450 internal water leak - PeachParts Mercedes-Benz Forum

bclem · #1 04-30-2011, 11:41 PM

I recently bought a '80 450SL and it's getting water in the oil. Compression is 180# +/- 3# across the board. No plugs are showing any water contamination. When the engine reaches operating temps there is a good jet of steam coming out the breather hose on the rt vc. There is also "cheese" on the filler cap (none on the rockers) and a little "cheese" and condensation on the dip stick just above the oil level.
It looks like the water pump may have been replaced in the recent past.
The resevoir level will drop about an inch in 20mi of driving.
The car has not overheated since I've owned it.

I was thinking that maybe there was a failure of a water passage seal between the block and timing cover but the steam makes me really suspect something involving head/block combustion or exhaust areas.

Can these motors pop a head gasket in such a way as to cause this without blowing into the cylinder ? The cooling system is not being over pressurized.

I don't mind pulling the motor to do whatever repairs are nescessary but I sure could use some help troubleshooting this so I can focus on the right area.

Thanks for any help or opinions

meltedpanda · #2 05-01-2011, 09:22 PM

sounds like a crack in the block, away from the heads??

bclem · #3 05-09-2011, 12:05 AM

I "think" the leak may be in the "o" ring seals between the timing chain cover and the block behind the water pump. I discovered that the bolts mounting the pump (and straddling the o-rings) were all loose. It also looks like someone was either trying to remove the timing cover at one time or did remove it and didn't do a very good job of re-installing it. Besides the loose water pump bolts both the right and left upper mounting bolts that are located inside the heads were missing.
Now I'm researching the proper way to R&R the timing cover but have hit a snag RE the oil pump. The manual says to remove the oil pan and then remove the oil pump before removing the timing cover but removing the pan requires either dropping the sub frame or removing the engine ????????
What am I missing here ?

rowdie · #4 05-09-2011, 01:02 AM

You are not missing a thing. That is the way it has to be done.

meltedpanda · #5 05-09-2011, 12:45 PM

I thinl pulling the engine is easier than dealing with the subframe

Im just saying...

rowdie · #6 05-09-2011, 01:09 PM

LOL. I dropped the engine and trans out of my '73 by removing the subframe.

meltedpanda · #7 05-09-2011, 01:31 PM

older n wiser I guess, or at least wiser

rowdie · #8 05-09-2011, 01:36 PM

Don't know about that. I was new and dumb to the MB. Didn't even know about the subframe recall. I thought it would be easier than angling the thing out on my own from the top.

bclem · #9 05-09-2011, 08:21 PM

Well.. i do have new subframe bushings to go in it already so that would deal with that job too. How did you attach the chain hoist to the front of the engine? The stock lift point on mine is a bracket bolted to the top of the water pump. I thought maybe i could make a couple that bolted to the front of the heads (at the old alt and PS mount points) and grab it with my cherry picker.

rowdie · #10 05-09-2011, 10:26 PM

One bracket on the WP. A bracket on each side of the engine toward the back attached to the intake. If I had it to do over I would go out the top.

bclem · #11 05-14-2011, 03:40 AM

I shopped around for a motor support and ended up buying this one.
http://www.harborfreight.com/automotive-motorcycle/lifts-stands/1000-lb-capacity-engine-support-bar-96524.html
it is suprisingly well built but I think i'm going to add some diagonal braces to the ends. And since i'm going to drop the sub-frame i'm going to replace the sub-frame mounts, front brake rotors,pads and hoses as well as the sway bar bushings, shocks and tie rod ends.