One was a behr (german), one was French made. Both made the engine run hot, stopped as soon as I tried the hollow thermostat approach.

__________________
"I would rather be ashes than dust!
I would rather that my spark should burn out in a brillaint blaze
than it should be stifled by dryrot.
I would rather be a superb meteor,
every atom of me in magnificent glow,
than a sleepy and permanent planet.
The proper function of man is to live, not to exist.
I shall not waste my days in trying to prolong them.
I shall use my time."

-Jack London 1876-1916

1983 300CDT (running WVO since 12/05)
1981 300SD (parts car)

yes I agree the diesel has to run at +160 deg.f. or it will not burn the carbon,and moisture fron the engine. and most all internal compution engines will run when warmed up at 100 degrees over the abundant air temp.so if its 100 outside the engine can saftly run at 200 deg fer.

I mean, I understand that there is more carbon buildup at a lowered temperature, but:

A. Carbon buildup is a byproduct of any explosion, right? I know in firearms a significant amount of carbon is produced by the explosion. So isn't there technically going to be carbon building up in my combustion chamber, prechamber, and piston crown anyways? Isn't this what the principal behind the Italian tune-up is? Removal of carbon from injector tips, prechamber, etc, etc?
B. Wouldn't the engine wear less due to less metal expansion (less heat-less expansion) and thereby reduce friction?
C. Wouldn't loss of power due to lower combustion chamber temperatures be made up for by lower engine compartment temperatures leading to colder air intake and colder turbocharger meaning denser air packing?

__________________
"I would rather be ashes than dust!
I would rather that my spark should burn out in a brillaint blaze
than it should be stifled by dryrot.
I would rather be a superb meteor,
every atom of me in magnificent glow,
than a sleepy and permanent planet.
The proper function of man is to live, not to exist.
I shall not waste my days in trying to prolong them.
I shall use my time."

-Jack London 1876-1916

1983 300CDT (running WVO since 12/05)
1981 300SD (parts car)

check your manual. the benz stat is not like the typical domestic stat. a domestic stat is simply an on or off stat. when the car is cold it blocks all flow to the radiator. while it is blocked off there is no water circulating around the hot parts of the engine. like the exhaust valve area.

a benz cooling system is like a racetrack that has a short cut across the infield. when the motor is cold the stat acts like a diverting gate and sends all water back to the motor but KEEPS IT CIRCULATING ALL THE TIME. this way there are no hot spots.

now as the motor warms up the benz stat gradually opens the gate and flows the water onto the big racetrack (the radiator). and as it gets really hot ALL the water flows to the radiator. this will give you maximum cooling.

if you take the stat out you will allow the water to spit and flow half to the radiator all the time and half will recirculate back to the block without ever getiting to the radiator. so on a hot day your car will run hot because you are not getting max flow to the radiator.

and on a cold day you will never warm up.

and 60 degrees is too cold. you wont burn off the byproducts of combustion in the oil and wont burn off the water from condensation.

dont take my word for it look it up in the book.

these thermostats are marvelous devices. the factory engineers know what they are doing.

__________________
[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.

i meant to say split the flow not spit. funny mistake in context of a discussion of water.

__________________
[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.

That's interesting, that was never mentioned in any of the posts when I was reading the controversy over this topic (I suppose because it is the final word in the matter). I'll try buying a good thermostat and putting it in, and just hope it works. Thanks for the advice.

__________________
"I would rather be ashes than dust!
I would rather that my spark should burn out in a brillaint blaze
than it should be stifled by dryrot.
I would rather be a superb meteor,
every atom of me in magnificent glow,
than a sleepy and permanent planet.
The proper function of man is to live, not to exist.
I shall not waste my days in trying to prolong them.
I shall use my time."

-Jack London 1876-1916

1983 300CDT (running WVO since 12/05)
1981 300SD (parts car)

Now that I think of it, Doktor Bert said he used this method in all his other cars (domestic) and had seen good results from it, so I suppose he wasn't aware of this thermostat design difference.

__________________
"I would rather be ashes than dust!
I would rather that my spark should burn out in a brillaint blaze
than it should be stifled by dryrot.
I would rather be a superb meteor,
every atom of me in magnificent glow,
than a sleepy and permanent planet.
The proper function of man is to live, not to exist.
I shall not waste my days in trying to prolong them.
I shall use my time."

-Jack London 1876-1916

1983 300CDT (running WVO since 12/05)
1981 300SD (parts car)

OK, so I did the pan of water test to the one thermostat I had lying around hoping it was good (brand is Vernet Calorstat, French). At 180F, which is a little over 80C, the rubber seal in the center was only open a couple (maybe 4 max) millimeters around the edges. I can't believe that this is as far as it goes. Is this a bad thermostat? Does anyone know what the best brand of thermostat is, because I have had no luck with this brand or the last Behr I got.

is ok as far as i know. i believe it should open about 1/2" or a little more. 4mm sounds like not enough.

__________________
[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.

One bit I'd like to throw in to the mix...

did ya ever concider that the temp gauge might be wrong? It's happened to me before.

__________________
2003 VW Passat GLS 1.8t wagon 73k mi
1998 Dodge Dakota Sport 228k mi
1974 VW Karmann Ghia Coupe 74k mi (for sale)

I just replaced my entire instrument cluster so the gauge itself is good.

As far as the temp. sensor, I have been told by many people that it is extremely unlikely to fail.

__________________
"I would rather be ashes than dust!
I would rather that my spark should burn out in a brillaint blaze
than it should be stifled by dryrot.
I would rather be a superb meteor,
every atom of me in magnificent glow,
than a sleepy and permanent planet.
The proper function of man is to live, not to exist.
I shall not waste my days in trying to prolong them.
I shall use my time."

-Jack London 1876-1916

1983 300CDT (running WVO since 12/05)
1981 300SD (parts car)

I have had the VDO temp sensor fail on me twice and send my temps in a tizzy, giving me a heart attack.

About the thermostat, in India, the MB partner uses a locally made thermostat rated at 72C which keeps my temps at 85C max even when the outside temps are at 45C+

One thing I have noticed is that MBs tend to heat up in stop and go, not under extreme load, most MBs have trouble dissipating heat during these situations and the best thing to do is to put a high RPM Aux fan.