The 6049M is something to do with oil pump flow at very cold temps...Not something to worry about this time of year for sure. I'm actually pleased at how my engine has gotten a bit quieter in a 1000 miles with GTX in the sump...2K more and then more than likely Pennzoil Platinum


Goose

 

Just a heads up that Castrol GTX is now back on GMs GM6094M approved motor oil list as of August 8 2007.

 

Good deal. Wonder what the flap was?

 

Although I have been using Mobile 1 in my Colorado, but I prefer Castrol Syntec or Amsoil. I'd buy Royal Purple if I could find it.

I used Mobile 1 in mt '85 Vette and lost oil pressure right out of the stall. Engine was noisy. Quickly drained and refilled it with Syntec 5w50 and pressure came back and noise went away.

On the law suit issue, I had thought it was the other way around. Syntec was the full synthetic and Mobile 1 was not.

Used AMSOIL in a race car (H/Prod SCCA) and gained 5 psi oil pressure at race temps. Our car picked up MPH and was able to run down the back straight at old Riverside Raceway with the F/Prod cars. That was like getting another 200 cc of engine size.

A lot of the Nostalgia Top Fuel guys here on the left coast are running the Purple. I only see it at the races.

Ran GTX in the 70's in my Vega GT and went 80,000 miles before the engine failed. Bore was ok, I spun a rod bearing in a long sweeper turn at high RPM. Lost oil pressure when all the oil that was not up in the head sloshed away from the pickup.

 

I still think it depends on the individualsa use and vehicle.

My experience with Castrol was just the opposite. Used it exclusively for years. But in 1995 I installed full digital gauges in a specialty vehicle. And had the gauges certified for accuracy (you know, the old friends, again).

Running acrossed Interstate 8 in 110 degree ambient, between Gila Bend, AZ and El Centro Calf., I noticed oil pressure running at a constant 38psi (straight 30W). That concerned me. I was advised to change to another brand and did. NEVER WITNESSED anything lower than 49 PSI after that (most of the time more like 50).

Again, I just think it DEPENDS......

I don't drive vehicles, like I mentioned above, any longer....AND, I seldom drive at those rates of speed....if ever. So I probably would use the Castrol again. That jsut scared me because I had A LOT OF MONEY INVESTED IN THAT CAR.

 

Just found this in a Google search:

http://groups.google.com/group/rec.a...3b4df1a70546e6

Regarding Castrol, here is a quote from the Car and Driver article:
"Late in 1997, Castrol changed the formula of its Syntec 'full synthetic motor oil,' eliminating the polyalphaolefin (PAO) base stock (that's the 'synthetic' part, which makes up about 70 percent by volume of what's in the bottle) and replacing it with a 'hydroisomerized' petroleum base stock."

Looks like I'll be staying with Mobil 1 or AMSOIL

 

Bob- You might want to see what Mobil 1 has done recently


Goose

 

Good advise Goose. I wonder where you read that?

I don't have an issue with the hydrocracked synthetics. I have an issue with paying PAO prices for hydrocracked synthetics.

 

I think I'm just going to stick with Wal-Mart SuperTech conventional...worked in the S-10 through 200,000 miles!

 

Based on my race experiance with synthetics I want a full synthetic. My hotrod has been on a Syntec diet since it was broken in, but What started out as full synthec became only partial and as such I'm gonna make a change. Might be M1, but I'll search a bit first. Then the HHR will get the same.