Overhead service

[randyc]

I own a 2000 Pete dump truck with a 3126B Cat in it. I was recently asked by the mechanic that does my work if I had ever had an "overhead service" done on it. I didn't even know what that procedure involved and why I should or shouldn't have it done. I've put about 200,000 miles on it in 3 years. It has a total of 505,000 miles on it. Can someone explain what an "overhead service" is? I have noticed lots of power loss in this truck and have already addressed anything else it could be as well as being hooked up to the computers at the Cat house and was told that everything was in good condition. Sorry I sound so stupid but I'm just a driver.

[Orangetxguy]

I own a 2000 Pete dump truck with a 3126B Cat in it. I was recently asked by the mechanic that does my work if I had ever had an "overhead service" done on it. I didn't even know what that procedure involved and why I should or shouldn't have it done. I've put about 200,000 miles on it in 3 years. It has a total of 505,000 miles on it. Can someone explain what an "overhead service" is? I have noticed lots of power loss in this truck and have already addressed anything else it could be as well as being hooked up to the computers at the Cat house and was told that everything was in good condition. Sorry I sound so stupid but I'm just a driver.

It's a "tune up" for your injectors. It helps fuel mileage, eases that little rattle you here coming from Miss Kitty, and maybe even stops some of the shaking while you sit and idle.

Usually runs about $275.

[randyc]

I recently had the injectors replaced because of bad o-rings. Would the service still be beneficial?

[Kranky]

An "overhead" on a Cat motor is a valve adjustment and Jake brake adjustment.

.

[Fredog]

I have mine done once a year, it usually costs about 300 bucks, like Kranky said, they adjust your valves and jake, they also will see if you have a loose or leaking injector which could save you thousands of dollars if they catch it before it lets loose., so to answer your question YES, you should have it done.
KW recommends every 250,000 miles

[heavyhaulerss]

I recently had the injectors replaced because of bad o-rings. Would the service still be beneficial?

if what you say is true. the overhead would of been done after the replacing of the injectors. if this was done within the last 100,000 miles I don't see a need to redo a overhead

[jasontherock]

I have also heard that this needs to be done. I saw a sign outside my local cat dealer for a "valve adjustment" I posted the flyer below. Is this same thing as an "overhead"?
Thanks

[Fredog]

I have also heard that this needs to be done. I saw a sign outside my local cat dealer for a "valve adjustment" I posted the flyer below. Is this same thing as an "overhead"?
Thanks

yes it is, and if they are giving a free oil change, I cant get there fast enough, a dealer oil change usually runs close to 300 bucks

[BanditsCousin]

I think KW may recommend it at 250K on a Cat, but 500K on a Cummins.

[bob h]

if what you say is true. the overhead would of been done after the replacing of the injectors. if this was done within the last 100,000 miles I don't see a need to redo a overhead

On an EUI engine (ISX, C15, S60, etc) the valves SHOULD be adjusted when injectors are replaced... because the rocker arm shafts are removed to replace inj's. This 3126 is a HEUI fueled engine and does not require removal of rocker shafts to replace inj's, therefore the valve adjust was likely NOT done during this service.

[devildice]

I was just at the San Antonio, TX Rush Perterbilt today and they are advertising an overhead special with PM Service (Oil change, oil filter, fuel filter & lube) for $300 out the door, they claim it's a $400 savings and the offer is good until the end of the year. The service guy also said they will throw in a "21 point" inspection too although I didn't have time to ask him what that consisted of. Will more than like head back there tomorrow or the day after and have it done.

[BanditsCousin]

$300 is an AWSOME price on any engine for an overhead and PM.

[devildice]

$300 is an AWSOME price on any engine for an overhead and PM.

Yeah that's what I was thinking. My truck has 521k+ on it and I doubt that it's ever been done before so tomorrow I am heading over to the shop to "git-er-done"

[heavyhaulerss]

On an EUI engine (ISX, C15, S60, etc) the valves SHOULD be adjusted when injectors are replaced... because the rocker arm shafts are removed to replace inj's. This 3126 is a HEUI fueled engine and does not require removal of rocker shafts to replace inj's, therefore the valve adjust was likely NOT done during this service.

I.c. t.y.

[randyc]

My problem with this truck is loss of power. The reason I was asking about overhead service is because I've tried everything else I can think of. The injectors were replaced. The motor was hooked up to the computer at the Cat house and everything checked out perfect and they even updated it with the most up to date software. I had my air to air checked thoroughly for leaks and all was fine there too. The truck is not consuming excessive oil, it's not smoking. Only thing I can think of is maybe some sort of problem with the turbo. I'm open for suggestions. The motor is a 3126B and it's supposed to put out 300 hp which it did when I bought it 3 years ago but slowly it has lost power. It feels like about 200 hp now. It has 500k on it. I've put about 175k on it in 3 years. It's a dump truck that never touches the interstate. I rarely run it over 60mph. It's mostly 20-30 mile short hauls. I even replaced the radiator. It never runs over 200 degrees even on a 100 degree day. Any help would be appreciated.

[devildice]

Got the Overhead service done, PM service with all CAT filters, 21 point inspection, and a clutch adjustment for $335.02 out the door!!!!

[shadowsknight]

Have you charge air cooler tested. If it's leaking air then you are loosing compression and horsepower.

[CanTech]

Things to check:

Charge air cooler for leaks- You have done this already. Did they give you a psi drop over 1 min?

Boost output under load- Take a look at your gauge to see your maximum boost psi. If you see a decrease over time you could have waste gate or boost leak issues.

Injectors not atomizing fuel properly - injectors are getting worn out and are in need of an exchange- Expensive!

Compression issues- Check for excessive oil consumption and blow by at the blow by tube near your oil pan when your engine is at operating temperature.

Top end set- will not give you noticeable horsepower or fuel savings. Maintenance reasons only. As valves recede into the head it decreases valve lash between the valve bridge and the rocker arm. Each top end set should be performed at 250,000 miles for regular service trucks. For trucks that are severe service and use engine brakes often should be done a little sooner.