I have a 56+ mile round trip commute with primarily freeway at the speed limit.

The 1992 240 GL (3.1 LH-jet, M47 II, 165,000 miles), runs up the temp gauge above the 09:00 (9AM) position to like halfway between there and the orange line about seven minutes into the drive as ambient temps drop. Turning on the heat control valve level to max heat brings heated coolant into the HVAC coolant heat exchanger. The heater control valve has been replaced by a prior owner of this vehicle.

Yet in the evening, some 9.5+ hours later, I take the 1992 Volvo 240 GL back the same route, and with heat on or off, the faker temp gauge remains steady at 9AM or slightly above.

Slapping the dash makes no difference in the temp gauge needle position no matter the drive time.

The engine seems no hotter than the other two 240s, or the four prior 240s I'd owned.

In warmer weather, the temp gauge needle is slightly above 9AM and remained.

So, while I've searched the FAQ and the bb using the google site:brickboard.com in the search query expression string, the anecdotal evidence suggests a failing thermostat.

This 1992 240 GL has a replacement blackstone radiator and the coolant hoses seem perhaps, at most, four or six years? Still supple and sturdy. The upper hose is the normal Volvo 240 warm.

There may be mineral precipitate in the lower radiator portions, yet the entire radiator gives out heat, even at the bottom.

My only worry is the added stress the coming Winter temps place on the thermostat.

Thanks,

cheers,

LOL Grumpy Cat meme.
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LOL cats!