Can a engine be damaged by running too high visc?

[ledslinger]

Above 50 degrees F, can an engine that is specced for 5W-20 or 5W-30 be damaged by running an x-40 or x-50?

Barring revving on a cold start or other abusive situations?

Ever heard of an engine damaged by running thicker than specced viscosity oils?

Is the only risk slow galley filling and a small loss of fuel mileage?

 

[ARCOgraphite]

No anticipated issue except on certain variable timing and other hydraulic engine mgmt systems that are designed around an expected hot viscosity. There is no "slow gallery filling" either. Dont run more viscosity than you need though - it just throws away HP and torque. Too thin a vis is where you get into trouble on a stressed engine.

 

[fdcg27]

The short answer is no.
There may be very specific applications which would suffer from a thick oil in fairly warm weather, but I don't know of any.

 

[stenerson]

I can't answer for every case but I ran m1 15w50 for 9 years on vehicles
spec'd for 5w30. Vehicles still running great, no damage as far as I can tell.
I stopped doing that this year though.

 

[jstutz]

Originally Posted By: stenerson
I can't answer for every case but I ran m1 15w50 for 9 years on vehicles
spec'd for 5w30. Vehicles still running great, no damage as far as I can tell.
I stopped doing that this year though.


Any noticeable differences that you could feel or hear. I know many people that run 15w40 and 15w50 in everything and are perfectly happy. I used to run the heavy stuff also but after visiting this forum for a while i backed it off to at least a w30 weights in most of my stuff. I actually have QSHP 5w20 in and it does great. I did loose about two or three psi oil pressure hot and idle. What did you change too?

 

[stenerson]

I also backed of after bumping into this forum. But truthfully I
couldn't notice any difference, even in very cold weather. I'm
sure some folks have a better ear or feel but I couldn't tell.
I did it because the mechanic at work told me that was the way to
go. He has 300K on his chevy pu and gave me all kinds of numbers
about his compression etc. being like new.
I'm using 5w30 on truck now and just put the last stash of 15w50
in Caravan. I might keep using it on that old beater, it seems
happy.

 

[ledslinger]

I haven't changed anything yet. I am just looking at options to best utilize my oil stash. I have some 5-40 and 10-40 I might run during the summer in engines specced for 5-30.

 

[ARB1977]

I ran Mobil One 15W50 once in my speced 5W30 Honda Civic...no noise but ran like poo.

 

[calvinnnnnnnnn]

high viscosity perhaps makes the engine work harder, therefore slight increase in wear, but very marginal

following the owners manual will net the most miles out of your engine....

 

[jstutz]

Im running the QSHP 5w20 in the 4.3l blazer. In my previous post, somehow i forgot to put what i was running in it. Here in NC, i have a very hard time telling a difference between any of the different viscosities unless its pretty cold out, then i do notice it turns over easier with the w30s. The only time i really felt i could tell a difference is when someone gave me a bunch of castrol 20w50 and i do think i could tell a difference for a little while. Once it is warmed up, i cant tell a difference really between the thick stuff vs the thin stuff. I wonder if it has to do with the different engines. All of my stuff up until recently was all trucks. I bought a little ford with a 2.0l auto transmission and it is gutless. When the AC comes on you almost need to get out and push. In my trucks, i can barely tell if the ac is on and sometimes i cant tell. So the difference in feel in i ran 20w50 in the mercury is probably going to be more noticeable than in my 350's. I wonder if this is why some can tell and some cant.

 

[aquariuscsm]

The answer is nope. I run a 50 weight all year round. Always have,always will.