sammaw

So done a bit of work on the 2002 c4 cab with 67k miles. Imsb ln pro, rms, a gear box leak, gear box mount. Then most of the suspension( nearly the value of the car I know maybe not smart but I want to keep this one ). Ask about aos but they said they tested it and it was fine. Did major service and ask d them to check any thing else that needed to be done. Every thing on the car has been running great. Done about 80 miles. Today when warm the warning low oil pressure flashed up and the little oil light came on. Did my temp and pressure checks all in the normal range. 1.5 bar pressure. Temp just over 80c. Stopped checked oil. Normal level. Took the risk and drove it the 5 miles to the indo and they plugged the piwis in but no faults or errors on the dme. But they could see the instrument error on the piwis. Suggest it is the switch. And will try change it out on Monday.

Question is, could this potentially be the aos? As when I put some power on the oil light goes away and when backing off the throttle it beeps and the warning and light pop back on. Or is it more likely to be the switch as suggested.

concern is on Monday it has a date with a boat for shipping and it will put a spanner in the works of not a simple fix.

thanks in advance to any suggestions

DBJoe996

Could be as simple as the oil pressure sending unit. Known to go bad and give erroneous readings.

318touring

^ +1 very simple and inexpensive fix.

However, if I was you, I'll buy AOS and coolant tank, and get VAT back. As you'll most likely need to replace those too. Sourcing those in NZ will be a rather expensive exercise.

Blue Chip

Keep in mind - the pressure sensor gauge and the warning light are on 2 different circuits.

Odd that you're showing good on the pressure - but the warning light is coming on....

spruden

I vote oil pressure sender. I bet the gauge dropped to 0 when the light came on and it bounced right back up to "normal" when you looked.

I've seen two 996's have the exact same symptom when the oil pressure sender failed.

wildbilly32

That's exactly what mine did! The message on the dash said "oil pressure sensor failure." I still soiled my drawers! Changed the sensor been good for last two years!

Bash Hat

If you really had zero pressure I'd imagine you'd hear a lot of not very nice noises coming from the engine compartment. Would think it has to be a bad sending unit.

RngTrtl

This is true, but keep in mind those two circuits are on the same sensor.

sammaw

Thanks for all the suggestions, I was hoping for the sender unit as this has been replaced a couple of years back. However this time it was different as the needle wasn't bouncing at all. The Indy phoned me before saying they have fixed it. It was the sender unit. I started to head out to pick it up when I got another call that the light had come back on. So they need more time to investigate. Getting to the 11th hour now. Will report back what they find. Fingers crossed

strathconaman

When my oil pressure sensor failed, I got the warning about sensor failure, but no other warning lights.

Still, this is a known area of weakness. If the dipstick confirms that the oil level is good, change the sensor ($80.00 and 1/2 an hour with the proper tool: a crow's foot wrench).

If it was something else (like the oil pump)...you would probably know already.

RngTrtl

Low oil pressure can also be caused a weak or broken oil bypass spring. I cant remember the actual name for it, but if it fails it will result in low oil pressure.

porsche951

My 2002 did this a couple times a few years back and I did nothing about it. Yesterday it did it again 3 times on a 20 mile commute to work. Pressure would drop to zero, oil light would come on for a couple seconds then light would go out and pressure resume to where it should be. Commute home that evening no issues. Checked oil this morning and it is fine. So I'm assuming faulty sender?

RngTrtl

sounds like it. the one sensor is really two sending units in one. One goes to the gauge, and the other goes to the oil light and computer. its a pretty easy repair if you use a crows foot wrench and go in from the bottom.

DBJoe996

Read this as well - https://rennlist.com/forums/996-foru...p-upgrade.html

Imo000

It's amazing how no one thinks this is actually a low pressure problem. Pull the sump pan and have a look at the oil pick up screen. Then hook up a machanical pressure gauge to the engine and see if there is a problem. If all checkes out only then assume it's either a sensor or wiring problem. Also, the shop should have replaced the air oil seperator. If it's old or unknown age, replace it when the transmission is off. It is a consumable item.