Use a light or a heavy 30 in a 4.3?

[TechnoLoGs]

Light side of 30 or heavy side of 30. Thank you!

 

[TechnoLoGs]

*1991-1994 Chevy 4.3 V6 with multi-port fuel injection, not throttle-body injection.

 

[lexus114]

Recommends 5w30 (I believe) so that. I don't think any particular cst matters in it.

 

[volk06]

Not going to make a difference. But on that year model, I'd lean towards the heavier end of the spectrum.

 

[Astro14]

For that engine, I would select oil on the basis of cost...not tiny viscosity differences...save your $$ for better uses...

 

[tig1]

The differance in vis means nothing. Use a high quality dino 5-30, and change it every 5K.

 

[donnyj08]

Originally Posted By: tig1
The differance in vis means nothing. Use a high quality dino 5-30, and change it every 5K.



^ I agree. A cheap but good Dino oil. 5w30 MS5K would be my choice.

 

[KCJeep]

We had a 99 4.3 for 12 years, wish I hadn't gotten rid of it. Anyway it did use some oil, less so when it was a bit thicker, so I'd go heavy 30 myself.

But the 4.3 will digest just about anything very well.

 

[147_Grain]

While it probably doesn't matter much ....... the technical answer to the OP's question is that for a driving style with short trips, a lighter 30-weight would perform better. Use a heavier 30-weight oil for extensive driving around town or in the mountains.

 

[nitehawk55]

I own one in my GMC , it likes any 5W30 .

 

[Gabe]

Originally Posted By: 147_Grain
for a driving style with short trips, a lighter 30-weight would perform better.


Short trips can really thin out an oil - it might be better to go with a thick oil here.

 

[fireman32]

a friend of mine has a 95 s 10 with the throttle body 4.3 vin code "z" and last time i talked to him which was a few months ago he was just shy of 470000 miles, he was hoping to reach a half million by the end of the year, asked him what kind of oil he used and he said castrol 20w50 since day one! not saying to run that thick of oil, i wouldnt do it but that just tells ya these engines def dont mind a thick oil haha

 

[147_Grain]

Originally Posted By: Gabe


Short trips can really thin out an oil - it might be better to go with a thick oil here.


MORE frequent LOF changes are needed to offset the lack of contaminant burn-off when operating an engine over an extended period of time. A thicker oil might help a little with fuel dilution, but it still needs to be changed more often during severe conditions and has a increased negative effect during frequent cold-starts.

A thinner oil is advisable for a lot of cold-starts / short trips because the engine is not fully warmed up and the oil's viscosity is still plenty thick.