Using heavier oil in high mileage 5.7L Chevy
- Thread starter Atlee
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1.Nothing wrong with 20 psi @ idle hot.
2. I wouldn't trust the stock oil pressure sender any farther than I could throw it.
2. I wouldn't trust the stock oil pressure sender any farther than I could throw it.
I have a a fair bit more on my odo, and I have no hesitation going to a 0w30 this winter. I ran 0w40 last winter and it was noisier and took longer to warm up than I like on the -20 to -40 days. I also ran 15w40 for the first time this past summer to see how it would do and because you can get it for cheap. I am looking at some fall deals on 5w30 right now for and will probably bite on a bunch for next summer and just stick with Xw30 flavor.
I think I would group the stock voltage gauge in with that throw ^^ as well....
I think I would group the stock voltage gauge in with that throw ^^ as well....
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To the guys advising that 20 psi hot idle is to low on the OPs listed engine, obviously dont know anything about that engine. To the OP, Please do some more research. The oil pressure you describe, assuming a stock engine and oil pump, is absolutely normal and could have very easily came that way from the factory. That said, there is quite a bit of variance so the most important measure is the past. If it used to always run 30 psi hot idle and now it runs 20, then be concerned. If it is 20 and has always been 20, it is perfectly fine. If you want to go to a thicker oil for a feel good, go ahead. These engines are not picky about viscosity. That thing will run a long healthy life on anything from 5w30 to 15w50. Base your decision on how you use the truck and the climate your in. If your doing a lot of short trips lean away from the thicker stuff, if you fire it up and work it all day or drive fifty miles to work, nothing wrong with jumping up a grade if you want to. Sorry for being harsh in the beginning, but there is no way anyone that knows this engine would say 20 psi hot idle, without any past info, is an issue. Sorry.
For 1 don't go around calling 95k a high mileage engine. Especially not that kind of engine, there are hundreds of k more to go as long as the rest of the vehicle holds up and you keep maintaining it. I don't know oil pressure specs for that motor but several other posters are confirming its ok for it.
All that said I would still use a 40 weight. I just feel that *Most* 30 weight spec'd motors feel, sound and run just a little smoother on a 40wt. They're only 1 "grade" apart so the effects, positive and negative are fairly small but in my experience the quieting and "smoothing" of the engine are enough to hear and feel and the gas mileage hit is not. Done this extensively in my old Tercel and running it in my new Ranger. To get specific I'm using Rotella T6 5w40, best of both worlds, 40 weight that is much closer to conventional 10w30 thickness in the cold. Next year I'll probably run dino Rotella over the summer to save money and switch back to T6 in the fall. Your van would do just awesome on the same routine, no question.
All that said I would still use a 40 weight. I just feel that *Most* 30 weight spec'd motors feel, sound and run just a little smoother on a 40wt. They're only 1 "grade" apart so the effects, positive and negative are fairly small but in my experience the quieting and "smoothing" of the engine are enough to hear and feel and the gas mileage hit is not. Done this extensively in my old Tercel and running it in my new Ranger. To get specific I'm using Rotella T6 5w40, best of both worlds, 40 weight that is much closer to conventional 10w30 thickness in the cold. Next year I'll probably run dino Rotella over the summer to save money and switch back to T6 in the fall. Your van would do just awesome on the same routine, no question.
+1 for 20 PSI @hot_idle being fine for that engine.
There's one thing that hasn't been mentioned in this thread, and that's why is oil pressure needed? The obvious answer is that it's needed to force the oil to flow and to make it reach all the places in the engine that need it.
Ok everyone knew that already. But did you know that if you increase your oil pressure solely by using a thicker oil then you don't get actually get any extra flow - not even one teeny weeny bit more. And it doesn't help the oil reach any extra places that it otherwise mightn't have either. Think about why and you'll know it makes sense.
BTW. The above is not to deny that the same amount of flow but with a heavier oil could be desirable in an engine with badly worn mains.
There's one thing that hasn't been mentioned in this thread, and that's why is oil pressure needed? The obvious answer is that it's needed to force the oil to flow and to make it reach all the places in the engine that need it.
Ok everyone knew that already. But did you know that if you increase your oil pressure solely by using a thicker oil then you don't get actually get any extra flow - not even one teeny weeny bit more. And it doesn't help the oil reach any extra places that it otherwise mightn't have either. Think about why and you'll know it makes sense.
BTW. The above is not to deny that the same amount of flow but with a heavier oil could be desirable in an engine with badly worn mains.
Originally Posted By: Atlee
I have a high mileage(95k+ miles)1995 Chevy Extended Van w/ a 5.7L engine. The owners manual calls for 10w30 oil. However, when idleing the oil pressure dips to the next to lowest mark for oil pressure, I think 20# psi. As soon as I give it gas, the needle jumps to about 60# psi.
Is it ok to stick with the 10w30 oil or should I go to 10w-40 oil?
Thanks for any advice.
20 psi oil pressure at a hot idle is fine. I would verify with a good mechanical oil pressure gauge to be sure. No need to jump up a grade. Does it burn any oil? Any knocking? 95,000 miles on that engine, its still a baby. Stick with the 10W30 oil, when it starts burning oil, knocking, or pressure drops to 10+/- psi at a hot idle, then worry.
I have a high mileage(95k+ miles)1995 Chevy Extended Van w/ a 5.7L engine. The owners manual calls for 10w30 oil. However, when idleing the oil pressure dips to the next to lowest mark for oil pressure, I think 20# psi. As soon as I give it gas, the needle jumps to about 60# psi.
Is it ok to stick with the 10w30 oil or should I go to 10w-40 oil?
Thanks for any advice.
20 psi oil pressure at a hot idle is fine. I would verify with a good mechanical oil pressure gauge to be sure. No need to jump up a grade. Does it burn any oil? Any knocking? 95,000 miles on that engine, its still a baby. Stick with the 10W30 oil, when it starts burning oil, knocking, or pressure drops to 10+/- psi at a hot idle, then worry.
Originally Posted By: uart
+1 for 20 PSI @hot_idle being fine for that engine.
There's one thing that hasn't been mentioned in this thread, and that's why is oil pressure needed? The obvious answer is that it's needed to force the oil to flow and to make it reach all the places in the engine that need it.
Ok everyone knew that already. But did you know that if you increase your oil pressure solely by using a thicker oil then you don't get actually get any extra flow - not even one teeny weeny bit more. And it doesn't help the oil reach any extra places that it otherwise mightn't have either. Think about why and you'll know it makes sense.
BTW. The above is not to deny that the same amount of flow but with a heavier oil could be desirable in an engine with badly worn mains.
didnt know this, thanks for posting.
+1 for 20 PSI @hot_idle being fine for that engine.
There's one thing that hasn't been mentioned in this thread, and that's why is oil pressure needed? The obvious answer is that it's needed to force the oil to flow and to make it reach all the places in the engine that need it.
Ok everyone knew that already. But did you know that if you increase your oil pressure solely by using a thicker oil then you don't get actually get any extra flow - not even one teeny weeny bit more. And it doesn't help the oil reach any extra places that it otherwise mightn't have either. Think about why and you'll know it makes sense.
BTW. The above is not to deny that the same amount of flow but with a heavier oil could be desirable in an engine with badly worn mains.
didnt know this, thanks for posting.
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Actually, in a heavily worn engine, heavier oil can and will flow better to parts at the end of the line.
The previous thin oil can leak out too readily from large clearances along the way, and won't have pressure to flow to the far reaches of the oiling system.
The previous thin oil can leak out too readily from large clearances along the way, and won't have pressure to flow to the far reaches of the oiling system.
Originally Posted By: mechtech2
Actually, in a heavily worn engine, heavier oil can and will flow better to parts at the end of the line.
The previous thin oil can leak out too readily from large clearances along the way, and won't have pressure to flow to the far reaches of the oiling system.
Hi Mechtech. I'm not closed minded on this so it's up for discussion, but I've heard some pretty convincing explanations that it doesn't (increase flow) anywhere.
You might be able to persuade me otherwise if you can point out non-linear effects that are relevant. But if you take a linear hydraulic model (electrical analog) with a current source (pump) driving any possible network of resistors, series (galleries) and shunt (leakage) then it's a provable fact that if you multiply all the resistances by the same factor (eg double them all) then the flow remains everywhere constant.
Actually, in a heavily worn engine, heavier oil can and will flow better to parts at the end of the line.
The previous thin oil can leak out too readily from large clearances along the way, and won't have pressure to flow to the far reaches of the oiling system.
Hi Mechtech. I'm not closed minded on this so it's up for discussion, but I've heard some pretty convincing explanations that it doesn't (increase flow) anywhere.
You might be able to persuade me otherwise if you can point out non-linear effects that are relevant. But if you take a linear hydraulic model (electrical analog) with a current source (pump) driving any possible network of resistors, series (galleries) and shunt (leakage) then it's a provable fact that if you multiply all the resistances by the same factor (eg double them all) then the flow remains everywhere constant.
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