BMW Coolant Leak Inside Bell Housing

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After truly believing that there was no further way for this car to have a coolant leak I was proven wrong yesterday. It has been leaking coolant onto the garage floor and yesterday I found it is coming from inside the bell housing between the engine and the transmission. Over the past few years I've replaced all 13 or so coolant hoses, the two transfer tubes under the intake manifold (and their o-rings), the rear coolant manifold, the valley pan, the electric water pump, the engine-driven water pump, the heater core, the heater core pipes through the instrument panel (all three of them), the electrically-controlled water valve, the radiator, the pressurized coolant tank (plus the cap, the level sensor and the two smaller hoses that connect to the radiator), the fan, the fan shroud and the viscous clutch. I didn't know anything was left but now due to this leak I have found there is a "cover" on the aft end of the engine inside the bell housing that commonly leaks. The gasket for the cover is a $4.03 part and is likely all that requires replacement.

Of course the transmission has to come out to replace the gasket which in and of itself isn't a horrible job on this car. The problem is going to be removing the forward exhaust system (two catalytic converters) where they meet the exhaust manifolds. The studs are rusted to oblivion and if they don't snap off during removal they will surely snap while trying to reinstall the exhaust pipes. This will likely require removal of the manifolds to repair, which is relatively easy on one side but very difficult on the other side. Not to mention that it's equally likely the studs in the head will break trying to remove the manifolds. I am not up to removing the heads on an M60 engine.

So this might be it for the old BMW. After thousands in repairs over the years and hundreds of hours of labor a $4 part is going to kill it off. The leak is pretty good so there's really no way I can ignore it and if it's like any of the other coolant leaks on this car it will only get worse with time. The gasket is #6 in the diagram below with the cover being #5. Even if the cover needs replacing too that's only about $60 more.

Oh and the engine driven water pump is leaking again and the bearing is starting to feel like gravel but hey, it's been about 100,000 miles so I guess I should expect that.

 
Sorry for your (coolant) loss.

Since you apparently have little to lose, and, assuming you dont get better suggestions, might be worth trying the GM ginger tabs?

This was suggested to me recently, but the leak "got better" and I forgot to ask the gf to bring some back from the UK, which I'll probably come to regret.

If you do try the job, candle wax on the studs is another trick I've never tried.
 
I love BMW V8s when they are new- but I prefer the fours and sixes for long term ownership.
Although an E39 M5 is still a tempting proposition.
 
Originally Posted By: Chris142
No way that something up front is leaking and running down the valley and out the bell housing?

No unfortunately. Because the engine is relatively short compared to the 6-cylinder you can see down on top of the bell housing between the intake manifold and the firewall. It is dry as a bone up there.

I can see the coolant dripping out of the bell housing and there's some inside if I put my finger in the hole. It's coming from inside.
 
I thought about the coolant tabs and other leak stops, I might try it. It will surely clog up the electric heater valve but that could be bypassed.... I think...

It's leaking pretty good and anything that seals up this leak is probably going to seal up a few other things too.
 
Originally Posted By: tig1
Is there a freeze plug on the back of the engine?

I don't know. I haven't seen any freeze plugs on this engine, at least not any that are like the ones on cast iron blocks. Someone who I know mentioned that they seal up the boring passages with some kind of non-replaceable plug on the aluminum blocks.
 
I'm not a BMW guy, but is there any chance the exhaust could be cut off & welded back on (obviously by an experienced welder)? That sounds easier than dealing with all the rusted hardware (?)
 
Originally Posted By: MCompact
Although an E39 M5 is still a tempting proposition.


Agreed, I'm on an active hunt for a low mileage one.
 
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