1998 S70 Oil light On-no leak and its fulll

bmball73 · Post by **bmball73** » 13 Nov 2015, 15:34

I have a 98 Volvo s70 and my oil light came on after driving about 15mins. There is not a leak and the oil is filled. Also, the heater is not working....I didn't know if these two were related. Any thoughts?

Post by **erikv11** » 13 Nov 2015, 16:27

Well this wouldn't explain them being related (can't see an obvious connection between them actually), but for the oil light check the oil pressure sender connector, it may have come unplugged. It is under the intake manifold, you can see it pretty easily with a flashlight.

For the heater do you mean the fan will not blow air? Does it work on the highest setting, or not work no matter what?

Post by **abscate** » 13 Nov 2015, 17:37

Check the fuse listings to see if there's a common fuse.

Don't run engine until you confirm oil pressure

Post by **bmdubya1198** » 13 Nov 2015, 19:29

Check the fuse first for the heater. I don't think these issues are related. Any signs of leaking heater core?

Post by **cn90** » 13 Nov 2015, 19:39

Stop driving the car until the diagnosis is made.
Possible culprits for low-oil pressure:
- Low oil level (you said you already checked it).
- Clogged screen on oil pump
- Clogged oil filter
- Engine sludge

As mentioned by others, hook up a pressure gauge and take readings, then report back.

Post by **erikv11** » 13 Nov 2015, 23:44

Despite everyone else ignoring it, the first thing to do is to check the wire and connector I posted about!

It is easy for the little white plastic plug to come unhooked from the pressure sender, and when it does the light turns on.

Post by **abscate** » 14 Nov 2015, 01:02

Erik is correct on the wire being the first thing to inspect.

Post by **bmdubya1198** » 14 Nov 2015, 06:57

Yeah, do the easiest first. Saves lots of time if it is the culprit!

Post by **cn90** » 15 Nov 2015, 07:52

Learned something new...

In the BMWs, the oil pressure sensor works differently:
- Engine OFF: circuit is CLOSED (zero Ohms).
- Engine running with good oil pressure > 7 psi: circuit is OPEN.

I guess Volvo design is different.

Post by **JimBee** » 15 Nov 2015, 12:00

The obvious concern, of course, is that oil pressure might have fallen. So I agree with the above suggestions, first look for the easy solution. Maybe even try changing out the sensor. If the oil light is still on, is the problem in the circuitry or actual low oil pressure?

O'Reilly's Auto Parts sells the gauge you'll need to find out. Carquest has the fittings to hook it up if O'Reilly's doesn't. You might not need to start it, just spinning it over for 30 seconds with spark plugs out and 12v. wire to coil disconnected should produce enough pressure for a reading on the gauge.

Good luck.