Okay, so the greasecar wouldn't get warm for a long time. Unclipped mono and no change so decided it was the tstat. Replaced it today, car warmed up at idle very nicely. Too nicely.
Now at idle it can get over the 100 mark on the gauge.
Burped by putting nose up (drive is uphill so put it in the driveway) and idled for 40 mins or so. Started getting hot at about 20 mins. I turned the defrost on high and that allowed the gauge to go down. But only to just above 80.

Went to pick up the DD, about 8 miles, and the temp gauge went high again. Went lower with the defrost on. But again, not to 80 mark.

I want to drive it tonight to the bar but don't want to overheat on the hwy.

Any other ways to burp?
Thanks

__________________
Ginny in Denver-ish
78 300SD, 265K (mine)

Remove the upper hose from the radiator and fill the head completely with coolant right to the top of the hose. Quickly reinstall hose.

Drive vehicle.

Problem solved.

I am having a very similar problem with my 240 that all started when i replaced the radiator hoses. I have not be able to improve it at all since. My car will warm my up in less than 2 minutes. It will run fine then all of the sudden temp just goes up to 115 or so then back down to 100 driving around town. I have noticed temp gauge is pretty erradic. It jumps around a bit sometimes pretty quickly. If i run on the highway for a while i can get it to 90 and it will stay there until i come back to stop and go traffic. Running heater will instantly drop temp to 85-90 but then it will climb back up. I've checked everything. I had the radiator rotted out and cleaned, i flushed the system and put new antifreeze in. Checked for air and doesnt seem to have any in the system. This all started when i changed my radiator hoses. It never once went above 85 degrees prior to that. Also, i have NO leaks. I'm stumped. Sorry for hijacking your thread btw.

__________________

I'm not.

Read post #2.

Follow it.

did you test the thermo first??

__________________
1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

Thank you Brian.
Problem solved!
Took another 3/4 gallon of coolant!

I'm a girl and still get a bit misty eyed every time you come to my rescue.

__________________
Ginny in Denver-ish
78 300SD, 265K (mine)

Good job.

Everybody who has not done this procedure finds the same result........overheating........not enough coolant in the head.

Help is what we do here!

I dont understand how you can get more coolant in that way. As soon as you tilt it down it will spill out. if i take it off right now i'm sure all lose quite a bit. but, i guess it won't hurt to try.

__________________

You don't understand because you don't realize that you cannot fill the head via the expansion tank. The thermostat is in the way and it prevents filling of the head.

When you fill via the upper hose, the coolant can go nowhere other than into the head..........when the thermostat is closed.

Plus, how does it get past the tstat this way?

__________________

Ok, just tried this. As i assumed, the hose was full. I lost more coolant that way from the top of the radiator then i could put in the hose. It took none this way.

__________________

I'd still wager that you've got air in the head. Get the vehicle on an steep upward incline so that the radiator is higher than the head...........and run the engine for 20 minutes.

Then, after it cools, repeat the attempt to fill the upper hose.

...with the heater on full blast.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

For one thing, i dont have a tank. I have a 240. Only way the thermostat is open is when its hot and under pressure. How can you get anything past that when its closed?

__________________

I don't think he understands that the upper hose connects to the head inboard of the thermostat.

Attached Thumbnails