Using heavier oil in high mileage 5.7L Chevy

Status
Not open for further replies.
A

Atlee

Joined
Jul 15, 2006
Messages
5
Location
Mechanicsville, Virginia
I have a high mileage(95k+ miles)1995 Chevy Extended Van w/ a 5.7L engine. The owners manual calls for 10w-30 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 10w-30 oil or should I go to 10w-40 oil?

Thanks for any advice.
confused.gif
 
95K on a 5.7L is nothing. I have a buddy with a 93 that has nearly 400K miles on it running dino oil the whole time with no rebuilds. 20psi is pretty normal for that engine. My 97 Chevy K1500 has the 5.0L V8 always runs around 20PSI at idle when the engine is warm. According to some specs I read a while back the minimum oil pressure at warm idle is 7PSI. IMO I would stick with a good quality 10W-30, no reason to worry.
 
20 psi hot at idle and 60 psi hot at speed is perfectly good oil pressure. Stick with 10w30.

My motorhome has a 7.4L Chevy V8 and 15,000 miles. It gets hot oil pressure of 56 psi at road speed and 24 at idle.

My F150 has 145,000 miles and gets about 20 idle and 44 hot. Again, just fine pressure
 
I'm going to have to disagree with the above consensus; I think 20 PSI at hot idle is being too low with 40 PSI being closer to ideal. I'd definitely move up to 10W-40 or 15W-40 if it were my van under those circumstances. JMO
 
Why don't you give Maxlife 10w40 a try... if the climate is not too cold...my 78 Pontiac had best oil temp guage readings when I used straight 30w Pennzoil...however if it gets cold a 10w40 would be better...try 30w if climate can handle it...In fact my old Pontiac ran so smooth with straight 30w compared to anything else that wished I lived on the Equator so I could run it year round...Alas I live in Nebraska where I see average highs of 17F in January...
 
Quote:

I'm going to have to disagree with the above consensus; I think 20 PSI at hot idle is being too low with 40 PSI being closer to ideal. I'd definitely move up to 10W-40 or 15W-40 if it were my van under those circumstances. JMO

Click to expand...


This is not your newer LSX style SBC. MIN oil pressure specs on your standard Gen 1 SBC are 1 psi per 100 rpms. Mind you those are bare min, 20psi hot idle on the described engine is perfectly fine.

My advice is to install a mechanical oil pressure gauge to verify actual oil pressure.
 
Last edited:
I cannot fathom the reasoning that would lead to saying 20 PSI hot idle oil pressure is too low.

What Atlee indicates for his oil pressure is a classic example of good oil pressure.
 
Sorry, I don't know the year break, but per GM bulletins, since they have increased oil pump volume, pressure can go as low as 6lbs at idle with no problems.
 
I have a 1998 Chevy 5.7 that rolled over 177,000 today.It only gets regular dino at 3000 miles. It will use 1/2 quart which is what it used when it was new. I have not started to think of mine as high mileage being as it still runs like it did in 1999.
 
Sorry, I hit the button too quick. My oil pressure is 20 psi at hot idle and about 40 psi at hot run. I have only run 5w30.
 
Merkava, your oil pressure (42 and 66) is just fine. I had a 460 Ford that got around 35 and 60. You can look up the spec pressure in a Chilton manual. It's in a table of all the engines and years, listing hp, torque, and other parameters.

Here is the 88-89 Chevy listing of spec oil pressure:

2.2L 56@3000 rpm
7.4L 40@2000
5.0, 5.7, and 4.3 18@2000

Most of the 90s Ford pushrod V8s and the big six are listed as 40-60(or 65)@2000 rpm.

I find the Chevy listing of 18 psi a bit low, but that is the spec (unless Chilton got it wrong). OTHO, the old rule of thumb for minimum is 10 psi per 1000 rpm, although I aways felt the first 1000 rpm should be higher, that is start at maybe 15 or 20 psi and go up from there.

The chevy spec is 40 for my motorhome 7.4L and I get 55 on 10w30 Maxlife Synthetic. Good enough for me. I sure won't go thinner just to get down to spec.

My pickup 4.9L Ford six specs 40-60@2000 and was getting around 35 on 30 weight, so I went to 10w40 and get around 42-44. Good enough for me.
 
To add to my original post, the van, which is the chassis for a 1996 Roadtrek Class B RV, was a one owner whose son, a master mechanic at a new car dealer, changed oil in it every 3-4k miles using Motorcraft 10w-30.
 
I'd go with a heavier weight in my '88 chev, with 203,000 miles. But I live where the winter temps are very cold and I don't drive it enough to get even 3K miles in a year. Just sticking with 5w-30 here with annual changes.
 
Quote:

20 psi hot at idle and 60 psi hot at speed is perfectly good oil pressure. Stick with 10w30.

My motorhome has a 7.4L Chevy V8 and 15,000 miles. It gets hot oil pressure of 56 psi at road speed and 24 at idle.

My F150 has 145,000 miles and gets about 20 idle and 44 hot. Again, just fine pressure

Click to expand...
I agree with Tallpaul. Some vehicles run 10psi per 1000rpm. I don't think 20 psi is to low..
 
Quote:

I agree with the 10w-40 or 15w-40 guys. Your bearings apear to be worn some and the 15w-40 will reward you down the road. Just my 2cents worth.

Click to expand...
On what basis to you think the bearings are worn some? And even if they are, which is to be expected on a high mileage engine, the oil pressure is in a very acceptable range, both idle and at speed. Now I would have no problem with him thickening up his 10w30, but at most 50/50 with a 10w30/10w40 mix. That would give him about a 12 cSt 10w30 vs the typical 10.5 cSt.
 
I was having the same problem with my '95 Olds LSS, 3.8l Supercharged engine, 110,000 miles. Car was a rental early in its life so who knows how it was broken in. The oil pressure light was starting to flicker at idle on hot days, running Supertech Synthetic 5W-30. I looked at the charts and decided to run Pennzoil High Mileage 10W30, which runs at the high range for viscosity, 12 cSt @ 100 deg. C. 500 miles since that change and so far, so good.

Like another poster said, if you're worred about oil pressure, verify with a mechanical gauge, but 20 psi at idle is fine for a 350.
 
Status
Not open for further replies.

Similar threads

Twisted1
High mile 4.6 Ford - Ok to use heavier oil?
2 3 4
Replies
60
Views
2K
thastinger
A
1989 Isuzu Trooper oil with high mileage
Replies
11
Views
680
Alexis
Sweebation
What oil to use in 2005 6spd corvette
Replies
17
Views
596
twX
T
Used HIgh Mileage oil in my low mileage vehicle, am I causing damage?
2
Replies
26
Views
5K
zrxkawboy
SubZero350
Detergent or Non Detergent oil? 1954 Chevy 235 inline-6
2 3
Replies
47
Views
4K
Brons2
Back
Top