Volvo 240 oil light

Most likely problem is a bad switch -a loose filler gasket will have no effect on oil pressure unless it allows a lot of oil to escape.

What oil are you running and how long has it been there? If the oil is too thin - lost viscosity or contaminated with gasoline- that would also cause the problem.

Check your filter and oil type . Maybe your using a very thin oil or there's issues with a bearing ? Does it sound normal and was the traffic extra heavy and maybe a warm day ?. We had this issue on new Ford Falcons in Australia with very thin synthetic oil,so Ford used a thicker viscosity oil which solved the issue . Look after it as the 240 is a wonderful model .

Just coincidental to adding the oil- which is certainly possible given a car with almost 230,000 miles on it- or?

The oil is 4000 miles old plus 1 new quart; viscosity is 10-30.

Yes, it's due for an oil change (4000 miles on this oil, plus the new quart added yesterday. The manual says 5000 miles between changes but I usually do 3000).

It's a little rough when first started in the morning, runs very smooth once it warms up. I have been attributing this to the fact that the #2 spark plug is stuck and hasn't been changed in over 125000 miles while the other three have been changed twice, so the gap in the #2 is probably well off spec by now. It sounds fine, no odd noises from the engine and drives well. A bit of valve tap when cold. No active oil leaks that I can see, but it did go a quart down over 4000 miles so the oil is leaving somewhere or getting burned (no tailpipe smoke, though).

It was not excessively warm (65 F) when this happened but traffic was very heavy. In those situations the temp gauge runs above the middle point for the past year or so.

It's been the best car I have owned, although with nearly 230000 mils on it the maintenance needs have been high over the past couple of years (various bushings and this, that and the other thing as all Volvo 240 owners know). I hope to get a few more years out of it- I'd like to get it to 300000 miles, anyway.

Check the wire coming off the oil pressure switch due to the age the insulation may be brittle & cracked & the bare wire is touching the metal oil filter

I'll check that, thanks.

If that stuck plug misfires you can get gasoline in the oil. That will cause the problem you are experiencing. Change the oil and see what happens. If the light still comes on at idle you need to put a guage on to check pressure - and LIKELY replace the switch. But you DO need to get that stuck plug out and changed.

That happens frequently

-- Boris

ANd turns the oil light on either under load or decel when the engine rocks. Not very often THAT will cause the light to come on only at idle, and the light goes out when you speed up the engine a bit, even in neutral.

Everyone's hearing hoofbeats and looking for unicorns when there's a whole herd of ponies stomping their feet right in front of them.

Wires et al seem to be OK and no reoccurrence, oddly enough, of the problem since last Tuesday. Huh.

Mine had a spade or pin connector to the pressure sender that corroded/wiggled, etc. Wire was loose and/or corrupted in the crimp and the spade was loose on the sender. Trimmed it back and put a new spade crimp and the oil light stopped randomly scaring the crap out of me. (coincidently, most often the light came on when it was raining... maybe just to make me get out in the rain and confirm there was still oil in the beast.)

Oil light comes on at idle? My first thought would be to get the oil pump checked out!

It could be a switch as surmised by others, but I wouldn't risk my motor.

Reminds me how one day I noticed the oil light coming on in my 1st wife's car (she fancied herself as a bit of a tomboy and mechanic). I pointed it out to her and she waved me off with "but I only put oil in last month, the light must be faulty!". Facepalm.

-P.

So far no reoccurrence. My mechanic got the spark plug out and changed the oil on Friday. The 240 has quite a bit more power now, I have noticed. The old plug was very worn, the central electrode was practically down to the insulator and the side electrode was very thin.

Next up, I suspect it needs a new set of suspension bushings all the way around.

I suspect that plug was misfiring, diluting the oil with gasoline. You didn't by chance have the mechanic check the idling oil pressure after the oil change? Might be a good idea to have a guage thrown on to confirm.

Possible. It certainly seems like it was misfiring judging by how the car runs now.

I did not but will have that done when I take it back for the suspension work.