Oil for my LS1 GTO

[Torrid]

I've been contemplating going to a 5w40 and I'm a bit partial to Mobil 1 products. My Walmart recently started carrying the 5w40 TDT and I'm thinking of making the switch, but I've yet to even find a VOA for it. I'm curious of the ZDDP in the oil as I run a ZDDP additive in mine and I'm getting sick of making motor oil cocktails if the 5w40 is as good of a solution. Right now my mix is 4.5qts M1 5w30, 2qts M1 15w50 with 1oz of ZDDP Maxx. I'm planning on running a UOA after this run to see how it is working out for me, but I've seen UOAs for TDT showing 1300 Zinc 1200 Phos which is awesome for used numbers. I already like the viscosity of the 5w40 based on published numbers, but wanted to verify the numbers on ZDDP in particular. I'd also be running it in my V8 S-type as it makes stocking oil easy.

I know that I run a bit higher than necessary ZDDP, but it runs smooth and it's cheap insurance.

 

[cchase]

I realize this doesn't address the root of your question but any SM/SN rated 5w30 that meets GM4718 spec will work fine in your LS1.

 

[ltslimjim]

I've heard a lot of issues with that engine losing oil if it has suffered a lot of wear/blow by(not sure of the 'whys') and people, IMO, make the mistake of trying to increase their oil pressure by going to a thicker oil, like a 20w-50 etc.

IMO, just like using 5.5 Q of 5w30 and using 1 Q of 'oil honey', it is all just another route to masking a problem.

If I'm not mistaken, as well, I believe your car has a 'measurable' amount of oil loss at the PCV valve. I'd suggest getting a catch-can set up/filter. If you have this problem your intake is probably coated with varnish at least(where ever the PCV goes into the manifold for vacuum) and on down into the engine over the heads.

As for the oil you should choose? I'm not sure. I always say go with your stock recommendations and work at whatever is wrong to avoid having to play with which oil grade you use.

 

[Durango]

Torrid,

I have the same engine as you in my 08' Impala SS and use Mobil 1 as my standard in 5w30 weight. I wonder exactly why you need to go to a thicker oil when the 30 should be fine.

Durango

 

[ls1mike]

I have a heads and Cam LS1 Trans Am and always run plain ole' 10W30 Mobil 1. It does just fine.

 

[A_Harman]

I have a 2002 Camaro Z28 LS1 with 154k miles.
I have always run M1 5w30, and it's just fine.
There is no need to go to a 40-weight on the LS series of engines.
There is also no need to supplement the oil with high levels of zddp, as the valvetrain uses roller lifters. If you want more wear protection, use M1 10w30 High Mileage. This is an SL spec oil that has 1000ppm of P, instead of the 800ppm that SM oils are limited to.

 

[Corvette Owner]

I have always run 5w30 in my LS1 1998 Corvette. With 130,000 miles on it it uses less than 1/2 quart of oil in 6500 miles. There is no need to use a heavier oil than 10w30 in an LS1. There are some very small passages in these engines.

I always used Mobil 1 until recently. I noticed that the last few years, my UOAs were showing increased lead ppm (up to 21 ppm). I suspected (as many) that Mobil was changing their formulation.

Recently (past 2 years) I switched to Castrol Edge, and my lead ppm decreased by 3 times ! Edge is a thin 5w30, almost 5W-20 weight oil. No problems, in fact my engine is quieter running this oil (many have said this with Edge).

I would recommend 5w30 Castrol Edge (think with your dipstick !)

 

[Win]

I used synthetic 10w30 in my LS1 GTO from about 500 miles to 30K when I traded it for the G8.

Never had any detectable oil consumption. If you want to run a 40 weight, I'd consider the M1 0w40.

I run synthetic 5w30 or 10w30 in my Jags, both V12 and V8.

I have 0w40 in my G8, but I'll probably go back to 10w30 in it.

 

[Torrid]

I actually have never had it burn or loose any oil, even with 6 month oil changes. I'm just thinking of the summer months. I'm in the desert and I haven't had it during the summer since I installed my oil pressure gauge. It tended to be noisy on cold startups even with just the 5w30 and ZDDP additive has even made startup smooth and quiet.

I have run the 0w40 M1 and I think it is apparent it shears a lot just like a lot of UOAs show. It always gave me noisy startups in the last month before an oil change. I just figure a 5w40 would be good for all year around inluding the desert summer heat.

 

[ltslimjim]

Startup noise wasn't from noisy lifters etc, just high cold engine idle etc? Choice of oil can impact some engine noise, especially after an oil change(flush included or not) and even if you have the 'easiest' starting oil for cold weather of course your engine will idle high while its cold out.

For, LV 40 may not be 'bad' for the summer, but I don't see any reason to go away from 30 during the winter. IMO, if you have to something seems to be off mechanically and a thicker oil may just be masking a developing problem(or just normal wear).

 

[A_Harman]

How cold does it get in LV in the winter?
I've been through there in the summer, and it's hot.

 

[Torrid]

A really cold morning usually is above 35 degrees. I've noticed most car dealers use 10w30 year around here.