Improove your oil press 1HD-T

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Club 4X4 Panamá
Apr 4, 2003
Hello all ..I always wonder why I can't found local something more appropiate for our weather down here .. something full synth 5W-50 as you can get in gassers .. but well ..

My question came today with the discover in my manual of oil cooler relief valve .. ( part # 15690-64010 ) and I wonder if replacing it along with the valve and spring of the oil pump valve will improove the oil press at idle ..

all comments and ideas are appreciated .. ( today was a hot day down here .. )


I don't think changing anything to do with the relief valves will help your idle oil pressure - just your maximum.

When I did the 7M swap in my '85 pickup I was worried about oil presure, rod knock, all the usual 7M issues. I put a slug behind the oil pump pressure relief spring thinking the same thing you're thinking. Bad idea. My max oil pressure was stupidly high and it could easily blow out the oil filter gasket. :bang:

On cold startups with 10W30 the oil pressure gauge needle was as far right as it would register so I still don't know what the maximum was.

It did NOTHING for hot idle oil pressure. The only thing that can actually improve that is tighter oil clearances throughout the engine.

Or, you can do what a lot of people do and run thicker oil to make the gauge read higher and make yourself feel better. I don't really understand why people bother - I don't think you're getting any better protection, you're just trying to pump thicker fluid. You probably gain pressure at the expense of volume being circulated.
Today when I jun in Marilu to go for lunch .. my inside thermometer was @ 140°F :eek:

I'm running Castrol semi synth 15W-40 .. and my oil temp as much is 140°F when that my oil press it's 12 - 14 PSI ..

I'm in range .. just would like to see a bit more PSI at idle .. more like 20 would make my happy .. :frown:
You can always boost your idle a bit. I always use the hand throttle on mine to set it to around 1000 rpm when climbing a steep hill. I once found out that I was able to run out of vacuum at idle having to back down a very steep off camber hill. Scared the hell out of me.

As for the oil, I've discovered that not all 15W40 oils are the same. The Castro Tection I was using had a higher cold start and idle pressure than the Delo or Rotella I have been using. I stopped using it in the winter because I felt my start oil pressure was way to high. Still, it had the same 15W40 rating.
Ya turn up your idle. My 13B-T in the 74 never goes below 800rpm . Same with the 12H-T in the 61 again 800rpm. Low idle kicks the s*** out of diesels.

If I remember correctly the hot oil presure @ idle was 10psi and full load was 30psi on my old power wagon with the 6B-T cummins. I do know from experince that Delo has slightly higher readings than Rottella especially when it comes to hot presure @ idle.

Sorry for hi-jack David. I dont like to see low oil presure @ idle so instead of tearing down a perfectly good motor I just turn up the idle like canucksafari suggested.
I would suggest a good 20-50w
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I will do a 20W-50 if I found it in diesel version .. my only chance are the Mobil 1 which claims to be safe for SF and CF ( gassers and diesels ) and run full synth 5W-50 ..

Just not sure of the concecuences of non specific oil in my old engine ..
I know its a different motor, but I am replacing my oil pressure relief in my 13BT soon, hopefully it makes a difference. 80-100psi running pressure and 35-40psi idle is to much!

Motor only has about 30,000km on it though so still might be abit tight in the bearings.
I replace my beb's about 2 years ago .. ( was in good shape the old ones ) just for peace of mind .. but that don't make any difference in my oil pressure ..

Right now I have about 50 PSI cold start @ idle .. which it ok .. and actually it raise good with more rpm .. I was just thinking in options for the idle oil press ..
What does an oil pump that is getting worn with age look like? I'm guessing that idle pressure might get lower due to lower revolutions, and running pressure would still be acceptable because the pump spins faster? Is the issue even a possiblity, or do they last forever?
there is a gear in the pump than can be replaced thought it's about tolerances that make them work like new again .. but there is also an O-ring and the front plate that are a important part in the oil pump performance ..

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