Hi,

Further to our coolant loss that appears as a patch of water under our 740, a friend of mine recommended pouring some radiator sealant into the radiator which would seal the leak for me.

Is this to be recommended? I've heard that it shouldn't be used.

Simon.

It might cure the leak...temporarily but from my own experience, and that of others, it's very likely to bung up the heater matrix and leake you with bugger all heating. Which is fine in death valley but a pain elsewhere. Get a new rad.

Big Rich.

P.S. If the leak is obvious and accessible, i've used fibreglass resin to effect a temporary repair in the past and it's still going strong 3 years on.
--
745 valver, 245 (sadly deceased) and, temprarily, some strange Peugeot turbo wheesel thingy that does 19 light years to the gallon.

Radiator sealant is OK if it's a last resort, or the car is a real POS.

Otherwise, Volvo's parts aren't that expensive, even a radiator. I dig the plastic tanked radiators but some people hate them. They last a long time.

The bottom line is, figure out where it's coming from. Leaks never get better, but if you fix it, you solved the problem for good and saved yourself the headache of three subsequent system flushes to get the rest of the debris out of the system. I serviced a car that someone had put sealer into. Probably three or four times. All that was wrong was a cracked radiator hose fitting, and they thought they'd solve it by plugging a crack that kept growing.

Heater hoses and the heater valve are common. Don't let that go unnoticed.

Also, that same car was back a month later for a water pump. Whether it was related or not, I don't know. I just remember because it was a Volvo and I never particularly noticed a lot of Volvo owners doing that.
--
1992 940 wagon, 72k
make people envious; smile often.

You're sure it's the radiator and not the water pump, right? OK, if the radiator is leaking and it's still got the original plastic one in there, replace the radiator. Many people convert to metal radiators, three rows deep versus the original two.

This is one of those "do as I say, not as I do things". We're still running the plastic rad in my wife's 90 740 and same thing with my mother-in-law's 89 740. My gosh, are we crazy or what? Actually I'd be reluctant to send one of those cars out on a long hot road trip as-is.