Was informed by my new mechanic not to put synthetic oil in my 08 hhr 150k miles. I just want to put the best oil in my car. What should I do?

 

5W30 Dexos synthetic, the recommended oil from the engine manufacturer, don’t go cheap with Dino oil! You will regret it!
Do not use “high mileage “ oils either, snake oil!

 

Getting harder and harder to find non synthetic oil. Most oils are either what they claim as full synthetic or a synthetic blend.

 

Did you ask why? Sounds like a mechanic that heard something from someone somewhere about something he didn't understand.
Many years ago, some "common knowledge" was don't mix dino and syn or change from one to the other. That has been debunked for like 50 years.
Dexos is a syn/syn blend specification. I'm not sure if dino oil comes in 5w30.

 

So would you agree synthetic/synthetic blend is still synthetic?

 

Here is the long version of why you use synthetic oil…

Engines in HHR’s have oil spray jets that spray directly on the chains and guides.
Conventional paraffin based engine oils “coke” up when heated, creating sludge. Your oil spray jets will stop up and wear your chains and guides out much more quickly.
Synthetic oils were developed with the advent of jet engines for this very reason.

So, if you want your engine to live longer….use synthetic oils.

 

There were and probably still are synthetic blends that carried the Dexos I mark, and presumably meet the standard. I haven’t seen one in awhile.

GM can up with the Dexos I standard and began requiring it not because something about their engines changed, but rather, because crappy oil, even with other industry designation tags, was damaging engines.

“Synthetic” alone means nothing. I’m sure the geeks in the lube labs could synthesize a 5-30 swill that could lock up your engine in a day if they wanted to.

My 2011 2.2 gets any “full” synthetic, whatever that means, as long as it’s Dexos I as specified in the manual. My 2010 2.0 turbo gets the best synthetic I can get, but it must be Dexos I.

 

Synthetic blend is a play on words. Like 5% synthetic, maybe less? I dont think they label the percentage on the container. My former 2011 gets NAPA full synthetic 5w30. Made by Valvoline but usually 1/3 to 1/2 the price. My son owns the car now. 3500-4000 mile intervals and we change it. 224k on the clock and the only engine parts replaced were the VVT solenoids a DIY job and about 10 minutes to do it. It gets a NAPA gold oil filter also. ( made by Wix) There are plenty of brands that I have used. Pennzoil, Castro, Valvoline, Mobil One, Kendall, and others, All with great results. Pay no attention to the oil reminder on the DIC and go by mileage seems to be working fine for us. Cant figure out why Pennzoil Ultra Platinum isn't Dexos approved but Pennzoil Platinum is. Oh well, one of life's mysteries. The mechanic was stating opinion, not fact. I havent seen a Dexos non synthetic oil in years, that I can remember.

 

Dexos is a synthetic specification, thus no dyno oil is Dexos. I don't think there are any syn blend Dexos oils anymore.

Dexos must contain specific chemicals. Pennzoil Ultra Platinum is "made with Natural Gas" Pennzoil Platinum is not.