Heavier oil

[Keepinitoldskool]

I can tell you from experience that it wont. My valve seals were eating so bad I don't think 90w would have made a difference. Valve seals cost like $20 and should take around 3 hrs to do.

 

[ram1220]

Are valve seals the cause of a bit of blue smoke at start up? My 90 Sierra 5.7 runs like the day it was new. Doesn't use oil either. But I do have a little blue smoke on the first start up every day.

 

[kennythewelder]

Yes. Chevy has been known for this issue for many years. If it isn't using any oil between oil changes, and it only smokes a little within the first few mins of start up, I wouldn't worry about it at all. The last 3 or 4 small block Chevys I have had have done this and I keep driving them for 10s of thousands of miles with no other issues.

Are valve seals the cause of a bit of blue smoke at start up? My 90 Sierra 5.7 runs like the day it was new. Doesn't use oil either. But I do have a little blue smoke on the first start up every day.

 

[thz71]

Mine uses about a quart to every tank of fuel lol

 

[AgentYager]

I run a tad thicker oil (10w-40) in my L67 in my Regal only because it's getting up there in miles and the oil pump is getting tired, and lots of city driving I do notice about a 8-10 psi of oil pressure increase once it's hot. Though with leaking valve stem seals like you have, it isn't going to make any difference.

 

[RyanMerrick]

Funny you guys mention the 180 thermostat. I actually just pulled my 180 out to replace it back to the 195 that was originally in there. Why is it that the 305's require 5w-30 and the 350's require 10w-30?

I run Mobil 1 5W-30 year round. The engine turns over more easily in the winter months.

Remember that the first number (5W - "Winter"), is the viscosity in cold weather, and the second number (30) is the viscosity at operating temperature. Therefore, at operating temperature, 10W-30 and 5W-30 are the same.

 

[Smitty1021]

So I decided to try and run 10-40. I also replaced my oil pressure switch bc I must have broken one of the connector prongs inside the switch when replacing my distributor a few months back. I've come to notice that at cold idle I have good oil pressure, around 40. While driving cold it's up around 60. But at hot idle I'm running around 15 and the check gauges light pops on. It must be right on the edge bc if I bump the idle up only by about 100 rpm the light turns off. While driving hot I'm up around 40-50. This a sign the oil pump may be starting to go out?

 

[Keepinitoldskool]

Oil pump or crank bearings.

 

[Smitty1021]

Could it also be from using a heavier oil that the pump is having a little bit harder of a time pumping oil at idle?

 

[kennythewelder]

A heaver oil sholud give you more oil pressure, not less, as it is harder to pump. Also cam bearings will affect oil pressure. As the main, rod, and cam bearings wear, it is easer for the oil to pass through them resulting in lower oil pressure. When the engins heats up, everything expands, resulting in a drop in oil pressure. 30 PSI at idel in an engine that is at operating temp is normal, 15 PSI is low and is most likely a sign of woren bearnings. Oil viscosity can be increased by adding a thick addative like STP, if you can find it.this wll make the oil thicker and raise the oil pressure at idel, but this is not a permanent fix. The only way to permanently fix this is to replace the bearings (a rebuild )