My statement was that real race engine builders do not think twice about running 0W5. That statement is true and was not directed at you, rather to the straight-30 wt aficionados, to make a point that straight 30wt oil is not necessary to protect an engine, not even in Florida.
I know very well that some respected builders run heavier weights. That really isn't the point. The point is:
If 0/5 oil can hold up to 500 miles with tach to the redline around a track, 5W30 is probably more than sufficient for your daily trip to the grocery store.
There is no advantage to running an oil thicker than that, particularly not a straight 30-weight, at least in terms of engine protection. There are however several well-documented disadvantages.
That said, folks are welcome to run whatever they like in their crankcase. Leading the horse to water, beating it after it's dead and all that....

 

This oil debate is simply disturbing. Keep your fetish in the garage where no one can be exposed to your perverse obsession.

This is an XJ forum, not a petroleum engineers forum.

 

R u kidding?......the last oil thread went well north of 100 posts.

 

What a cluster. If you're running between 25 and 75 psi you're generally in good shape. More or less than that could indicate an issue under certain conditions. Doesn't mean as much as you'd think and certainly doesn't need to be turned into a discussion about straight 30W oils.

 

Yay oil threads!!!!!!!!!

Ok to get us back on topic I have a serious question. My 4.0L runs at about 60psi constantly, even at hot idle. Sometimes it will drop to the 40psi range at idle but only if it is sitting for a while. Is this good or bad?

Please don't fire me... I actually want to learn something!

 

What grade oil and filter are you running? These have a lot to do with the pressure you see. A restrictive filter will lower oil pressure by resisting flow before the sensor, and heavy oil will increase pressure by being harder to pump in general.

60 PSI is a little high but these sending units aren't exactly reliable. If you're concerned about it I recommend checking the connector and its wiring for chafing, melting, and corrosion. Anything that will increase or decrease the resistance of that circuit will screw up readings. Plus the sensor may be inaccurate. If you're really concerned there are mechanical test gauges that affix to the port.

 

Have your oil pressure tested with a mechanical test gauge. Factory gauges in just about any vehicle r one tick above worthless. U will then see, with a real gauge, that oil pressure fluctuates up/down with both engine rpm and temperature.

Read Motor Oil 105.

Oooops, sorry Mr. salad, I was typing while u were posting.

 

The mechanical gauge will tell you what your true oil pressure is.

However, in this case, it is pretty clear that either the sending unit or dash gauge is faulty. The engine simply does not run at constant 60 psi and switch to 40 psi once and a while.

Given that sending units are the most likely failure point, if you want to skip additional diagnostics, you may want to go buy another oil pressure sending unit. I would get either dealer or NAPA. They are around $45-50. It takes a 1-1/16" special socket (deep may be fine depending on make) or wrench. However, it could also be the wiring or the dash gauge.

 

Where is this located? Also, is it really a concern or can I just go on with my life? It idles smoothly and I don't hear any abnormal noises. I have other concerns that need to be addressed and such little time to address them.

 

Doesn't the owners manual say what your pressure should be at with certain weight oil? Expect slight, if any noticeable difference with different weight oil.

 

The sending unit is right above the oil filter. Its not going to affect the performance or operability of the vehicle. Main thing if you end up with a hole in your oil pan, the pump fails, etc. then you may not know until you start hearing noise and then its too late.

 

What a waste of having a help forum when so many of you did nothing more than drag out this forum by arguing about who's right. None of you are engineers who work in the study of oil and there are always articles and professionals around who'll contradict any article you post, share etc... so please can we use these HELP forums for help instead of filling up pages of a thread with bickering like 15 yr old's who want to be right?

I, like you EPK5150, have higher than normal Oil Pressure Gauge reading. I have 5w30 Valvoline oil in my 96 XJ 4.0 4WD and a new k&n oil filter, as well as a new Oil Pressure Switch/sending unit. I've never known my gauge to ever hover around the 60 mark so if you have an answer to what is the cause of this, possibly, or how to find out the cause of this, I'd greatly appreciate it.

-Jessica

 

Great post Jessica. It sucks having to read through pages of bickering with the hopes of finding a useable idea. Then when you post a new thread with a similar question you get flamed. I will be replacing my sending unit this weekend and will post an update of the outcome on monday.

-Eric

 

Arguing? Nah,gotta kinda look at it as sittin' around the campfire shootin' the bull.

Cause? Inaccuracy of the set up. For instance have you ever looked at the size of the orffice in that sending unit? My XJ cruises at 60+ psi and hot idles at just under 40 (never lower). If you want accuracy hook up a mechanical gauge. Also you may want to think about switching to a Wix/NAPA Gold oil filter.

 

Well its good to know I am not the only one whose oil pressure is reading a little on the high side compared to some others. Either way, once I replace it I will let you guys and gals know.