Hi all,
I replaced my radiator and water pump on my 94 940na about 2 months ago. I just noticed leaking from the temp sending unit in the plastic radiator tank.
The seal was a pain to get in the first time, even with lubricant. I still must have damaged it somehow. Is there a homegrown fix for this? I have used 2 appropriate sized o-rings to seal the back of the waterpump to metal heater line and it has worked great. I would try an o-ring approach on the radiator too, but the o-ring won't hold the sending unit in place and pop out under pressure. Any ideas?

Palmer
--
1994 944na, 1980 265 V8, 1989 244, 1987 745ti

Hi guys,
Thanks for the responses. My Volvo dealer is about 50 miles away and I was looking for something as a temporary fix until I could get the proper piece.
I ended up with a part from the HELP section at advace auto. The part is a GM auto trans dipstick seal and cost $3. It is a little longer than the original that made installing easier actually. I idled the engine up to temp and no leaks so far. I'll only drive the car springly until I can get the right seal. Thanks again,
Palmer
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1994 944na, 1980 265 V8, 1989 244, 1987 745ti

I've had some unhappy results with aftermarket seals (waterpump's square O-ring to heater pipe; thermostat) so for those kind of non-costly items I get gen. Volvo from the dlr.

My n/a 940 is also a 94 and has no temperature sender in the rad, just a plastic plug in the seal (it's LH 2.4 - you must have Rex/Regina). My attempts to get the old one to stop leaking using various gasket goos and RTV didn't meet with success. New plug and seal from the dlr was about $5. I lubed the opening and the seal with straight glycol - it's pretty slippery stuff undiluted. Got the seal partially inserted and squeezed it home with judicious pressure applied with a big pair of channel lock pliers. One year now, no leaks - but I use a 240 (Black) 75kPa reservoir cap.

--
Bob (son's 81-244GL B21F/M46, dtr's 83-244DL B23F/M46, my 94-944 B230FD; hobbycar 77 MGB, and a few old motorcycles)

Dear Palmer,

Good p.m. and may this find you well. Contact Nick Bauer at www.fcpgroton.com. He likely has - or can get - a replacement seal.

When you get the replacement seal:
(a) drain the coolant (use petcock on passenger side of the engine, towards the fire wall; if I recall correctly a 12mm or 13 mm wrench operates it)
(b) remove the failed seal and temp sender
(c) dry the area thoroughly, using a hair dryer (NOT a heat gun) on "medium"
(d) using your fingertip, thinly coat the inside of the opening in the radiator, with liquid dishwashing soap; wipe clean any soap, that gets on the radiator's outer surface. This will ease the seal's insertion
(e) coat the inside the the seal with RTV silicone sealant.
(f) seat the temp sender into the seal
(g) coat the underside of seal lip with RTV silicone sealant
(h) press the seal into the opening, until it is fully seated (flat against the radiator's surface)
(i) allow a few hours - overnight is better, if possible - for the RTV to set-up.

This should prevent any leaks. If the seal pops out, then:
(a) the cooling system is generating too much pressure (you might want to switch to a black coolant overflow tank cap)
(b) the opening in the radiator is "off spec" (the radiator will have to be replaced).

Hope this helps.

All the best, for a Good, Healthy New Year.

Yours faithfully,

spook