ixanay_on-the_exjay

The story...

I just had to swap my 0331 head because I had the crack. Unfortunately I cannot verify how long this has been happening as when I purchased it the head was cracked. I drove it for about 150 miles total between purchase and swap. Before I swapped I only saw the oil pressure go down to around 30psi. I honestly wasn't really checking too frequently since I wasn't doing a lot of driving considering I didn't want to do further damage. This is all to say IDK if I actually have a good 'before' hot idle temp.

My hot idle oil pressure reads at about 15>19 psi via the gauge on my dash. If I watch it it moves slightly up and down (maybe has to do with TPS code I have) My operating psi is averaging about 40 while over 1600 but I've seen it creep to about 37 while on the highway.

So.. the facts

Hot Idle - 15>19psi
Operating (30 mins+ hot weather) 37>45
Cold Start - 45
On (cold or hot) start my gauge likes to lag and slowly come up to pressure. See video


If my gauge is true, which is an assumption I'd like to make right now while I look for a mechanical gauge, i'm hitting close to the lower limits set out by Jeep. With my new head and no coolant in my oil can I expect my engine to maintain these numbers for a while? My worry is that these bearings are in free fall and my crank or cam is going to explode and crush all my XJ hopes and dreams within the next few months all because I didn't catch it soon enough... Help set me straight? Thanks all.

Ralph77

I think those numbers are fine. My understanding is that 13 at a hot idle is acceptable. Not like you rebuilt the engine. Just did the head. So.... MY '00 reads about 21 at a hot idle. About 164K on her. But I am going to be checking that soon with a mechanical gauge cause I doubt it is that high and I want to know how far off my gauge really is.

tjwalker

I think you are likely okay. For sure, if those numbers are accurate, I wouldn't even remotely think about any other kind of internal intervention. Get a mechanical gauge to verify for peace of mind.... but just drive it. Enjoy your XJ!

Oil pressure spec: You are within these specs!
*Not less than 13 psi at HOT idle
*Between 37-75 psi over 1600 rpms

ixanay_on-the_exjay

Thanks TJ. I've seen your comments on the subject in other threads, definitely good to see this advice is consistent regardless of previous coolant damage. I will sleep better about the engine now. On to the next thing =]