Oil question... Is this BS?

[Blackened]

Okay I might be splitting hairs with this, but it's really got my curiosity...

A co-worker of mine has a ram air T/A with the "classic" valve train noise that can easily be heard at idle in most LS engines. He says that he switched from the manufacturer reccommended 5w30 oil to 10w40 and it quieted them down.

Is there any truth to this or is this just a situation of wishful thinking on his part? I haven't had the chance to hear his engine as of yet, but was wondering if there were any drawbacks to using the heavier weight oil if there is even any truth in it.

One other thing... I was told that I should be using 10w40 anyway due to the fact that Texas gets extremely hot in the summer and not all that cold in the winter. Is there any validity to that statement? Thanks in advance for any replies...

[z62jag]

I run 10w50 in my 300zxtt in the summer (10w40 in winter) but that's dyno oil. I don't think the same thinking applies when runnning a synthetic. I run 10w30 Mobil 1 all year round in the Z06.

[xsiveone]

It's possible. It is a thicker oil. If it is quieting it down because it's thicker, it's probably not flowing as better either. If I had the choice of valve train noise or valve train wear, I'd take the noise any day.

That being said, I don't think that little difference in viscosity would do much of anything.

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[george]

Stick with the 10-30 mobile and get a 160 t-stat and fan controller. Engine will run cooler and you can hear the valve train. As mentioned, I'd rather hear my engine also.

[Ranger ZR-1]

at 150,000 I switch the Jeep to 20w-50 (that was 10 years ago), but it rattles so much I'm not sure what the engine sounds like anyway.

The thicker oil will quite it down and increase pressure in an older engine

[Subdriver]

I run AMSOIL 20w50 in my motor, but I beat the heck out of mine on the track with oil temps running 250-270 constantly.

Even in Texas, the factory recommended 5w30 should be fine, but I don't think 10w40 will hurt the motor. You may lose a few HP due to extra friction induced drag from the heavier oil.
AMSOIL makes a great SAE 10w30 synthetic which would work well in Texas.

If you are worried about the high temps, take a look at this comparative oil test done by an independent lab in March 2003 (posted on my site with permission from AMSOIL):
Comparative Oil Test of 10w30s

[RocketSled]

The only reason GM recommends the 5/30 oil is for MPG. You can certainly run heavier weight oil, particularly in warm climates, with no negative mechanical effects other than slightly higher pumping losses.

[jdk]

I'd go with 10-30 in texas.


About the clicking, since the cars run hydraulic lifters it's entirely possible that a higher viscosity oil will make less noise.

[xsiveone]

AMSOIL makes a great SAE 10w30 synthetic which would work well in Texas.

That's what I use. 5W-30 in the winter because of cold starting here in the north.

I've never liked using high viscosity oil like a 50W. Of course, Subdriver races his car, so.. It's too bad you can't keep your engine in it long enough to find out if it helps or not. I know it's not oil related or anything. Certainly hope you have better engine luck in the future though.

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[Dope]

I run 10W40 redline in the summer anyway. 0W40 mobil 1 in the Camaro for winters.

Dope

[NVGRWUP]

Originally Posted by Subdriver

I run AMSOIL 20w50 in my motor

Are there any warrenty issues using oil other than Mobil1 5-30W? Owners manual mentions a GM Motor Oil Spec; Does AMSOIL meet that?

TX/MR

[Subdriver]

Are there any warrenty issues using oil other than Mobil1 5-30W? Owners manual mentions a GM Motor Oil Spec; Does AMSOIL meet that?

While AMSOIL is API certified for gasoline engines with starburst symbol, the product listing doesn't specifically address GM standard GM4718M. I have contacted AMSOIL technical staff about this.

However, AMSOIL warrants that its lubricants are fit for use according to the written recommendations of AMSOIL. See the full warranty on the link at the bottom of their homepage:
AMSOIL Homepage

AMSOIL does recommend the SAE 5w30, SAE 10w30 for the Corvette Z06 and also recommends a 25k mile or 1 year change interval with this oil (with AMSOIL filter change at 12.5k or 6 months). In addition, they recommend the Synthetic ATF and SAE 75w90 Gear Lube (with "fill for life" change interval for normal use).
AMSOIL Application Guide
AMSOIL Product Change Interval Guide

For me, since I am racing on the track, it doesn't really matter since no one will cover failures. So I use what I feel is the best protection, which given my high operating temps is the Series 2000 Synthetic 20w50.

[xsiveone]

Are there any warrenty issues using oil other than Mobil1 5-30W? Owners manual mentions a GM Motor Oil Spec; Does AMSOIL meet that?

No. As long as it meets the GM standards. You can switch grades and oil brands as long as they meet the standards. They should be in the owners manual.

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[Subdriver]

I contacted AMSOIL Technical support last night to confirm that their oil does in fact meet GM Standard GM4718M.

Here is their reply:
"In response to your inquiry, yes AMSOIL Synthetic 5W30 Motor Oil (ASL) meets the GM 4718M specification."

[xsiveone]

"In response to your inquiry, yes AMSOIL Synthetic 5W30 Motor Oil (ASL) meets the GM 4718M specification."

Wouldn't doubt that it would meet or exceed the GM specs.

Thanks for confirming this Subdriver.

When are you leaving for the race?

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