Serious Coolant Leak

[christiansm93]

Hello R3v

I recently did some some maintenance to my 89 vert. Some things a buddy and I replaced were head gasket, spark plugs, distributor cap and rotor, all necessary gaskets, water pump, and timing belt. I took the head to the machine shop to get cleaned and valves adjusted.

The problem I am having today is a major coolant leak from the exhaust manifold. White smoke appears when the headers get warm and the coolant is literally spewing out from under the manifold.

I am unsure where to start at this point. Each exhaust manifold only had 4 bolts on them. 3 on top and 1 on bottom center. It's a miracle I didn't have an exhaust leak before.
Here are my next thoughts

1. I may have slightly scratched the head gasket when trying to install the head. I'm not sure how delicate these things are.
2. Due to the fact that I have only a total of 4 studs on the exhaust manifold, I may have an exhaust leak causing coolant to spew out.
3. Head bolts may not be torqued properly. I followed the pattern from center out. Starting with 22ft lbs then 2 90° turns. Some may have been torqued more than others.
4. Compression test was not done prior to install

Where should I start first? I am really lost and want to start knocking things out from easiest to hardest first. I don't have much time to work on this during the week due to my job so weekends it's going to have to be.

Please let me know if any more info is needed.

[TobyB]

There's no coolant in the exhaust manifold, so you likely have a head gasket leak.

I'd start by making sure there aren't any hoses loose or leaking, and then dive in.

You just have to find where it's coming from, and I'm gonna guess, on that side, it's the head gasket.

[101]

^^^ yup.

On the exhaust side, there's only three options for a coolant leak. Head gasket, coolant drain plug for the block or a freeze plug.

Do make sure that coolant is not blowing back from the water pump area or a hose attached to the water pump.

[christiansm93]

Thanks for the reply. So basically I need to take the head off and replace the gasket right? New head bolts and head gakset is needed. Is it also possible that the head is needing to be resurfaced?

[christiansm93]

Is pressure testing the head necessary as well?

[101]

It's almost impossible to remove an aluminum head off any BMW engine and not have some degree of warpage over time. Sounds like your machine shop may have just cleaned it and adjusted the valves?

If that's the case, you'll definitely need to pull the head again, and sent it to a reputable machine shop in your area to have it inspected for warpage, cracks, etc. It's common to have to have a few thousands of material removed off the mating surface of any head.

While the head is off, make sure there are no gouges in the block mating surface. Clean the block surface gently (I use auto trans fluid and a plastic brush), and keep it surgically clean. Chase the head bolt threads and make sure there are no fluids at the bottom. Q-Tips are my go-to tool for that.

When you go back together, use only the BMW OEM gaskets and head bolts. Other brands may be acceptable, others are known poor quality choices. You can ask on here if you have a specific brand in mind. I'm an OEM kind of guy.

And valve adjustment WILL change once the head is bolted on. What looks properly adjusted on the bench will likely not be in adjustment once its back on the block.

Pressure testing - yup - I'd have that done too.