E30 m42 coolant leak

[CFeld]

The coolant is leaking between the engine and transmission. It can't be the rear main seal because that was recently replaced and oil would come out as well. None of the heater core hoses are near it or leaking so it can't be that. What is left that could be leaking a significant amount of coolant.

[varg]

There is nothing on the back of the engine that could leak coolant aside from an unlikely head gasket leak, it is probably running back and dripping down. There is a fitting for a heater hose that is prone to corrosion and leaks on the driver's size of the cylinder head under the cylinder 4 intake runner, it is most likely that. I can't see any of the other common M42 leak points flowing down where the engine meets the transmission, most would just run down the driver side of the block.

[CFeld]

Yea. I honest have no idea what still to check. Are you referring to the heater core output?

[e30davie]

How are you seeing the leak? can you see it leaking when engine is running?

You can get one of those coolant system pressurisation widgets that you pump compresed air into the radiator. Then you can listen and look for the leak with the engine off.

[Balleristic31]

The port on the back/intake side of the head that goes to the heater core often gets corroded and may be leaking.

[CFeld]

I can only see the leak between the transmission and engine when running and it continues for a couple of minutes after stopped. Tomorrow I'm going to take off the intake manifolds and see if I can check all the hose clamps to make sure they were properly tightened. I also just finished rebuilding the engine and cleaned the corrosion off the fitting that's on the head with a wire brush during the rebuild.

[CFeld]

It wasn't leaking from the coolant hoses. Next up is dropping the trans

[TobyB]

Is there a freeze/ core plug on the back of the M42?

t

[CFeld]

No but I found the leak, it was off the return hose off the distribution thing on the side of the engine. But the engine blew up so it doesn't matter now.