Low Oil pressure....

Hello again. LOL! Got another question. My oil pressure gauge is acting real strange. When its cold out, while driving, its usually at about 40. Pretty normal. If I come to a stop though, it usually drops down to about 5 or 10. I just had an oil change and its full. I do have an oil leak though, from the oil cooler lines. Could the pressure drop have something to do with the leak or could the oil pressure sending unit be faulty? Oh yeah. When its warm out it usually drops to about 35 or so. Help.....

1991 GMC Jimmy 4.3l

Hello? Why is it that no one ever wants to help me. Anyone?

Here is my take. No, unless it is pouring. I have a 93 s-10 Blazer with similar problem. I bough it 2 years ago and thought the pressure was normal until I bought service manuals and they showed 40-60 lbs for these (4.3 W) motors. Mine will run 40 most of the time except at idle, when driven for 30min+. Can drop to 20 lbs, if using 5-30 oils. My oil lines just started leaking a bit, no diff. I do not know if mine has real issues or maybe it has a bad sender unit. It runs real well so I have not investigated it much, but I know it will hold better pressure with 10-30 oils and even certain brands make a little difference when driven a lot. castrol seems to hold up better. I am thinking of switching to a 0-40w synthetic this spring to see what that does. I guess the best thing is to get the pressure checked to see if the sender is bad....

Anyone else? Anymore ideas?

I dunno id like to help ya but i have the same problem...only the weather doesnt seem to matter. When my engine is cold the pressure stays right up where its supposed to be. Its also where its supposed to be when my foot is on the gas, but when im idling and engine is at operating temperature the oil pressure drops right down. It also drops pretty low if i put it into overdrive. I hope someone can help with this, doesnt seem to be hurting anything, but im curious to know.

I dunno id like to help ya but i have the same problem...only the weather doesnt seem to matter. When my engine is cold the pressure stays right up where its supposed to be. Its also where its supposed to be when my foot is on the gas, but when im idling and engine is at operating temperature the oil pressure drops right down. It also drops pretty low if i put it into overdrive. I hope someone can help with this, doesnt seem to be hurting anything, but im curious to know.


That is normal.

The oil pressure will be higher when the enine is cold. This is because oil is thicker when cold, cause a higher pressure.

When it's hot, it gets thinner and flows better. This will cause the oil pressure to be lower.

You need about 10lbs of oil pressure for every 1000 RPM's...up to a given point. Obviously if your at 8,000 RPM's you won't have 80 lbs of oil pressure. This is cause the oil pumps are designed to only reach a certain limit.

What type of oils are you guys using? If you are really concerned, you can try a little bit thicker oil.

Yip, the oil pressure is also related to the engine rpms. When the engine is revving high, so will the oil pressure, when the engine is idling, the oil pressure will be around 10psi.