Oil for a GMC service van?

[Markzip]

I have to change oil soon on my GMC 3500 and want to have the best product for this vehicle. It has been changed at 4000 mile intervals for the last 7 years with Mobil semi-synthetic. The company is now requiring us to change our oil at 6000 miles. I decide after the dealership changed oil brands to a dino oil(maybe a coincidences ) I started to get piston slap at start up only and the check oil light goes on at 4000 miles but doesnt need oil and pressure gauge is always 40-60psi. So I am purchasing my own oil and performing it myself for this GMC Savanna 6.0 and will reimbursed for the cost. Looking for an opinion as to extended changes and a higher mileage van with 175,000 mostly highway miles that does not burn or leak oil. I put in Citgo semi-synthetic and a Mobil 1 filter the last time. The lists of oil I have now is
Walmart HM 5w30 and 10w30
Pennzoil Plat. 5w30
Quaker State Defy 5w30
Sheel T-6 5w40
Mobil HM and Extended 5w30 and 10w30 (not my perferred option to use)
Hoping this is enough information to have an educated opinion.

 

[LeakySeals]

According to the UOA's on here the GM's love Platinum which is going cheap right now at walmart. Mobil 1 HM 5w30 full syn is a step above the Mobil oil's you mention. What I use in the hard working work beater Camry in my sig. Its a good oil also.

 

[Corvette Owner]

+1 for the Mobil 1 HM 5w30 full syn. Easily good for 7500 miles.

 

[GSCJR]

Rotella T6 5w-40

 

[SteveSRT8]

Originally Posted By: Markzip
I have to change oil soon on my GMC 3500 and want to have the best product for this vehicle. It has been changed at 4000 mile intervals for the last 7 years with Mobil semi-synthetic. The company is now requiring us to change our oil at 6000 miles. I decide after the dealership changed oil brands to a dino oil(maybe a coincidences ) I started to get piston slap at start up only and the check oil light goes on at 4000 miles but doesnt need oil and pressure gauge is always 40-60psi. So I am purchasing my own oil and performing it myself for this GMC Savanna 6.0 and will reimbursed for the cost. Looking for an opinion as to extended changes and a higher mileage van with 175,000 mostly highway miles that does not burn or leak oil. I put in Citgo semi-synthetic and a Mobil 1 filter the last time. The lists of oil I have now is
Walmart HM 5w30 and 10w30
Pennzoil Plat. 5w30
Quaker State Defy 5w30
Sheel T-6 5w40
Mobil HM and Extended 5w30 and 10w30 (not my perferred option to use)
Hoping this is enough information to have an educated opinion.


We run a fleet of 3500 Savanas here. PP is a great choice.

Be very cautious of the 'slap' diagnosis. You probably have carbon knock, which can sound remarkably similar. Also these vehicles have a PCV setup that requires a cleaning every once in a while. Run 30 weight as long as you can maintain 40 psi at 2000 rpm. If not then switch to 40w. IME this occurs around your mileage or higher depending on your care.

If your truck has the OLM use it. It is VERY accurate on the v8's and will result in virtually unlimited engine life!

 

[Markzip]

How do you resolve carbon knock? Thanks for the info.

 

[Markzip]

Farm and Fleet has PP for $2.39 after a 5qt $10 rebate. Should it be 10w30 then.

 

[Markzip]

Somebody told me it was piston slap so I assume it was. How do you resolve either problem?

 

[SteveSRT8]

Originally Posted By: Markzip
How do you resolve carbon knock? Thanks for the info.


use a fuel additive. We put two cups of Kreen in a full tank of gas and it is done.

I'm sure many other fuel additives would also work.

Real piston slap has no resolution and is simply an annoyance. No effect on engine life at all. I have an 04 "slapper" 3500 Savana with almost half a million miles on an original drivetrain that works every day.

 

[bullwinkle]

I would be picking up some BOGO Pure One filters (if you have a Pep Boys nearby), if cost wasn't an object the M1 HM is a good choice-but 4K (or even 6K) is a short enough interval that almost any decent 5W30 PCMO would be fine. I don't see a year on your Savana, but since you stated it had a 6.0 I'm assuming it's newer than the '99 & 2000 5.7 Vortec Savana 2500 company vans I used to drive.

 

[dnewton3]

Not sure how this made it into the oil filter section, but I'll move it to where is belongs.


As far as lube selections, any dino oil should be able to easily protect the 6.0L Vortec to 6k miles; you don't "need" syns for this application if that is your OCI limit. As mentioned, the OLM seems to be quite reasonable in GM vehicles; what is it predicting?

 

[threeputtpar]

Either the Blain's conventional 5W-30 or the full syn will be more than enough for a 6k mile OCI. The conventional is on sale right now for $1.89/quart, no rebate to mess with.

They even have the Purolator Classic on sale for $2.50 each. Great time to stock up on oil and filters.

 

[TFB1]

Originally Posted By: threeputtpar
Either the Blain's conventional 5W-30 or the full syn will be more than enough for a 6k mile OCI. The conventional is on sale right now for $1.89/quart, no rebate to mess with.

They even have the Purolator Classic on sale for $2.50 each. Great time to stock up on oil and filters.


After experiencing start up knock in a 26K mi Ford 4.6, I tossed my Classics in the trash, never knocked before or since using a Pure One...

 

[GMBoy]

Originally Posted By: SteveSRT8
Originally Posted By: Markzip
I have to change oil soon on my GMC 3500 and want to have the best product for this vehicle. It has been changed at 4000 mile intervals for the last 7 years with Mobil semi-synthetic. The company is now requiring us to change our oil at 6000 miles. I decide after the dealership changed oil brands to a dino oil(maybe a coincidences ) I started to get piston slap at start up only and the check oil light goes on at 4000 miles but doesnt need oil and pressure gauge is always 40-60psi. So I am purchasing my own oil and performing it myself for this GMC Savanna 6.0 and will reimbursed for the cost. Looking for an opinion as to extended changes and a higher mileage van with 175,000 mostly highway miles that does not burn or leak oil. I put in Citgo semi-synthetic and a Mobil 1 filter the last time. The lists of oil I have now is
Walmart HM 5w30 and 10w30
Pennzoil Plat. 5w30
Quaker State Defy 5w30
Sheel T-6 5w40
Mobil HM and Extended 5w30 and 10w30 (not my perferred option to use)
Hoping this is enough information to have an educated opinion.


We run a fleet of 3500 Savanas here. PP is a great choice.

Be very cautious of the 'slap' diagnosis. You probably have carbon knock, which can sound remarkably similar. Also these vehicles have a PCV setup that requires a cleaning every once in a while. Run 30 weight as long as you can maintain 40 psi at 2000 rpm. If not then switch to 40w. IME this occurs around your mileage or higher depending on your care.

If your truck has the OLM use it. It is VERY accurate on the v8's and will result in virtually unlimited engine life!



I was hoping you would contribute your experiences here!

And everything you say is true...I decarbon my 6.0L Sierra Denali about every 3rd oil change or so. I've never had any knocking sounds, but I like keeping it maintained and clean inside.

 

[SteveSRT8]

Originally Posted By: GMBoy
I was hoping you would contribute your experiences here!

And everything you say is true...I decarbon my 6.0L Sierra Denali about every 3rd oil change or so. I've never had any knocking sounds, but I like keeping it maintained and clean inside.


Thank you. The carbon build up in the heads is a bit surprising but we do tons of very lightly loaded stationary ops at around 1700 rpm, this combined with almost all city driving leads to a remarkable amount of buildup.

Easy to fix if you know what to do, but I meet tons of GM owners who imagine that their motor is on its last legs and in reality it is still just fine and easily fixed with an additive!

 

[Markzip]

Ok took my 2006 GMC Savannah into the dealer and much to my amazment it was not piston slap. The dealer found broken exhaust manifold bolts and replaced them and the problem is gone. It runs much better also and quieter. I did splurge and used a Mobil one filter and Pennzoil "P" and it starts better in the cold warms up quicker. It seems to respond to the gas pedal much faster also. Just my opinion since I have been driving it for 175,000 miles. Some good deals right now on Mobil one,Pennzoil P and Shell T-6 at Farm and Fleet and Menards. Final price 3.59,2.39,3.25/qt.after sale and rebates. Thanks for the advice and knowledge shared.