To 20w-50 or not?

[Sal Lubrano]

I have been running 15w-40 for about a year now but I have check my oil pressure and would like some opinions on my oil pressure. At idle I am at 12-13i with the coolant at 175 and the oil about 180-185 on a WOT I max out at 50 psi. I want to put in 20w-50 but would like some opinions. I know the motor needs a rebuild soon but should I stick with the 15w-40 or go 20w-50?
Thanks for the help and this new board rocks.

 

[Black Car]

If you are wanting more pressure, you could change out the oil pressure relief/bypass spring to a higher pressure one(longer).
You should have no trouble with the 20w50 unless you are up in the cold part of the country. Then I would stay with what you have.

Gary

 

[FastRegalWE2]

If you are wanting more pressure, you could change out the oil pressure relief/bypass spring to a higher pressure one(longer).
You should have no trouble with the 20w50 unless you are up in the cold part of the country. Then I would stay with what you have.

Gary

+1

 

[Ormand]

The oil pressure you have is plenty, and is higher than many other people have. Why do you want more? Oil pressure is one of those areas where "enough is enough", and going higher is not a good thing.

 

[ronbuick]

I would stay with what you are using , delo or rotella?? or a 5-40 synthetic.

Ron

 

[ESP Products]

50 psi at WOT is not enough; 50 at cruise is enough. Heavier oil will help with the pressure, but not much. You have a problem, fix it. I would spend $25 - $60 and get a new thrust plate or/and oil pump. It's not a difficult change/installation. You're not throwing your money away; you can use these later when you do the engine rebuild.

Hope this helps you.

 

[Sal Lubrano]

50 psi at cruise which is about 2000 rpms? Did these cars ever have this new? What pressure at WOT? Those numbers see, very high for these motors.

 

[ESP Products]

50 psi at cruise which is about 2000 rpms? Did these cars ever have this new? What pressure at WOT? Those numbers see, very high for these motors.

We build these motor all day long. Most Buicks/engines that leave here are at 20 psi at idle, hot idle. Like I said cruise is about 50 psi, maybe 45, but I would be worried with anything less. At WOT you should be up near 70 psi.

Hope this helps you.

 

[TurboDave]

50 psi at cruise which is about 2000 rpms? Did these cars ever have this new? What pressure at WOT? Those numbers see, very high for these motors.

My 87 which still has the original unopened motor, usually runs just over 48 while at cruise. Pushes just over 60 at WOT, and settles down to around 15 at hot idle.

This on a motor with 135,000

 

[RobsIron]

10 lbs per 1000 rpm is adequate.

 

[Ormand]

50 psi at WOT is not enough

Like Robsiron said, 10 psi per 1000 rpm is "adequate". I know it does't bring any money into ESP, but it's still adequate. However, you should be able to get that pressure running 30 weight. If your engine builder was sloppy, then you may need more, like maybe 70 psi.

 

[onslow]

Hi Sal-


I live in California low desert...so it gets real hot in summer. I have 80K on engine.

At a cruise last weekend, I asked a similar question to yours of a now-retired master mechanic...he used to work on Ferraris, our cars, and lesser metal.

I run M1 15-50 and asked if he thought I should use that in winter and switch to 20-50 in summer. He said either weight would be fine for our turbo motors.

Based on his expertise and the previous post by ronbuick and Black Car, if your engine is running well during all seasons, I suggest staying with the oil you are using.

You might want to use one of the oil additive packages like the Valvoline Synthetic to ensure that you give your valve train the minerals it might need in its advanced age...certainly would not hurt.

Steve

 

[onslow]

Hi Sal-


I live in California low desert...so it gets real hot in summer. I have 80K on engine.

At a cruise last weekend, I asked question similar to yours of a now-retired master mechanic...he used to work on Ferraris, our cars, and lesser metal.

I run M1 15-50 and asked if he thought I should use that in winter and switch to 20-50 in summer. He said either weight would be fine for our turbo motors.

Based on his expertise and the previous post by ronbuick and Black Car, if your engine is running well during all seasons, I suggest staying with the oil you are using.

You might want to use one of the oil additive packages like the Valvoline Synthetic to ensure that you give your valve train the minerals it might need in its advanced age...certainly would not hurt.

Steve

 

[turbobuick]

Like Robsiron said, 10 psi per 1000 rpm is "adequate". I know it does't bring any money into ESP, but it's still adequate. However, you should be able to get that pressure running 30 weight. If your engine builder was sloppy, then you may need more, like maybe 70 psi.

For a stock 245hp GN I would agree it is adequate but when is the last time you raced a low 14 secound GN? Maybe 14's is "adequate"??

You need at least 20 at idle and 70 at WOT for anything over stock. I wouldn't be happy on anything I ran hard with less than 20 psi hot at oil temps over 160*. You have a problem with anything less and it needs addressed unless you plan a rebuild soon.

I would not want to run more than 10w40 in a 231 Buick turbo V6. The heavier weight oil is to hard on the front cam bearing/cam sensor/oil pump and can wipe the #1 cam bearing.