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Oil pump?

Deere65

Deere65

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Location
,Rogers,Arkansas
So a little background first which isn't much but I bought this truck back in the summer with issues it needed injectors, a new crossover pipe, valve covers resealed, boost solenoid, lift pump not working etc. When I had the drivers side valve cover off I seen a drop of coolant in the oil just below where the valve spring sits so cleaned up oil real good and pressurized the system. Yep it was a crack. Replaced head with a new one from clear water cylinder heads. I only replaced that head. And yes I made sure the push rods were in correctly.

After a few miles(like 50 or so) I started noticing the oil pressure was extremely low at idle when hot.(like needle right next to the red). When the engine is cold it holds around 60.

Installed manual gauge and here is what I'm seeing. When cold I'm at 60 just like dash gauge but what the dash isn't showing is how much the pressure is bouncing and after a minute or two the pressure will slowly drop to about 50 and then suddenly jump back to 60 and it will do this several times and then eventually just slowly continue dropping.

So before the manual gauge I figured this was caused by having new stiffer valve springs on one side and that loaded the cam to one side and killed cam bearings but now I'm kind of wondering about the regulator in the pump sticking and releasing until it gets really hot and just stays stuck?

I should also add that the oil cooler was removed by previous owner. I installed one hoping this would help. It didn't.
 
Sounds like your cam bearing assessment is correct to me. You can throw an oil pump at it, shouldn’t hurt anything other than $100 and a day or two depending on your situation.

I was searching for “BEST” oil pump a feew years back and all roads led back to melling. As in once I spoke to Melling I found they produced them for every manufacturer I could name and it was all repackaging game.
There was one exception that for an extra $40-50 was a kit with a few spring options for dialing into your specific needs. Cant remember who it was that offered it, though Melling still made it.

They had great customer service- didn’t take long to talk directly to an engineer their.

You may find the coolant that got into thr oil atthe time helped wipe the bearings. Pulling the pan and looking at a rod bearing may not be a bad idea- catch it while fixable if anything went on other than your new valve springs.
 
No oil cooler? Yeah Overheated engine oil in the past and that can take bearings out.

Coolant in oil. :vomit: There is no faster way to wipe bearings than coolant in oil. I would check the turbo bearings closely as they are the first to get ruined with coolant.

These engines priority oil the cam bearings and they appear to be where oil pressure gets lost. So if you yank the engine make sure to do the cam bearings and measure the cam for undersize journals as well. You could have a mains crack leaking oil.

@Will L. did not mention you can put the high volume oil pump in from the later year piston squirter blocks. This might buy you some time.

A Oil Sample sent in could help decide to toss a pump at it or yank and rebuild/replace. Cut open the oil filter and see if you can read part numbers (lots of metal) in it.
 
The day after I brought the truck home I changed the oil and it was black as coal so if had antifreeze in it it wasn’t enough to change it’s color. Then after changing the head I changed the oil again.

When I noticed the pressure low the first thing I done was pull the filter and cut it open. I found nothing. Since I’ve started trying to figure out this issue I have cut open another filter and still nothing.

I know it’s pretty rare for a pump to fail but what’s got me how the pressure drops to 50 and then suddenly jumps back to 60. I have never seen that.

Maybe the bearings are so far gone there’s no more metal to find. That or like war wagon said cracked mains. That’s my biggest fear
 
They are the biggest liquids pump mfr there is. They never seem to miss an opportunity. Cheapest to best. All classes of industry. Yet being the world wide monster they are, they still will let schmucks like me with dumb questions talk to engineers in the name of customer service. Hmm, always make customers happy and you grow a business? Wierd concept nowdays.
 
I do know that on My 93 K1500, 350 engine with just over 200,000 miles, it dropped to about 15 pounds OP at idle, hot.
I installed a new timing chain/sprocket set and an oil pump, oil pressure came back to 40 on the road at operating temp and 30 pounds at idle.
I would say give the oil pump a try and see what it does.
 
I took a video of the gauge and was wanting to show you all but I can’t get it to upload. Any way I think I’m going give the pump a shot. If it doesn’t work I won’t have to buy one when I rebuild it.

I’m really thinking that since it didn’t have a cooler on it the excessive temps of the oil either cause the regulator to start sticking or the spring has gotten weak
 
sctrailrider said:
There are 2 oil valves under the oil filter inside the block, maybe one or both have trash in them and are sticking.....
Click to expand...

Yea I have replaced both. When the oil cooler was blocked off they removed the orfice plug covering the cooler bypass. So I got a new plug and the cooler and filter bypasses just in case it was one of them. Took a while to find the filter bypass valve everyone had the wrong p/n. Had to order 5 different ones before I found the right one to fit the block. Guess a 599 block is different than the rest on that part
 
I got it on YouTube. Here’s the link. Quality isn’t great. This is when the engine was cold at idle. It done this several times then eventually drops slowly.

 
So how it instantly jumps back up at around 42-43 seconds.... hmm-I know it is exactly how you described it- but watching it is an eyebrow raiser.
I see why you’re thinking bypass valve in oil pump.

Ya know, oil filters have them too. What ever filter you are running- take it off and cut it open for inspection. Wh
Wix 57202.
 
Your right it definitely raised my eyebrows. Especially after watching it do that several more times.

I’m actually using a john deere branded filter which I think is actually built by Donaldson. It’s actually for multiple gm vehicles including the 6.5.

I’ve had a couple of them cut open to check for metal. They don’t have a bypass in them and so far have found no metal either
 
Expanding on @sctrailrider : There are 2 oil valves under the oil filter inside the block
1) Oil cooler bypass.
2) Oil filter bypass. Thus our oil filters do not have (or need) a built in bypass valve. One size fits all filters may have one anyway for another application it fits.

Cold oil going through the oil cooler because the bypass is stuck closed could cause higher pressure. IMO Bypass the oil cooler again because Sci-Fi has to be plausible: the truth does not.

Looking at the gauge "jumping" IMO a stuck valve even in the oil pump isn't going to make a gauge jump. What could make a gauge jump? Think of the "squirt" holes drilled in the crankshaft lining up to lube the rods (nevermind they can always provide flow/pressure through the bearing when the holes are not aligned) allowing more flow and pressure drop when the holes align. Lifters moving can uncover a high leak area and going a step further installing the pushrods upside down can wear the rod and rocker arm quickly. IMO this would have a lifter tick. Cracked mains can spread to leak worse when the cylinder near it fires.

These are just guesses. However it looks like you need to pull the engine and see what's going on. Before you do I would pull the valve covers just in case it's a pushrod or lifter issue. We had another member on here rig up a primer, feed the oil pump, and look for where the oil was leaking from at a high rate. *shrug* Easier to yank the engine.

Then if you have a tight budget look at Military surplus 6.2 engines as a 6.5 is just a punched out 6.2. Heads are the only major difference, but, I have run 1985 6.2 longblocks (yeah 6.2 heads) to replace turbo 6.5's.

The oil overheating from a lack of an oil cooler and coolant in the oil mean oil failure to me. Again I suggest a close inspection of the turbo because the turbo bearings get hurt the easiest.
 
I was under the impression thee were some 6.5s using the 90* oil filter adapter that did NOT have the bypass in place. No clue where or when I read this- it could have been misinformation. Regardless for this situation, as your filter has none.

But it seems to me pressure is up as there is a restriction, then is slowly clears. Then after a bit the item gets in the way again causing the peak in pressure. Over extended time as the oil warms and becomes thinner, the pressure gradually lowers. But if the pressure spike continues, even at lower ranges, something is impeding flow.

Because all this happened after the head work, I would be very tempted to pull that valve cover and take a peak.

Man I wish our injection lines wrapped around the valve covers so they could be removed easier. I have seriously thought about having some custom lines made just for that.
 
It would be interesting to make a primer and try the hot and cold tests .
 
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