Hey all. My 740 sedan has a leak for the engine coolant and I have to check it and refill it about every 1.5 weeks. Is there a method to finding the leak?

 

look for green coolant leaking out around the engine comewhere.

common spots:

• any of the coolant hoses, including the heater hoses, the overflow hoses, or the main radiator hoses
• the radiator itself
• the water pump shaft, or the seal above the water pump under the front end of the head
• the head gasket outside, often below exhaust headers #3 and 4 (towards rear right of engine)
• internal head gasket leak into the oil, symptoms are white milky froth on inside of oil cap, and/or on dip stick

last two == head gasket, $$$$.

 

Throw in some sealant liquid of a good make like barsnleaks or k-seal and solve your problem if you cant find the leak.

 

Green coolant? Why would my coolant be green?

 

Volvo brand antifreeze is green, so are many other conventional antifreezes. I tend to use Zerex G-05 which is yellow. I guess I should have been more general.

 

Is it common for the head gasket to leak?

 

Yes. That is the second cause of death to old cars.

 

HGs are very common failure item on these cars, due to overheating or just due to age. Also, they are probably the easiest HG to replace given some mechanical ability. If you are inclined to use a LEAK SEALER, use Blue Devil. It's costly, $65, but it DOES work and won't cause damage to radiator, etc.

 

our 240 has over 400k miles and the valve cover has never been removed. its had new camshaft seals recently, but that didn't require removing the valve cover, never mind the head. it burns no oil.

I'd say the ONLY time I've had a head gasket fail on a B230F(T) has been from overheating (2 of them on different cars).

 

Hello, have a tiny whiff of coolant odor coming into cab of 1995 940 turbo wagon. Volvo mechanic recommnded Blue Devil radiator/block sealer to stop (perhaps a pin hole leak) heater core leak. Bought 16 oz size. Where would I pour it in? Will it mess up my engine? Have 217k miles and going strong!! Any advice appreciated!!

 

I would just pour the stuff into the coolant container.

 

thanks for the info.....my son who is an excellent mechanic will replace the heater core. He has volunteered!! He was also leery of what kind of damage this stuff might do to other parts/engine/sensors. He says it's a quick fix, but will only put a patch on the real problem. I want this car to go to 300k at least!!

 

The heater core on a 740 is a lot easier than it is on a 240 at least. it still requires disassembling a fair amount of the dashboard.

 

I have a 940...thinking it is very similar to the 740's. My son did his Dodge truck a while back....definitely not the easiest job!!

 

yeah, 740's are really similar to 940. The fan is behind the glovebox, I think the heater core can be accessed from the passenger side, which is way easier than the 240 where the fan and heaterbox were directly behind the center console, and require full dashboard removal... and on the 240, all the relays were scattered behind the dashboard at random places, whereas they are centralized on the 7/9's.