1997 Isuzu Trooper Limited 140,000 miles.

I've owned it since 2000 and ever since then it has had a manageable oil pressure issue. When the oil starts to break down the Trooper starts making the tell tale ticking noise to let you know it is time for an oil change. After the oil change everything is fine. Oil pressure runs a hair under 85 at 3,000 rpms.

This is the way it has been since it had only 30,000 miles on it. I've put on about 100,000 miles since then. My mechanic always said just let it be and do the frequent oil changes. Lately I've started wondering if all of these years we should have at least dropped the pan and at checked for screen blockage. Since he has not explored the pressure issue I assume he thinks it's something big like bearings or pump. He has never said.

The oil pressure is now running a little lower, even after oil changes it's around 79 at 3,000 rpms. I'm concerned it is now starving the oil system and doing more damage.

I guess my question is, should I try something like SeaFoam in the oil to clean everything up? Some have told me not to because if it is a bearing issue it could cause a worse pressure issue by removing carbon and gunk that is actually helping to seal and improve the pressure. Or worse that it could release carbon and gunk that will block the screen and starve the system even more.

Any help is greatly appreciated!

Thank you!

Tim

I had a '94 with the 3.2L V6 in it, and had similar issues. I could always tell when it was time for an oil change because the pressure would drop and it would start tapping. Fresh oil at the right level would bring it right back into step and no worse the wear. The drop you're seeing in typical pressure (85 -> 79) is most likely just the result of the engine being 140K old and not due to any significant issues, I would say. As long as you keep the oil level at a reasonably full state, change the filter with the oil, and don't abuse the thing, I don't think you should have any significant issues. This is assuming, of course, that you don't have any significant leaks or burning oil indicators from the truck.

FWIW, I used SeaFoam in my V6 about once a year just to clean things out. I'd put it in, run the truck about 60 miles, and then have the oil changed. Your mileage may vary.

James

It helps to know someone else has had the long term low pressure issue. I've had the issue since at least 30,000 miles, so it's not really age related.

I can't use 10w30 weight or it will sound like it's going to throw a rod. Did you have to run heavier weight oil to keep the pressure up?

I kind of feel dumb to have driven it all of these miles without actually understanding what the underlying problem is. Did you ever determine what the source of your low pressure was?

Thank you!

- Tim

Not sure what is meant by "85 -> 79" ?

I have a '95 Rodeo V-6 3.2l

240,000 miles.

Oil pressure gauge(stock) reads: 0 30 55 110

Once warmed up at 70mph running conventional 5W-30, my oil pressure is around 30.

My resting pressure was about 25-30 as well, but running at 3000 RPM, as Tim stated, pressures would of course be higher. The 85->79 was in reference to his measured oil pressure, which had fallen from 85 to 79 over the course of time and miles.

Tim, I never fully found what the issue was (if there was a serious one) that caused the drop before the truck went other directions. I never noticed any serious indications of excess wear or anything when I was doing service on it either. The valve cover gaskets at the plug holes leaked, but that was about the worst thing going on, since I never sprung for the later version boots. I should say that I was usually running 5W30 in my truck as well.

James

James, Thank you for your response. I guess I'll leave well enough alone.

Just one more quick question. Did you ever have an issue when you started the truck and heard the tell tale ticking, then shut off --> restart and it would go away?

It now happens to me about 30% of the mornings and this is right after an oil change. :-(

Thank you again.

Tim

Check your oil level, keep it filled!
Change your oil, I try for 5K miles.
Mine seems to like penzoil platinum the best, go figure?
I can't say that I am anal enough to log my oil pressure numbers, but it stays between the low and high dots.
This is on my '96 trooper, same as the '97.
I just rolled past 260K miles and its not showing any signs of stopping yet, the stupid thing still has the OE clutch in it!

I have been wondering, it seems a lot of people are using very light oil....the owners manual for my 94 Trooper calls for 20W50 in the summer, anything as low as 5W30 is strictly for temps below 40 degreesF. I was wondering why people are using such light oil when at the same time a lot of people are seemingly have oil pressure issues (the manual also calls out a minimum of only 8 lbs pressure at idle...even with over 150K miles mine does that no problem, as long as I have the specified weight oil for the ambient temps).