Tech / General Engine Is your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!

Sponsored by:

Oil 10W30 or 10W40

Reply Subscribe

Search this Thread

Old

Oct 14, 2010 | 02:52 PM

#1

Thread Starter

Junior Member

Joined: Aug 2008

Posts: 43

Likes: 0

Oil 10W30 or 10W40

I have a 1986 IROC-Z with a 305 TPI Engine, it has about 140,000 miles on it. A friend on mines said that I should use a heavier weight Oil because of all the miles the car has.

I this true or should I stick to 10W30?

Old

Oct 14, 2010 | 02:55 PM

#2

Moderator

Joined: Jan 2000

Posts: 20,981

Likes: 11

From: Mercedes Norte, Heredia, Costa Rica

Car: 1984 Z28 Hardtop

Engine: 383 Carb

Transmission: 4L60

Axle/Gears: 3.54 Dana 44

Re: Oil 10W30 or 10W40

Is your oil pressure low?

Old

Oct 14, 2010 | 04:24 PM

#3

Thread Starter

Junior Member

Joined: Aug 2008

Posts: 43

Likes: 0

Re: Oil 10W30 or 10W40

When I first turn the car on the pressure is high (about 60) but when the gets to operating temperature the oil pressure is less that half (between 25 30).

Old

Oct 14, 2010 | 04:45 PM

#4

Senior Member

Joined: Jun 2005

Posts: 502

Likes: 0

From: Savannah GA

Car: 1986 IROC

Engine: 355" TPI

Transmission: 700R4

Axle/Gears: 3.42

Re: Oil 10W30 or 10W40

Your pressure is fine. You can continue running 10w30 but 10w40 wont hurt either.
I have been running 10w40 since the motor was rebuilt in 05./

Old

Oct 14, 2010 | 04:57 PM

#5

Moderator

Joined: Jan 2000

Posts: 20,981

Likes: 11

From: Mercedes Norte, Heredia, Costa Rica

Car: 1984 Z28 Hardtop

Engine: 383 Carb

Transmission: 4L60

Axle/Gears: 3.54 Dana 44

Re: Oil 10W30 or 10W40

10W40 would just eat up a little bit more HP, then.

Old

Oct 14, 2010 | 08:40 PM

#6

Thread Starter

Junior Member

Joined: Aug 2008

Posts: 43

Likes: 0

Re: Oil 10W30 or 10W40

So if I use a heavier weight oil I will loos Horse Power?

If this is true, then there is no real benefit in using 10W40.

Old

Oct 14, 2010 | 08:50 PM

#7

Senior Member

Joined: Jun 2005

Posts: 502

Likes: 0

From: Savannah GA

Car: 1986 IROC

Engine: 355" TPI

Transmission: 700R4

Axle/Gears: 3.42

Re: Oil 10W30 or 10W40

Its a small loss.

Reply Subscribe

Related Topics

Thread

Thread Starter

Forum

Replies

Last Post

[CA] 1989 Trans Am w/ just 32k miles for sale

jrdturbo

Firebirds for Sale

26

Mar 31, 2016 02:58 PM

[ON] 353 GEN 1 SBC: What's It Worth Where You Are?

skinny z

Engine/Drivetrain/Suspension Parts for Sale

5

Oct 5, 2015 06:23 PM

[MI] 2000 Camaro SS M6

meeklay812

Camaros for Sale

1

Oct 1, 2015 03:46 PM

2 Mystery Wires

Gordonr1973

Electronics

0

Sep 29, 2015 11:59 AM

Was trying to find fuel pump relay. Now, no oil pressure

j00sh

TPI

1

Sep 27, 2015 09:49 AM

10w, 10w30, 10w40, 2000, 30, 305, 40, camaro, chevy, heavier, heavyer, hurt, jose, oil, san

First
Prev
1 / 1
Next
Last

All times are GMT -5. The time now is 02:44 AM.