If you have two motor oils:

Mobil 1 15W50 and another Oil SAE50

At operating temperature which oil protects better? Are they about the same
thickness?

Now what about at a low temp below freezing?

I have a slight knock in my engine when it heats up and the dealers service manager says I should just use 50 weight oil. Does this make sense. Comments would be appreciated. He says that it would be too time consuming to find the problem at this stage. Would have to use plastigages? all over the place because the amount of play would probably be very small.

Thanks,
Michael

 

No way!

Dont use 15W50 unless your engine gets really hot!

and it does not!

For a knock, I would fix it as fast as I can, forget the dealer, or just sell it!

For oil use (Castrol GTX high mileage SAE 10W-40), which will give you a thicker oil than 10W-30 but not to thick as the 50!

but I would take it to some where else than the place you took it and do not tell them what the honda dealership said and let them figure it out there selves!

But all the info I gave may not be the best, just go with what you think you should do!

 

also if I am correct 15W50 is the same thing as sae 50, usally it would be written as (SAE 15W50)!

 

Not exactly the same... But at 212deg.F they're the same.

SAE 15w-50 means two different things. The '15w' part means it has a certain viscosity when cold, corresponding to a 15-weight "standard" oil. The '50' part means it ALSO has a certain viscosity at 212F, corresponding to a 50-wt oil.

SAE 50 just removes the requirement to match any particular viscosity when it's cold. I suppose a SAE 50 oil could be like peanut butter at 0.F & it could still technically satisfy the SAE 50 requirement.

 

the sae 50 will be heavier than 15w-50 even at high temps. the additives used to make it a 15w when cold will hurt it's hi temp capabilities after say 1,500 of use. sae 50 is basically for racing or real heavy duty applications where cold stats are not an issue. like already mentioned your mechanic is tard and the heaviest you should go is a 10w-40, but even still if it gets below 20 degrees you need a 5w-30 or 5w-40 if that is made.

 

I think a sae50 would pretty much kill ur engine on cold starts during the winter

I tried 15w50 from Mobil once but after some research I drained it and used mobile1 5W30. Thats the oil I would reccomend, and as for the knock it has to be fixed not covered up.

 

A change in oil should not be used to fix a knocking noise, that could be a huge problem you need to have it looked at asap, by somone other than this retard at the dealer...

EDIT: Are you getting any check engine lights from the knock sensor?

 

I don't think the 94 Accord EX has a knock sensor???

MIchael

 

Yeah I say get some Mobile 1 5w30..dont kill your engine with that extra heavy stuff...just find out and fix whatever is causing the knock...