[werdnash2002]

The dealer where I bought my used 05 GTO put regular oil in it and I just realized now from the sticker on the windshield. I put 400 miles on the car, do u think Its harmed the engine at all? I dont know what happens with these engines if you use regular oil.
Andrew

 

[Jeffs386]

its not a problem at all but I would go back and have the synthetic put back in

 

[EEZ GOAT]

if its not a pontiac dealer you cant hold them responsible. they dont know. but if it is they should know better

 

[werdnash2002]

yea I did and they agreed to change it at no charge. On another not before I bring it back in I noticed twice today idle when I start the car the revs are boucing up and down between 500 and 1500 and stalling sometimes. The car has a cam but usually never idles like that. Any ideas?

 

[werdnash2002]

oh and it is a pontiac dealer, a huge one too

 

[noz34me]

oh and it is a pontiac dealer, a huge one too

Sad commentary; can anybody say "jacklegs"?

I think Mobil 1 is stamped right on the oil filler cap too- - -

You would think they would get a clue.

 

[Tom]

shhhh, dont tell anyone.

GM made mobil 1 the factory fill in the vettes a few years ago. as soon as they made it the factory fill they deleted the external oil cooler.


will regular oil ruin your motor? it didnt ruin any motors before they switched to mobil 1.

 

[UdnUdnGTO]

Relax Tom, regular oil will not ruin your engine. Difference in oils is management of by products of combustion. Just get the cheap crap out of there and you will be fine. Synthetics do not respond to such chemicals as sulphuric acid like dino oil, etc. Good catch, you are right, a Pontiac dealer should have known better, but think about who does oil changes in most dealerships, it ain't the techs.

 

[roadracer]

I don't know about the 05's and 06's, but the early 04's came from Holden without Mobil One. Both mine and my wife's car were that way. I changed hers to Royal Purple at 500 miles and I use Red Line in mine which I put in at just over 500 miles.

 

[socal gto]

Hey roadracer which do you prefer? I am trying to decide on which to get Royal purple, redline, or mobil one.

 

[Subdriver]

Hey roadracer which do you prefer? I am trying to decide on which to get Royal purple, redline, or mobil one.

Of the above three choices, I'd recommend Redline, though it is expensive. An alternative that performs well and is what I use in my Z06 on the track is AMSOIL. AMSOIL performs well as can be seen from this AMSOIL commissioned Comparative Motor Oil Test.

:cheers

 

[derf]

Of the above three choices, I'd recommend Redline, though it is expensive. An alternative that performs well and is what I use in my Z06 on the track is AMSOIL. AMSOIL performs well as can be seen from this AMSOIL commissioned Comparative Motor Oil Test.

:cheers

I bet if I bought an oil study, I could show that any oil I chose would do well....


That being said, AMSOIL isn't a bad oil.

As far as running regular oil in an engine, it's actually better for initial break in than synthetic. It's better at helping the rings seat properly. I ran regular dyno oil for the first 1500 miles on my GTO before switching to synthetic. I'm about to break in a newly rebuilt engine and I have straight 30 weight non detergent oil for that break in. Once I get a few miles on it, I'll switch over to synthetic.

 

[Subdriver]

I bet if I bought an oil study, I could show that any oil I chose would do well....

A few years ago when I was trying to decide what oil to run in my Z06 on the track I had the same initial thought, so I went looking for it. But after spending way to many hours on corporate websites such as Mobil 1, Redline, Royal Purple, Castrol, etc I realized AMSOIL was the only one who had data such as the above linked test. That meant something to me. But, I was still skeptical, so I spent more time perusing hundreds of used oil analysis reports on the oil forums before convincing myself to give it a shot. Been happy with it ever since. Even had a few oil analysis reports such as this one done on my customer's cars:
Corvette C5 AMSOIL Series 2000 0w30 Used Oil Analysis Report
:cheers

 

[socal gto]

What derf said is right. I am studying to be an aircraft mechanic and that is exactly what they do for the break in period. First they will use a straight mineral oil then they will switch to an ashless dispersant oil.