So, I posted yesterday about oil psi numbers and noticed today they were even higher. At cold start it got up to 57psi. After getting to operating temp and pulling into my parking lot at work, I let it sit and run a few minutes at operating temp (199). The psi bounced between 30-40 while sitting idling in park and never went below 30. I'm hoping it's just a clogged filter, so I am going to do an early oil change either tonight or tomorrow. I'm using rotella now, so should I stick with it? Also, what's the best filter available at any parts store? Lastly, should I do an engine flush i.e seafoam in the crankcase before changing the oil? Thanks.

 

At cold start it should be higher than warmed up. Oil is thicker until heated, and the bypass of the filter is allowing oil to "sneak" around the filter media. This is about the absolute high pressure the pump can make before the spring loaded relief valve in the front cover reacts. So the cold part is good, and you'll see about same idle and revved up.

When oil warms up to normal temp range, it is at the operating viscosity. The filter bypass valve has switched back to pushing oil thru the media. So pressure will be less.

Spec is 50 psi at 2000 rpm hot, and 10 psi at idle. Oil light on at 7 psi. But drop back to the very similar engine in the D1 and the spec is 30 - 40 PSI at 2500 hot. Same oil pump 94 - 04, D1 or D2.

The filters in our tech section are very good https://landroverforums.com/forum/di...estions-46975/, I use the Purolator / MANN unit. I do like 44 hot at speed, and about 16 at idle. 180K+ on a D1 with Rotella dino. The larger filter add oil capacity. This helps with sludged engines where the oil takes so long to drain back to the pan that the pickup can actually become exposed (suck air) and oil PSI light come on when you are at 2000 rpm, then go out at idle. Adding extra oil is a little insurance, and that semi you passed carrys like 40 quarts in their oil sump.

Engine wear will impact oil PSI, if main bearings or the valve train are worn, the PSI won't be as high.

I would hope a new filter would do the trick. If you have the external oil cooler that can be a choke point as well. Same in a D1, where it is built into the rad.

Oil flush can help, but don't expect magic if the innards are highly sludged.

 

Thanks Savannah, I will do all that tonight. I think it may be the detergents in the rotella working. I changed the oil right after I got the truck about 2k miles ago, and used rotella (most likely the first time ever used in it). The psi has been slowly getting higher and higher over the past two weeks, so I hope it's just the oil filter slowly clogging with gunk that the oil has cleaned. I did use the cheapest oil filter they had last time I changed it (don't even remember the brand). Hopefully that's it. No other symptoms though. Runs fine.

 

Changed the oil (rotella 15w40) and filter (purolator) which was already on there. Oil was pretty black. Anyway, the psi finally got down to bouncing between 12-17 at idle, so I think I'm good. I'm thinking I may not have been letting it warm up enough. I drive very short distances in heavy city traffic (which is also why I get 9-10mpg). I think even though the coolant was warmed up, the oil never got fully warmed up. However, seeing how black it was after less than 2k miles, it sure didn't hurt to change it anyway.

 

You wont get higher oil pressure because of a clogged oil filter, the oil pump has a by-pass valve so if the filter is clogged or the oil is to thick (like when freezing butt cold) it does not go through the filter.

 

So you're saying it probably just wasn't warmed up enough? Either way it needed an oil change based on what came out.

 

Where you live its plenty warmed up after 10-15 min of run time, less in the summer.
You cant judge the condition of a oil by the looks.
It never hurts to change the oil and filter sooner than later.
How short are you trips and how long do they take?

 

2 or 3 miles and maybe 10 min in 40-50F weather. Once I let it sit for 5-10 minutes after the oil change and at 200F coolant temp it started to come down. Finally, it came down to settle around 15.

 

Warm oil works better. As you have observed, the oil PSI starts out high even at cold idle, because the inside the filter bypass is in effect. As oil warms, idle PSI drops. A bad filter might hold it up (staying in bypass), or if filter was really clogged up, the engine bypass would come into effect. In bypass mode the PSI will be higher as there is no pressure drop from the oil passing thru the media. You want to see the oil PSI drop down at idle to know that filter and bypass valve are working as expected.

The filter bypass valve when oil is warmed up can operate when filter is clogged (those 25,000 mile oil changes) or during wide open throttle sometimes (rather send dirty oil than not enough oil).

Short trips are tough on any vehicle.

 

With the test I have done in the past, I always check for cold idle pressure within a minute or two of run time, other wise it is not an accurate reading.