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talotto 06-21-2009 09:21 AM

Cat C7 Valve Adjustment
Has anyone ever done this themselves? I've done valve adjustments on regular auto engines, can I do my own on my C7? It's in a 2004 Itasca Meridian, pusher, so I know I have to get to it from under the bed.

It's not that I'm cheap (although one could argue that) but there are no Cat maintenance facilites locally that work on RV's so I hate to take days to travel to/from a repair facility if it is something I can do myself.

If anyone's done it and can provide specifics I'd like to know more.


tomsm 06-21-2009 09:44 AM

Tony - if you don't get any help here, try the CATRVCLUB forum on Yahoo. There are a couple of write-ups in the "Files" section of that forum detailing the procedure for doing the valve adjust on a 3126B. I "think" the C-7 would be the same, but I'm not sure...

wagonmaster2 07-21-2009 10:43 PM

I would like to do my adjustment on the C-7 330 HP Cat engine as I also have done this adjustment on Chevys, 4 cyl Trackers, and Hondas, but the biggest problem I can foresee on the diesel engines is how do you revolve the engine to different positions while doing the adjustments?
Most gas engines can be turned either with the fan belt, flywheel, or damper pulley, but none of that is easily available with the diesels and the starter would turn too far.

2004 Meridian 36G

talotto 07-22-2009 06:08 AM

Cat C7 Valve Adjustment
Well, I looked at the 4236 procedure and got a quote from Mustang Cat in Bryan, TX. For about $400 they did the valve lash and flashed my ECM. It was easier to write the check than do the work. - Tony
2004 Itasca Meridian C7

UPS 34 07-24-2009 03:18 AM

Look and see if you need to do it. Mileage Down? Noise ? Why do it. Because Cat said so... I would check and see if you need to do it. I was a Diesel Mechanic for many years. If mileage is the same and noise level is the same. I would not waste my time or money.

NALSO 07-24-2009 06:31 AM

Cat C-7 Valve Adjustment
Talotto (Tony)

What is the access to the crankshaft pulley (harmonic ballancer) nut like? Do you think that you can get a socket attached to a ratcheted breaker bar with an extension on it down there? This would have to be at least 3' long.:banghead:


wagonmaster2 07-24-2009 09:39 PM


Originally Posted by UPS 34 (Post 526316)
Look and see if you need to do it. Mileage Down? Noise ? Why do it. Because Cat said so... I would check and see if you need to do it. I was a Diesel Mechanic for many years. If mileage is the same and noise level is the same. I would not waste my time or money.

UPS - I have been around gas engines since the mid '50's and familiar with their sounds, both good and bad. This is my first diesel (2004 Cat C-7 330 HP) and when I questioned a shop early in my ownership about valve adjustment they said the same thing you did, "listen for a change in noise". My question is, as noisy as a diesel engine is anyway how do you tell if its gradually getting any noisier? I almost feel like my diesel engine could be ready to fly apart and I'd never be able to tell the difference. On a gas engine I can hear valve tappet noise, connecting rod noise, piston slap, main bearing noise, but the diesel is all noise all the time.

2004 Meridian 36G

NALSO 07-27-2009 07:11 AM

Noisy Diesel????

Buy yourself a "Stethoscope" for automotive use, with this even a novice could become an expert in locating any unusual noises.:dance:


wagonmaster2 07-27-2009 07:39 PM

Nalso - Good Idea. I've used a long handle screwdriver shaft or long metal extension before in isolating a noisy water pump, alternator, or belt idler, but don't know if something like that would help me remember the sound of valve tappets to tell when they were getting noisier or how noisy is really too much.
May have to get one anyway since I've got a noise in my Jeep Wrangler that may be an idler or tension roller.


Cat 08-26-2009 09:48 PM

The valves get tighter as they seat or wear in to the valve seats. As the seats wear the valve clearence decreases--- you will not get noise. The first valve adjustment is the most important. The higher horsepower with less cubic inches means its more critical to do the adjustments no matter whose engine you are using. And your warranty may not cover a burnt valve or damaged valves if you have not adjusted the valves. And Its easy to do.

ninos 01-31-2010 09:52 PM

I have a 2006 discovery with 22000 miles when should I adjust the valves? 330hp c7

wagonmaster2 01-31-2010 10:13 PM

I think the recommendation is between the 3rd and 4th oil change, which is supposed to make it between 33,000 miles and 44,000 miles. I have just over 43,000 on my 2004 Cat C-7 so I'm looking to have it done this spring.


Cat 02-02-2010 11:43 AM

First adjustment 11,000 miles after that every 100,000 miles.Right out of the Cat Operation and Maint manual.

wagonmaster2 02-02-2010 10:36 PM

That 11,000 miles was orginally written for OTR trucks and has been revisited and updated by Cat. Just about any Cat mechanic will tell you that 11,000 miles on an engine like an RV is will not be broken in enough to warrant a valve adjustment that soon. Go to the CatRvOwnersClub web site for more information on this.


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