Originally Posted By: jdavis
From what I've read, TGMO is practically a 30 weight at operating temps..
Ummmmmm. No.
Believe none of what you hear and half of what you see.
Originally Posted By: Oil Changer
You have your facts mixed up. TGMO is a light 20-grade. You'd be better off using P4 5W-30, a light 30-grade for all your vehicles if you want to stick with one grade/formula. It's better to error on the side of too heavy than too light.
Originally Posted By: jdavis
From what I've read, TGMO is practically a 30 weight at operating temps..
I agree it's better to er on the dude of caution.
But let's put this into perspective.
If the engine is operated lightly and a 20 grade is being used elsewhere in this engine then one could assume a 20 grade could be used in this application.
The only way I would consider it is if the engine is operated lightly,and used oil analysis confirm the oil isn't contributing to engine wear.
So to do that you'd need a couple or 3 used oil analysis using the prescribed 30 grade to establish trends.
Then use your 20 grade and compare it to the trended data. If all looks consistent then your good to go.
I suggest sending a pm to caterham. If anyone would know if you can get away with it he would.
If you'd got real oil temp and pressure gauges make a note of typical pressure and temps.
If the oil temp exceeds 240f consistently I would NOT go thinner. If oil temps are lower than that typically,and adequate pressure can be maintained then I might give it a shot.
