IM JUST WONDERING IF ITS REALLY NECESSARY...I WOULD LIKE MY CAR TO BE RUNNING A LITTLE COOLER THAN IT IS... FOR SOME REASON IT RUNS WARMER... THAN MY OTHER 300 D "s THAT IVE OWNED...

How hot is it running (at what outside temperature)? The short answer is, yes you need a thermostat to get good circulation through the radiator. Do you need a new thermostat?

Turn off caps lock, its annoying.

How warm is it running?

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1985 CA 300D Turbo , 213K mi

its normally at more than half .. when outside temp is 80 ... it almost feel like youll overheat with a little more heat..
also my radiator top part where the upper hose attaches got screwed it broke.. do you think i can have the top part replaced or the whole thing.. and finally do these aluminum radiators get clogged up as well? thanx.

diesel price in downtown los angeles california... finally dropped down to $2.41 gallon... .. it quite a change compared to $3.30 two months ago...

would a 240 radiator fit in a 300????

but i assume a 240 rad will fit in and hook up. but it wont be adequate under full load conditions. i wouldnt do that.

also you need a stat in a benz to get full heat and full cooling. it is a bypass stat and will direct the flow where it is needed. if the car is cool it directs the water back to the block to get up to proper operating temp. once the temp comes up it will gradually direct all the water to the radiator. wo a stat the water flows both to the block and the radiator and will neither heat up properly when it is cool nor cool off properly when it is hot.

so first replace your stat and then evaluate whether the rad is good or not.

good luck

tom w

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[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.

A thermostat starts closed and opens at a certain temp and lets coolant flow thru the whole system, and lower than that temp it starts to close and does not let coolant flow thru the whole system- ie radiator. You can check and see if your thmst is working by putting it on the stove in a pot of water and heating the water. Use a themometer and see what temp it opens at. Nearly all marine diesels in the tropics run better off without a thermostat as they warm up quickly and it would be open anyways, and if it "breaks" and does not open you over heat the engine. If you remove the thermostat the only real detriment is that you will have longer warm up times, and be a bit less efficient at these lower temps. I as a mechanic have never heard of or seen a major problem of thermostat removal in diesel engines in warmer climates. If it gets below 50, you don't qualify as a warmer climate...

If you look at a diagram of the 617 turbo cooling system, you will see that removing the thermostat will not cause the majority of the flow to go through the radiator, as it will with some other engines:

http://skinnerbox.steaky.org/Service/W123/w123CD2/Program/Engine/617/20-005.pdf

It is not a good idea to run these engines with no thermostat. You can test the thermostat in hot water, but if should be replaced if it is not functioning properly. The correct thermostat for your car begins to open at 80 C (176 F) and fully opens at about 95 C (about 203 F). When the car is warmed up it should normally run in the 80 - 100 C range. It should only exceed 100 C under heavy loads and/or high temperatures.

An over cooled engine experiences more wear than one running at the proper temp. Also engines run more efficiently and generate more power at the proper temp. Removing a working thermostat then putting an engine back into normal operation is a bad idea.

A 240D radiator will not work in a 83 300D. The 300D has a overflow tank and plumbing for it the 240D does not.

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

keep it they way it was designed to be...with everything in proper working order...fix what isn't...too cold is bad as well as too hot.

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Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

Most of the wear on an engine occurs during the warm up period. By removing the therm, you are extending the warm up period.

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Auto Zentral Ltd.

All good posts!! Listen to these guys.....

Try this as a LAST resort.

http://dieselgiant.com/thermostatreplacementandmodif.htm

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1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

I did the same thing about three years ago on my now sold 300TD, worked great for florida summers and stop and go traffic with the air on full blast.