I experienced the irregular jumping of the temp gage going periodically from 11:00 to 7:00 (where normally the needle is at dead center, 9:00 on the gauge).

I went to Napa and got their "OEM" thermostat and replaced it. Now the needle sits at 10:00. I checked and found out that these thermostats are available in a variety of temp settings (82, 87, 92 degrees C). The one I put in is 87*C. The one I took out was 82*C.

Does this mean that my car is supposed to run with the 82*C thermostat as that is what had the needle sitting at 9:00 on the gauge???

From what I've read, that is usually a thermo used in warm weather environments. I'm up in Minnesota and through this past freezing winter my needle still always sat at 9:00. Some past posts have indicated that it is recommended to have engine temps higher and that they shouldn't be lowered. My confusion comes from the fact that if this old 82*C thermostat i took out was improperly replaced by the previous owner then should not my gauge have read a cooler engine with the needle pointing at 8:00 or something. Or was something re-calibrated???

Basically I have an 87 240DL with the B230F engine and would just like to know what the proper thermostat rating should be. Like i said, I have the 87*C one in now and the needle on the temp gauge is indicating a hotter than normal temp.

I know this may be a little confusing, but what I read about these temp differences, and what I'm experiencing in reality are two different things.

Thank you in advance for any help bricksters.
87-240DL

Sounds like something is a bit off in the Compensation board. The highest temperture T'stat should have your car running at 9:00. so the fact that it is a bit over begs the question.. Comp. board or clogged radiator.

The "floating gauge from 7:00 to 11:00 leads me to believe it's the Compensation board but you changed the thermostatt and now it's on the High side but consistant.

with the car being an '87, I would think you also have a lot of buildup on the Radiator fins. When I did my Timing belt and had the Fan and Fan shrowd out of the car, I used a garden hose and blew water through the radiator fins from the Engine Compartment outward. just the opposite direction as the wind blows through it. I was amazed how much 'stuff' was in my driveway after doing that. It borought my temp. downa very little bit, it wasn't high to begin with but the radiator was disipating heat better for sure. Give that a shot. easy and painless to the wallet.
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'75 Jeep CJ5 345Hp ChevyPwr and two motorcycles: it wasn't Volvos safety , it was Longevity that sold me

I strongly advocate for the factory stat, the 92*C unit, and also a factory part. There are HUGE differences between stat manufacturers (actually most are made to order by a "rebrander"). I have not run into troubles with NAPA stats in Volvos, but have in other brands.
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JohnG 1989 245 MT @216,500

I too am in Minnesota and replaced my thermostat a few months back with 92C unit. I also removed temp. comp. board and get accurate readings on temp now. No over heating problems, temp needle sits at about 9:10, just above the little 9:00 dot. Engine runs more efficiently, am getting 2-3 mpg better with new thermostat and am looking foreward to the new found winter time heat.

Steve Cole in Mpls.
1987 245DL 234k

You should use the standard 92°C thermostat. If your gauge is acting erratically, it's almost certain that it's due to poor connections in the instrument cluster. There is a "temperature compensation board" that's connected to the back of the instruments, which often creates faulty readings. Sometimes it's due to the 4-pin connector on it simply being dirty. Removing and reinstallign it sometimes cures the problem. Also, replacing the unit should cure it, if the board itself is faulty. The sensor on the engine is not often the problem. However, the wire for that sensor runs through the grey connector on your firewall, under the hood. I just recently had to repair a corroded wire for my temp gauge in my 87 240. That's common too on cars of this vintage: Volvo's wiring leaves something to be desired in it's old age.
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Rob Bareiss, New London CT ::: '87 244DL/M47- 221K, 88 744GLE- 202K, 91 244 181K, 88 244GL 145K

Your car should be fitted with the 92degC. the 87 is for very hot climate and turbo I believe and 82 is for carberettor cars (to prevent pre-ignition etc - old school).

The temp guage is not really a reliable sensing device as they can go wrong (see archives on temp compensation board... should find a lot about loose contacts etc).

Assuming your cooling system works correctly, is clean and thus has sufficient cooling capacity the temperature of the engine outgoing water should be 90-94 deg C subject to load, typically the radiator should give a temp drop over the radiator of 10 deg C. With a clean system and a new good quality termostat, my experience is that everything is just fine, but the guage does not function correctly. There is a testing methode were you put a fixed ohm resistor in place of the sensor which should give a certain gauge reading. I would have to look up the value.

The correct temperature is important as the engine management system is tuned for 92 deg. It does sense the temp and if it is too low it will enrich the mixture, creating higher gas mileage and more wear on the cat etc.

I had a 87degC fitted in my B200F and found it run better with the 92degC, especially more even coasting and better mileage.

It is a common fault, you should be able to find al lot of info on the board to help you out.

Reg,

Jorn 92 240 B200F M47 175kmiles