I have an 88 XJ6 (XJ40 technically Ive been told) After the car warms up and i come to a stop the oil pressure drops then goes back up. Oil light never comes on tho. Anyone know what i should do? Im new to owing a Jag and im no mechanic by any means. Love the car so i wanna keep her alive. Thanks Everyone
Dial gauge pressure change
Typical fault. Currently it is only replaced by a two threshold indicator -> 0bar / 4 bar
A dial replacement is also available
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Do an oils change and check to see that there are no sparkly bits in the bottom of the tray as you pour the oil out into another container.
These engines are generally bullet proof, typically running well into 200,000 klms and more. As Tomas has mentioned the senders get flaky over time and Jaguar replaced the senders with ones that just peg the needle at mid point.
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I just did an oil change with no sparkles in there. Thanks for your time
Every car has this issue sooner or later.
Rock auto has replacement sender units - - you can fit an idiot switch as suggested above but replacement senders used with a resistor is what many of us used.
Get an actual mechanical oil pressure gauge kit from a standard auto parts store and use it to get a true reading from the engine. However one warning, The thread into the block where the oil pressure sender attached to the oil galleys is a 1/8 BSP (british standard pipe) so if you get an aftermarket oil pressure gauge kit here in the USA it typically comes with a 1/8 NPT (US thread size for pipe threads). So if you try to thread in the 1/8 NPT male threaded adapter into the 1/8 BSP threaded hole on the side of the block it may feel like it is threading in but in actual fact it will permanently deform the 1/8 BSP threads. So there are places that will sell a 1/8 BSP to 1/8 NPT adapter which is what is really needed to do this job.
If you need more information on where to attach the oil line adapter, just ask.
BTW, my 1994 XJ40 with almost 200K miles carries 40psi oil pressure at idle (after warmed up) and 80psi while running down the road so make sure you get an oil pressure gauge kit that reads 0 to 100 psi.
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I have an 89 and the pressure rises under load and drops at idle, I think this is normal as my van does the same thing.
Maybe an aftermarket actual pressure gauge kit does have a non Jag thread, but why fit one of those?
The rock auto part I fitted works fine, was made in Spain and threaded in no prob.
Larry, I am talking about a MECHANICAL oil pressure gauge kit that comes with a plastic line and a gauge. That way he can see the actual REAL pressure from the engine.
Yes well the senders do that, I’m not referring to the switch sometimes fitted that just centres, I’m talking about the sender units as fitted OEM.
I’m sure the units you refer to are more granular in reading than the OEM system but why fit that when you can just fit an aftermarket unit? If it reads too high as some do, it’s easy to sync it to the in-dash gauge with a 75ohm resistor.
I’m saving that gif to post in the climate change threads
old OEM sensor LMD5640AB, new OEM JLM20791
I change the climate in my cars that have climate control!
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