Just a quick query about oil weights

Status
Not open for further replies.
Originally Posted By: Audi Junkie
Just to comfort the OP, 5w30 generally shears to a 20 weight anyway.

I beg to differ. The last 30-weight I used stayed within 0.5 cSt of its original viscosity @ 100 C despite a good amount of fuel dilution and a lot of acid build-up over a 7900 mile OCI.
 
why is the op afraid to list the type of vehicle? It has been asked 3 times, and now I will make it a fourth,

what kind of car?
 
I think the original poster thinks the thick oil would be better because of some high performance engines use it.
I use 10-40 Redline because my engine is clearanced for it.

Oil must not only provide lubrication but also cool the bearings.
if the engine is clearanced for 20 and you use 40 it will have LESS oil flowing through the bearings and they will run hotter.

This is the problem with running a stock production engine really hard they are not designed for it.

In order to achieve the right balance between the right pressure and flow the oil needs to match the engine clearance.

The best option is use a 5-20 or 5-30 and do not drive it like it was stolen because it was not designed for it.

I drove a sprint car for several years and something that most don't know is what is done before they are started.

You hear about how they use heavy oil that is true but the engine is purpose built for a heavy oil when it is hot and before we would push it off we put a salamander on the oil tank and the heat blows passed the oil tank and through the radiator

When they pushed me off I would run a lap to get it normalized and the oil and water were both up to temp right away.

if it was not hot yet then you take a couple more laps to warm the oil but the heater usually had it up to around 200 degrees right at start up.
 
Alot of good advice here. On the other hand if you had the 5w-40 and had to use it up and didn't have an application that was more suitable for it I wouldn't expect any noticeable longterm harm by running the 5w-40. Are there warranty considerations here? What is the vehicle?

Although the 5w-40 probably isn't optimal it isn't going to grenade your engine either. My .02.

REDDOG
 
Go with 10w30 synthetic. Forget the pansy 5w stuff.
56.gif
 
Originally Posted By: Black Bart
I think the ...................Oil must not only provide lubrication but also cool the bearings.
if the engine is clearanced for 20 and you use 40 it will have LESS oil flowing through the bearings and they will run hotter.

This is the problem with running a stock production engine really hard they are not designed for it.......................

The best option is use a 5-20 or 5-30 and do not drive it like it was stolen because it was not designed for it.................


Interesting point, if the engine is not designed to be pushed to the limit constantly, the oil will suffer earlier in it's life cycle and not protect as well as it should under extreme operating conditions.

Perhaps occasional spirited driving can be forgiven. I note it was repeated twice in the same post.

I think this is a word of wisdom, that is often NOT mentioned.
 
Last edited:
I guess it depends on the definition of driven hard. If it sees the whip, no big deal, but your typical Accord is not designed to be flat shifted at 6800 rpm up and down a mountain all day.

If it gets tracked regularly a 5w30 might be a better oil.

If it's a Mustang GT that goes light to light all night three days a week and doesn't get time to cool off except when it's sitting at the gas station, I would say go to the thicker oil because the engine sees the kind of loading in the bearings that might need that and it may see the oil temperatures where it becomes an advantage.

It's not like the engine didn't run on 5w30 for years before they changed the spec to 5W-20 in most cases of the 5W-20 specification. At the same time, 5W-20 is at least an equal of the 5w30 in most everyday scenarios in a lot of these engines.
 
Originally Posted By: garystevens
Hi, is it okay if I put 5W-40 in a car with a 5W-20 recommendation?

I don't like 5W-20, it's too thin for my tastes and I think 40 will be great in the summer, so will I run into any problems, or should I be okay?

Thanks in advance.
So,then, you are drinking the stuff? The 5W-20 goes down a little easier. Cheers!
 
Status
Not open for further replies.
Back
Top Bottom