Oil Pressure

[quinryan]

Man, it isn't the problems that I have with FrankenJimmy, it's that they're all either harder than they need be or just weird.

Gettin' kinda cold here in Colorado Springs at night now. So, the 6.2 coal-fired (it just seems that way) is cold as ice in the AM. Nothing new or unique there. But what is weird is that it shows less oil pressure when its cold than when after it hits operating temp.

First fire, it shows 30-35 lbs. Okay OP, but not exciting. Five or ten minutes later, and after watching the temp gauge go up and back to 200*, I have idle OP of 65-70 pounds. I always thought that the OP should read more when cold, and this is part of why we have multi-viz oils in our modern times.

Heads are rebuilt, all filters are under 3K, and it runs good, if too smokey (still haven't fixed that. I know what it is, bit damn that's a small adjuster screw).

It IS blowing a lot of blue (oil) smoke out the driver's side exhaust, with none coming from the passenger side. It is real blue when cold, and then tapers off to a blue mist after warm-up. Rings, right?

 

[hunter29078]

Are you sure the oil hole in the heads are not obstructed. That can cause the blue smoke sometime because it keep the oil backed up on top of the heads. It does sound like some kind of obstruction. Less pressure when it is cold because it is thicker and thiner when it is hot, allowing it to flow by a minor obstruction easier.

 

[quinryan]

So, colder, thicker oil equates to lower OP readings? Okay.

In the event that there is an obstruction in my heads, hopefully this can be fixed via just pulling the covers?

In related note: you know all those engine cleaners out there, the ones that clean the inside, such as "Engine Flush" (really ATF I know). Is there any merit to these products with a diesel?

 

[hunter29078]

I have had this happen with gas engines. I pull the coves locate the oil holes and take a clean piece of wire and jab into the hole. Hole should be in lower corners of the heads. A wire hanger works well. I am always scared of engine cleaner on older engines. Seams like they cause oil leaks, it will also break all the crud loose and create more problems.

But yes colder temps create thicker oils. I am not sure how cold it is where you are but I know in very cold places a thinner oil is recommended for cerian temps. In most owner manuals of newer cars it give different oil specs for different temp. But with my diesel I always use the heavy wieght rotella oil. I would not vary from that.

 

[diesel4me]

My thoughts are the diesel fuel not getting ignited during your long cranking sessions trying to get it started ,is diluting your oil--so its thin at first,once the engine warms up some of it evaporates and the oil regains viscosity ..I'd change the oil and fix the hard starting problem and see if that improves the oil pressure--if anything you should have higher oil pressure when the oil is cold and thick right after a cold start,and notice a drop later as it fully warms up--not the other way around!..you might have a partially plugged up oil pump intake screen,that restricts thick cold oil from getting in,but passes enough freely after warming up to restore "normal" pressure...one '87 6.2 engine I got for parts had NO screen on the pump,just a pipe that had a 45 degree angle cut on the end--not sure if it was just missing,or if GM designed it that way?...

 

[quinryan]

Actually, the one problem that I don't have (yet?) is hard-starting. I let the glow plugs cycle twice, hold the pedal down, and crank. FrankenJimmy will fire w/i a few seconds, and idle properly quickly.

I know how mulit-vis oils work and expect thicker-when-cold (even 15w) to result in higher OPs at first. The difference between cold OP and hot OP is almost 25-30 lbs, with the higher on the cold end.

Of course, this presumes that my OP gauge and sender function as designed. Nothing such is a goven with this thing.

Any input on engine flush products? I have heard that they're not the best with diesels, but then again, one hears a LOT of things these days.

 

[4xcrazy]

I've done the trans fluid trick once or twice, never really noticed any difference in anything though, ran it for a few hundred miles, swap out with new filter and good oil.

What type of oil HAVE you been using?

 

[quinryan]

I've been using Rotella 10w-15. I tossed a can of Restore in their and since it burns a lot of oil (left bank only it seems), I put a bottle of Rislone in their the last time it was a quart down.

Always open to other ideas.

 

[GsxrMike]

I don't know about diesels but I just put a quart of Marvel Mistery oil in my truck and the lifter noise went away within 100 miles or so.

 

[ktmoutfront]

My 6.6 will run low pressure until it starts warming up. Not as bad with new oil. Go figure. If I run the block heater over night, I do not get this happening. It sure cranked hard this morning.

30 degrees out now with high winds. Winter is here.

 

[diesel4me]

I've never heard of 10W-15 Rotella oil,or any other brand with that viscosity...!..was that a misprint maybe?..if not,maybe the low viscosity of that oil is what reduces the oil pressure cold and it thickens a bit once its warmed..


I use
15W-40 year round in my diesels and its gotten down to -10 a few times,they usually start fine as long as I remember to plug in the block heater when it goes below +20..
I usually put my trickle charger on them too overnight to ensure my old batteries will whip them over fast enough..

I have seen some nasty results inside an engine from using that "Restore" crap!..I stick with oil boosters like Marvel Mystery Oil or Lucas if I want to add anything to my oil..that Restore stuff is like metallic paint,has copper,lead and silver particles in it that supposedly "fills cylinder scratches and worn bearings with real metal"!..more like grinding compound,IMO--you'll really need to "Restore" your engine after using that stuff..