CAT 3126B oil change interval

Covers engines and transmissions
chuckster
Posts: 286
Joined: Thu Aug 27, 2020 4:53 pm

CAT 3126B oil change interval

Post by chuckster »

I found this on a search of a diesel truck forum where a senior member said for a CAT 3126B "The book says 10,000 miles or 250 operating hours or 6 months whichever comes first for an engine with a shallow oil pan and 15k miles, 400 working hours or 6 months for an engine with a deep oil pan.

Sound about right? I don't want to drop the stacks 'o Ben's if not ready for new oil yet!
Chuck & Mitzi
'01 Safari Zanzibar 3646 (side entry)
Cat 3126B / Allison MD3060
Magnum M-Series "Blue Max" chassis
2016 Jeep Grand Cherokee Overland toad
ProCycle
Posts: 135
Joined: Sat Oct 03, 2020 1:28 pm

Re: CAT 3126B oil change interval

Post by ProCycle »

The mileage and hours sound about right. I won't be changing mine every 6 months though.
When you're talking about 7+ gallons of oil for a change getting oil analysis is a cost effective strategy.
Have your oil analyzed at 8K-10K and make the decision to change based on the results.
Jeff
1997 Ivory Edition 3740 Cat 3126 Allison
chuckster
Posts: 286
Joined: Thu Aug 27, 2020 4:53 pm

Re: CAT 3126B oil change interval

Post by chuckster »

I wanted to share this that was given to me on another web site.
Oil Change Guide - Cat.png
Oil Change Guide - Cat.png (55.23 KiB) Viewed 6602 times
Last edited by chuckster on Fri Jul 29, 2022 11:33 am, edited 1 time in total.
Chuck & Mitzi
'01 Safari Zanzibar 3646 (side entry)
Cat 3126B / Allison MD3060
Magnum M-Series "Blue Max" chassis
2016 Jeep Grand Cherokee Overland toad
chuckster
Posts: 286
Joined: Thu Aug 27, 2020 4:53 pm

Re: CAT 3126B oil change interval

Post by chuckster »

Found this on iRV2.com CAT powertrain forums from a guy who is obviously a mechanic on CAT diesels:

"User "Cat" is absolutely spot on. Both oil and fuel side cause the issues related to pump and injector failure. I cant qualify who makes "cheap" filters. I can qualify that filter media >6 micron will cause long term systemic issues. Ask your supplier for the micron level if you are not buying Cat brand filters. Others do make high quality filters that are at or <6 micron. I have now replaced more that 25 (HEUI) pumps and every one of them are owned by people that ignore oil changes. If you want to protect your system then change your oil more often. Oil and filters are cheap in comparison to pumps and injectors. Target 5,000 miles. If you end up at 7,000 due to traveling then you are still within what I consider safe range. People that go 12-15K are the ones that buy (HEUI) pumps and injectors.
People that say to me, "My manual says 15,000 miles". I say: "How's that working for you" as they are writing me a check for $3,800.00 for a new pump replacement.
The 3126 and C7 has received a bad name in the RV industry because of a very simple corrective action that the owners ignore. Oil changes. The other brand out there with red paint drops valves in cylinders. I'll take the Cat engine and spend my money on oil and filters rather dropped valves. One other note regarding "Oil" quality and contamination. Starting a cold engine and allowing to idle at normal idle, say 750 rpm, for extended periods is not recommended. If you start up your engine cold then either set your cruise so the idle is around 1200 rpm or foot the pedal until the temp comes up. This helps burn the fuel due to combustion temperature. Any diesel has issue with the amount of fuel at cold start up and extended idling will allow un-burnt fuel to build up, "Stacking", on top of the piston. This eventually will push past the rings and end up in the sump reducing the oil's ability to do its job. This can cause foaming and the HEUI pump does not like cavitation."

I hope this helps others think about HOW OFTEN they change oil. It does for me. I'd rather change oil at 5K-7K max then pay $6K for a HEUI pump and labor. CAT oil and filters seems like a cheap insurance plan to me.
Chuck & Mitzi
'01 Safari Zanzibar 3646 (side entry)
Cat 3126B / Allison MD3060
Magnum M-Series "Blue Max" chassis
2016 Jeep Grand Cherokee Overland toad
astrnmrtom
Posts: 167
Joined: Thu Oct 31, 2019 8:49 pm

Re: CAT 3126B oil change interval

Post by astrnmrtom »

My goal is to keep my HUEI happy so 5000 miles is my change interval. I do the changes myself so it's cheap insurance. Been on the road full time two years and I'm always able to find a spot to change the oil. Even if I'm doing oil changes twice as often as the book says, I can still do a whole lot of them before I even come close to the cost of a HUEI and injector replacement. In the transportation department where I worked, they ran a lot of buses with Cat engines and HEUI pumps for a lot of miles. I asked the mechanic if they had problems with the HUEIs, his answer was "Nope." They do regular, severe duty interval oil changes and he's been happy with Fleet Guard filters. Figured that was good enough for me, I did decide to go with Cat filters as the price difference wasn't that great. I always carry a spare on the road because when full timing, I'm not always near a Cat dealer when the time comes for an oil change. After installing a Fumoto valve, doing an oil change on the RV is easier than it is on your CRV. Lots more room to work! Pouring 7 gallons back in it the slow part.
Tom and Pris Masterson, w/ Buddy the 18 year old Siamese cat.
1998 Serengeti 3706
300hp Cat 3126, Allison 3060
900 Watts of Solar
17cf, Fisher & Paykel residential Refrigerator
Dragging four telescopes around the US seeking dark skies.
chuckster
Posts: 286
Joined: Thu Aug 27, 2020 4:53 pm

Re: CAT 3126B oil change interval

Post by chuckster »

Sound advice, Tom. Cheap insurance. I just picked up 7 gallons of Shell Rotella T4 15W-40 for a hair over $100 at Walmart. I’ve got about 5K since the last oil change and have two 1200 mile round trips to the Oregon coast over the next 3 months before I put the coach away for the season. I was agonizing over whether I wait to change oil at the 7500 mile mark AFTER the trips and then store or do it now before the trips. I live down the street from a CAT dealer so scooping up parts is convenient when I need to.

Have a picture of where you installed your futomo valve? Did it replace your drain plug? I
Last edited by chuckster on Tue Aug 16, 2022 7:29 am, edited 1 time in total.
Chuck & Mitzi
'01 Safari Zanzibar 3646 (side entry)
Cat 3126B / Allison MD3060
Magnum M-Series "Blue Max" chassis
2016 Jeep Grand Cherokee Overland toad
Highwayranger
Posts: 1
Joined: Wed Mar 17, 2021 9:52 am

Re: CAT 3126B oil change interval

Post by Highwayranger »

I agree 5000 miles or once a year with conventional oil . I have 4000 miles after a year and changes it . Oil looks dark . I do start it once a month .Side note I just changed my fuel filters and found out the truck service company that I when to a year ago put in filters with a 6 micron rating on the secondary filter >It Should be 2 microns .Also after changing it I spent all day trying to restart it > Found out online that you can buy a primer pump at Cat for $139.65 PN 105-2500 . Went picked it up and 15 minutes later and it was running . This pump mount to the secondary fuel filter . Pull off the two bolts , pull off the plate , cleaned off the gasket and install nice steel pump . If you ever run out of fuel or change a filter this is a great setup . I know you can find some online for a third the cost but when you are dealing a $10000 used Cat or a $20000 rebuild might be the place to spend a little more .
astrnmrtom
Posts: 167
Joined: Thu Oct 31, 2019 8:49 pm

Re: CAT 3126B oil change interval

Post by astrnmrtom »

Yes, The Fumoto Valve replaced my drain plug.

What's great about the valve is the ability to start and stop the flow. If you add a piece of tubing you can drain the oil into milk jugs or any other handy container. Since I'm full timing and don't really have a place to store empty containers, when the time comes I get 2 cheap Walmart 5 gallon buckets with lids, and split the amount between the two buckets. So far, the auto parts stores I've taken the used oil to have been fine with keeping the buckets. Here in Washington State the stores say they can't keep the empty containers and that I should just toss them into the trash, which I do. I figure in places that are ok keeping the container, that the kids working there are happy to get a couple nice new buckets with lids for free once they are drained.

I'm sure an occasional longer interval won't hurt. Depending on where were are at, I'll sometimes change my oil ahead of time because I'm in a place that allows it, and future campgrounds don't. I keep a cheap tarp with me so nothing gets on the ground. Even with the tarp I'll set the bucket on one of those larger puppy pads, same with removing the filter. It's easy to wad them up and toss them in the trash. The tarp is my backup.

Oregon coast is beautiful. Love the drive along 101. My late father had a house in Gardiner, a tiny town North of Reedsport.
Tom and Pris Masterson, w/ Buddy the 18 year old Siamese cat.
1998 Serengeti 3706
300hp Cat 3126, Allison 3060
900 Watts of Solar
17cf, Fisher & Paykel residential Refrigerator
Dragging four telescopes around the US seeking dark skies.
ProCycle
Posts: 135
Joined: Sat Oct 03, 2020 1:28 pm

Re: CAT 3126B oil change interval

Post by ProCycle »

I have one of the Fumoto valves but I'm disappointed. It drips. When I first installed it it would leave a 6" puddle overnight. I drained the oil, took the valve apart and cleaned it thoroughly. Now it only drips a few drops a day. That still makes a significant oil spot under the coach.
Jeff
1997 Ivory Edition 3740 Cat 3126 Allison
chuckster
Posts: 286
Joined: Thu Aug 27, 2020 4:53 pm

Re: CAT 3126B oil change interval

Post by chuckster »

Highwayranger wrote: Wed Aug 10, 2022 10:18 am I agree 5000 miles or once a year with conventional oil . I have 4000 miles after a year and changes it . Oil looks dark . I do start it once a month .Side note I just changed my fuel filters and found out the truck service company that I when to a year ago put in filters with a 6 micron rating on the secondary filter >It Should be 2 microns .Also after changing it I spent all day trying to restart it > Found out online that you can buy a primer pump at Cat for $139.65 PN 105-2500 . Went picked it up and 15 minutes later and it was running . This pump mount to the secondary fuel filter . Pull off the two bolts , pull off the plate , cleaned off the gasket and install nice steel pump . If you ever run out of fuel or change a filter this is a great setup . I know you can find some online for a third the cost but when you are dealing a $10000 used Cat or a $20000 rebuild might be the place to spend a little more .
Good info. I had the fuel filters changed 5K miles ago. I get 8 miles to the gallon so I’ve burned around 625 gallons of diesel. Know how often these two fuel filters/separators need to be changed?
Chuck & Mitzi
'01 Safari Zanzibar 3646 (side entry)
Cat 3126B / Allison MD3060
Magnum M-Series "Blue Max" chassis
2016 Jeep Grand Cherokee Overland toad
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