My 89 240 B230F engine runs hot. I cleaned the exterior of the radiator last fall and it ran cool all winter while the weather was cold. Now that the weather is hot, the car runs about 75-80% up the gauge. Sometimes when I turn a corner, the gauge will drop to below half and stay there all the way home. Weird. How does one backflush a Volvo? My guesses are do a backflush, or change the thermostat, or maybe there's an air bubble trapped in the system. I know last fall someone said to do a mod on the instrument cluster circuit board due to some goofy thing on the temp gauge, but I don't know if that's the whole issue.

Any experience or advice?

Thanks
dave

 

Maybe you should replace the thermostat then replace the radiator and then rebuild the motor......or maybe you should go get a IR lasee temp gun first and foremost and save yourself A LOT of time, frustration and $$. I don't know about you but I'm not rich and I do not like to throw out GOOD parts. Please TEST your temp while car is running and "running hot" Point it directly at the thermostat housing on the nut. make sure it reads 180-190 degrees Farenheight. If it does,move onto your radiator. Take the temp of both sides first left(passenger side) then right drivers. Temp should read at least 20-30 degress lower on the right. If temp is the same on both sides you have a bad radiator. If all is good there you have another problem. It may just be a bad temp circuit board, I see it ALL the time. Or it may be a weak fan clutch. But if you really want to do a coolant flush just pull the lower rad hose while car is hot and let drain. Hook hose back up and fill resevoir with whatever product you want to flush with and water(make sure it's Volvo approved) run the car until hot and drain again. Fill back up with equal mixture of 1 gallon water to 1 gallon new lifetime coolant. I never flush I have always just drained and filled with fresh coolant but to each their own...Please save your time and $$ by testing first Hope this helps

 

Thanks for the reply. I thought about a non-contact laser temp gun. I'll have to do some shopping. I didn't know where in the system the temp would vary, also did not know Volvo's were into marginal cooling systems.

Thanks
dave

 

No problem. My best friend owns a Volvo shop here in Seattle. He has been working on 240's for 30+ years and in my opinion is the best 240 mechanic in the state...maybe the country. Whenever someone has an issue with their car running hot, the first thing he does is take the running temp with his snap on laser temp gun. You would be amazed how many cars are actually runnning at a normal temp and just have a bad temp circuit board. Trust me, before my friend started training me I was the king of pull, pray and replace...didn't really get me too far except a thinner wallet and no "how to" knowledge. I never got any smarter. Any monkey can pull and replace parts, a true mechanic or diagnostician know how. Trust me once you start actually doing the proper tests when your car has a problem you will be AMAZED how easy it is to fix it correctly the first time. Also,you will feel really good about it and gain knowledge and be able to share your experience with others so they to do not chase their tails too... Knowledge you seek it is....

 

That's why I'm on here asking question: no money to spend on it, and hate just swapping good parts.

dave

 

I had the same problem with my 87 240. I agree. If I had listened to volvoguys advice, it would have saved me time and a few bucks. Turns out my board was bad, my tstat was too low a temp (71c) AND my rad was bad. But, nonetheless, his advice was the same to me as it was to you, and I'd follow it. Even a 25 dollar temp gun will save you money as 2 gallons of antifreeze will cost you that. I did a drain/refill then had to replace my radiator anyway. 25 bucks wasted.

 

Mine does the same thing, even after I replaced the thermostat, radiator etc..I think the gage is broken because if I tap it, it will go back down to normal. Plus it will even do this if the heat is on. It will never go into the "red zone" but it will come back down if I tap the gage.

 

Everyone go invest in a ir laser temp gun