Do I worry about 100 deg c.
 

I have both the 84 500SEL and the 91 300D 2.5. Both cars are going up to 100 C when the outside temperature is over 100 deg F and in city traffic. They both will go back down to maybe 95C when out on the road at 55 mph or so.
Do I need to be worried about this? We don't have this kind of heat very often and I have not had any problems with either car running hot.

Thanks for your opinions.

PaulM

I would not worry too much about it but I would suggest verifying the fan clutches are working properly.

sounds like normal operation.

I'm seeing the same thing in my 2.5 now as well. Seems to depend on engine load. like accelerating to get on the highway vs just cruising at 75 on the highway. Never seen it go above 100c yet.

Engatwork, the 500 has a new fan clutch (BEHR). Today, we went out riding in the 500 just to see what it would do at 90 to 93 deg outside. It got up to about 95C or a little more when we were stoped in traffic but cooled back off to around 90C at 50+ mph.
Everyones comments have set my mind at ease.

Thanks everyone

PaulM

My '95 E300 was behaving similar. It has a dual auxiliary fan set up. If either of your cars have similar, I'd heartily recommend removing the fan shroud from the front and cleaning out the accumulated leaves and dead bugs etc. which are trapped between the lower half of the shroud and the condenser.

Another common place for junk to get trapped is between the condenser and the radiator. I like to remove the radiator, spray that out from the backside with a garden hose, and also spray out the condenser from the back. Repeat whenever you have a cooling problem.

oh yea, second this. This area will plug up over the years.

Thanks for the ideas however I have had the radiator out and I cleaned it with Greased lightning followed by high pressure air. I also cleaned the condenser from both sides the same way. This cleaning did help some and made the A/C work a little better (it already worked great).

Thanks again

PaulM