Would 25W-40 oil be way to thick? Reason I ask is because I can get it for free. I run 10W-40 now and have oil pressure instantly after start up even when it is really cold. Looking for opinions, don't want to do something stupid to save a few bucks.

 

Maybe in summer, I wouldn't dare try in winter.

 

Yeah that's what I was thinking. The W is the viscosity when warm right? and the other number is the viscosity when cold? Or do I have it all wrong?

 

"w" is the winter or cold viscosity ........25w-40 = 25 weight when cold /40 weight when warm

 

Where the hell can you get 25w-50?
20w-50 is everywhere, but 25?

I agree, dont use it in the winter, unless you live in the south where it is warm all year.

 

Its Quicksilver marine engine oil. I work at a boat shop and we have it in a 55 gallon drum.

 

Gotcha, be careful with that.
You might want to do some serious research before using marine engine oil in your Rover.
As I am sure you know marine engines run at a different temp than a car engine and thus the oil is formulated differently.
You might run into sludge, varnish or other problems.
If you were just topping off with it or doing a short oil change I would say go for it, but if you are looking for it as a alternative educate yourself first.

 

Yeah I totally understand, thats why I posted the question. Marine engines normally run collar than a car, 150-170 is what most have for a thermostat. What I have read about that oil online is that it has added rust inhibitors to protect against corrosion and "Eliminates thermal breakdown under extreme RPM, temperature and heavy-load conditions." I've seen a few people run it in their vehicle no issue, but they weren't rovers.

 

only thing is...might change it out sooner...but why not just run rotella t or valvoline maxlife in a 40w. Only thing your gaining with running 25w40 is that it would not shear down near as fast but if thats what your worried about might as well run straight 30 weight, but in our rovers you GOT to change out by at least 5K miles...so it doesnt really matter as long as you run a good oil.

 

I change mine every 3K, and have been running Castrol GTX high milage 10W-40 for the last 30K