Hi, my name is Jenny. i have a 1991 volvo 240. When i run the heat in the winter the will say it is overheating but the mechanic keeps saying it's just a broken gage. This morning it was smoking a bit and stopped when I turned the heat off. Looks like something may be leaking under the hood. Any ideas since the mechanic couldn't find anything? If you need more info just ask. i don't know what else to include. Thanks.

 

With the car running (hot) you should be able to see where its leaking from. Lots of times you can't see splits in the hoses until the car is fully warmed up.

 

Ok, thank you. It's probably the radiator. Had to fill it, even though the mechanic says it's fine. Has NO coolant. Ugh. I need a new place to go that is reliable.

 

I agree with checking the hoses, If it only smokes when the heater is on , then start with the heater hoses first.

 

"I need a new place to go that is reliable."

That is a very good idea. It sounds like you're leaking coolant from one of the rubber hoses. There's 2 for the radiator, 2 for the heater (they go into the firewall behind the engine), and 2 for the overflow tank. The temp gauge could also be bad. On '86+ 240s the temp gauge has a compensation board inside the instrument cluster and it is a common failure item.

 

You could also buy or borrow a pressure tester that will help determine where the leak is coming from.

 

My 1991 Volvo 740 has a bypass vavle in heater hoses at the firewall, it had a nipple where return hose connects crack and it gave me fits finding the leak. The valve is to shut off water to heater core when running the AC. to help get air as cool as possible. The valve is not expensive and easy to replace. You can even bypass it with just a nipple as a friend of mine did (no real differance in the AC between his car and mine).

 

gforce: That bypass valve for the heater core is a very good idea and I plan to add one to mine. Not so much for the A/C to operate more efficiently but to provide a better coolant flow in the head during the summer when the heater is turned off.

 

blue goose, never thought about more waterflow to the head but it makes alot of sense, especially here in texas. Hope you had a wonderful New Year!!

 

I had a '72 Toyota in Hawaii with no factory-installed heater. Instead of two heater hoses to the firewall there was just one short hose from the head back to the water pump pipe, as I recall. That's where I got the idea of modifying the Volvo setup. Any improvement to coolant flow in the aluminum head seems like a good thing.