The new C15 acert engine

Newburgh, NY

#454 Aug 23, 2010
I want to bypass the dpf and everything that goes with it! Anybody done that?

Ithaca, NY

#455 Aug 25, 2010
I have a 2006 KW W900L with the C15acert 500hp.I do heavy hauling and I really have no complaints about it.I'm getting 5mpg average which isn't bad considering the hauling I'm doing.My words of wisdom would be use Cat oil when changing it,it really does matter,keep a eye on things like your hose clamps on air intakes a little loose and you will lose alot of power.I see one post of really poor mpg,things like soft tires hubs low on oil,brakes dragging,may sound dumb but the little things can cost alot in fuel.One thing I do is use howes fuel conditioner in it.I use it about every two weeks in summer and always in winter(i live in upstate n.y in the snow belt so jelling isn't an option I'm willing to take.)My engine has 210000,i got the truck last year with 140000 on it.
matts world

Hawthorne, NJ

#456 Sep 2, 2010
Does anyone know of any problems with the C15 acert besides poor fuel mileage?

Waterloo, Canada

#457 Sep 4, 2010
05' C-15 seems to crack exhaust manifolds relatively easily. When happens replace all three manifolds. Creates huge loss of power and fuel loss and performance loss.
rogers cat

Ogden, UT

#458 Sep 6, 2010
pull stepdeck with a t600 got the acert cat c-15 set at 475 heavy haul 1650 torque 13sp doesnt pull for shit and fuel mileage is s a joke had older cats e and b models good motors for the die hard cat fan would swap this thing for a cummins or detroit in a heartbeat this is my last cat
Peterbilt long nose

Salem, OR

#459 Sep 12, 2010
Does anyone know the frequency that cat injectors should be replaced. I have a 2005 C15 with 530k miles on them now.

Jonesboro, AR

#460 Sep 12, 2010
I just got an 04 KW with a C-15. First trip out on the road i noticed it was sluggish and was getting very poor mpg's. I picked up a load in Atlanta and was headed to Knoxville when all hell broke loose in the mountains. It wouldn't pull and was running like a Briggs and Stratton. I pulled over and checked everything but couldn't see a problem. I called a shop I knew in Knoxville and told them I was coming in.

The mechanic took a look over it and came back with his list of problems. The valves was so far out of adjustment from someone tinkering with it that the engine was creating a excessive amount of backpressure. It caused the turbo bolts to come loose...One actually broke off on the high side turbo. It loosened a section of the flex pipe and blew out the exhaust manifold gasket!!!!!!

I told him to replace everything and do a good over head on it and he said he would get it purring like a Cat should. He did a great job and now this engine purrs and roars down the road like a Cat is supposed to. I'm getting 6.2+ mpg and no more problems.

Please if you don't know what your doing with this high tech engine. Then leave it up to the experts. Some Gomer that "knew what he was doing" screwed mine up. Thankfully I got it fixed the right way and now I'm back on the road with no worries.

Jonesboro, AR

#461 Sep 12, 2010
If you want to know the name of the shop I used then you can email me. I won't spam here. I'm an honest O/O and the shop I went to did me right. The guy there was very up to date on Cat engines and knows his stuff. A long as I'm in this business I will go there if I can for repairs and recommend them too.

Jonesboro, AR

#462 Sep 12, 2010
My email is

Valley Stream, NY

#463 Sep 16, 2010
Im in the shop now went in cuz I had oil in my coolant resevoir they told me it was the oil cooler gone bad then they told me my intake cooler was bad and pushing water into my cylinders while in there they recommended that I change the water pump .I wonder whats next I have 609310 miles on this 04 acert

Kokomo, IN

#464 Sep 16, 2010
Pittsburgh power makes free flow mufflers for my intl which currently has the muffler with the built in cat conv they want 189 for it

Bryson City, NC

#465 Oct 17, 2010
I just purchased a 2006 pete with the acert c-15 475hp turned yp to a 550 with 3.36 in the rear. It was dynoed by a cat dealer in st. louis believed to be the secong largest in the country. i have alot of blowby, almost looks as if its on fire at night, and cant idle without the nasty smell coming through the vents. can anyone help me out with what i need to do, or why its got excessive blowby. this is my first truck and not to sure with the mechanics of it. Thanks

Joshua, TX

#466 Oct 27, 2010
I have a C15 Caterpillar engine in a 2001 Peterbilt, It has developed a serious miss, is slobbering fuel or oil, not sure which, no smell, out of the exhaust and only running half full on the primary fuel filter. So far I have tried the following, had an overhead ran, had the # 3 injector replaced ( was showing to not be firing properly, had an injector cut out test done, had the injectors recaliberated, replaced the fuel lines, replaced a check valve on the return side,cleaned off all the ground cables to the batteries,replaced the fuel filters numerous times with caterpillar filters, still the problem persist. The only code it is showing is a Code 71 for a key switch fault, will the key switch cause these kind of problems or is there something else that anyone can suggest may be the problem or how we may fix the problem. Noone else seems to know what the problem may be. It is costing us a fortune trying to eliminate the problem

Winfield, TN

#468 Nov 10, 2010
u can have to overhead run and have the emisions turned off in the head and my twin turbo runs with my brothers 3406e both are 550 hp
Big Bill

Vancouver, Canada

#469 Nov 16, 2010
How do you turn the emissions off in the head.I assume you mean the VVA?How is that done?

Castlegar, Canada

#470 Nov 18, 2010
I own c-15 acert 625 hp and 2050 torque, excellent engine. Have it cranked up by cat. they will change fuel numbers. Off cat dyno with 598 to rear wheels and 692 to flywheel. Runs great. fuel mileage with 78000 plus runs 7.8mph

Show Low, AZ

#471 Nov 26, 2010
chris wrote:
Cat is the best damn engine ever!!!
If you don't like a caterpillar, then you don't know what 2 like.
NO other engine has the torque and smoothness of a cat diesel
The older cats might have been something to brag on, like the 3406 and many others.But these new engines are crap, because of a poor head design. These things are rough from idle all the way to pegged out. The only thing I have found to make them run and continue to run,is turn them up to maximum horse power and fuel with out chipping the ECM and it will pull any load up any hill at top spead with excellent fuel millage.I'm a rig mover and we max our trucks out at 150k easy everyday, and the only problems weve had since the motors were turned up is a few sensors.But they were cause by faulty connections which reduce power by at least 30%.By the way, if you run one hot you will eventually be spending 25k on a complete rebuild.Can't say the new cummins are much better either. mabye a piece of mind for someone, it's not a p@#$ing contest guys.

United States

#472 Nov 29, 2010
I have a 2006 fl.xl with 329000 mils c15 435 with a 13 355rears i can only get 5.9 to 6 mpg.What can i do to get better fuel millage.Motor is not turn up @ all just a 435 with 1200 lbs of torque.
Cletus Klauser

United States

#473 Dec 1, 2010
I have a 08 put in service march of 10 nothing but trouble poor poor fuel mileage 4.5 5.5 flubbers alot sounds luke air in filters but good pressure , crankcase filter has alot of water regen system took 110 thousand miles to fix I think it works now low turbo boost most of time very sharp western star really stands out but worst motor trouble in 30 years !!!

Cincinnati, OH

#474 Dec 5, 2010
To get more umph from your stock c15 is to pinch off hose on waste gate this will let your engine produce more boost but you need to be watch pyro guage so you can back down when it reaches high exuast temps ps cut off tie before taking in for repairs it will void warentys

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