5w-40 and low km car

[KING46Calais V]

Interested in everyone's opinion. I have a 6.2 with 19k on it and still completely factory standard. It's now out of warranty and wanted to move up to HPR5 from the GF-S.
I don't think the extra 10 will be an issue esp considering how loose the LS3 is to begin with. I reckon it prob would have been safe enough to use from the get go if there wasn't an issue with warranty.
Does anyone think the low k's warrant staying with the lighter oil until the numbers get up there a bit more or would you move to the HPR5 now?

Also, what does everyone think about engine flush?

 

[Skylarking]

With modern synthetic oils that meet GM’s Dexos standard, a flush won’t be needed since the Dexos oil itself has some good cleaning properties within. Well that’s the theory anyway.

Me, I feel that simply shortening the oil change intervals to 7500kms will help much more than any flush will ever do And I’m not a fan on using a flush in an older engine that has never used a flush

As for the weight of the oil, it used to be based on the temperature of vehicle operation and the manufactures had an oil table within the owners booklet (or under the bonnet if we go way back) that guided the owner. That oil table indicated the acceptable oil weigh for a given operating temperature range where such could be related back to winter or summer driving…

But in this world of Corporate Average Fuel Economy, CAFE, the push has been for car companies to reduce their gas guzzler tax. So the corporation saves some dollars via lighter oils and lighter piston ring pressures, etc, but it fcuks the owner in the process as his car uses more oil (which oddly seems opposite to the CAFE save the environment ideology). So I’d say GM/H recommended oil weight is specified more because of accountant pressure around gas guzzler tax than pure engineering around engine longevity... Go figure…

Meanwhile many forum members have said that a heavier oil quietens these LS3 where the engines seem to like it more than the factory recommended light weight cooking oil… Again go figure…

Being that my car is approaching end of warranty in 2025, I have more time to ponder such stuff but conceptually I have no issue with using non Dexos oils at a heavier weight… But I’ll note the responses that other forum members make

 

[greenacc]

I would be extremely surprised if 5w40 caused any problems. I've seen posts from members saying they use heavier oils than that in LS engines.

 

[chrisp]

I would be extremely surprised if 5w40 caused any problems. I've seen posts from members saying they use heavier oils than that in LS engines.

The Holden dealer that I had my car serviced at used 5W40. I used to question it as it wasn’t Holden specification, and they gave me some explanation (that I can’t recall), but didn‘t stress over it too much.

 

[Ron Burgundy]

HPR5 is excellent oil. I believe it would be just fine in LS3 especially in Australian climate. I used it in my 2010 SV6 for 8 years.

It meets many specs for euro cars that GFS does not.

In my case, I used GF-5 for a while and then 3-4 yrs ago switched to Mobil1 EP 5w-30. No good reason. Just a victim of marketing and Mobil endorsed sticker on many euro sports cars. I figured if they back it , it must be just fine even if it is a result of some endorsment deal

 

[Ron Burgundy]

Btw Penrite's lube guide now also recommends enviro plus 5w-40 for LS3. Nothing wrong with that one either.

 

[3rspecB]

I switched to Penrite enviro + 5w40 when warranty ran out. No issues from what I can see/hear. Uses stuff all oil in between services. I noticed the 5w30 used a little more oil in between services. I'm also thinking about moving to penrite hpr 5w40.

 

[RevNev]

I don't think the extra 10 will be an issue esp considering how loose the LS3 is to begin with

Thicker oil maintains higher oil pressure when hot, but it flows slower than thinner oil too, so thicker oil doesn't mean better protection unless the bearing clearances are loose enough to cause excessive hot oil pressure loss. Race engines will typically run looser bearing clearances to prevent heat induced and high RPM nip ups and is the reason many dedicated race oils are in the 20w50 and 25w60 ranges.

 

[lmoengnr]

Do a viscosity test between Enviro 5W-30 and HPR5 and you'll notice bugger all difference.

HPR5 is a bloody good all-round oil.

 

[Redline457]

The Holden dealer that I had my car serviced at used 5W40. I used to question it as it wasn’t Holden specification, and they gave me some explanation (that I can’t recall), but didn‘t stress over it too much.

The Holden dealer i use also uses 5W40 is my LS3