Temperature showed just less than 100C

[brabus]

I hate to be posting repair questions, but my car is suicidal.

Today was amazingly hot and humid. I put on my a/c and drove to my destination. Half way there my A/C was barely blowing cold air.

My temperature indicator showed just less than 100C. After turning off the car I wanted to see how hot it was under the hood. The heat was incredible. Everything within the engine compartment was far too hot to touch, even the body panels.

The engine fans turn and the auxiliary fan was on all day.

Is something in needing of repair or should I focus on additional radiators or something?

[diesel don]

Tons of posts on the forum regarding this subject. Have fun searching the different opinions.

My two cents is that you can spend a great deal of time and energy obsessing over the issue without much results. I was unable to bring my operating temp down (similar to yours) and eventually just lived with it. Nothing ever came of it.

If all the fans and cooling systems appear to be functioning, I think we're just victims of this unique MB quirk.

dp

[PaulH]

100C is ok on a hot day. As long as you were not near the temp. red line, my owner's manual states that it is OK and will happen. You may want to have your sensor checked, however, just to be sure that you are getting the correct temp. reading. Do you have R134 in your AC? ( Get ready for a hundred different opinions. )

[Brian Carlton]

I have a different perspective of the 617 now that I have the SDL.

The 603 can warm itself up to 100°C. when under moderate boost, with the a/c off.

However, with the a/c on, it will have a difficult time getting over 105°C. even on a long upgrade.

So, look at the situation this way:

The 603 has no issues at 105°C. and it has an aluminum head.

Therefore, all you folks with 617 engines can relax and worry about other things. You can probably run the 617 up to 120°C. if you have proper coolant and sufficient pressure in the cooling system.

[Jim H]

Keep in mind that the coolant at a temperature of 100C is right at the boiling point of water at atmospheric pressure. Other metal parts of the engine will be hotter in normal operation.

Engine oil is expected to run about 100C so that moisture will boil away, so the valve cover will be at 80C or so.

Heat under the hood is normal, and as human beings we are always impressed with normal underhood temperatures, since we cannot relate to them properly in our normal skin...

Best Regards,
Jim

[ltrain300D]

I have an '83 300D with 243K on the clock. It had 193K when I first bought it, and it ran cold (barely 80 degrees celsius in the Florida summer). After a new radiator, thermostat, fluid, etc., my temp gauge now reads at around 100 degrees celsius. However, I wanted to see for myself if it was really running at 100, so I brought it to my dad's firehouse and he put an IR or laser heat gun on it in various places where it would be hottest, and the warmest temp we found was 187 degrees farenheit when warmed up (about 86 degrees celsius) - so I know I'm getting readings about 14 degrees celsius wamer than what it is running. If you have access to a IR or laser heat gun, do it - you might be surprised.

[mbenzgoodyear]

I have see a product called Water Wetter, that is suppose to lower the temp in the engine by 10-20°F. They have one for gassers and one for diesels. I havent heard anything bad about the stuff yet, and was thinking of trying it myself.

You can check it out here:
http://www.redlineoil.com/products_coolant.asp?productID=70

If anyone has any input on the stuff from first, second or any hand experience please advise.

[brabus]

Damn, I had hoped people were not going to say "this is just how my car runs"



It is R134A
Should I go back to R12 I'll pay 25 bucks a pound if it works.