The Cat C9 Engine. Facts, Walk Around, Sensor Locations, and Maintenance. Know Your Engine.

The C9 is a popular Cat Engine Found in RVs, small trucks, equipment, and generators. Learn the sensor locations, maintenance tips, inspect the parts, and component locations. This is part of the "Know Your Engine Series."

[@Toromont123]

Thank you for mentioning early oil change intervals. Every customer that asks me, "What should I do for my engine?" when they own a HEUI I always tell them that clean oil is critical to the life of the engine. I have literally had trucks towed into the shop, and all I had to do to get them to fire up is put more oil in them; because the owner hadn't changed the oil in forever.

[@AdeptApe]

+Toromont123 I can't believe people would buy such an expensive machine and not pay any attention to the maintenance of it.

[@Toromont123]

At a dealership level we usually see these engines in straight trucks, light load stuff that people treat like cars. They just don't take the time to learn about what they own in the same way that an owner operator with a C15 would. Knowledge is power for any owner.

[@jaloncola8805]

My grandpa had a caterpillar pick up truck with the 3126 he showed me how it ran and what it sound liked. And he showed all the parts of the engine that he had to change.

[@andrewhaig5417]

Im 53 and been out of the industry for quite a few years doing sales in Hydraulics, which is crap. Your videos have given me a great deal of confidence to go back in and work as a Diesel mechanic again.

[@AdeptApe]

+Poster Art Thank you, just don't message me in the future cussing me out because my videos convinced you to start wrenching again 😀.

[@tallahatchiewoodcrafts8696]

great info,and videos,i have a 1999 c12 in my rv i would like to learn more about.

[@stuntteamracing8816]

Thanks man! I may be buying a C9 soon and this video helped a lot. Please make one for the C11 next.

[@leevice2077]

Your effort in putting information to public helps me understand better compare to all trainings I been through. your the kind of instructor our dealership needs to hired. thanks always Adept Ape...GODBLESS

[@AdeptApe]

+Lee Vice Thank you for the very kind words. I'm glad you like the videos.

[@cwj9202]

You made an excellent point about keeping the engine oil clean. A few years back we purchased a new 950H equipped with a Horizen Cleare-Air DPF. The first engine oil change was performed @ 450 hours (oil resembled sludge). You probably know what happened to the HEUI pump and injectors thereafter.

[@AdeptApe]

+Chad Jessup They lived happily ever after? I'm going to guess they got replace soon thereafter. I think the HEUI system makes sense on paper, but the components are just too sensitive to last long enough enough compared to the MEUI style systems on the C13 and C15.

[@chuckspage3853]

Well done. Looking at a Class A right now with a C9, this makes me feel better. Kudos

[@yassokarim2228]

Great video and priceless information... keep up the good work.

[@philramsey8588]

I like your advice and the dog is great

[@SketchyBuilt]

You're awesome man. I just put in my application for CAT your videos have been a huge help.

[@AdeptApe]

+Jdog9945 Thank you, hope you do well.

[@SketchyBuilt]

Thank's man keep up the great work!

[@williamnapier3802]

Hay man I'm looking to put a c9 inplace of a c7 in a Kenworth t 300 think it will fit?

[@cadenpayne9049]

So did u get hired from CAT?

[@andyramone8497]

Thank you sonmuch for your super informative contents. I must say you're a dam good mechanical teacher.

[@dunnellonpc]

Very informative and helpful. We just purchased an RV with the C9s engine and have already had a turbo failure. We believe, and I think your video confirms for us, this was the result of a faulty DPF Regen system. It’s currently in the shop awaiting the new turbo. We’re also addressing the failed emission issue and hopefully will have a sound and reliable engine when we’re finished. I also learned from your video that we have the common rail injector system. Thanks for the helpful information. Any comments or suggestions on this engine going forward would be appreciated.

[@atazahran292]

Thank you man

[@mzee5533]

The only C9 I've worked on was the CAT Digger 335 we run 250hrs then service but it is super awesome Adept. Keep those videos rolling mate. Thumbs up soon you'll rich 1 million views

[@AdeptApe]

+Muchie I would love to reach one million subscribers, but my goal is ten thousand for the channel. I figure I can get there soon, thanks for commenting.

[@robertpearl1833]

The video was very informative

[@tynewtoniii]

First!! Love you vids man

[@AdeptApe]

+Tyler Newton Thanks, I've got to figure out the audio a little better for the webcam and these videos will be even better.

[@80sfordguy]

Definitely, I'm unsure about the smaller mid-range I6's or 3208 cubic in sizes and physical sizes vs vehicles they can fit in with relatively little fab work.

[@scarter176]

Thanks!

[@AdeptApe]

Hey, Thanks so much.

[@joellagpacan9340]

Again good info. Might be purchasing a service truck with the C-9 engine, up to 450 HP on this engine? I might have to get my C-9 re-rated, Thanks again for all you do for this industry JSL

[@AdeptApe]

+Joel Lagpacan Thank you for commenting, you always have will informed comments.

[@jaimelopez3991]

Hi there, great video! Thanks. What is your recommendation on the change interval of the belt? Serpentine belt? Thanks

[@johnniehenderson4036]

How do the hold up in dump tucks I'm looking at a 2008 kw with a 425 c9

[@dougsmith3935]

What are the names/type of engine jacks are you using. I’m looking for something like that for my Rv engine. Thanks hope to hear back.

[@abdulramanrat2417]

Keep on the good work... Pls I want to know how to diagnosed cat engine with computer most expecially c9

[@GIGABACHI]

More, please. 👍😆 And yes, do please try to workout the audio bugs...other than that doing a great job. 👍

[@AdeptApe]

+JIGA BACHI I ordered a new Microsoft webcam today that will hopefully work with the microphone better than the Logitech one. It's nice having generous fans that have sent money in to the channel to help the quality too.

[@jaimelopez3991]

Thanks for the video. Could you tell me what’s the correct oil level in the oil dipstick? Thanks

[@krak-serwis928]

I have a problem with the engine C9DI. no work load, under load "suffocating" on whether there is a problem? All the new filters

[@boriyussif7526]

Thanks very much and may almighty Allah bless you

[@yassokarim2228]

Planning to use 5w-40 Synthetic. If it was your vehicle would you still change the synthetic oil around 7500 miles or would you go longer?

[@deanstauffer4199]

I recently purchased a 2007 Fleetwood Revolution with a C9 Cat. Watching your video shows you have a lot of knowledge about them. I believe I'm having issues with the intake air heating system. It is hard to start and the wait to start light doesn't come on. Can give me a place to start the trouble shooting.

[@jeffr9720]

I also have this same engine and coach combo. Would like to share notes as I am chasing an intermittent no start situation

[@scarter176]

Josh, could you address fuel flow for C9 and TIT and egt for same. Any test cell video would be helpful in to the proper fuel flow at various loads and respective egt for each cylinder and turbine inlet temp.

[@samuelherbert]

Hey... I sail on a tug and I've got a C9DI Marine engine.. We use this engines for the generator and we have 3 of them here.. The problem now is that, this one engine isn't taking load, ie when its sync and taken on load, the frequency drops and then it trips.. After couple of times, now the engine doesn't even start abs it displays a code as spn 656 fmi 11... It refers to injector 6 failure I guess.. Wat do I do..? Should I just go ahead pop the Injector and fix a new one or should I call cat team to check with the ecm..? Thnx in advance..

[@irmacristinacoronado8053]

I have fraighlander M2 C9 and it was driving down the road and all the sudden it shut off, where can i find the electric diagram for the ECM does any buddy might know?

[@iflyp38]

Would a bypass oil filtration system aid the oil change intervals? Would an Air-Dog system help the fuel system function better? Especially for the S series?

[@donforsyth8579]

I have a 2005 motorhome with the cat c9 400 that I bought about a year ago. I have been watching your videos and find them very informative. We are currently traveling and I noticed the check engine light come on. At first it was just a solid light. After awhile it started blinking and I realized from you genius it was a flash code and started counting. It flashed 25 - 37 - 46 - 25 - 35 and then stopped and repeated the same code. I looked up what the different codes and where the sensors are. My question is, do I have a problem at each sensor or is there a central point responsible for the different codes I am seeing. Thank you for any help you can provide.

[@williamwhite9943]

ADept, have you seen a C9S Shutter under various loads above 1500 rpm. I have one that will rattle your teeth out. Its not missing but it feels like someone it cycling the power on and off to the ecm at 5hz.

[@conniemaule4586]

I have a 07 Freightliner Business Class with a Mercedes engine that I use as a Over The Road Expidetor, I'm looking at changing the engine out and putting in a CAT C9. My question is do you know of a mechanic shop/CAT Dealership that can do this. I call Freightliner and there are basing Parts Changer.

[@LEEHUMMEL1]

on the c9 where is the block cooling drain plug can you send a picture thanks

[@bowwoe]

Hey Ape we have an ex US military spec C9, Serial LFE01365. I need to get throttle control. Just need 2 speeds. Low and high idle. Not sure of pin configuration on ECM. Can you help?

[@thetripman]

good info thanks got a question for you i have a C9 in a yacht that is having trouble holding rpm it likes to lose about 200-500 rpm after a while someone told me there is a throttle cup that needs to be looked at i have not heard or seen that any help?

[@AdeptApe]

+thetripoflife A throttle cup? Hmmmmm, unless there is some weird yacht only part on your engine, I've never heard of a throttle cup. There are injector cups, but if they fail you'll get fuel in your coolant. My guess if it's losing rpm is you have a problem with the engine like the HEUI system low boost or if the engine seems to be running fine the ECM may be losing throttle signal from the throttle lever or pedal. You'd want to hook up to the engine and see if the ECM is showing a constant throttle input from the lever or pedal while it's losing rpm. Now most of those pedals are a PWM signal so you could put a multimeter on the pedal and see if it's sending out a constant signal.

[@dieselhead7961]

Do you know anything about the 3406B/3408 engines? I have a few dump trucks that run those and they're starting to get up there in age so I'm curious as to what to expect for failures and if Cat can help me in terms of parts and service.

[@AdeptApe]

+Dieselhead I've worked on a handful of 3406B engines and seen a couple 3408 engines. Cat is pretty good about providing parts for their older stuff. I know fuel pumps, nozzles, piston packs, and the like are still available for the 3406.

[@pauljosephtimothyraboseawe2694]

Awesome bro. Bro I've a question for you . Having problem on a cat330D L excavator no power during load with a C9 engine.....thank you bro.

[@justynsudyka6793]

You ever solve your problem? Have an identical machine and assumed it was a fuel issue. Replaced fuel filters, flushed tank, et. When machine tracks up hill or digs it stalls under load.

[@kennethbullins445]

Do CAT or Adept Ape have a position on Bio Blend Fuel in Petro Diesel? I own 4 diesel engines and only my Mercedes Bluetec Diesel cautions about BioBlend above 5%. Recently I was filling the Mercedes-may contain 5 to 20% was tagged on the pump. Mid way through the fuel run-check engine illuminated. On the next fuel stop with 100% petro diesel, the check engine extinguished. It seems more often when filling my motor home with C9 it's Bio blend diesel. This video will be my reference video. Thank you.

[@AdeptApe]

+Kenneth Bullins Cat has a specification about biodiesel. I'll try to talk about that in the next Diesel Talk.

[@user-nn1gm9iq2b]

I love your Chanel .......are there any way te be in touch with you ? I do have a problème in a c9 engin !!

[@VocalVirgo]

How can I find out if an RV has the (C9)ACERT engine if the date of motorhome manufacture is 6-21-2007? The ACERT engines were being produced, being applied to vehicles “mid 2007”. Those dates are so close, LOL. Obviously, I’m going to try and avoid the engine with ACERT… But how do I find out?

[@uncommonoffroad]

Can you engine swap a c9 for a c7 without significant modifications? Do the motor mounts, transmission bolt patterns, ecm interfaces etc all basically work the same. F750 RV with allison

[@lilmojitoskoolie5353]

I have a c9....gutless. whats the best engine to upgrade to without overwhelming my trans and pumpkin. C9 or could I go c13 thanks in advance

[@billcassabaum2785]

Do all of the CAT C9 engines have ACERT technology?

[@monstarsauto8759]

Where does the hose in the back of the head goes on a c7??

[@d2friezen226]

What is the life mileage of the C 9 with reasonable care. Looking at a used RV with 167k on it

[@80sfordguy]

Ape, man it would be awesome if you did a video on repairs/diag on a CAT V8 like a 3208 or a 3408. I'm curious about the differences between V8's 3208 & 3408, I6's C7, C9. I'm also curious about the engine just smaller than the C7. Comparison! Cummins ISB5.9 359 ci, ISB6.7 408 CI, ISC8.3 505 CI and a ISL8.9/9.0 is 545 CI all of which are available with high pressure common rail. The ISC & ISL are the same block & bore but, the stroke it longer. Naturally if a ISC will fit, so will a ISL. primarily the ISB's 5.9 & 6.7 are pickup truck up to 36' box trucks like a budget or u-haul rental trucks. I want to install one of those 3 mid-range I6's or maybe a 3208 CAT engines in my 85 3/4 Ton pickup.

[@AdeptApe]

+Norwood E. Jatho, Jr. I can try to get a video on a 3208 up one of these days, but I haven't even seen a 3408 in several years. I'm sure there are still some out there, but rare these days. Cat doesn't make a smaller engine than the C7, it has smaller engines, but they are normally made and designed by Perkins, which is a much less known company. I'm going to try and make some more of these engine walk-around videos in the future, kinda depends on what I'm working on.

[@80sfordguy]

Adept Ape ok cool, how about the 3116, 3126 and 3176? Aren't those smaller than the C7 and C9? What are the cubic inch sizes of those 5 engines? Are all of those 5 engines available with turbos or CGI? What about the 3208, what's the cubic inch and is the 3208 available with a turbo?

[@AdeptApe]

+Norwood E. Jatho, Jr. So a good question on that one. I actually don't know the 3208 displacement off hand but I'll look it up, I think it's around an 8 liter I think, but I'll check. So the 3116 is the precursor to the 3126, which is the precursor the C7, so they are pretty much the same block and displacement, just different fuel systems and changes over the years, all 7 liter engines though. The 3176 is a different animal though, I've only worked on one and they have a crazy valvetrain setup, I can't say off hand if it transformed into the C9 or was scrapped, I would have to look into it more as they are a rare engine to see.

[@edwinvasquez9966]

Sir adept ape how check valve or relief valve of caterpillar C9 engine thank you

[@dakotabrookefam4555]

Can you take a 70 pin c9 out and install a 70 pin c10 would the electric components work

[@alexj1773]

Hello Adept, can you make a video but instead of C9 can you do it for a Cat 3126? I have a 2002 Kenworth T300 Box truck with 400,000mile. Also i notice now that every time i run the truck it make a noise like (clack,clack,clack,clack its like its has bells inside) i put 1st gear then released the clutch and it's start making that noise only when i press the pedal to increased the speed not when i have it on neutral and i floor it, can you help me out?Thanks.

[@AdeptApe]

+Alex J I'm going to try and make a video like this about every Cat engine. Has the engine always done that or just started?

[@tutivaz]

Hey Adept. I got a question. I work on cats all day long but we all get stumped every now n then. I have a cat C9.3 that turns on every morning fine. Once it’s hot (Operating temperature) and gets turned off it won’t start. It will start with ether but I don’t want to keep using quick start. Any suggestions???

[@justindudley8233]

The only time I've ever had this issue in a vehicle was a 5.9 Cummins with a 46re transmission and the transmission temp sensor was bad. It would take either to get it going and if you stayed in the throttle in neutral it would run. As soon as it went into gear you had to wait until it came below 185 to start it again.

[@mromar7877]

Cv merci

[@danielco0999]

hello adept I'm fixing a c9 NO ACERT engine and has a code that I could not eliminate, the code is 655-11 which says nozzle number 5 open circuit with undefined damage, I changed the injector solenoid, also change the injector for a new one, and I do not know what else I could do ... you could guide me to eliminate this fault, the engine in minimun rps 1200 works with missfire and max rpm 2200 works fine .. thnks

[@canalsimonense]

daniel barajas torres Did you diagnose the electrical circuit?

[@Krossf1re]

Do the C9 and C7 have parts commonality? Is it basically a bored+stroked+sleeved C7? I have a 3126 torn apart and wonder if I could use the C9 rotating assembly to keep a mechanical engine (pre-99 EPA req) with larger displacement. I can machine or have pistons made, already planning to bore the block and press in sleeves (since 31** are parent-bore). Thanks Josh’

[@toyoscio]

Why bother?

[@Krossf1re]

@@toyoscio modern emissions mandated hardware decreases engine longevity and hinders fuel mileage greatly. Aside from increased maintenance costs and additional component weight, there is the legality issue of forced minimum epa standards operated in certain areas - depending entirely on age of power unit data plate. I’ve seen this done with late 3406C’s stuffed with C18 internals (in older trucks or gliders). I transitioned to medium duty so as I can work on my own stuff in-house, and I make more money in this segment. The downside is less robustness built into the engines designs (from *all* manufacturers not just CAT, see navistar VT/DT/maxxforce and DDC DD5/8). Since a crate MD engine costs into the 5-digits, many times exactly as much as an HD, it should have the same b10/b50 life as the larger cousins - and be serviceable just as they are to extend it.

[@toyoscio]

@@Krossf1re Thanks I undestand,

[@scarter176]

I guess CAT exited the OTR market shortly after the S series Engine

[@kman4823]

What year did the C9S come in to play?

[@AdeptApe]

+K man 2007 engine year, many 2007 model year trucks did not have them though because they usually had a 2006 engine.

[@zackzunic3005]

nice job could you do a c-7 thanks

[@AdeptApe]

+Zack Zunic Yes sir, I'm getting a lot of requests for that now actually. I wish I had one out of a truck to really do the walk around though. I'll try to get a video out soon.

[@zackzunic3005]

thanks nice job mixing it up with the bug gun,gotta get one of them

[@AdeptApe]

+Zack Zunic That thing is super fun, not really Diesel related, but just about everyone that watches my videos needs a Bug-A-Salt.

[@bleojuandrei]

Hello I have seen you have a lot of experience on HEUI systems. I have a C9 engine with crank and no start. While cranking, my engine speed is not rising and injection actuation current stays 0%. Can you give me a hint? Recently I have replaced engine harnesses and all sensors(even speed timing). If I take out any plug from the timing sensors I don’t get an error code, injection actuation pressure goes up but up to 45-50bar(60bar is starting pressure). If I use starting fluid the pressure goes above 60bar but no start(as there is no injection actuation current). CAT D6R LFM prefix

[@chrislandsbury8423]

I see this model has an exhaust brake, I thought some C9 engines had actual jake brakes. I know the cummins in competition the ISL series has jakes

[@dieudonnengah4721]

Pleas can u help me with details for the c7.1 sensors location

[@leehickmott9783]

Hi, that plug at the back of the engine by the fuel sensor, I have a C9 in a MH 3049 material handler and that plug keeps blowing O rings. Anyone have any ideas why? And how to correct it.

[@brunolamote]

What isyour opinion on doing an cat C9 engine rebuild at home (read farm with basic workshop). Tools are not a problem what we don’t have we can buy. As reference I have rebuild a john deere 8L (with linepump) engine, an old perkings ( 4 cilinder) and many head gaskets on other john deere engines common rail ant rotary fuel pumps. The main reason for the question is the 115 €/hour(122$) workshop fee from the licensed cat importer

[@AdeptApe]

+Bruno Lamote A C9 engine is pretty dang simple. There is no specialty tooling required to do practically anything on it. The injectors don't need any height tool, the HEUI pump isn't timed, and the overhead adjustment is really simple.

[@brunolamote]

Adept Ape I have disassembled my C9 engine, indeed it is a simple engine, all the pistons except one have excessive wear, on the worst one, one of the rings was broken, the others had just big tolerances also the top of the pistons strike the liner, so I taught 6 new liners, 6 new piston and al the seals, but I see cat has complete packs for that engine, but not my C9 CLJ10818 (serial number), would I dare just to order one of the others and buy the specific stuff afterwards? What is your opinion on this, thanks for the info

[@nurudeenharuna4945]

I have 950 g don't start y

[@patooyee]

Does the C9 have half the cam shaft bearings of a normal engine, the screwed up rocker arm shaft design, and the inverted torx fasteners like the C7?

[@AdeptApe]

No, you are thinking of the C7.1 which is a Perkins engine. C9 is an actual Cat designed engine.

[@blasphemi6906]

Are the c9 air compressors timed?

[@user-ng8mf6bi5h]

No

[@RonnyMecanico]

Como montar los unmto de granaje de motor

[@urgentcareguy3]

What kind of HP and Torque figures does this engine develop?

[@AdeptApe]

+urgentcareguy3 I believe the particular engine was around 400 HP and 1000 ft lbs, I'd have to look up the exact specifications though.

[@RonnyMecanico]

Como mota los punto de granaje de motor C9 cartepilla

[@toshadaninayak398]

Sir my engine exhaust manifold going to red hot please help some suggestion

[@zythr9999]

Junk it.

[@mechcntr7185]

Did you say the C9S can have a common rail fuel pressure of 30,000 psi? Did you mean 3,000 psi?

[@AdeptApe]

+mech cntr 30,000 or even higher is capable on these common rail engines.

[@mechcntr7185]

Good to know thanks. Wow that is a high pressure.

[@robertjessie]

❤🎉❤❤❤

[@kennethbullins445]

Why two thermostats?

[@AdeptApe]

+Kenneth Bullins Redundancy and more coolant flow.

[@kennethbullins445]

Per the CAT C9 engine manual, "engine will obtain operating temperature in a few minutes." Operating temperature is 205F and it was about 30 minutes. Too long?

[@christopherconley6704]

Can I put a c9 Caterpillar and a pick up truck

[@AdeptApe]

Sure, just load it in the bed with a forklift. You're welcome. To actually answer the question, yes you could, but it is going to be a taller, heavier and longer than a V8 gasoline engine so it really depends on how much room you have in the under hood area, then getting the motor mounts, transmission, driveshaft and differential to handle the torque.

[@christopherconley6704]

There is a project I would like to start I have a 1989 F250 Did I will like the try the put A C9 Cal a pillar and thenAnd I was wondering if that would saidOr what would I have to do to make it a smooth Ride

[@christopherconley6704]

Thank you did not see that part

[@toyoscio]

LOL thank you for the laugh.

[@f-j-Services]

I can't stand electrical stuff like efi on engines. Just got a 1066 International with a DT414. 414 CI 6.8L Many many hours of pulling are on it, it has 4200 hours on it right now. I think its the cat Acert engines that my dad and many others hate a lot, they added all the emissions stuff and all that. (I think it was the Acert). Though, There are pros and cons. . .

[@AdeptApe]

+34486 SCI I don't mind the electronics as much, as a technician they make troubleshooting cylinders and monitoring parameters much easier, but add a great deal complexity and expense to the engine at the same time. So as an owner its easy to figure out the older stuff without all the specialized computer equipment, of course the newer engines with the DEF and EGR, seem to be going a little nuts. Thanks for commenting.

[@f-j-Services]

Yeah, Some smaller trucks now I hear run DEF... What next, Eco Cars?!

[@brunolamote]

I dont mind the electronis because they can make a enigne more efficient, but on the other side came the emision standards and that put's extra complexity and (useles) parts to the engine also more back presure on the exhaust.

[@f-j-Services]

I hate cat converters. I think they are what produce cancer they are so bad. Back pressure for them things is like 3 psi? Like really?!

[@toyoscio]

Crap engine when installed in NABIs

[@emilspageofrandommachinery1714]

Those C9's dont like being in crawler jawcrushers that Metso builds (LT105) even if you follow service as instructed don't be suprised by gone injectors around 4000 hours, 2 - 3 rockcrushers that all have repeated failures at 4 - 5k hours. Sure 2100rpm all day long an shitty Swedish diesel that barely lubes is probably a reason they fail so often. Also belt driven waterpump??? what were the designers thinking there? it should have been geardriven. The latest crusher i ran shreeded the belt this summer and another one 2 weeks ago, only cat belts and a 1year old cat waterpump. cannot find any reasons the engine eats belts exept revs, big pulley on crank and small on pump, might lead to insane waterpump speeds and hence belt load? V belts btw.

[@AdeptApe]

+Emil's Page of Random Machinery & Other Things of Interest. I'm surprised it has v belts and not serpentine. They used those darn belt driven pumps on the C7 and C9, but they usually aren't much of an issue.

[@archiecurrie8452]

Put the camera down and get back on the tools. You don’t tell anything I couldn’t look up on SIS