Pressure is continuing to climb, it sits just below 40 at idle now.
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Very High Mileage truck oil suggestions
- Thread starter SirReal63
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You really need to verify the oil pressure with a mechanical gauge. If your getting significant fluctuations it could also be a bad stepper motor on the gauge cluster. I had to rebuild my cluster because of multiple bad stepper motors.
I'm glad your doing some research on these engines and oil pressure issues/causes. Fantastic engines but the cast aluminum oil pump housing is a week link in my opinion.
Either way, verifying the the pressure and a $150 pump and are a lot cheaper than good used engine.
I'm glad your doing some research on these engines and oil pressure issues/causes. Fantastic engines but the cast aluminum oil pump housing is a week link in my opinion.
Either way, verifying the the pressure and a $150 pump and are a lot cheaper than good used engine.
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SirReal63
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I understand what you are saying, and mostly agree. I have probably read at least 50 different threads on the net concerning the low oil pressure. It makes me wonder how many good engines have been changed because of a clogged screen.
A mechanical gauge is on the list, GM didn't make adding one very easy on these engines, or at least I haven't found an easy way to do it yet. The gauge has stopped dropping and the pressure is holding steady at about 40 at idle and is behaving like it should.
Access underneath is not very good on the 2500HD 4WD, that changes the labor. This engine is probably living on borrowed time as it is. If I have to pay my mechanic the labor to drop the diff and swap out the oil pump, it makes sense to just throw a short block on it for a few thousand $$ more. It would not be just a $150 pump, it would be a lot of labor and the money the mechanic charges for that. If I could do this myself easily, I would, on a 2WD truck it is easy, the 4WD not so much.
I am not sure it is worth putting too much money on an engine that has 297k miles on it. The internals are unknown, I would expect worn bearings at the least.
If the truck were to be used a daily transportation it would change things, but it will not, it will be a farm truck so if it blows it gets a new block. I may try and drop a 5.3 in it at that time, I won't need the extra grunt of the 6.0 and it is so much easier to find.
I truly appreciate everyone's input, it makes a difference to me. I don't know everything, and after 50 years on this planet I find learning much easier today than 30 years ago.
A mechanical gauge is on the list, GM didn't make adding one very easy on these engines, or at least I haven't found an easy way to do it yet. The gauge has stopped dropping and the pressure is holding steady at about 40 at idle and is behaving like it should.
Access underneath is not very good on the 2500HD 4WD, that changes the labor. This engine is probably living on borrowed time as it is. If I have to pay my mechanic the labor to drop the diff and swap out the oil pump, it makes sense to just throw a short block on it for a few thousand $$ more. It would not be just a $150 pump, it would be a lot of labor and the money the mechanic charges for that. If I could do this myself easily, I would, on a 2WD truck it is easy, the 4WD not so much.
I am not sure it is worth putting too much money on an engine that has 297k miles on it. The internals are unknown, I would expect worn bearings at the least.
If the truck were to be used a daily transportation it would change things, but it will not, it will be a farm truck so if it blows it gets a new block. I may try and drop a 5.3 in it at that time, I won't need the extra grunt of the 6.0 and it is so much easier to find.
I truly appreciate everyone's input, it makes a difference to me. I don't know everything, and after 50 years on this planet I find learning much easier today than 30 years ago.
There is an oil galley plug on the front drivers side of the block. It's metric. It's pre filter but will work for testing op.
A 5.3 will drop in but you may need to take it to a tunner after install to get it running right, dunno.
A 5.3 will drop in but you may need to take it to a tunner after install to get it running right, dunno.
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SirReal63
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I did read about the oil galley plug and didn't go much farther with investigating it. I do believe some tuning will be required for the 5.3 but that seems easy enough to get, if/when the time comes. The engine sounds fantastic, with plenty of power so I will just ride it out for a while. We aren't taking any trips in it, just short excursions to the farm.
Honestly,300k sounds like a lot of miles however those engines if properly maintained isn't really high mile.
I've got a 99 z71 with 270k on it. It'll roast the tires off at will and doesn't consume a drop of oil,so don't go buying a new long block just yet.
As far as dropping a 5.3 where a 6.0 used to be you'll need it either dynotuned or get an ecu from a 5.3.
I've got a 99 z71 with 270k on it. It'll roast the tires off at will and doesn't consume a drop of oil,so don't go buying a new long block just yet.
As far as dropping a 5.3 where a 6.0 used to be you'll need it either dynotuned or get an ecu from a 5.3.
15W-40 and drive on.
If you are trying to make it last longer you could use Archoil AR9100 when you change oil or Liquid Moly Ceratec at the next oil change.
We have not tried AR9100 yet but did test Liquid Moly Ceratec in a Polaris 325 engine and tore it down after 11 hours of low rpm run time. It did put a glass like finish on the top end and the bad crank still had not chewed up the new rod bearing totally but it was starting to knock under load.
The prior owner had blown the oil cooler line and ran it without oil at highway speed and spun the rod bearing and chewed up the crank so it was a good test bed since the engine was going to be torn down to properly fix. We picked up a tight used crankcase with crank and connecting rod read to install.
We use Rotella T6 mainly but for a high mileage gas engine I have been impressed with Mobil 1 10W-40 High Mileage. It may be the moly that gives it the cling that I like.
300K road miles would not concern me for your usage.
If you are trying to make it last longer you could use Archoil AR9100 when you change oil or Liquid Moly Ceratec at the next oil change.
We have not tried AR9100 yet but did test Liquid Moly Ceratec in a Polaris 325 engine and tore it down after 11 hours of low rpm run time. It did put a glass like finish on the top end and the bad crank still had not chewed up the new rod bearing totally but it was starting to knock under load.
The prior owner had blown the oil cooler line and ran it without oil at highway speed and spun the rod bearing and chewed up the crank so it was a good test bed since the engine was going to be torn down to properly fix. We picked up a tight used crankcase with crank and connecting rod read to install.
We use Rotella T6 mainly but for a high mileage gas engine I have been impressed with Mobil 1 10W-40 High Mileage. It may be the moly that gives it the cling that I like.
300K road miles would not concern me for your usage.
SirReal63
Thread starter
Clevy and Gale, I appreciate the thoughts. I won't be changing the engine until it completely dies and will try and get as much life from it as possible. I spent a little time looking into the nano ceramic additives, very interesting stuff. I may try the Ceratec or the AR9300 after a few oil changes, the AR9300 looks like science fiction for friction but looking at the industries that were the testbed for the product, it may be the real deal. I may order some of the AR9300, it certainly isn't expensive if it does half of what is claimed.
As far as the truck goes, the oil pressure issue appears to be remedied for the moment. The gauge is no longer dropping and is holding steady pressure, very much in line with what I would expect to see. I almost never rave about any product, my sales and marketing days are long over but I have been impressed with Kreen. I bought a case of it a few years back to gently remove some sludge on a BMW 740i and it did a fantastic job on that. I cannot say with certainty that it cleaned the screen under the sending unit, but I also cannot say it had no impact. The truck gave no hints of low pressure, though the gauge did.
I would encourage anyone with low oil pressure to not overlook something as simple as a clogged screen, especially if the engine is otherwise running fine (I am still trying to figure out why a screen would be put there?). Far too many mechanics will happily change an oil pump and sending unit and then swap an engine if that didn't correct it. My own mechanic is no exception, and he is one I trust.
As far as the truck goes, the oil pressure issue appears to be remedied for the moment. The gauge is no longer dropping and is holding steady pressure, very much in line with what I would expect to see. I almost never rave about any product, my sales and marketing days are long over but I have been impressed with Kreen. I bought a case of it a few years back to gently remove some sludge on a BMW 740i and it did a fantastic job on that. I cannot say with certainty that it cleaned the screen under the sending unit, but I also cannot say it had no impact. The truck gave no hints of low pressure, though the gauge did.
I would encourage anyone with low oil pressure to not overlook something as simple as a clogged screen, especially if the engine is otherwise running fine (I am still trying to figure out why a screen would be put there?). Far too many mechanics will happily change an oil pump and sending unit and then swap an engine if that didn't correct it. My own mechanic is no exception, and he is one I trust.
Go by the rule: 10 psi. of oil pressure per 1k rpms. So if your registering 6-10 psi at idle your fine. Now if your seeing 30 psi above 3k rpm you might have an issue.
Your oil pressure seems acceptable to me. If the truck where mine I would run the Cheapest 15W-40 dino I could find. Walmart Super Tech would be one to consider or whatever I found on sale. Being a fleet truck I doubt its ever had expensive synthetic.
I would run it until it drops-only similar experience I've had was the old 5.7 TBI '94 Suburban I had for a while-with 5W30 hot idle in Drive oil pressure would drop to around 10 PSI, I would get a lifter tick, but no other ill effects. 15W40 cleared that right up, and eventually stopped the tick as well. Sold it with 220K & AFAIK it's still going strong.
SirReal63
Thread starter
I used 15w40 Rotella T, it was on sale. The pressure is staying at about 30-35 at idle and 40-45 at speed. I will run the Rotella T for a few months then go with the Rotella T6. I am fairly convinced it was the screen under the gauge that was clogged and causing the sending unit issues. The Kreen appears to be what made the difference in unclogging the screen.
I will run it until the engine dies but based on how it is running, that may be a long ways off.
I will run it until the engine dies but based on how it is running, that may be a long ways off.
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