Oil questions, 1995 Silverado 5.7L

[GRWOil]

I've got a 95 Silverado, with GM's 5.7L V8. It was that in-between year were they had throttle body fuel injection. It's got 126K miles on it, with all original parts. I recently purchased a new car, so my Silverado is semi-retired now and gets driven very little, maybe 2,500 miles in a year.

I'd like to get an oil that I can leave in for at least a year. BUT, It's got a bit of an oil consumption issue, it burns or leaks a quart every 2,500 miles or so ( currently running Mobil 1 Extended Performance 5w30, it's run some kind of Mobil 1 5w30 all it's life ). The engine runs as smooth as it did when it was new, hot or cold, regardless of weather. BUT, the last two years I've started to have starting issues with a warm engine. Starts cold just fine, but when you shut it down and let it set ~15 min then try to start it again it takes some throttle input or it'll die. Starts like nothing happened on the second attempt.

My questions are: What oil should I run? Is there something I can do to remedy the starting issue?

I picked up some oil at Autozone on clearance that I can pick from, or if they aren't suitable, I'm open to suggestions.

5qts 10w30 Quaker State Synthetic.
11qts 5w-40 Pennzoil Euro Platinum
5 qts 15w-50, 3qt 0w-30, 1 qt 0w-20 Mobil 1. (figured I'd try blending)

I'm real curious about going up to that PEP 5w-40, as it was basically free after rebate. Gotta' find a use for it now!!!

 

[Merkava_4]

I think 5W-40 would be good for it.

 

[69GTX]

Out of that group I'd try the Pennzoil Platinum Euro 5w-40 which is a tad thicker than the Mobil 1 and Castrol EDGE 0w-40's. And getting it for essentially free is nice. All those other 30 grades are a tad weak imo, even the Mobil 1 0w-30. If you had the Castrol EDGE 0w30 that would be closer to a 40 grade.

You should get less consumption on that PPE 40. The Mobil 1 Extended Performance 30 grades are all weaker than the regular Mobil 1 5w30. I'd go with regular (or HM) before using EP. The Mobil 1 30 grades are mostly Magnesium add packs. So a move to PPE will be a change to a high calcium, no magnesium oil. I have some Pennzoil Platinum Euro 5w40 on the shelf slated for my '99 5.7L down the road.

 

[GRWOil]

Originally Posted By: 69GTX
Out of that group I'd try the Pennzoil Platinum Euro 5w-40 which is a tad thicker than the Mobil 1 and Castrol EDGE 0w-40's. And getting it for essentially free is nice. All those other 30 grades are a tad weak imo, even the Mobil 1 0w-30. If you had the Castrol EDGE 0w30 that would be closer to a 40 grade.

You should get less consumption on that PPE 40. The Mobil 1 Extended Performance 30 grades are all weaker than the regular Mobil 1 5w30. I'd go with regular (or HM) before using EP. The Mobil 1 30 grades are mostly Magnesium add packs. So a move to PPE will be a change to a high calcium, no magnesium oil. I have some Pennzoil Platinum Euro 5w40 on the shelf slated for my '99 5.7L down the road.


Good to know other folks run 40 weight oils in these engines. I was a little worried about it because the temp chart in my owners manual said 5w30 or 10w30 only. Can't be that much difference between 5w30 and 5w-40, right?

 

[69GTX]

Originally Posted By: GRWOil
Good to know other folks run 40 weight oils in these engines. I was a little worried about it because the temp chart in my owners manual said 5w30 or 10w30 only. Can't be that much difference between 5w30 and 5w-40.


I know some well thought of enthusiasts on the LS1 engines that have been running 0/5w-40 oils on low mileage cars for a decade or so. That gave me less anxiety in moving up from 5w30 to weaker 40 grades. Considering many others swore by GC 0w30 back around 8-10 years ago, those were strong 30 grades, not much different than today's 40 grades. You could run Amsoil 30 grades which are nearly 40 as well. My car has the same warning about not using anything but a 30 grade. And probably some of that was to adhere to CAFE or mpg standards. In my 6 speed they put in the absurd 1-4 up-shift under lower acceleration to add a tiny bit of mpg. I'll bet they were close on the required CAFE/EPA standards. They certainly couldn't have recommended a 40 grade, even if for hard use it was the better oil. It's also true that for moderate temp startups the 5w30 will perform slightly better than the 0/5w-40's....at least for Mobil 1.

 

[jhellwig]

Originally Posted By: GRWOil
Originally Posted By: 69GTX
Out of that group I'd try the Pennzoil Platinum Euro 5w-40 which is a tad thicker than the Mobil 1 and Castrol EDGE 0w-40's. And getting it for essentially free is nice. All those other 30 grades are a tad weak imo, even the Mobil 1 0w-30. If you had the Castrol EDGE 0w30 that would be closer to a 40 grade.

You should get less consumption on that PPE 40. The Mobil 1 Extended Performance 30 grades are all weaker than the regular Mobil 1 5w30. I'd go with regular (or HM) before using EP. The Mobil 1 30 grades are mostly Magnesium add packs. So a move to PPE will be a change to a high calcium, no magnesium oil. I have some Pennzoil Platinum Euro 5w40 on the shelf slated for my '99 5.7L down the road.


Good to know other folks run 40 weight oils in these engines. I was a little worried about it because the temp chart in my owners manual said 5w30 or 10w30 only. Can't be that much difference between 5w30 and 5w-40.


I run 40 weights in mine. It doesn't care what kind. I am using pup0w40 in it now.

95 is the last year for tbi. It is a non roller cam motor with restrictive heads. Super easy to work on. My 95 is 8600 gvw so it has less emissions junk to deal with.

 

[FCD]

I would run Shell Rotella T6 5W40 in it, or indeed if you want to try the Pennzoil Platinum Euro 5w40 in it go ahead.
The hot start issue is probably because your truck is vapor locking, ( fuel evaporating because of the heat ) i have a carbureted classic car and it happens sometimes in the summer.

 

[FZ1]

I would stay with the 5w30 you are running and change the oil 1x per year every Fall.

 

[crazyoildude]

First off i would find out where the oil is going maybe check the oil pressure gauge switch first if there is no visible smoke some of those had valve guide issues...If you used Mobil 1 all its life that engine must look real good because M1 keeps engines very clean...I would Use Mobil 1 High Mileage 5w30 and see if that helps..
It's Good oil and you can get it almost anywhere.

 

[pacc]

There has always been debate on if a 30 or a 40 grade oil is better on the big block engines, it runs fine on either. Asides from oil and for the consumption issue, how is the PCV system on your engine?

I do not think your delayed when warm start issue has anything to do with the oil.

 

[Alex_V]

My preference would be Maxlife 10w30, or if you never work the truck 5w30 wouldn't be a bad thing on startup. Out of your stash the Quaker State Synthetic or Pennzoil 5w40 won't hurt it - very little in the way of regular maintenance will.

 

[terminaldegree]

For a one year OCI with slight consumption issues, I'd probably pick a 10w30 synthetic, and would consider an Xw-40. How cold does it typically get where you live? Lots of short trips?

Wouldn't be afraid of running a 40 weight in a 350 like yours. There are hundreds of thousands of boats with that engine that do so.

 

[Chevy538487]

In my 92 we ran castrol gtx 10w30, truck had over 300k when u sold it!

 

[Triple_Se7en]

Conventional oil like Pennzoil Conventional is fine for one year duration of approx 3K OCI - won't create any additional wear and much cheaper.

No need to overhink this. You don't need a synthetic to leave it in the crankcase for one year.

 

[Noshow13]

Originally Posted By: crazyoildude
First off i would find out where the oil is going maybe check the oil pressure gauge switch first if there is no visible smoke some of those had valve guide issues...If you used Mobil 1 all its life that engine must look real good because M1 keeps engines very clean...I would Use Mobil 1 High Mileage 5w30 and see if that helps..
It's Good oil and you can get it almost anywhere.

I was thinking the same. I would definitely stick with Mobil 1 since that's what it's been running on, no reason to switch.

 

[BrocLuno]

A qt every 2,500 or so - and you call that oil consumption. I'd take that any day of the week on any older V8

Mix away and use what you want. It's just like being on the road and having to top off at the station. Millions of folks do it every day all across the country w/o issue. 4 qts of their fav and a few weeks later they need oil, so they buy some and add it. No big deal

rule 1 - some oil is better than no oil ...

rule 2 - clean oil is better than dirty old oil...

So keep it full and use up your stash

 

[jorton]

I don't think you can reverse the starting issue or the consumption issue with a different oil.

If you end up blending you should go with 80/20 ratio because you don't want to risk setting up an additive clash scenario for the 1 year oil change.

 

[69GTX]

There's no overthinking using a synthetic as you can buy PP/M1/Edge/Quaker State Ultimate Durability/Synpower for $10-$13/jug during the year....actually less than Pennzoil Conventional, Castrol GTX, Mobil Super 5000, Valvoline Conventional. At the same price, the synthetic is a no brainer....and it will perform better.

 

[wtd]

Any conventional oil will last the year with those miles. You don't need to waste the money on a synthetic. I have two 98 chevy trucks that only go about 3,000 miles a year each and have mainly run a conventional most of the time. My 98 K1500 with the 5.7L is only running Trop Artic 5w30 blend because I got it very cheap on sale. The 98 K3500 with the 7.4L uses Pennzoil High Mileage 5w30 because it had a couple of small oil leaks.

As far as your hot start issue, when was the last time you changed your coolant or your thermostat? Does your truck run hot? When was the last time it had a complete tune-up?

 

[GRWOil]

Originally Posted By: terminaldegree
For a one year OCI with slight consumption issues, I'd probably pick a 10w30 synthetic, and would consider an Xw-40. How cold does it typically get where you live? Lots of short trips?

Wouldn't be afraid of running a 40 weight in a 350 like yours. There are hundreds of thousands of boats with that engine that do so.


It rarely gets below 0F here, at least during the day. Our winters are very hit or miss. As for short trips, now that it sets at home with my dad, it doesn't go very far. Most commonly it'll go 7 miles to home depot, then back again. It gets up to operating temp pretty much every time it's driven.

Originally Posted By: crazyoildude
First off i would find out where the oil is going maybe check the oil pressure gauge switch first if there is no visible smoke some of those had valve guide issues...If you used Mobil 1 all its life that engine must look real good because M1 keeps engines very clean...I would Use Mobil 1 High Mileage 5w30 and see if that helps..
It's Good oil and you can get it almost anywhere.


There is a slight pooling of oil on the top of the motor next to the left valve cover, it fills back up if I wipe it away. I replaced the valve cover gasket, and nothing changed. When I had the cover off, I didn't see any varnish. looked new aside from a splash of oil in the corner. I have no idea where that oil is coming from. The rear main seal isn't leaking, and the bottom of the engine is relatively clean oil free.