I read in my manual that my 1981 300d has a capacity of 11 liters of coolant. today when i flushed and replaced it would only take 4 quarts or about 4 liters if i'm correct. I don't understand why. I also changed the thermostat.

Earlier today I finished replaceing a radiator that was cracked. While i was at it i replaced the thermostat. Since the trans fluid leaked out when i changed the radiator i just changed the trans filter. It's all back together with flush and water in it. Trans fluid replaced. I only ran it for a minute so far and the thermostat gage hasn't moved. My son, whose car it is, said something about the thermoustat gage not working. Can either of you for see a problem that would cause the thermostat not to register.

I'm pretty sure the stat went in correctly but i'll check. A minute or 2 after i started it a second time to run the flush through the stat began to jump back and forth eratically. After 10 minutes of idle, while flushing, the water was only warm when I drained it out the drain cock. On the second fill, with just water it ran 10 min, again the with the heater on max, the stat fluctuated at around the 120 mark. When i drained it the water was not verry hot. At least not when it dripped on my hand.
I got what i think were very good directions from the diesel giant. Well it will have to sit until i can get back to it next wed. Thanks. If you have any further guidance please, if you have time let me know.

I just read that there is a venting screw on the stat housing. Is that used to assist in draining or for removing traped air when refilling. I hear that there are also ?sending wires? that could have become disconnected. Does anyone know what they do or where they are so i can check this out.

I surely thought it would much more simple than this. RAY M

on capacity, i doubt you got the block drained so that would make it take a lot less liquid.

yes the tstat thing is an air bleed.

until you get all the air out the performance will be erratic.

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.

If I Can Only Drain 4 Of The 11 Liters In The System. Should I Fill The 4liters With Full Strength Zerex Go5 To Get Close To The 50/50 Mix That's Recomended. Do You Think There Is Still Alot Of Flush In The System Still And Will It Hurt It If There Is. Ray M

What coolant was in the before? If it was green stuff, you're not doing the engine any favor by adding a gallon of G-05. The next time you see the car, drain the radiator AND the block and fill with one kind of coolant in an appropriate proportion with water.

Sixto
93 300SD

That is what i did. Any links on how to drain the block. This is new to me. Thanks sixto

The block drain plug is just ahead of the starter. There's a pic in this thread -

Nightmare locating thermostat, drain plug

Sixto
93 300SD

I did find this everybodychech it out.
Courtesy of Brian Carlton

You can't see the starter or the block plug from the top. They are below the manifolds.

Go underneath, on the passenger side, and find the starter, neatly tucked into the side of the block, below the manifolds and at the very back of the engine.

Now find the very forward end of the starter.

Go three inches further forward and about 1 inch vertically upward and there will be a bright hex plug that sticks out of the block. That's the block plug. It won't be difficult to remove.

Courtesy of Boneheaddoctor

I'll look...if you can feel the bracket that goes from the top rear bolt of the mount pedital to the exhaust manifold...then feel the area around 10-11 oclock based on that within a hands width....it will be the only hex head you will leel in the area...you can see it from underneath but not from above.
passenger side...look at the bottom of the photo close on the right side you well see the passenger side motor mount pedistal.....its just behind and obove that. Where the red circle is....which is near the front edge of the starter and just above.