Cooling System Riddle 1991 350 SDL - Page 5 - PeachParts Mercedes-Benz Forum

babymog · #1 02-05-2011, 08:34 PM

The thermostat on the 60x engines is on the side of the block, and it is a really bad idea IMO to run a 60x engine without coolant in the head. Really bad.

toecutter · #2 02-07-2011, 08:08 PM

Quote:

Originally Posted by babymog

The thermostat on the 60x engines is on the side of the block, and it is a really bad idea IMO to run a 60x engine without coolant in the head. Really bad.

that being the case yes bad idea, really bad. and totally pointless, if the head has no coolant, there's nothing to make bubbles in. too bad, it's a relatively easy test. like i said, i couldn't remember where the t-stat housing is on this engine, in most of the enigines i deal with the housing is at about the highest point on the engine. top, front and centre.

but quite often if you shut it down, and hear "blub blub blub" in the waterjacket, be patient and look real close at what's going on in the overflow reservoir (even put the hose into a clear jar) you'll see the fine fizz as the level rises.

another simple diagnostic, get it up to running temp and get a feel on both the top rad hose and the bottom hose. there should be about a 20° c difference between the two, bottom being the cooler. if they are both hot to the touch, this would indicate either faulty thermostat or clogged radiator.

GregMN · #3 02-18-2011, 03:13 PM

I just finished replacing the head gasket. That seems to have fixed the problem. I drove 25 miles at 70mph with no coolant loss and no high pressure in the cooling system.

I still do not know why combustion gases were never detected.

Thanks for all the other suggestions, but, "if it walks like a duck, quacks like a duck, looks like a duck, it must be a duck".

cscmc1 · #4 02-18-2011, 03:16 PM

That's great news -- glad to hear it!!!

lgreeley83 · #5 02-17-2014, 07:52 AM

Good read. Still own the car? How's it holding up.

GregMN · #6 02-17-2014, 10:15 AM

The head gasket repair has held up fine. It doesn't get driven much anymore, too many cars. I have driven it to AZ and back 4 or 5 times (3800 miles). It has been sitting out under a couple of feet of snow. I haven't driven it since last Aug. I spent an hour digging my way to it, then getting the snow off the hood on Friday. I put a good battery in it and started it. It was maybe 10 degrees out.
It has rust issues, and I need to replace the upper ball joint (which I have in a car out in the woods). Then I am ready to drive it to AZ again on VO. Everything still works on it, A/C, CC, PW, PL. It has a lock up diff. that really helps in snow. But it is rusty, and the B3 valve in the transmission leaks, so no reverse. I have a spare trans, I just haven't taken the time to fix it. I drove it for 2 years w/o reverse.
I am shopping for a new car for my wife. I will probably have to travel to get what I want. I have a couple I am looking at in AZ. So, may drive it to AZ and leave it there. Maybe sell on CL for fuel money home, or see if a scrap yard with pay anything for it. Or, just give it to a forum member in the area.
I really love that car.

Mxfrank · #7 02-17-2014, 02:53 PM

If the cap is ok, take a close look at the filler neck in the header tank. Look for cracks or irregularities in the sealing surfaces. I would almost go so far as to suggest substituting a new tank.