Is it time to change oil viscosity?

[TURBO2]

I have a 1986 GN with around 108,000 miles on it. I'm using the factory suggested 10w-30 and have about 70 psi oil pressure when cold, but once it heats up the pressure drops to only about 17-18 psi. Should I switch to 10w-40 or 20w-50?

 

[dynoman]

Same as mine with 10w30 .... 70psi cold -- 18psi hot idle .

 

[THensley]

stay where your at all good

 

[deezdad]

What temp tstat? Stock, 180, 160 ?

 

[TURBO2]

What temp tstat? Stock, 180, 160 ?

160, but it goes beyond that since I put in the front mount intercooler. I have to put in some higher rate cooling fans to fix it.

 

[V6sleeper]

Many dont agree with this but i run Vr1 20/50 in NY summer and 10/40 in the fall/winter for 20 years , with only showing a 3 psi hot idle difference

A front mount will put you over 200 degrees on the streets without good dual fans

 

[deezdad]

Only my opinion but I wouldn't run a thicker oil with that cool of an operating temp especially with the fan upgrade.

 

[KC87]

The manual in my (87) says 5-30. Only used 10-40 from the start.
Back in the day Kenne Bell I would say was the big guru and always used 10-40 and recommended it.
And the 10-40 today is way better then 40 years ago
All those 6.2l engines GM has to recall use 0-20. One of the changes will be to have owners switch 0-40 or perhaps
5-40. Hoping to push it over the warranty.
I guess if you're buying new today you pick your poison and hope for the best.