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99 XJ Sport - Oil Pressure Dropping / Check Guages

R

reeldba

NAXJA Forum User
Location
North Carolina
Hi fellow XJ folks. I have a '99 XJ Sport. Recently, at idle, the oil pressure has been falling off to zero, until I tap the gas.

I am assuming the head isn't cracked. I can't decide if the sensor is going bad or if the oil pump is going.

I was thinking that the right way to attack this is to get a manual oil pressure gauge first and verify that the pressure is in fact falling off.

Based on that, I would know if the sensor is the likely culprit or the oil pump.

Make sense?

Thanks!
 
The most common reason would be the cam bearings, the oil pump doesn't usually cause problems!
 
Verify the pressure because sending units fail pretty regularly.

Cam bearings can be a culprit, it would not be a common failing, sender, main bearings, bad oil filter, clogged oil pick up screen are more common. Bad oil pump can happen just don’t read about too many these situations being solved by a new oil pump.


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Does you engine make loud clattering noises at 0 oil pressure? If not then you actually have enough oil pressure to run the engine. Could still be too low, definitely test it mechanically


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reeldba said:
Hi fellow XJ folks. I have a '99 XJ Sport. Recently, at idle, the oil pressure has been falling off to zero, until I tap the gas.

I am assuming the head isn't cracked. I can't decide if the sensor is going bad or if the oil pump is going.

I was thinking that the right way to attack this is to get a manual oil pressure gauge first and verify that the pressure is in fact falling off.

Based on that, I would know if the sensor is the likely culprit or the oil pump.

Make sense?

Thanks!
Click to expand...

Sounds like a plan. It's pretty common for the sensor to go bad and become erratic like that.
 
Green Mesa XJ said:
Does you engine make loud clattering noises at 0 oil pressure? If not then you actually have enough oil pressure to run the engine. Could still be too low, definitely test it mechanically


Sent from my iPhone using Tapatalk
Click to expand...


Not really. Which is why I was thinking more along the lines of a faulty sending unit. Thanks for the response!
 
Green Mesa XJ said:
Verify the pressure because sending units fail pretty regularly.

Cam bearings can be a culprit, it would not be a common failing, sender, main bearings, bad oil filter, clogged oil pick up screen are more common. Bad oil pump can happen just don’t read about too many these situations being solved by a new oil pump.


Sent from my iPhone using Tapatalk
Click to expand...

Thanks for the response. I'll be looking for a pressure gauge to test with and I'll probably wind up replacing the sender this weekend.
 
What weight oil are you running?

If you are running a Fram oil filter, throw it out and put in a WIX.
 
x2 for everyone above, also i recommend an oem sending unit. i to have a 99 and have had 2 napa and one AZ which all failed, they all read a bit odd to. replaced with a new oem and it reads as it should following your RPMs. also the wix is a good filter. i run purolator, just dont cheap the filter, fram are proven crap if your running one.
just my op/ 2cents :D
 
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