Start soaking the thermostat housing bolts. Spray them warm, tap them with a hammer and walk away. Repeat, repeat, repeat...

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

They guy was a WWI vet. He also said words to the effect that there is nothing worse than old worn-out equipment (that includes vehicles).

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84 300D, 82 Volvo 244Gl Diesel

Amen to that!

Finally got my new thermostat from Pelican, and first step, drain coolant. Well it was the color of chocolate milk! Also corrosion on the metal parts to which the hoses attach. So i knew it was time for a complete flush. Drained the radiator, and removed the block drain bolt, which was miraculously easy, but idiotically so positioned that it splooshes all over the back of the starter. Ran garden hose thru the radiator and block til it ran reasonably clear, then filled with some used but clean diluted antifreeze and water, but decided to put off the thermostat job to see if clean antifreeze made a difference. It did not, still running a bit over the 60 deg. line. The IR thermometer pretty much agreed with the gauge. The plan is to run about a hundred miles, maybe adding some radiator flush medicine, and flush again. This time i will put in the right stuff, and of course change the thermostat.

Thanks for all the advice about this and other problems i have had. COOL!

Uhhh, you may have a bigger problem on your hands.

Before any diagnosing began, at the very least, did you open your radiator and peak inside? What was the level? Was there froth? Oily residue?

It’s difficult following your logic as you’re mostly taking steps associated with running hot. At the very least, you have a thermostat problem that for whatever reason, you seem to be avoiding.

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1981 240D 4sp manual. Ivory White.

I read some other posts, and am aware there could be other problems, but the coolant level has remained about the same, maybe needing a few ounces once every 10,000 miles or so; no oily froth, or foam under the oil cap. Temp never went much over 80, maybe pushing 90 if driving over 70 for prolonged periods in hot weather. I am thinking it is that the coolant has never been replaced, on my watch at least, about 80,000 miles. So i am planning to go forward with flush again, and replace with the right stuff. Maybe i will wait a little longer, see if the current stuff turns brown in a few hundred miles, before reflushing and refilling.

I have the new thermostat in hand, and of course will replace it when i do the next flush

I finally put in the new thermostat, and she is running a little over 80 C again.

But i have changed water and coolant, and flushed the radiator and block with the garden hose at least 3 times, and after driving 100 miles or so each time, it is still coming out brown. I used 3/4 of a bottle of Prestone radiator flush once, and the other 1/4 bottle the next time.

No froth; the stuff i initially drained and let sit did not have oil floating on it after 2 weeks, not overheating, so i am wondering how many times it should take to flush a cooling system that likely has not had the coolant changed in the 170 K on the odometer (80 K on my watch).