Rear engine M60 coolant leak suspects?

[bubba966]

Ok, for some reason the search is broken. So I can't search for this at least at the moment.

Was headed out to my car from a stop at Best Buy and say a little puddle of coolant underneath the car. Was pretty sure it wasn't there when I pulled in so I took a look. And that's when I saw the drip coming from the back of the engine. Popped the hood and couldn't see any leak from above. Hadn't leaked much out, but I topped it off anyways.

So, what usually leaks towards the back of the engine and in a place that's not easily noticeable?

Didn't seem to be the heater valve connections. Couldn't see the aux. water pump well enough to tell if that was it.

[Tiger]

Heater valve seals... not the hoses... and the infamous coolant bypass tube between the waterpump and back of engine.

[bubba966]

Ok, where are the heater valve seals, and which waterpump does this coolant bypass tube run to?

That coolant tube runs underneath the engine cover, doesn't it?

[yaofeng]

Back of the engine picture. Ignore the hose loop. Your automatic has one hose which goes down to the transmission cooler on the driver side and up the other side.

http://i21.photobucket.com/albums/b274/yaofengchen/BMW_95_540/DSC_3368.jpg

http://i21.photobucket.com/albums/b274/yaofengchen/BMW_95_540/DSC_3369.jpg

[bubba966]

Back of the engine picture. Ignore the hose loop. Your automatic has one hose which goes down to the transmission cooler on the driver side and up the other side.

So, you must be talking about parts 6 & 7 here http://www.realoem.com/bmw/showparts.do?model=HE63&mospid=47410&btnr=11_1247&hg=11&fg=35

And as you've pulled your auto out you just looped those two together, right?

Will try looking at those when I'm underneath the car Sunday during my strut assembly swap.

[winfred]

worst case it's the valley pan, i've done a few v8s that it was leaking on and to change it you gotta pull the intake and the water pump, you can usually see if that's it by looking straight down at the back of the intake at the block where the heads meet the block, you can just see the edge of the well under the intake and if the pan is leaking you will see a little wetness, when it is leaking the coolant usually drips down between the engine and tranny as that's where the well under the intake empty's into

[KBarcellos]

The bottom of my expansion tank developed a bunch of stress cracks, took me quite a while to figure it out as from the outside it looked fine.

[632 Regal]

take the engine cover off and tighten the hoses and inspect what you can. The manifold connection is aluminum and can be loaded with corrosion causing the leak. tightening the clamps is a quick fix. cleaning the aluminum is a PITA and a weekend project unless you have tiney hands to get down in there.

[bubba966]

Will check the valley pan tomorrow.

Did get a good look at the 'water hose inlet' that connects to the tranny cooler and saw some evidence of a leak at the top connection, and at the bottom at the crimp connection. Couldn't see enough of the hose to tell if it's just leaking at the top of the hose and running down and collecting on the crimp connection. Will check that out a little better tomorrow and maybe tighten it up a bit while I'm at it. Didn't see the 'water hose outlet' though. Will pull the expansion tank out and try to get a look at that, and give the tank a good once over as well.

Thanks for the suggestions guys. Keep 'em coming if there's something that hasnt been mentioned yet.

Would love to just replace everything, but there's not the $ to do it all right now. I bet that it'd all add up to a good bit 'o $. Just those hoses to the tranny cooler are $60 each...

[Jr ///M5]

A good light and a telescoping mirror will help you be able to see underneath the fittings and the water manifold in the rear.

If it is the valley pan causing the leak, it would be a good time to replace the PCV plate in the rear of the manifold, manifold intake gaskets, thermostat and water pump all at the same time. I know all of the parts add up to more than you would want to spend, but in the long run, you won't be doing that job again for a long, long time. R and R of the intake manifold is labor intensive.

Hope it's something simple and you can reach it ok....and if it is, forget all I said about the above...=)

JR