coolant from rear main seal arggghhh

[stever318is]

I just put the oil pan and pickup on the 91 318is that was given to me(it was completly gone with the pickup too) I didnt bother with replacing the upper do to cost i just quick steeled the one crack and filled with oil to see if it was worth it. Anyway it runs with a good tick. BADDDDDDDD thing is it is leaking a drip drip of pure green coolant from rear main seal area defenit internal. Also good bit of smoke from header area. What am i looking at  SCRAP the motor, used M20 motor in garage parts car. Any suggestions

thanks

steve 88 325 driver
87 325i parts
91 318is down and out

[stever318is]

the coolant is leaking down from under the intake there is a nipple buried at the head for a small coolant hose that then elbows to the plastic coolant pipe OMG how do you ever get a new hose clamp on that. Also it was pooling(coolant) right where motor and trans bolt together could this explain my drip at bellhousing internal.

steve

[bmwman91]

There is a bunch of stuff with coolant in it under the intake manifold.  It is all part of the throttle body de-icing system.  It is also notorious for being a huge pain in the rear.  Some patience and a little wrenching around should solve the issues.  The hoses might be cracked and leaking, or just needing new clamps.  I am not sure how coolant would be getting onto the header, unless the head gasket somehow has a hole in it over there.  Does any white smoke come out of the exhaust?

[stever318is]

sorry for the being so vauge but its on the drivers side under the intake boot recessed eay back on the head or block, small 3/8 size nipple. History car sat 3 years rats had chewed into coolant temp sensor wiring and after i fixed that idle evened out white smoke out tail pipe ceased. Also the engine is running quite now. THe coolant pipe comes out 2 inches into a plastic tee then enlarges to say 5/8 molded heter hose and ducts down inot a plastic tube connected to the block. The rats hat chewed through the 3/8 portion of the tee therfore i have to snake a new 3 inch section of 3/8 hose onto this nipple then get the hose clamp to tighten. It looks like a blast. Otherwise I think I have a strong runner.

[e9nine]

BMW decided to be "smart" and tie in coolant and vaccum lines together so it appears like a f'in rats nest.

In summary -- You have a main coolant line flowing out of the head that flows into the throttle body cooler plate and back into the head.

[bmwman91]

Sounds like you should just do a good "outer" tear-down on the motor.  I'd say yank all the accessories, hoses, etc.  Replace what needs it.  Hopefully this is not your daily-driver!

[rob_e30]

BMW decided to be "smart" and tie in coolant and vaccum lines together so it appears like a f'in rats nest.

In summary -- You have a main coolant line flowing out of the head that flows into the throttle body cooler plate and back into the head.

It looks something like this...

[e9nine]

As a tip for those of you who go through this. Look at the picture carefully. Then go look at your car.

The hose from the valve cover goes to the "nipple" under the throttle body.

The hose from the "intake bellow" simply goes to the the ICV.

It's only made more complex by the fact that BMW designers "held" vaccum and coolant lines together.

If you want to do the TB coolant supply delete. Simply route the coolant out of the head and back in or cap it off at your own risk. I will NOT label this as the chosen method as some are suspectible of making a mistake or misreading and thus causing an overheating situation which then leads to you know what.

As mentioned earlier, simply take the intake bellow and intake manifold off and you will be able to take your time and engineer something nice and reliable. It's a good time to replace the intake mani. gasket and end up with a 100% smooth idle as well

Thanks for the pics above Rob_e30!!

[stever318is]

Thanks for the pics, mine has been capped off - gonna redo it. What a mess combining vaccum and cooling hoses.

[D. Clay]

If you want to do the TB coolant supply delete. Simply route the coolant out of the head and back in or cap it off at your own risk. I will NOT label this as the chosen method as some are suspectible of making a mistake or misreading and thus causing an overheating situation which then leads to you know what.

Re TB coolant delete: route coolant out of head and back in to what? Does the water outlet to the TB play a role in cooling the head? Would there be any problem with plugging the water outlet from the head and the one on the plastic pipe eliminating the circuit altogether?

[e9nine]

Re TB coolant delete: route coolant out of head and back in to what? Does the water outlet to the TB play a role in cooling the head? Would there be any problem with plugging the water outlet from the head and the one on the plastic pipe eliminating the circuit altogether?

Out of the head and back in if you don't feel comfortable plugging it. Sorry for the omission.

The TB plays no role in cooling the head.

There's no problem in eliminating the "circuit" but it's done at "your own risk."

I have seen the circuit eliminated on a friends car but at the time I did mine, I simply routed it back in.