Caterpillar 3116 is a bad Engine?

Hello Guys,
Newbie here... I am looking to buy a M1078/1079. I did some research on internet, and it seems like Cat 3116 engine has such a bad reputation out there. People is avoiding Cat 3116 all together.

How does it perform in the truck? Can someone share with me some of your experience? Thanks a lot

They use them in the m35a3 and they worked well there.

Once again using search would head off what will become a "my engine is better than yours" thread.

Did you know that if you scroll down you will see the threads that are similar to yours?

And, they should have easily been found with a search using this thread title.

My M35A3 is equiped with the CAT 3116. Good engine, starts on the first revolution of the starter, runs strong. Do a little info search on the engine. They are utilized as marine powerplants and perform well. They are a little more $$ to maintain, however, if you buy an MV for collection/fun purposes, you will never wear it out

I've never had too much trouble with these engines in my experience as a mechanic in the National Guard. Biggest issues we have are starter solenoids, HEUI pumps (caused by clogged fuel tank vents starving the pump for fuel, scores the inside of the housing), Injector tips (that's caused by operators putting gasoline in the truck, it burns the tip off). I've never had to replace an engine on one of these trucks but then again, most of ours are lower mileage units as in nothing in our fleet has over 50,000 miles in the unit I'm in. We run them on the governor for 200 mile trips on a regular basis at a cool 61 or 62 mph when we are headed to Annual Training or the Rifle Range.

Sandcobra, is this experience with the A3 or LMTV?

No M35A3 experience. Just FMTVs with Cat C7's

Thank you SC for this useful post. I just replaced my HEUI pump on the C7 In my M1078. Thought the cause was the common catch all for the HEUI "dirty oil" cause. Just checked the tank vent line and it was clogged.

justin wehring

Caterpillar upgraded the oil cooler gaskets because they all leak. They also changed the high pressure oil line design a few times, also leaked. I've rebuilt a bunch of the 3116 and 3126 engines. Make sure you use anti seize on all bolts, especially the front cover.
It was a good engine. I liked it when it was fully mechanical, still have the injector setting tools. 2¢

They are good engines.But they are throw away engines.Not rebuildable from what I was told.

Jakelc15 said:

Caterpillar upgraded the oil cooler gaskets because they all leak. They also changed the high pressure oil line design a few times, also leaked. I've rebuilt a bunch of the 3116 and 3126 engines. Make sure you use anti seize on all bolts, especially the front cover.
It was a good engine. I liked it when it was fully mechanical, still have the injector setting tools. 2¢

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What is the difference between the engine in the 2.5 tons and the engine in the 5 tons? They are both the 3116, but the 5 ton version is rated for higher horsepower. Is it all in the fuel injection system and how it is set up? Could you take one of the 2.5 ton and bump the horsepower to the same as the 5 ton, without compromising reliability?

They are both the same engine just tuned differently. I took mine to Cat and they turned mine up. They shimmed the injectors and changed the timing. Its a BEAST now !!!!!

I hate this mind set that we as a country have gotten that everything is throwaway and get a new one, they can be sleeved and rebuilt as was said earlier. I think that the worst thing that can be said about them is they are expensive to maintain as far as parts go.

Csm Davis said:

I hate this mind set that we as a country have gotten that everything is throwaway and get a new one, they can be sleeved and rebuilt as was said earlier. I think that the worst thing that can be said about them is they are expensive to maintain as far as parts go.

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They are just a whole lot cheaper to swap in a used motor than rebuild .

Caterpillar is typically more expensive than Cummins and Detroit

Thanks for all your input, and I just bought my M1079. I will report back when I get it running... hopefully, it won't fail me

Apparently a lot of the stories about the engines grenading etc. out there in civvyworld were due to a big run of early castings done in France which had some...what's the phrase..."significant metallurgical issues" (i.e. made of pot metal), which CAT caught and dealt with. I do know that CP Rail in Canada runs a whole fleet of GM Topkicks for work trucks, and when I was at one of their auctions a couple of years ago noted every one up for sale had a blown engine, and one of the CP Rail guys shook his head and told me they "weren't loved" by the railroad.

That said, they're in tons of motorhomes, commercial vehicles, marine uses and so forth - and reading around on the web doesn't really reveal anything that you'd call plague-level with them...though I do remember the problematic ones always seem to have one of among two or three of the *same* problems.

I noticed last night that the late model MTV tractors going out to auction have CAT C7 engines and not 3126Bs