws and pop a new gasket in there? Is it that simple?

thanks

[e30huh]

check the TB cooling hoses and gasket.

[!kid]

checkhoses that go from the back of the head to the heater core and from the heater core to the throttle body and to the thermo housing.

the torx screws (not sure of size) can sometimes be hard to remove. i had some snap on me once. if they look a little rusty or corroded, let them soak in some pb blaster or WD-40 (pb blaster is best)

[m30power]

well I replaced the gasket because that was the source of the leak! everything looks good to go now!

thanks guys

throttle body cork gasket was the cause

[CabrioPunk]

Sweet! Easy enough. Forums rule.