[2003 V40 2.0 NA] Weird oil pressure issue

[Matthew01]

Hi everyone! I’ve been on the Dutch volvoforums for a while now, but thought i’d try and get some help on the english side of things.

My dad’s V40 had an oil pressure (sensor?) issue earlier this year. The light suddenly came on when we were driving along the highway and we stopped immediately. Oil level was low, so we filled the car up and went on our way. 20 minutes later the light came on again and we decided to get the car towed to a mechanic. They ended up finding nothing, apart from the oil being rather nasty. (the engine has never sounded rough or bad in any way) They said dirty particles floating around in the oil must’ve upset the sensor. They replaced the oil and told us to drive as usual. And indeed, after 2 days of driving around the oil light disappeared and didn’t come back on. Until yesterday, which was coincidentally the first time we drove on the highway since the light came on earlier this year. (car is 90% in use for city driving) This makes me think it’s an issue with maybe the oil pan seal or the feed tube being clogged up causing problems at higher RPMs for a prolonged time. (cutting the engine and restarting makes the light go away, it’ll only come on if you drive at high speeds for more than half an hour!) The oil is at a perfect level, basically touching the max line on the stick. My dad is set on it being the sensor again and is just driving the car around without hesitation, which I can understand, since the engine is running silently and smoothly, and no power loss at all, but I still think it’s risky and it would be a shame if the block were destroyed.

Any tips to what it could be? Maybe i’ll manage to take a look at the engine if i know what to search for.

—M

[gatos]

Why not trying to replace the oil pressure sensor and see if it helps. While you are down there, also check the wiring to the oil pressure sensor connector.

[loely]

Did you ever think off a mechanic pressure gauge to check the original?These dont miss.

[bobthecabbage]

Yeah, you can't beat getting an oil pressure guage on it. That way you can measure the idle oil pressure, 2000rpm pressure and high rev oil pressure.

It's not difficult to do, just screws into the oil pressure switch hole, every garage will have one.

I don't know if its an oil pressure sensor or and oil pressure switch (or both). A sensor would measure the pressure (and could be read with diagnostic equipment) whereas an oil pressure switch just says, yes oil pressure/no oil pressure.

For vw/skoda applications its the behaviour of the oil pressure that contributes to the oil light being on. There is a delay to allow oil pressure to build and if it doesn't trigger in the time frame the light will stay on, even if the pressure reaches the required level after that. The output from the switch will also be read at different rpms to determin whether the light is on.

If there is a pressure sensor, then it will read the actual pressure in real time and determin the status of the oil light that way.

Also if there is an oil level sensor, that will also trigger oil warnings.

At the end of the day, you need someone with VIDA (technical manual) or a haynes manual (maybe) to tell you what values and sensors you are looking for.

Could also be a bad contact on the oil pressure switch connector.

I think my take home point is that the oil pressure light could be triggered by more than one sensor and is likely being interpreted by a computer rather than just being connected to a wire on the switch to give you on/off.

It is likely that with volvo diagnostic equipment, the car will tell you the reason for the light being on (but not the cause).

As you say, it could be the screen on the oil pickup is clogged, the seal has gone allowing air to be drawn in, or as in some engines, the oil pick up has snapped off (not sure if thats a volvo problem, definitely in some other makes.

Anyway, an oil pressure guage on a warmed up engine will tell the majority of the story.

[loely]

It is likely that with volvo diagnostic equipment, the car will tell you the reason for the light being on (but not the cause).

The equipment that tells the cpu diagnostic get the info from the same pickup used for the oillight.

As you say, it could be the screen on the oil pickup is clogged, the seal has gone allowing air to be drawn in, or as in some engines, the oil pick up has snapped off

If that is the case you would be hearing the bells ringing inside the motor.

[bobthecabbage]

Originally Posted by loely

It is likely that with volvo diagnostic equipment, the car will tell you the reason for the light being on (but not the cause).

The equipment that tells the cpu diagnostic get the info from the same pickup used for the oillight.

As you say, it could be the screen on the oil pickup is clogged, the seal has gone allowing air to be drawn in, or as in some engines, the oil pick up has snapped off

If that is the case you would be hearing the bells ringing inside the motor.

Yeah okay but an oil light is just a light, its on or off. The cpu can record data that tells a story. At the very least it can tell you why the light is on eg oil pressure too low at idle, oil pressure too low at intermediate revs, oil pressure too low at high rpm.

It still doesn't beat connecting up a manual guage as well as doing an electrical test on the sensor and wiring, very easily done with a multimeter.

That is what needs to be done and the results of that test will determine where you go to look for the problem.

When you say bells, do you mean like church bells or more like morris men?

[loely]

Yeah okay but an oil light is just a light, its on or off
That is right, it works like a switch.Only the CPU can not get info from that on/off switch.The oil gauges will have 2 wires that come out + neg ground on the engine or two different points to keep an eye on your pressure.
And the bells you heare,remove the oile from your motor and let it turn .After a while you will hear the "Bells" I mean.Can tell you it is not a nice sound.

[V40T4R]

Originally Posted by bobthecabbage

Yeah okay but an oil light is just a light, its on or off. The cpu can record data that tells a story. At the very least it can tell you why the light is on eg oil pressure too low at idle, oil pressure too low at intermediate revs, oil pressure too low at high rpm.

It still doesn't beat connecting up a manual guage as well as doing an electrical test on the sensor and wiring, very easily done with a multimeter.

That is what needs to be done and the results of that test will determine where you go to look for the problem.

When you say bells, do you mean like church bells or more like morris men?

Mike Oldfield his tubular ones maybe =)