With air conditioning on and outside temp at 75-80 on the freeway temp gage will stay at 95-100. Is this too hot?

for a horse or a car?

__________________
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

83 300d turbo diesel

how long does it stay at 100 celcius.. under heavy load then goes down to 95 80's or the whole time..

no 100 is not too hot. when it hits 120 start to worry

__________________
have no worries.....President Obama swears "If you like your gun, you can keep it

When the air is going full it gets close to 100 if you turn it to economy it will go down to 85-90. I had a local mercedes shop test the fluid he said it was fine and did not recomend a flush.

Good it does not ever get close to 120. the car has 102k miles and runs perfect. i love it

...has similar summer conditions to Nevada. I found switching the thermostat in 83 300TD to one that opens at 76 C instead of the stock 80 C to help with the cooling when the a/c was on during hot summer days in stop/go traffic. The thermostat for 1970's 450 engines is such a thermostat and will fit right in to our system.

__________________
Der Panzermann und Fraulein Fahrvergnuegen

1991 420SEL 201K "The Big Blue One"
1985 300DT 205K chassis/285K engine nee California emissions "Goldbug"
1983 300TDT 255K "The Womble"
1983 300 DT 214K "Sea Sprite"-Rear-ended a truck
1983 300SD 285K "The Donor" Gave his life so that others can live
1980 500SL Euro 105K "Der Panzer"

You temperatures sound normal to me. Mine will get into the 95-100 range on hot days. As long as you stay out of the 115-120 area, I wouldn't worry about it.

my '85 300D Turbo is also the same way, if its between 80 -90 deg F outside temperature, my water temp gauge reads between 80 - 100 deg.C if i'm cruising between 70 - 75 MPH with the AC on and no load but just myself, my question is why is it that if i drive uphill or drive at about 85 - 100 MPH or i'm in a stop and go traffic, my water temp gauge suddenly rises to above 100, about in the middle of 100 - 120(redline) deg. C. but when i drive back to normal speed range, without stopping, between the ranges of 40 - 75 MPH the water temp gauge just drops like a rock to between 80 - 100 deg. C. any idea what wrong with my cooling system??

a) my thermostat is stock 80 deg. C. should i go to 76 deg. C ???
b) do i have a bad fan clutch or fan blade ???
c) do i have a bad water pump ???
d) do i have a bad radiator ???
e) for some reason, my car doesn't have the tube or pipe that goes between
the top front side of the water pomp housing and the front of the
cylinder head. both ends of this piece is almost similar to the ends of the
ALDA banjo bolt except that it is all made of metal. do i need to install
one of those on my cooling system to solve my overheating problem ???

once again my car is a 1985 300D TurboDiesel , California Version.

My favorite solution for higher than desired temperatures on systems that have been maintained internally is to remove the radiator and spend a couple of hours doing a thorough job cleaning the external fins........all the way through the fins.

You generally need a compressor, or a pressure washer, or some condenser cleaner, or a combination of the three.

When you get done, you should be able to hold the radiator up to the sun and see clear through the tubes, without looking at any crap. I'll bet that the radiator is 50% clogged in the fins, if it has never been thoroughly cleaned.

Your temperatures will drop by 5°C. if you perform this procedure properly.

Wow, thank you. I will definately try that. Whats your best suggestion on reomving the radiator? Simple wrenches, or will it need a special tool? Thanks

__________________
___________________
Rod - Ali
1986 300SDL (w126) - 111k
1991 420SEL (w126) - 123k
1981 300SD (w126) - 205k (passed away 2/20/06)
1985 300SD (w126 - 185k
http://img172.imageshack.us/img172/4481/sig1hd.jpg

The transmission cooler hoses need to be unthreaded from the radiator.........and you'll need to plug them somehow if you don't want trans fluid all over your driveway.

If you are doing the SD, you'll need to separate the oil cooler from the radiator. It's one nut and bolt at both the top and the bottom.

Be VERY careful with the overflow hose from the top of the radiator. If there is any doubt about removing it from the radiator nipple, without breaking the nipple, then cut the hose off and replace it.

You'll also need to unclip the fan shroud and leave it on top of the fan.......otherwise you can't get the radiator and shroud to clear the fan.

also be very careful with the oil cooler. it is very thin aluminum and if you dont get it all hooked up exactly right on the side of the rad it will chafe and rub a hole in the side and you will need another one. and that will be expensive.

if you ever need to detach the oil cooler lines (brian didnt recommend this and i dont either) you need to be very careful there too and use two wrenches as the fittings are large and the parent metal thin and it is supremely easy to twist the fitting out of the cooler. dont ask how i know.

good luck. it is a pretty easy job but with the oil cooler around it has the potential to get expensive if you make a mis step.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Maybe its your coolant temperature sender switch?? You may be getting a bad reading. Replacing the switch on my 95 C280 solved my overheating which was basically what you are describing. Your car should run pretty much rock solid at 80 degrees C except under extreme conditions which may run the temp up to 90 degrees C or so. The switch is cheap so you may want to try it. Also make sure your radiator cap is good.