Synthetic is the only way to go. I run Amsoil in mine, 15,000 miles between changes, its nice only having to get under the truck about once a year .

 

? all you people running synthetics, here is my 2 cents, why would you want to keep running the debri that the oil picks up from the engine for so long, you may get 12 to 15000 miles at each change, but does the oil filter last that long? I have been going to jiffy lube since day 1, truck now has 125000 miles on it. using their oil and having it changed every 4500 has been great for my engine, plus oils theys days, you dont need synthetic unless high horsepower or gruely off road

 

First of all, I'm amazed in 125,000 miles worth of trips to Jiffy Lube someone didn't forget to refill your oil or put the plug back on at least once! I won't let ANYBODY change my oil, ESPECIALLY a Jiffy Lube or Pep Boys type place. I personally know too many people who have had nightmare mishaps happen at them. I've also known some guys who have worked at those places I wouldn't trust to be able to take my garbage can to the curb without f*cking it up!

Secondly, I will agree that 15k is TOO long, especially with the Amsoil type of synthetics that are proven to actually thicken (gain viscosity) over a period of repeated heating/cooling cycles. You start out with say 5/20 and by the time you hit 12k miles that oil is actually 20/50. It's why it lasts so long, but in these days of tight tolerances, it just can't be good.

However, true synthetics (not synthetics that are based on conventional oils) do offer a lot of benefits over conventional oil. They hold their properties in heat longer (meaning they won't foam or sludge like conventional oils), they hold viscosity weight (do not thicken) in cold weather environments and they have a much higher saturation point - meaning they can suspend much more solids away from metal surfaces much longer than conventional oils can. Because of the superior ability to suspend solids on average you'll see more dirt & debris in a filter at 3000 miles with conventional oil than many high quality synthetic oils will deposit into the filter at 6000 miles. Although I'd still run a "premium" filter with synthetic if you are going for 6k changes as I have always done.

Do you NEED to run a true synthetic lubricant? No, of course not, but you should adhere to shorter change intervals with conventional oil and you can receive the same or better protection longer with a true synthetic...

 

but what about the oil filters, are they meant to last that long before they break apart?

 

I run the extended mileage filter (Fram) thats supposed to last longer. I run full synthetic and change 6k or 6 months.

 

agreed, although I am going to change mine at 5 this time because I have the Fram heavy duty one (grey w/ grip) but don't have an extended mileage one..if I start changing at 6k I will be saving money because its not like synthetic cost me double the price and I am changing my oil half as much. Plus my engine has extra protection with the additional additives in the oil.

P.S. anyone know where to get gear oil at the best price? looking to get rid of that Chrysler gear oil and will be changing to Mobil 1 or RP. Not looking for opinions on what the best gear oil is, just good prices!

 

Again, I see the claims by certain manufacturers of filters that I think are idiotic (Amsoil has an oil filter they claim is good for 25,000 miles).

But I've been doing full synthetic with a good quality, extended life filter, usually a Wix (NAPA Gold) but sometimes a Purolator or any number of the re-branded ones made by Champion Labs (Mobil 1, K&N, RP, etc.) every 6k for over 20 years now and have never had an oil or filter related issue. I've dissected some filters when I removed them and never had one look to me like it still wasn't capable of performing. I've had Blackstone test my old oil on four different vehicles (my current truck twice) and tests after 6000 miles always come back with glowing reports.

Again, I have no problem with conventional oils. But if someone is going to try to run one for extended intervals I would recommend sending in a sample. You should really know at about what time that oil is starting to break down, become acidic and lose it's protective properties. I know for a fact that if you sent in conventional oil up around 4500-5000 miles it shows A LOT more distress, broken down viscosity, foaming and contaminant (sludge) buildup than true synthetics do at significantly higher mileage change intervals...

 

If you just buy a second 5qt jug while they're on sale, just use half of the second now and the other half on your next change. No need to ever pay regular price for quarts. It's usually cheaper even with the extra filter. That's what I do.

 

I question if you have a clue what your talking about, you have obviously never used Amsoil or ever had it tested. So, dont speak about what you have not personally tested. I on the other hand, have ran it for 15K, and sent it to Blackstone labs for testing afterwards. It came back all within specs in every aspect and could have kept going longer, except for it was low on additives, but that was simply due to how long it was in there and not the mileage, probably took me a year and half to go 15K.

 

I am glad to hear the other side of the story, but there is no need to get nasty about disagreeing with someone.