Thanks!


Actually back in the 90’s I was living and working in Washington DC just moving to California. I had not converted to the Californian ways yet.:D


I basically snap those pictures right before removing the power steering belt. (You need to remove the PS and A/C belt to get to the Alt. and WP belt. What a pain!) By the looks of the pic, it seemed that I was peeling the belt off.:rolleyes: On another note you can see a frayed string on the A/C belt. That was from the excess amount of string after I cinched it down and I tied it. I hastily started it, it got caught in the pulley and tore off. :eek: I then promptly cut out any excess.

WOW, just wow....
 

My 83' 300SD has only one of two belts for the alternator-coolant section, and it recently threw it off. It's still there, just hanging around. I've been driving the car very carefully lately until I could replace the belts. I had no idea how stupid this was!

The frustrating thing is, as soon as I noticed that the car was beginning to get hot while driving (100 C), I called my MB dealership and asked them what the highest temp I could drive at safely, and told him my engine was running at 100 C. He said normal op temp for these engines is 90C and due to the immense Texas heat, 100C might be possible, but alright to drive at. He said if it starts to go above 100C then I should be concerned.

Well I've been concerned. I've driven it approx. 30 or so miles with it regularly at 100C and towards the end of my drive to and from work it might hit 110C for 3-5 minutes until I pull into the driveway.

I'm replacing the belts today, however, I'm fearful now that I may have damaged the engine.

What's you guys' assessment. Is it a pretty good chance I've screwed this engine by tooling around at a regular 100C with peaks at 110C?

:eek::eek: Do not drive that anymore!! 30 miles daily for how long?? How often has it hit 110C? IMHO you'd be extremely lucky not to have damaged that engine in the heat. You can warp/crack the head, though in a 617 thats not as common as in the newer engines with aluminum heads. I would absolutely NOT drive it without an alternator/WP belt unless it was an emergency situation close to a place where you can service the engine. :bomb2:

Edit: you should remember that the guage is based off of where the coolant temp sensor is located, so without circulation the coolant could have gotten even higher without it showing on the gauge.

Did you explain to the dealer that coolant was not being circulated through the engine? If you did, and the dealer did not object to your continuing to drive the car, you need to find another dealer.
These engines are robust so it's likely you are ok, but you shouldn't drive a car without a functioning water pump unless it's air cooled.

OM618, IMO you may have damaged the engine. Every time it is heated beyond it's design point, and especially without circulation to eliminate hot spots and localized boiling, you run the risk of overstressing the metal and the gasketed joint. These engines have some margin for abuse, and I believe you have used up much of that margin. Incipient cracking may have already begun. Fortunately you have an iron head that has much higher fatigue strength than aluminum (and a lower coefficient of thermal expansion). If you had an aluminum head, I think you'd already know the answer because the car would be in the shop getting a new head gasket at minimum and probably a new head. I think you should be extremely conscientious about maintaining normal cooling temperatures from now on, and perhaps the engine will be OK. Wintertime will be an additional stressor, although you live in a mild climate. Good luck!

Well, not 30 mi. daily. In fact, I went over my driving and calculated it out to be about 18 miles daily for the last three days. So, possibly up to 60 mi total since the alt-coolant belt fell off.

It's hit 120C once, and I then pulled over for a couple of hours and let it cool. I think it had hit 120C because most of the water had boiled off. I've kept the water full since that first day and it hasn't gone above 110 since then. It's hit 110 maybe thee times, for about 3-5 minutes each time until I pulled into my driveway.

Like I said, I still have one of the V-belts hanging there. I unfortunately can't get it back on because I don't have a wrench to fit up to the upper bolt on the alternator to loosen it up and get the belt around it. I'm waiting on a friend to bring me his wrench set, since I'm too afraid to take the car anywhere to buy wrenches.

What will be the first symptoms of a ruined engine from this situation?

The first symptoms would be head gasket symptoms. After the belts are on and the cooling system is properly filled and bled, the things to watch for would be coolant loss with no apparent leaks, overpressurization of the cooling system, whitish "smoke" from the exhaust, possibly harder starting and poor idle, water in the oil (milky appearance on dipstick and inside filler cap), oil in the water, continuing overheating with no apparent cause... Stuff like that.

The milkshake look on the dip stick and oil cap are when the engine is cold and the trapped water vapor has a chance to condense.