I feel that is a positive attitude under certain severe operating conditions. I do not know exactly what you mean by "...my trucks take a beatin" I have a gasoline powered engine that had the oil changed in the spring and again in the fall when no less than around 5000 kilometers were logged on the odometer between oil changes. When we purchased a new vehicle the older well maintained truck saw very little use. This resulted in the twice a year oil changes being too long apart even though the mileage was very low.

The unit had 40,185 kilometers on the engine when the oil (5W-30 Castrol petroleum) was changed on November 30, 1994. In the spring of 1995 there was only about 3000 km on the engine oil when it was supposed to be changed under normal conditions. Instead, I decided to skip the spring oil change and change it again in the fall, which would have been one year later. The oil on the dipstick looked like gray sludge due to the water condesation caused by short runs in the frigid temperatures during the winter when the engine often did not even reach operating temperature. During the next summer I drove the truck more frequently on short trips and by August the odometer had around 9,000 kilometers registered. Unfortunately, the oil on the dipstick still did not look much better. I had the opportunity to drive the vehicle down to Tennessee during that eccessively hot August weather in 1995. I intended to change the oil before the trip, but got too busy and decided to change the oil when I got to Tennessee. When I checked the oil upon arriving in Tennessee it was still near the full mark on the dipstick, but it was now shinny and clearer in color. The oil looked so good I did not bother changing it and thought I would wait until I got back home in Canada. The long days of driving and the hot weather heated the oil and boiled all the moisture out of the lubricant. The oil was then changed in November/95 with 21,536 km on the odometer. The oil in the drain pan looked like new shinny oil with a slightly darker color. There was no thickened lumpy portion of oil at the bottom of the drain pan. The drained oil did not smell burnt. Actully, the old drained oil did not look much different in appearance than the new 5W-30 Castrol petroleum oil that repace the old oil. High operating temperatures for long durations are for sure better for conditioning engine oil than cold operating temperatures for short durations.

 

I change oil every 6K and to go with the oil change I include tire rotation.

 

I keep asking but nobody is wondering why DC calls for 7500 miles or THREE MONTHS on schedule B oil changes?

 

I think they are covering their behinds.... After 3months, no matter the mileage, condensation or other contaminants may build in the crankcase.
I've always heard the "3months or 3000miles" phrase when dealing with gassers also... CYA is what they call it...

 

When it came time for the first oil change, I was on the road between LA and Utah.
I had the first one done at 8600 miles.
Dealer said everythjing looked great.
I try to do them every 5000 or so.
Depends on where I am at the time.

 

we have a BINGO!!!

 

First at 5000 and every 5000 thereafter.

By the way, THANKS to Jack for moderately moderating and keeping this site a "fun and informative" place to hang out!!!!

 

I guess i must be real bad first at 500 second at 1000 third at 1500 forth at 3000 then between 3-4000 depending on when I can get to it same reason as others get all particles assembly dirt casting sand etc.

 

I did mine at 1000. since then every 3000. I run my truch hard every day stop and go traffic.Will probly be due again next week.

 

I have herd that the filter eliments start breaking down after 3 months. I was told by my Amsoil dealer when I was running it in my 2nd gen to change the filter & add make up oil to bring to full when doing extended oil drains.

I've never cut open a mopar oil filter to see what kind of material is inside. Maybe it breaks down & could allow contaminents back into the oil. Just a thought.

 

The 3 month thing has no impact on my oil changes as I do them every 6-8 weeks (7500 miles), however, my manual (04.5) makes no reference to "7500 miles or 3 months". It only references mileage for service intervals unless I missed something. There may be some maintenance schedule differences in the model years.

The Fleetguard Stratapore Filters (I'm sure many others do also) use a synthetic filter media, and should not break down over time, but who knows.

I am not arguing over the "3 months" part. I just think that mileage will break down and contaminate the oil and filter more than time will. There are plenty of guys running dual bypass filters that run their filters for way more than 7500 miles/ 3 months. They use oil analysis to determine when to change a filter/change or add oil.

Since the topic was when did I do my first oil change. I did mine at 3750 then at 7500, then every 7500 since then.

 

Regarding the time constraint on oil drain intervales (i.e. 3 months), the rationale behind this is generally related to oil oxidation. Petroleum oils, because they naturally contain less consistent hydrocarbon chains, have an affinity to bond with electronegative oxygen, resulting in oxidation of the oil. Oxidation is very bad for lubricants. Refining processes for petroleum oil remove much of these undesirable hydrocarbons, paraffins, etc. but cannot remove them all.

But unlike petroleum oils, synthetic oils are produced from pure components that do not contain components that attract oxidation. As a result, synthetics are more intrinsically resistant to oxidation.

So bottom line, petroleum oils will generally break down from oxidation more quickly than synthetic oils. Usually 3-6 months is about as long as you want to let petroleum oil remain in an engine, regardless of mileage, because of oxidation. Synthetics on the other hand, can remain in an engine much longer, usually 6-12 months. So if you're a low-mileage driver, and you're changing your oil based on time (i.e. 3 months) before you reach the mileage interval (i.e. 7500 miles) then consider using a synthetic oil. This way you can extend the time interval (i.e. 6 months) so that you can reach the mileage interval. Otherwise, if you're a high mileage driver (meaning you're changing your oil based on mileage before you reach the time interval) then consider using a regular petroleum oil. So I generally use a petroleum oil in my vehicles that see lots of use because I'll be dumping their oil quite frequently, and I use a synthetic in my vehicles that only see occasional use because I may only be dumping their oil once or twice a year.

 

Is there a specific mileage when changing from petroleum oil to synthetic oil might occur? Seems I read something about 20,000 miles.

 

what he said

 

Is there a "break-in" oil that is used on these engines from the factory? I had heard that there is a break-in but of all the oil changes I have ever done I have never heard of a break in oil. Thanks

Kevin