Need help with 1996 Chevy Caprice 4.3 V8 fluids.

[Chris B.]

Hello, I need some advice and help with a 1996 Caprice I'm purchasing in another state. I had a mechanic I trust inspect the car and he said it was in excellent shape and he would have no problem driving it cross country in its current condition. I'm paying him do do all fresh fluids before the 19hour trip back home. It is the smaller 4.3 V8 with 117,000 miles. I saw a forum post that said this engine has non roller lifters and does better with conventional oil because synthetic makes the flat lifters not move correctly causing more wear because of the synthetic slickness. I found other posts saying that the LT1 5.7 and this L99 4.3 are in fact hydraulic roller lifters and do better with synthetic. Can anyone confirm what this engine is and if synthetic like Mobil 1 will be good for it?

Also what gear oil does the differential in these use? I use Valvoline 75w90 out of the flexible bladder they sell these days. Is this a good choice or is there a different gear oil it needs?

Any help with this is greatly appreciated! Thank you!

 

[GSCJR]

if synthetic like Mobil 1 will be good for it?

Yes

I use Valvoline 75w90 out of the flexible bladder they sell these days. Is this a good choice?

Yes

 

[Intelligent Molecule]

"I saw a forum post that said this engine has non roller lifters and does better with conventional oil because synthetic makes the flat lifters not move correctly causing more wear because of the synthetic slickness."

Out of my area of expertise, but I think this sounds pretty far fetched.

 

[Chris B.]

"I saw a forum post that said this engine has non roller lifters and does better with conventional oil because synthetic makes the flat lifters not move correctly causing more wear because of the synthetic slickness."

Out of my area of expertise, but I think this sounds pretty far fetched.

So this person said that "conventional oil has advantages in non-roller lifter engines. Synthetic can be too slick and reduce the rotation of the flat lifters causing faster wear"

Does this 4.3 v8 even have flat lifters? it was made in 1996

 

[PontiacHO]

It’s a roller cam engine. Use whatever you wish. I’d go 5w30 conventional for a few short oil changes before switching to synthetics. That way you can see at first if it’s going to use oil quickly and not have an investment in synthetic oil.

 

[wlk]

Hello, I need some advice and help with a 1996 Caprice I'm purchasing in another state. I had a mechanic I trust inspect the car and he said it was in excellent shape and he would have no problem driving it cross country in its current condition. I'm paying him do do all fresh fluids before the 19hour trip back home. It is the smaller 4.3 V8 with 117,000 miles. I saw a forum post that said this engine has non roller lifters and does better with conventional oil because synthetic makes the flat lifters not move correctly causing more wear because of the synthetic slickness. I found other posts saying that the LT1 5.7 and this L99 4.3 are in fact hydraulic roller lifters and do better with synthetic. Can anyone confirm what this engine is and if synthetic like Mobil 1 will be good for it?

Also what gear oil does the differential in these use? I use Valvoline 75w90 out of the flexible bladder they sell these days. Is this a good choice or is there a different gear oil it needs?

Any help with this is greatly appreciated! Thank you!

I have not heard of a 4.3l V8, those were v6s unless it was swapped with something else. Does it have a different motor? Had an 86 w 5.0l 305 v8 and quadrajet 4 barrel, loved that car. Those motors, 4.3l, will run anything you want, syn, conv or blend.

 

[nascarnation]

That's the old L99, a 262 cubic inch V8, based on the LT1. 3.74 bore X 3 stroke
Definitely a roller cam.

 

[4WD]

Remember that years ago Ford had a 260 V8

 

[facility1]

sounds like a nice test for Valvoline restore and protect 5w-30 or 10w-20.

 

[wlk]

That's the old L99, a 262 cubic inch V8, based on the LT1. 3.74 bore X 3 stroke
Definitely a roller cam.

Oh cool, never knew gm had a 4.3l v8 option. Always loved the 4.3l v6s in the S10's, we ran those at work forever. Thanks

 

[nascarnation]

The very first small block Chevy in 1955 was the 265 which was 3.75 bore and 3.0 stroke. So this was just a bit smaller bore size for whatever reason.

 

[BrendanC]

Valvoline EP HM 5w-30 or Valvoline Restore and protect 5w-30 gets my vote.

 

[Lawnman23]

I have not heard of a 4.3l V8, those were v6s unless it was swapped with something else. Does it have a different motor? Had an 86 w 5.0l 305 v8 and quadrajet 4 barrel, loved that car. Those motors, 4.3l, will run anything you want, syn, conv or blend.

https://en.wikipedia.org/wiki/Chevrolet_small-block_engine_(first-_and_second-generation)#4.3_L

The Baby-LT1. Virtually identical from external appearance.

 

[Chris B.]

Thanks gentlemen! So I already had the mechanic put in the Mobil 1 5w30 for the long trip home so its good to hear it a roller engine and not flat lifters, I wonder if that statement was true about syn causing problems in flat tappet engines?. I'll probably test the Mobil 1 at Black Stone Labs. Maybe switch to the Valvoline Restore. I just now heard about it for the first time. Is it proving to be any good?

Also I'm not sure exactly what rear end the cars has. Will the Valvoline synthetic with limited slip 75W90 for sure be a good fit for the rear differential?

 

[Lawnman23]

Thanks gentlemen! So I already had the mechanic put in the Mobil 1 5w30 for the long trip home so its good to hear it a roller engine and not flat lifters, I wonder if that statement was true about syn causing problems in flat tappet engines?. I'll probably test the Mobil 1 at Black Stone Labs. Maybe switch to the Valvoline Restore. I just now heard about it for the first time. Is it proving to be any good?

Also I'm not sure exactly what rear end the cars has. Will the Valvoline synthetic with limited slip 75W90 for sure be a good fit for the rear differential?

For 96 it will have either a 2.93 or 3.23 rear gear, dinky 7.5” 10 bolt IIRC.

Check the RPO codes in the glovebox. The 75w-90 is fine, the diff is nothing special. Limited slip was optional, code will be G80 if you have it.