M923A1 Oil Change Intervals

[Enty45]

I have a 1985 M923A1, and it is recommended to change the oil every 3,000 miles or 3 months, whichever hits first. Is this something to strictly adhere to or can you put more miles on before changing? I don't drive the truck often, but I do want stay on top with maintenance.

Thanks a lot

 

[jaws4518]

I have a 1985 M923A1, and it is recommended to change the oil every 3,000 miles or 3 months, whichever hits first. Is this something to strictly adhere to or can you put more miles on before changing? I don't drive the truck often, but I do want stay on top with maintenance.

Thanks a lot

I go by the running hours usually. 250 oil change, 500 trans oil. I just flushed my differentials @500 hrs. The oil was pretty dirty. Oil gets expensive to change every 3 months. I'll just say I haven't had any problems with those intervals. I changed my transfer case @500 too.

 

[ericp351]

Oil analysis preferred, but not always workable! I go by 3,000 miles- long time for me- and use modern oil with lots of detergents and Total Base # to kill acids, and I do stretch "time". Cost-benefit for me is look for a good price/sale and write off oil and filter cost as part of the game to protect engine. Oil dilution is a factor that ain't figured in for modern cars/ syn. oil thinking when they advertise 10,000 mile 'super oils'. Probably this is a "10 men = 10 heartfelt and smart opinions" type of question. 15w-40 or 5O, Rotella T-4 or completion at 3K VERY hard to argue down!

 

[jaws4518]

Oil analysis preferred, but not always workable! I go by 3,000 miles- long time for me- and use modern oil with lots of detergents and Total Base # to kill acids, and I do stretch "time". Cost-benefit for me is look for a good price/sale and write off oil and filter cost as part of the game to protect engine. Oil dilution is a factor that ain't figured in for modern cars/ syn. oil thinking when they advertise 10,000 mile 'super oils'. Probably this is a "10 men = 10 heartfelt and smart opinions" type of question. 15w-40 or 5O, Rotella T-4 or completion at 3K VERY hard to argue down!

Do you think 250 hrs is too long for a NHC 250? I was reading somewhere that anything with a turbo will do better shedding heat with frequent oil changes which I would concur with the 3k miles. I'm certainly no expert so I just listen and learn. 3000 / 55 = 54.545 hours. Let's say the average travel speed is 25 mph. 3000 / 25 = 120 hrs. That sounds more like it. Maybe every 150 hours? I apologize for bring topics like this back into the spot light but it doesn't hurt to bring this routine maintenance stuff up so that inquiring minds can see the latest posts on old topics.

 

[simp5782]

I ran small cams and big cams at 10,000mile intervals without bypass filters. 2 or 3000miles a week.

If you want you can spend your money on a puradyn bypass filter kit and never worry about changing the oil again

Puradyn TF60P 14V 28V Filter with Additives Part # 1005 Model PFT-60P *NOS* | eBay

You will be purchasing a Puradyn TF60P Filter System. On box: Part number 1005, TF60P, 14V, 28V.

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@Suprman had some of the systems with a diffuser plate at one point

 

[ericp351]

You asked, so I'll give you my opinion. I think 250 hrs ESPECIALLY if lots of starts/ stops, is a bit long. If clean , tight engine and great oil, lots of steady load, long hot running, IE industrial type operation, 250 hrs may be OK. Oil analysis is probably the way to figure that out. Also, be realistic as to your av. speed. Some of these trucks can be used at 45MPH as "Texas pick-ups", others at 5 MPH on a farm or logging. Most between that. Good luck, your call. 250 hrs ain't 1000. May be OK, I'd not push it.