judging oil wt on oil temps?

[leroyd92]

Its getting warm here and the boats are getting dusted off, today I was looking at my gallon of rotella 1540 and I was thinking about running the boats to see how hot the oil gets in them. Then I had the thought of,

"is it better to base oil wt on actual oil temps or (app spec)"???

Not really just for boats, but I was curious about everything really...

Like, if it were -40 here today I'd most likely use 0w20/30 in my truck instead of 5w30

I added an oil cooler to my motorcycle a few weeks ago, im expecting my oil to be 200° at hottest if its only getting to 165° in the low 80°s we've had....

What does everyone think? Ya or nay?

 

[Clevy]

165 isn't hot enough. If temps really are that low I'd consider thinner oil in the bike to be honest.
I use thicker oil in the summer only because I beat on my engines more and oil temps will elevate.
In the winter I'm not looking to break any speed records.
To be honest normal driving in all ambient temps doesn't require a grade change as the seasons change anymore. Oils are far more shear stable today and we have the ability to significantly extend drain intervals so seasonal changes really aren't as important as they once were.

 

[leroyd92]

Soon itl be 100 at midnight and 116+ during the day...

 

[BigCahuna]

But I'm sure the temp of the water the boat is using for cooling will be alot less.When I had my boat, water temps in mid summer were in the 75-85 degree range. My boats were older so they called for straight weight oils. I used to run straight 40 wt and never had a problem with running too hot. My raw water cooled boat ran at 160 degrees and my fwc boat used to run about 180 degrees.The lake water will always be cooler then the air temp, so I think you'll be fine with 15/40 Rotella.,,

 

[leroyd92]

Originally Posted By: BigCahuna
But I'm sure the temp of the water the boat is using for cooling will be alot less.When I had my boat, water temps in mid summer were in the 75-85 degree range. My boats were older so they called for straight weight oils. I used to run straight 40 wt and never had a problem with running too hot. My raw water cooled boat ran at 160 degrees and my fwc boat used to run about 180 degrees.The lake water will always be cooler then the air temp, so I think you'll be fine with 15/40 Rotella.,,


Cool, I was planning on shooting the oil pans with my temp gun and just seeing what comes of it... our Volvo 350 don't run over 3k rpm, we run our motors easy

 

[CourierDriver]

Here are some charts: http://www.bobistheoilguy.com/motor-oil-101/

 

[dparm]

165 seems quite low. Most cars will run their oil right around 200 F (as measured in the sump).

At an oil temp of 165, my car won't even allow you to redline the engine. You need to be above 180 I believe.

 

[BigCahuna]

RWC boat motors run at lower temps then cars do. If the boat is used in salt water too much heat will cause the salt to build up in manifolds and engine blocks. That in turn will case overheating or hot spots in the cooling system.,,

 

[ARCOgraphite]

I wouldn't put too much trust in the IR gun temp accuracy. Using them in the industry, ive found reading to vary depending on target finish ( e.g: flat black, oxide, StSteel, polish, colour, etc.) vs a called thinfilm tape, type K or J thermocouple ice bath calibrated.

 

[roadrunner1]

In raw water cooled marine applications the thermostat is generally 140f-160f. High oil temps should never be an issue, in fact low oil temps are more of a concern.

 

[camelCase]

Use a viscosity calculator to get a rough estimate:

http://www.widman.biz/English/Calculators/Operational.html