Waferboy

Have a 93 LX 5.0 and the oil pressure when warm and at idle is 5psi. The pressure does go up with rpm and is greater than 20psi at 2000rpm. The engine is tired with at least 170K miles on it, so I do expect some wear, but I get nervous when the pressure drops that low.

Now the 5psi reading is taken with a mechanical gauge and it has a fresh 10W-30 oil change in it.

Thanks in advance!

Waferboy

dawson1112

I was ok with the 5psi at idle up untill you said you were actually using a mechanical gauge. More than likely the oil pump is worn and needs replaced, or the pick up screen is really caked with gunk.

If it were the bearings Id expect the oil pressure to surge up and down at idle.

Waferboy

Thanks for the feedback. Yep, I'm not sure what to think. With the "rule of thumb" being 10psi per 1000rpm, I'm not really worried because the pressure does go up with rpm, but like I said, I just get a little nervous.

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mjr46

put some 20w-50 with some stp oil treatment........pressure will go up at least 8-10 psi, I have an old bronco that I do that for and the results are as mentioned

Waferboy

Yep, I had thought about that. If I under it right, the "W" number is the "winter" grade, right? I have concerns at the 20W as then temps are relatively cool here, but i get the idea. So the lower any of the numbers are the thinner the oil is. I guess I would want a 10W-50 for better starting cold and thicker running hot.

So maybe a 10W-40 would help, it is more readily available. I do see some synthetic 15W-50 that is reasonably priced.

I am just not read to pull the engine.

88 orangepeel notch

The W stands for weight, or how thick an oil is at a certain temperature. The lower the number, the thinner the oil basically. You'll be fine with 20w now, as I'm sure there won't be any more -20' nights anymore.

There's just not much you can do for a simple fix when a motor wears out. Your still fine until the bearings start talking to you. I've had cars last year's like this.

wgreenlee4

The "w" in like 5w30 actually does stand for winter. 5 would be the viscosity at winter temperatures and 30 would be the viscosity at higher temperatures (100C).

I'm not an expert on what the sbf's like, but I don't think it would make sense to try and keep the OEM winter grade while raising the operating grade. Because if your clearances are opening up because the engine is getting worn, they are opening up when the engine is cold and warm (not exactly the same but yeah). I would probably bump the winter and hot grades up together. Like the 20w50 mjr46 mentioned. I don't know much about the oil treatment, I've never used it.

In order to make something like a 15w50 you have to use a lot of viscosity index improvers (vii's). That's because manufactures start with the thin grade and add the vii's to make them thicker at higher temps. This is easier with synthetic base oils and that is why oils that have such a wide range like that are almost always synthetic.