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I have had a low hot idle oil pressure problem for about a year now.
Specifics are:
87 Renix OEM engine, 247,000 miles, unknown engine repair history prior to 225,000 miles. New high flow oil pump, new, but not really needed main bearings installed about 7,000 miles ago while replacing the oil pump, all of which had little effect on the low hot idle oil presure. Rod bearings looked new so not replaced (plastigauge showed no wear), crank (journals) looked new. No oil consumption, no blow by. Oil pressure switch is good (new).
Cold start idle oil pressure: 58 PSI.
Cruise oil pressure: 40 to 58 psi (hot..cold), at 2000 rpm
Hot Idle oil pressure in drive after a long run on the highway: Min 22 psi
This is with a mix of 20W50 and Lucas oil additive at 80 F ambient and 190 F coolant temp, and the larger 1 quart K & N oil filter upgrade/modification (Yucca-Man...)
Hot idle oil pressure is still too low for me (probably about 13 / 10) with 10W40 / 10W30 oil.
When I first bought this jeep it had major overheating problems, mostly caused by a calcium scaled up radiator. That has all been fixed long ago, but I never descaled the engine block.
So I am starting to wonder if my oil is getting too hot, causing the low oil pressure listed above.......and I am wondering if the oil is not getting cooled enough by the water coolant because of a layer of calcium scale on the water coolant side of the engine block?
Wish I had an oil temperature gauge to confirm this. But if I let it cool a short while, like turn it off for ten minutes, the hot idle oil pressure comes back up to nearly 30 psi.
Anyone ever have this particular problem before and solved it by descaling the engine water coolant section?
If I am right, a number of us with low hot idle oil pressure problems may have this calcium scale from prior owners abuse, causing this very problem.
By the way, I have a 165 F thermost, and during the winter my coolant never got over 165 F, and the hot idle oil pressure never got below 28, at normal idle speed.
I may try and get some oil temperature readings off the outside of the oil filter.
Specifics are:
87 Renix OEM engine, 247,000 miles, unknown engine repair history prior to 225,000 miles. New high flow oil pump, new, but not really needed main bearings installed about 7,000 miles ago while replacing the oil pump, all of which had little effect on the low hot idle oil presure. Rod bearings looked new so not replaced (plastigauge showed no wear), crank (journals) looked new. No oil consumption, no blow by. Oil pressure switch is good (new).
Cold start idle oil pressure: 58 PSI.
Cruise oil pressure: 40 to 58 psi (hot..cold), at 2000 rpm
Hot Idle oil pressure in drive after a long run on the highway: Min 22 psi
This is with a mix of 20W50 and Lucas oil additive at 80 F ambient and 190 F coolant temp, and the larger 1 quart K & N oil filter upgrade/modification (Yucca-Man...)
Hot idle oil pressure is still too low for me (probably about 13 / 10) with 10W40 / 10W30 oil.
When I first bought this jeep it had major overheating problems, mostly caused by a calcium scaled up radiator. That has all been fixed long ago, but I never descaled the engine block.
So I am starting to wonder if my oil is getting too hot, causing the low oil pressure listed above.......and I am wondering if the oil is not getting cooled enough by the water coolant because of a layer of calcium scale on the water coolant side of the engine block?
Wish I had an oil temperature gauge to confirm this. But if I let it cool a short while, like turn it off for ten minutes, the hot idle oil pressure comes back up to nearly 30 psi.
Anyone ever have this particular problem before and solved it by descaling the engine water coolant section?
If I am right, a number of us with low hot idle oil pressure problems may have this calcium scale from prior owners abuse, causing this very problem.
By the way, I have a 165 F thermost, and during the winter my coolant never got over 165 F, and the hot idle oil pressure never got below 28, at normal idle speed.
I may try and get some oil temperature readings off the outside of the oil filter.