Hi,
I searched for this and couldn't find any real answer. I've got a 2001 Blazer 4.3 Vortec with only 98,000 miles on the original engine and wanted to ask here on what type of oil you would use. I don't change it myself because I have a trusted guy who does it and he uses Quaker State oil (not synthetic). I always use 5w30 since I'm in Montana.
Just curious if anyone had thoughts if I'm fine to use the Quaker State or if I should use a different oil and if it would be better. I change it often already, but just put a new fuel pressure regulator on it and was told by somebody that this can lead to fuel in the oil when they go bad.
Thanks for any ideas!
--Matt

 

I have used PYB 5W30 Penzoil dyno oil since new in my 2002 Blazer and I'm at 205,000 miles with no oil related issues such as compression. I have averaged around 12,000 miles for my oil changes. I use a K&N filter most of the time.

In a Toyota Rav4 that I own I have 276,000 miles on that one and have used Kendall and Penzoil semi-synthetic 5W30 since new. Same thing, around 12,000 miles per oil change.

George

 

I swear by Valvoline high mileage all grades but that's just me. I have 5 W 20 in my 4.9 300 straight 6 F250 and I have the 5w30 in my 99 Bravada vortec 4.3.

 

Stick with what you're using and you'll be just fine.

 

I use synthetic in my car, my truck, and my Blazer. It just gives me peace of mind. My wife's car, on the other hand, is usually serviced at Oil Changers and has never had synthetic oil, AFAIK. It's never had any issues in 110k miles, and doesn't burn any oil between changes.

I think it's probably much more important that you change the oil regularly than exactly what kind you put in.

 

The thing to remember is that this engine was designed and developed back in the 1980s as a truck engine so no tiny oil passages or high heat components (such as turbos) were envisioned in its use. GM set it up for dino oil. Those who say "The dealer uses synthetic (or semi-synthetic) oil for the changes" are not accounting for the fact that it is done like that so they do not have to keep different types of oil in stock. Dealers do not plan on many old vehicles coming to them for oil changes, so they have what the new engines use and put it in everything now.

 

rriddle3 - that is actually why I asked the question because the dealership did say that the synthetic was the factory recommended. I don't trust them anyway (stealerships I hear them called here often). Think I'll just stick with the Quaker State since we change the oil often and that worked fine in the past.
Thanks to everyone who chimed in!
--Matt

 

I stick with 5w30, it's what the engine was designed for and as well as you upkeep maintenance nothing should go wrong on these 4.3s.

 

Rule of thumb years ago was stay with the oils that you have been using and don't change brands - old style sin had a habit of hardening rubber seals when it was used after dino oil - it's not a problem anymore.
I'm old school - oil and filters are changed at 3k miles - can't be all wrong the old 6.2 has 220271.5 miles [they usually blow at 100k]
I do 15-40 Valvoline in my two diesels and 10-30 Valvoline in my two Morfs along with Wix filters

 

I've run dino 10W30 in the summer and 5W30 during winter since I bought my Blazer new back in Oct 2000 and I'm closing in on 300,000 miles. No oil related problems in all that time, other than leaking oil lines to the cooler. New cars tell you that you must use full synthetic, as has already been mentioned. As long as you do proper maintenance, you shouldn't have a problem with using dino oil in these engines.

And 12,000 miles between oil changes is WAY too long, regardless of what the manufacturer recommends!