More Strange 240 issues - Read on!

Hey all,

A few months ago I asked for your help in determining a noise which
ended up being detonation. My mechanic suggested off the top of his
head that a radiator replacement would be in order. Instead I changed
the coolant and that has seemed to help a fair bit.

Here's the puzzling bit. My car has never dripped a drop and has
always kept all it's fluids in when parked. I noticed a week after the
coolant flush that the temperature was climbing again so I checked the
coolant level to find that the expansion tank was nearly empty! I
drove over to Mr. Lube and had them fill it up for me. I checked under
the car several times thereafter and have found no evidence of a leak.

Now, two weeks later, I drove accross town for about 15 minutes and
parked without incident. I retuirned to the car twice to get things,
both times approaching from the front and saw nothing on the pavement
but old dried stains. On the final return to the car I observed a
puddle of coolant and a splatter-pattern around it as well as a trail
where it has run into the gutter. I estimated about half to
three-quarters of a litre had spilled. I checked under the hood and
the expansion tank was almost empty again. I topped it up from a jug
and have been driving and observing it for the last 2 days and it has
lost no coolant and the tank is at max.

Could it be some kind of pressure release safety thing? The puddle was
almost right under the front license plate. The tank is dry on the
outside. The engine compartment is generally dirty so I can't see if
it came from high in the compartment or the underside of the rad.

Is this a sign that the rad is truly toast?

Thanks for reading this long-winded posting,
blurp

 

I had one like this about two years ago. There was a small split in the
bottom of the expansion tank. It would not normally leak because there
was not enough pressure to push the coolant out of the tank. But I kept
getting low on coolant and it was in the summer. One day I drove and
parked, came back out, looked and saw coolant under the car but not
under the radiator. I thought that maybe the problem was a different
car that had the spot before me. But I kept loosing coolant and adding
it. I thought I had a head gasket leak and was dreading that.

I took the thing to my mechanic and parked it in the lot and went in.
He said to go back out and bring it in for a look see. When I went out,
after stopping in the hot summer, enough pressure had built up in the
expansion tank to open the split and the expansion tank was leaking. I
real quick opened the hood and I saw the expansion tank taking a piss on
the exhaust manifold. Some of the coolant was evaporating and some was
rolling back on the exhaust pipe to a point just under the firewall.

The mechanic called Volvo for the exhorbinant price on the coolant tank
-- about $60-75 I don't quite remember. I was on the way over to Volvo
to pick it up when I got the bright idea to stop at the Volvo dealer's
contract body shop. I remember that they had a few totalled Volvos out
back. Fifteen minutes later and $20 bucks lighter, I had a 85 expansion
tank in my 78 Volvo (with many more years of service).