Oil Change remorse

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Feb 5, 2004
Yesterday I changed out my M1 5w30 which I have been using for all changes for the last 30,000 miles on my 5.3 chevy silverado. I put in the Truck and SUV 5w40 as it has been higly praised so far. I have not had any consumption of the 5w30 in the past. Will using a 40wt over the 30 that was giving me no problems possibley losen up anything that may make the engine start to use some oil? After all GM Specifies 30wt for a reason right??? Am I worring for nothing?

Guilt has set in..
I've been running Delvac 1 5W40 (Mobil 1 TSUV) in both Toyota V6 Trucks where toyota specs 5W30. It gets well over 100df here for 4-5 months a year. Sometimes up to 130dF on the pavement. I don't think there's a better oil out there for this kind of heat. All of our driving is stop and go with a lot of cold starts. I'm worried about fuel dilution. I know Delvac handles contaminants very well being a mixed fleet oil.

You won't have anything to worry about. I'd run it year round since they'll both flow the same in cold weather!
I use Delvac One 5w40 in a TDI (turbo diesel) I also use Mobil One in TLC's and Corvette Z06. In addition I use 15,000 mile intervals on the Mobil One 5w30 products. Since Delvac One 5w40 aka Mobil One Truck and Suv is SL/SJ (backward compatible) and is C1-4 rated, I would not hesitate to use Delvac One as a substitue for Mobil One. However the same is NOT true vice versa in the TDI (turbo diesel) Delvac is actually a better oil than Mobil One.
I'm using that oil in my Accord V6 now and think it will be good with summer coming up.

Possibly I might use a mixture of the 5W40 with the 0w30 R for the colder weather come next winter.

I "think" the 5W40 truck/suv oil might be just a pinch thick for winter time.

[ April 13, 2004, 10:46 PM: Message edited by: Hankrr ]
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