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Sythetic Oil Change Interval?

cujo8

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cujo8 Enthusiast

cujo8

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I love the concept of extending the length of time between oil changes by using a quality synthetic oil and long life filter, but how long is too long when it comes to our GM warranty? Some of these synthetic oils recommend 15,000 to 25,000 change intervals or once a year. I myself would not feel comfortable waiting that long to change my oil. The oil maybe up for the task, but I worry about the dirt and grime that always gets into the oil over time. Since I started using Mobile-1 oil and filters I've been changing the oil every 5000 miles and the oil looks very dark at change time. I would feel more comfortable extending my change interval if the oil still looked close to how it looked when I put in my truck, but like I said that is not the case.

I've read recently on this forum about PCV Oil Catch Can modification that catches the oily vapors coming out of the engine through the PCV line and prevents them from being delived to the intake manifold to be burned up by the engine. I'm thinking this modification may help to keep the oil supply as well as the intake and valves cleaner at the same time. I probably should have separated this last paragram into a separate post, but I feel that these are two things are related in a way.

Matt_ Senior Enthusiast

Matt_

Posted
Posted

You can't judge an oil by how it looks (edit: for the most part anyways. If it "looks" like molasses then thats a different story. But "darker" is rarely an indication of its current state of protection).

 

Almost all oils the recommend 15k+ intervals also have fine print with something along the lines of "as long as oil analysis is done to ensure that the extended interval is safe for that particular engine".

 

I myself am good with my 5k changes. It's the perfect interval IMO because i rotate my tires and give the entire vehicle a thorough inspection (brakes, bushings, joints, etc etc) and usually find issues before they turn into real "issues". Plus, its a chore that I actually enjoy doing :lol:

MikeNH Senior Enthusiast

MikeNH

Posted
Posted

Isn't the new Dexos oil synthetic too? If so, I'd think the oil life system would be programmed to that type of oil so I'd still stick with when that tells you to change the oil if I am correct. I don't care what the oils say, I'm with you in that I'd never, ever run the same oil for as long as they claim it's good for.

cujo8 Enthusiast

cujo8

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I just bought a 2011 GMC about a month ago and I changed out the factory oil at ~900 miles and it was already quite dark in that short milage period. I changed the Oil & Filter to Mobile-1 5w30 and Moibile's Extended life oil filter and I'll probable stick to the 5000 mile change interval that I've been using on my last truck.

 

What type of oil does GM used for the factory fill? I'm not sure if all Dexos oils are synthetic oils or not.

 

Lastly, you can get yourself into some serious trouble if you just listen to your DIC! At least that is what my wife tells me anyway, but I tell you obviously don't know DIC. :lol:

tanked_darren Senior Enthusiast

tanked_darren

Posted
Posted

I go 10,000km on synthetic, I use penzoil platinum used to use mobil 1. My OLM says between 10-20% when I do it.

 

 

FYI I know 2 different people who run AMSOIL one guy runs 0W-30 in his GMC van it has almost 300,000kms on it now. Other guy has the same truck and engine as me.

 

Both those guys change it once a year :lol:

 

 

 

You guys changing your oil because its "dark" are wasting your money. The frequency of oil changes if you owned a diesel would break the bank!

StinkyCheese Senior Enthusiast

StinkyCheese

Posted
Posted

I change mine when my DIC says to or if I'm going to take a longish trip (1000+ miles) and the DIC is under 20%. Usually rotate and balance tires when I get my oil changed as well. Don't know exactly offhand but oil gets changed between 5k and 8k, I'd have to look in my service log for exact #s.

Mulaka Enthusiast

Mulaka

Posted
Posted
What type of oil does GM used for the factory fill? I'm not sure if all Dexos oils are synthetic oils or not.

 

GM uses AC Delco dexos 1 oil as the factory fill on all 2011's. It is not a full synthetic; it is a synthetic blend.

Mulaka Enthusiast

Mulaka

Posted
Posted

I use Mobil 1 (the new SN / GF-5 /dexos labled version) and I will be going 7,500 miles. It's a good OCI...the best in my opinion. It isn't the bogus 3,000 mile myth, but it isn't going as long as the OLM% says either (which I feel is too long). Plus, the owners manual says to rotate the tires at 7,500 miles, so going 7,500 miles on the OCI seems appropriate...I just do everything at that time.

gnet158 Senior Enthusiast

gnet158

Posted
Posted

Good rule of thumb is to change your oil when the OLM tells you to while under warrany. I plan on doing this throughout the life of my truck. HTH.

DALE#3 Enthusiast

DALE#3

Posted
Posted

I also dropped my oil and filter at 1k believe in getting the break in fines out.Suppose to use detox,dealer told me mobil 1 is fine (FULLY SYN.) I was always lead to believe don't mix syn. with regular oil? Now DETOX is mixed? Go figure? I give up!

Nytemare Senior Enthusiast

Nytemare

Posted
Posted
I also dropped my oil and filter at 1k believe in getting the break in fines out.Suppose to use detox,dealer told me mobil 1 is fine (FULLY SYN.) I was always lead to believe don't mix syn. with regular oil? Now DETOX is mixed? Go figure? I give up!

semi-syn doesn't mean its synthetic oil mixed with dino oil....

 

 

its a Dino base with synthetic friction modifiers. Its actually a low viscosity Dino oil thats made to act like a higher viscosity using these synthetic modifiers....which will apparently increase fuel economy.

 

 

I change my oil around 20% on the DIC or at least thats when I make the appointment

05GMCZ71 Enthusiast

05GMCZ71

Posted
Posted

As has been previously mentioned, you can't go off of the LOOK of the oil. Oil, even synthetic, will change color many times, only after a few hundred miles, yet the protection/additives are still very much in use in that oil. If you are concerned, you can have oil analysis performed to get an idea on how your engine is holding up. A good rule of thumb though is every 5000-7000 miles or until your OLM light comes on. If you do alot of city driving/stop and go and not alot of highway, your oil/fuel dilution is going to be higher, and you would not want to go over 5000 miles, even if your OLM still has 50% percent on it.

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