after overheating Low oil pressure?

[markaboo929]

Ok so I have an 2003 4.0 in my 88 xj-ok had overheating issue and resulted cracked 0331 head-replaced head and now oil pressure seems lower than before-was low when head was cracked.It usually sat around 60 when started and when engine at operating temp was between 30 and 40 with 5w40 rottela at idle-now she is between 20 and 10 at idle and between 20 and 30 at hiway speed 3000 rpms.I wanted to know if the cam bearings have possible been burnt/damaged-Engine has 125,000 on it-I owned it since 10 k.I do not want to go the oil pump main bearing and rod bearing route to find the cam bearings are shot.SO next I am thinking if I used 15w50 oil and installed an oil cooler,may that be a long term bandaid? Has anybody tried that in other words.It runs real good and has no noise at all.Any thoughts?

 

[robsjeepxj]

I would pull the pan and check the bearings but that's just me. If their bad the motor probably won't last very long if you don't replace them. You can try thicker oil but doing it right is really the best course to take in the long run.

 

[RidgeRunnerXJ]

Did it leak coolant into the oil when the head cracked, and if so how long did you drive it before it was fixed? Coolant is very hard on bearings.

Years ago I had a FJ-40 Landcruiser, I rebuilt the engine and had a hose blow off on the way to get the emissions tested. Long story short.....overheated, blew the head gasget, I didn't know any better, drove it for a week, antifreeze in the oil, pulled the pan, bearings were shot, replaced main and rod bearings, still no oil pressure, cam bearings were shot too. Learned a valuable lesson.

 

[Talyn]

Antifreeze is like acid to bearings.

 

[SolarBell]

I had a 2000 XJ, same issue - overheated twice. Put a slight crack in the head that didn't affect how it ran but leached coolant into the oil. By the time I figured it out my oil pressure was dropping to 0 at idle. The easiest fix was a new long block. If you already replaced the heads I'd put a short block in it, otherwise a full rebuild is likely warranted.

I've read about folks who put in thicker oil and a high-volume oil pump, but all that does is keep up the pressure - the journals and bearings are still good and eaten.

 

[birchlakeXJ]

Jeep oil pressure spec:

*Not less than 13 psi at HOT idle
*Between 37-75 over 1600 rpms

If you're in this range, drive it.

 

[markaboo929]

Yeah that is the route I am going to do,drive it.It is between 0 and 20 at the gauge hot idle 20 - 40 at hiway speed 3000 rpm it used to be 20-40 at idle and 40-60 at speed-5w30 oil-have'nt checked it with a mechanical gauge-tried a new sender-same pressure-I will just use some 5w50 oil in the summer and use the shell 5w40 in winter plus lucas to buy some time to build a stoker.It probably will last a LONG time like that for all I know.It is my daily driver though.If I am going to spend $ on main/rod /cam bearings-not worth the $ and time it takes to repair-I am a tech/mechanic so labor is not too big of a deal.I really think it is cam bearings-it did not run long at all loosing coolant-just major overheat.Ehh...well now I have an excuse to build that stroker I have always wanted!:roll:

 

[old_man]

I would change to 10w40 and see what happens. If the numbers come up, I would drive it until it croaks.