I recently changed the oil but the car had been fine. it had been sitting a few days went to run into town and the oil lights on and the gauge reads nothing. Ive had the occasional issue with mice so i went looking and don't see anything. I started the engine back up and its quiet (quiet as it normally is cold - little ticking) and theres plenty of oil up top.

I did some looking and it seems the oil sending unit switches are known to just start reading poorly but to just stop completely without warning seems odd. Its dark and cold so aside from a few minute look over I dont see anything. Im going to grab a long extension tomorrow when it warms up a little and tap it a few times - Im hoping its just stuck before I dig out the oil pressure gauge and and all thats involved with that.

So while these things do fail, has there been a history of just It's good then it's not? It wouldn't surprise me but I thought Id toss one to the group.

Thanks

Joe

 

Disconcerting for sure there Joe, maybe just a change in the weather related electrical connection issue?

Sounds like the engine is behaving normally. If you do have to swap the unit there's a few threads about doing it, I went with a sensor that reads pressure from rockauto +resistor - didn't fit it myself though, Jim @manwich66 changed it for me when I was up at his place for a visit one time.

PIA though, Jim had to remove the oil cooler bypass to get a wrench on it from under the car. Good time to swap the $2 o-rings in the bypass though, so 2 birds with one stone.

I think DonB swapped his sensor for a switch a few times but my replacement has been fine so far and it's been quite a while (touches wood as he types )

All the best

Larry

 

Hi Joe,

My first question is whether you may have changed your oil to a thinner viscosity such as a 5W- or 0W- variety? The viscosity Jaguar recommends for the AJ6 in most climates is 20W-50. The use of anything with a lower viscosity may result in low oil pressure readings and rattling timing chains at startup.

Another possibility is that while changing your oil filter, you managed to disconnect the oil pressure sender. It's just a single wire with a female spade terminal that fits onto a male spade on the sender, so it's easy to pull off the spade or to break the wire at the spade terminal, where it tends to vibrate and weaken.

Other common causes of low oil pressure readings on the gauge are oil contamination of the spade harness connector or oil on the threads of the sender itself. As a single-wire sender, the ground path for the circuit is through the engine block and engine ground strap, so oil on the threads of the sender can interrupt the circuit partially or entirely.

Sender failure is not uncommon, but given that you have just changed the oil, I'd be more inclined to suspect a viscosity issue or disconnected sender.

Cheers,

Don

 

I've been using 15W40 for a while now with no issues. I'm over 200k so I wont go thinner than 10-15.

The thing was it wasnt right after but a few days later and I had used the car after the change and it was normal. I can see that its plugged in at the sender and the pig tail seemed tight as well. Tomorrow is going to be pretty cold as well as the rest of the week but as soon as it warms ill take the maf and air boot off to check the connections and give the sensor a tap. Its funny that its not that its reading low, but not at all which is why im thinking sensor or wire vs actual engine...I hope.

I'm thinking I replaced it a few years back as Larry suggested replacing those O rings , I can recall doing that when the intake was off but I dont remember if I replaced the SU when I did that.

Well I report back as soon as it warms a little.

 

Problem Solved.

Even though it’s well below freezing, I’m an idiot and I was outside looking at the car. I have the sensor a few taps and nothing but then just pulled the connection at the pigtail and reinserted it and boom oil pressure.

Dodged a bullet there. Thanks for the help.

 

Well that lasted one day, I went to drive it to the store and lights on and gauge is dead. I turned it off and ordered a new sensor.

 

I pulled the sensor and replaced it. The old sensor had to be less than 5 years old as I’m pretty sure I replaced it already. So just a poorly made sensor.

 

They get clogged Joe, the little hole plugs up then ...kaput! glad to hear she's rollin again.

Larry