Oil pressure help

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Ricko1966

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If anyone has part numbers for the proper temp sending units for the different years, that could be helpful. I picked up one for mine but definitely reads hotter than it’s running.
I can give resistance values 74-78 350 ohms cold. 79 up 1,365 ohms cold. I havev73 and earlier spec somewhere just can't find it right now g1852 is the 74-78 sender number.
 

ChuckN

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I can give resistance values 74-78 350 ohms cold. 79 up 1,365 ohms cold. I havev73 and earlier spec somewhere just can't find it right now g1852 is the 74-78 sender number.
Thanks!
 

84prspctr

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Here’s an update on the oil pressure after pretty much daily driving decent distances in 107-110 degree weather. Water temp never goes above 215, even in a parade. Oil pressure after running hard on the freeway will be at about 25 psi for 2400 rpm and about 30 psi at 3000 rpm at 210 degrees. At a stop light idling for extended time in gear at 500 rpm or so the pressure will drop just below 10, if I put it in nuetral or park with a 600 rpm idle it will come up to 12 psi hot at 210 degrees. No noises, runs smooth, 20w50 oil, 107-110 degree ambient temp out turning a constant 2500-3000 rpm on the highway for about 40 minutes one way. Pressure still sound safe? When it’s cooler out the pressure usually stays at 13 psi minimum and 35-40 psi on the highway
 

Rusty Nail

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I think that pressure is fine but I also think the oil is too thick. Additionally I would be aghast if my coolant temp ran at 215.
Do you haz a 195 stat inside?
Y U NO 10-30?

*edit

I glazed over this thread again and find it fascinating the new gage made different oil pressure. :rolleyes: I also wish to reiterate my previous comments in this post and think there is something going on with the cooling system.
 
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84prspctr

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The radiator is on the small side because it is in an old jeep truck. I don’t have a fan shroud either. I’m running 50/50 coolant in it too. Next summer I will put an aluminum radiator in it and electric fans. I have 20w50 in there because that is what was recommended by a lot of the shops around here because of the heat and how it never gets to freezing temps. I do not have a thermostat in there I have a restrictor plate. On a “normal” 95 degree day running modestly on the highway and around town it will stay at 175-180
 

84prspctr

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I went on this forum because it has a gm engine, Gm transmission, Gm steering, and a square body wiring harness
 

scrap--metal

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Pressure still sound safe?
Yes, those oil pressures are fine. Not good, but okay.
The radiator is on the small side because it is in an old jeep truck. I don’t have a fan shroud either. I’m running 50/50 coolant in it too. Next summer I will put an aluminum radiator in it and electric fans. I have 20w50 in there because that is what was recommended by a lot of the shops around here because of the heat and how it never gets to freezing temps. I do not have a thermostat in there I have a restrictor plate. On a “normal” 95 degree day running modestly on the highway and around town it will stay at 175-180
Without a thermostat, your truck shouldn't be running 215° even in 100° ambient temps. 215° isn't going to hurt it, but it's close to overheating. I'd bet your radiator is old and clogged up. A replacement would be near the top of my priority list, and you can do it without the electric fan(s) to start.

I also agree with Rusty that 20w-50 is too thick. Try 10-30 or 10-40 next oil change. Don't put anymore 20-50 in it unless the less viscous oil (i.e. 10-30 or 10-40) you try next further drops your oil pressure. The thicker oil is really a temporary solution to maintaining oil pressure.
 

84prspctr

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I just replaced the old plastic pressure line for the gauge, it was getting brittle. The pressure always “fluttered” a little at idle but not enough to really notice it. Now with the new line the gauge is fluttering a little at idle. Is this normal? I have a video but the quality is too low to see the fluttering. Sorry for the music in the video, I didn’t even realize it until I uploaded it
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84prspctr

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When it’s hot and the pressure goes down to 11 psi at idle the gauge doesn’t flutter. What would cause it to flutter like that?
 

Octane

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I just replaced the old plastic pressure line for the gauge, it was getting brittle. The pressure always “fluttered” a little at idle but not enough to really notice it. Now with the new line the gauge is fluttering a little at idle. Is this normal? I have a video but the quality is too low to see the fluttering. Sorry for the music in the video, I didn’t even realize it until I uploaded it
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Probably just a bad or cheap gauge.May be air pockets in the line?
 

scrap--metal

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What would cause it to flutter like that?
I wouldn't worry about that little flutter as long as the pressure is there.

Maybe a little stretch/flex in the line could cause it?
 

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