Never ending coolant leak!

[JoeyZ]

So im still battling with coolant leaks on my car. A little bit of background. Its an 86 325es I bought from a dude that said it had "A hose leak" so I snapped it up for $800 bones.

I test drive the thing up and down the road and it seems ok, the temp gauge never budges(I though was weird but chocked it up to the sensor or a jaked SI board).

I get it home and top of the coolant to try and find the leak and it starts gushing out of the block. The "Hose Leak" turns out to be a missing freeze plug, 2nd one from the back on the pass side. So I punch a new one in.

Top it off and no leaks until I run the car for a min. POP another freeze plug goes, same one but on the drivers site RIGHT behind the starter .
I managed to get one in, top it off and no leaks until I start it again.

Now I have a slow-leak that looks like its around the back of the head somewhere and the temp gauge still isnt budging (I replaced the batteries and cleaned all connections on the SI board and tested with a multimeter so I dont think thats the problem). I thinking maybe headgasket?

I have a headgasket and timing belt kit on its way in from Pelican so Ill likely do that anyway, at 160k it probably needs it.

Has anyone had this much trouble with the cooling system or something similar? HALP!

[vpilarrt]

There is a water pipi on the back of the block just below the head. That or its gasket or the hose connected to it may be leaking.
As long as you are taking the head off anyway I would go ahead and change all the freeze plugs. Those things usually don't go bad unless the car's been sitting for a long time (possible since its 27 years old but with only 160k miles). Check all the cooling hoses, they may be in bad shape from sitting also.

[JoeyZ]

Yeah the cars been sitting since 2011. The weird thing is it came with a spare head and ECU in the trunk.

[Todd Black 88]

I would throw a new rad cap at it, and get the cooling system pressure tested.

[JoeyZ]

m20b27, no radiator cap.
Could the cooling system be blocked somewhere making it build up pressure and popping things ?

[JoeyZ]

Whelp! After tearing the intake manifold off it turned out to be a combination of another leaky freeze plug and the TB to block hose has a rip in it.
I really want my car back on the road. Should I fix those two and call it a day or go ahead and do the head gasket/timing belt anyway?

[Todd Black 88]

m20b27, no radiator cap.
Could the cooling system be blocked somewhere making it build up pressure and popping things ?

Every car has a cap. It's the cap on the reservoir on the m20 b27.

[jclar]

Whelp! After tearing the intake manifold off it turned out to be a combination of another leaky freeze plug and the TB to block hose has a rip in it.
I really want my car back on the road. Should I fix those two and call it a day or go ahead and do the head gasket/timing belt anyway?

You should really just replace all the freeze plugs, at the rate that they're coming out you're asking for trouble by leaving them as-is. With the head off they'll be really easy to access.

The timing belt definitely needs to be done, and if you have the items needed to do the hg why not do that as well? I understand wanting the car back on the road, but having it back on the road and reliable is infinitely better than not being sure or having the timing belt break on you.

While you're at it, replace all of the cooling hoses and don't forget the one at the back of the head.

[e30kawi]

I hate to hijack an older thread, but my coolant light came on today, never seen a leak or puddle anywhere. Decided to poke around, it looks like all my freeze plugs on the passenger side have a slow leak. What would cause this? The motor was just rebuilt and almost everything in the cooling system was replaced except for the expansion tank and radiator. I replaced all the hoses and cap. Any ideas?

[jlevie]

A common cause for leaks at the freeze plugs is corrosion pinholes that result from a PO running plain water in the system or never changing the anti-freeze.

[e30kawi]

A common cause for leaks at the freeze plugs is corrosion pinholes that result from a PO running plain water in the system or never changing the anti-freeze.

They are brand new plugs, they were put in when I had the motor rebuilt in june. They seem to be leaking around the edges

[jlevie]

The plugs may not have been correctly installed. The driver used needs to be a good fit to the plugs, maybe 0.010-0.020" smaller in diameter than the ID of the plugs. Sealant is required and the plugs must be driven in straight. The best way is with a press, but with care they can be hand driven.

If the driver is too small, it will cause the plugs to cup. If driven at an angle the sealing surface will go oval. Either can result in leaks

[shadowracer]

+1 to what jlevie said, in my case I used indian head gskt shellac, and a 30mm impact socket which just fits in the freeze plug. I then gently hammered (tapped) them in making sure they were straight.

[e30kawi]

The plugs may not have been correctly installed. The driver used needs to be a good fit to the plugs, maybe 0.010-0.020" smaller in diameter than the ID of the plugs. Sealant is required and the plugs must be driven in straight. The best way is with a press, but with care they can be hand driven.

If the driver is too small, it will cause the plugs to cup. If driven at an angle the sealing surface will go oval. Either can result in leaks

Thanks for the help, I am going to call the shop that put them in and get them to fix them, I have a year warranty on the motor.

I wanted to make sure it wasn't another issue that could be causing them to leak on just one side.