Will using 10w40 in my high milage LT1 be ok or no?

[Bandit_LT1v8]

If it was summer id say run the 10w40 just to use it then switch back to 10w30 at the next oil change. If you were down to 5psi at warm idle id say run the 10w40. But in your situation I would run 10w30.

Now when the guy drove the car to my apartment (over 4 hour drive) the car was hot and the oil pressure was around 10 at idle.

But when I drove it around my apartment complex and let it idle a little it was around 20, but it wasnt fully warmed up.

I dont think running 10w40 for one oil change will hurt anything, right? Because I have no way to return it, I have to get a ride.

[firebird_1995]

Run it then. Low oil pressure isn't uncommon on these engines. The heavier oil will help that but just make sure to keep an eye on the cold startup pressure and don't flog it till its fully warm.

[Bandit_LT1v8]

Run it then. Low oil pressure isn't uncommon on these engines. The heavier oil will help that but just make sure to keep an eye on the cold startup pressure and don't flog it till its fully warm.

What should the cold start oil pressure be on LT1's? 40 or higher?

Also, Thanks for your help!

[HAND HERPES]

What should the cold start oil pressure be on LT1's? 40 or higher?

Also, Thanks for your help!

On my v6, it's usually really close to the first line past the middle one on cold starts. Once it warms up, it sits between the middle and the next line to the right.

Once you stop at like a light and the motor is hot, it will usually sit in the middle or just a tad below middle..

[firebird_1995]

I don't know that there is a cold start minimum, I was referring more to keep an eye on it to make sure its not too high.

[Bandit_LT1v8]

I don't know that there is a cold start minimum, I was referring more to keep an eye on it to make sure its not too high.

What is too high for an LT1?

Sorry about all the questions, I am just trying to learn a lot about the LT1.

[firebird_1995]

Over 80psi is too high in my opinion. As it gets colder outside the cold start pressure is going to rise. Depending on how cold it is where you live, it might peg the gauge at startup. After a few minutes of running it should start to drop. I wouldn't get on it too hard until the oil pressure settles down to 40 psi or so. Pressure is resistance to flow. Thicker oil doesn't flow well especially when cold. Rapid wear can happen during cold startups when the oil viscosity is too high because the oil isn't flowing, hence the high oil pressure. If the engine is well worn then the bearing clearances will be larger and will allow more volume of oil through which will cause lower oil pressure readings. If the engine is "fresh" or "tight" the bearing clearances are going to be less which allows less volume of oil through and higher gauge pressure readings. Like i said, you'll have to put it in and keep an eye on it. If it pegs and doesn't come off after a few minutes, the oil is too thick . If it explodes your oil filter, its too thick.

[Badbird_96]

What should the cold start oil pressure be on LT1's? 40 or higher?

Also, Thanks for your help!

All 3 of mine cold start is around 40 at idle then fully warm is around 18-20 at idle. I run 5w-30 full synthetic Mobil 1.