I was driving my XJR yesterday when out of no where I get a "Low Oil Pressure" warning. I drove a little while longer wanting to make it home but I noticed in my rear-view mirrior I was leaking oil pretty bad. The car started running very rough and getting shaky as I pulled over to the side of the road and right when I got to the curb the engine stalled and I had to have it towed back to my house. After letting it sit overnight I checked the oil stains and it pretty much leaked from all across the front of the engine. Has anyone heard of or had any similar problems to this? I would like to know what the exact problem might be before I take it to a mechanic.

 

I had this happen on my 99 XJR. It was a oil cooler hose. Mine busted when I was doing 75 mph. Had oil from the front to the back of the car. My mechanic did a great job cleaning that mess up.

 

YIKES! Just replaced the oil cooler hoses on my 85 Saab Turbo...they were 'sweating'...and they were 23 years old....cannot imagine such a failure on such a young car...must be real quality hoses then...sounds like something we should ALL check before another engine gets toasted by oil starvation.

 

You are describing the classic symptoms of an engine seized due to lack of oil. When the low oil pressure light comes on, you have only a few seconds to shut down to prevent engine failure.

 

oil cooler hit on curb, lines cracked or orings leaking, I would fill with oil and start up and look to see if you can see location of leak, if engine runs okay, or if low oil pressure is still on after refilling, If yes and engine runs rough or still stalls then start calling around for and engine. Andy has used ones Im sure, and so does ken at Motorcars, well they rebuild them

 

I just replaced my throttle body because of high idle problems. No more idle problems; however, the "low oil pressure" warning light came on after about 3 miles of test driving. At first the light turned-off after accelerating but after another mile of driving the light stayed on.

Before I left I checked the oil and it was full. After the light was permanently on, I checked the oil level again and it was still full. No abnormal engine noises and the car didn't freeze since I drove home another 5 miles.

Not the oil cooling hose since oil level is steady. Is it the idle on the throttle body, but the light does not turn-off after I rev the car. The oil pump?

 

I would check the oil pressure sensor and connections before tearing into the engine.

 

I ordered the sensor last night. Everything else looks fine (no leaks, oil topped off). Test drove the car today. Oil pressure wasn't on; however, 5 miles into the drive it came on. Also, when the light came on it seems like the lifters and vales were getting louder. When I got home, I turned off the engine, and restarted the car. The oil pressure light was off again and engine seem quieter. Light came back on after a short drive around the block.

 

If the lifters are getting louder at the same time you are seeing a low oil pressure light, it is not likely a faulty oil pressure sensor, it is truly low oil pressure. Recommend you do not drive it again till this is resolved.

"5 miles into the drive" implies that as the engine/oil is heating up oil pressure is dropping - you have a problem.

 

No lifters. Overhead cam running directly on valves.

I would suggest that you attach a real oil pressure meter to the sensor location with a warm engine to see exactly what the situation is regarding pressure.

 

Forgive my ignorance - haven't had the valve covers off on my Jag yet... BUT, if the cam lobes run directly on the valve stems, what set's valve clearance - shims? There's no hydraulic tappets of any kind? Is there a valve clearance check/adjustment service period recommendation?

EDIT: Went to JTIS, and the engine DOES have lifters, not in the classical pushrod/lifter configuration, but between the cam and the valve stem... they are not, however, hydraulicly adjusted - so the issue of lifters making more noise with low oil pressure is probably moot unless a film of oil beteeen the lifter's shim and the cam lobe quiets their operation.

From JTIS: Each cylinder head incorporates dual overhead camshafts operating four valves per cylinder via solid aluminium-alloy valve lifters. A steel shim in the top of each lifter allows adjustment of valve clearances.

Question remains, and I have not found it in JTIS, what is the recommended valve clearance inspection interval?

 

I think I remember (a common occurrence) having seen the clearances stated at one time but never, in three years of playing with the car and several forums, have I seen an issue with cam/valve clearance.

Yes, the cams push on shims within a sleeve. While there may be a wear issue there cannot be an oil pressure issue other than like you said, an oil film.

 

Yes, the proper clearance settings, adjusted by changing shims is specified in JTIS - but no suggestion of how often they should be checked.

 

solved my "low oil pressure" warning light. it was the oil pressure sender that was shot. easy fix, except for the small clearance to work the wrench.

 

the buckets"lifter" that ride between the cam lobes and the spring/valve package. Have a shim integral to the bucket, when you have the buckets out, flip them over and theyre stamped with a number that coincides with the lifter thickness to set clearance. You measure the clearance you have, figure the bucket thickness and either replace with a buckets with more or less clearance to get to what you want. on performance engines I like to run and intakes at .010 exhaust at .012. there is no time frame for checking cause you really should not have issue with them at all. but when you have headwork engine work etc done.....

 

Thanks, Brutal.