So this morning the Jag had the low oil pressure error come on while idling and cold. It eventually went away, but when I went to drive it, it started making weird rattling sounds from the valves under acceleration. It sounded fine at idle though, about ˝ mile away it gave a low oil pressure error again while I was at a stop light. So I immediately shut it off until the light went green, then pulled into a nearby parking lot. I let it sit and checked the oil, all seemed normal. Fired her up again, and it was like nothing happened… No more rattles, no oil light, nothing. I haven’t had a chance to get the oil pressure yet, but it is definitely on the to do list before I drive it again. What could be causing it? I’ve driven over 1k miles and the oil level is unchanged, so at least I know it is not burning much of it. Is the oil pump easy to change or a PITA? One other thought, the top portion of one of the tensioners is floating around the sump, I plan on removing the pan and pulling it out. Could that have caused the issue? In either case, I’d appreciate the input and will keep you all posted on my findings. Thanks in advance!

 

I had a customer with an XK8 that came from another shop and they told him it needed an engine. He brought it to me. We checked the oil pressure and it was below specs. We tore it down and replaced the oil pump and the pressure came up to specs and the customer has put thousands more miles on it since. I think it has 140k miles on it. It is quite a job but it's better than buying an engine.

Check the oil pressure first with a manual guage. then decide what's next.

 

Do I have to take apart the timing system to get to the oil pump? I hope not, I just had it all apart! I'll go pickup an oil pressure test kit from harbor freight and see what it is at. I'll probably drain the oil, pull the pan, clean it out, change the filter, and put new oil in. Hopefully the tensioner getting sucked into the catch screen was all it was... What should the oil pressure be at?

 

To swap oil pumps, it's all timing parts off unfortunately - the pump is driven directly by the crank, bolted to the cylinder block.

If you know a tensioner slipper is in the sump, will you be replacing the offending tensioner?

 

I replaced all 4 tensioners and timing chains 2 months ago. The plastic cap on RH bank fell off and is probably in the sump because I did not see it when I did the timing system.

 

The rattle is an intersting note, in that our engines do not have hydraulic lifters. I agree with the advice to get a test guage and hook it up -a long enough line so you cn tape it to the ouside of the windshield is nice.
They are pretty cheap at Harbor Freight, although I really do hate buying Chinese stuff.

 

There are 2 different oil pumps for the 4.0 engine. One has a pickup tube on the lower bedplate and one is direct to the pump (later style).
You have the plastic pickup tube to the bedplate if it is a 1998 XJ. You can pull the pan and pickup tube and see if the screen is blocked with debris.
It won't take half an hour to see if it is blocked.
Clean or replace it.
The pan seal might be reuseable if it is still pliable but a new one might be better to have in case!!!

bob gauff

 

Thanks for the comments. Hopefully the screen is just clogged... I wanted to pull the oil pan while doing the tensioners but i wanted so badly to drive it!

Yeah but they are cheap! lol. I went and bought the kit, it was 20 bucks. Then got a cylinder leak tester, which i think is a "blow by" tester?... It was on sale, and sounded like the same thing. I'll probably perform a compression test and do the blow by test while I do everything else, just to ease my collective mind. It hasn't burned hardly any oil, at least none that I can tell, for over 1k miles, which means I might be safe with the whole nikasil crap, but I still want test results . In either case, I'll keep you all posted. What oil pressure should she be at?

I was noticing during the timing job that I could not "find" the oil pump with the timing cover off... Does that mean it its behind the timing system on my year? If that is the case, does that mean I do not need to dismantle my timing system to get to it? If so that is awesome!

 

The oil pump is on the front of the crankshaft behind the cam drive chain sprockets. It is a gearotor type pump. You touched it several times if you replaced the primary chains or moved the lower sprockets.

bob gauff