Using Heavy 30wt/40wt in Car speced for 5-20/30?

[BTLew81]

Any real harm in doing this? My guess is no, but I am curious.

Thanks.

 

[Gregory]

I've run M1 0w-40 in cars speced for 5w30
run 10w-40 in cars speced for 10w-30
even ran 20w-50 in trucks speced for 10w-30

never noticed a problem in over 100k.

 

[aquariuscsm]

I`ve always run 20W50 in my cars and can`t tell any difference at all performance/gas mileage wise compared to 10W30.

 

[Audi Junkie]

Yes, it is a probelm on systems that use metered oil pressure for valve actuation. In part, this is why v-tech does not kick-in until a set temp. Too thick and oil won't service areas of the engine that require oiling. In a engine taking 20 weight, if you want to use a light 5w30 in hot weather, be shure it's good quality and can flow like it is supposed to. Heavier 30/40? Maybe if you have nitrous or aftermarket turbo/SC then an oil like GC or M1 0w-40, but that's as far as I'd go.

 

[BrianWC]

Originally Posted By: Audi Junkie
Yes, it is a probelm on systems that use metered oil pressure for valve actuation. In part, this is why v-tech does not kick-in until a set temp. Too thick and oil won't service areas of the engine that require oiling. In a engine taking 20 weight, if you want to use a light 5w30 in hot weather, be shure it's good quality and can flow like it is supposed to. Heavier 30/40? Maybe if you have nitrous or aftermarket turbo/SC then an oil like GC or M1 0w-40, but that's as far as I'd go.


I don't want to start a debate here-I'm just sincerely curious. If there is such a mechanical need for a light oil in VTEC cars, why does Honda spec thicker grades for other countries?

 

[BuickGN]

Originally Posted By: BrianWC
Originally Posted By: Audi Junkie
Yes, it is a probelm on systems that use metered oil pressure for valve actuation. In part, this is why v-tech does not kick-in until a set temp. Too thick and oil won't service areas of the engine that require oiling. In a engine taking 20 weight, if you want to use a light 5w30 in hot weather, be shure it's good quality and can flow like it is supposed to. Heavier 30/40? Maybe if you have nitrous or aftermarket turbo/SC then an oil like GC or M1 0w-40, but that's as far as I'd go.


I don't want to start a debate here-I'm just sincerely curious. If there is such a mechanical need for a light oil in VTEC cars, why does Honda spec thicker grades for other countries?


I've heard this before but I run Amsoil straight 30wt in my TL. I usually drive very easy during the warmup period but the other day I had to floor it pulling out onto the highway after about two minutes of run time and vtec worked like normal.