Valve adjustment really needed

[Sdhntr]

2006 5.9. Running great. No engine or drivetrain issues at all. About to turn 150k. Manual says to adjust valves at 150K. The only good diesel shop I trust is a ways away and will be rather inconvenient to take the truck to. I think this is over my DIY ability. So my question is, if truck is running well, do the valves really need adjusting? Any real downside to going another X amount of miles or waiting until I hear clicking or lose fuel mileage or something indicative of an issue?

 

[Ozymandias]

Leave it alone, if it is out of spec you'd recognize it, hear it miss.
The valve leash specs/range for the 5.9 are that lazy from factory that, almost, any setting is within specs.
It would need a serious mechanical problem to bring it out of the range, normal wear isn't one of them.
I adjusted mine twice and it was a waste of time and effort, I don't do it anymore.

 

[BigPapa]

I’d have to check, but I’m pretty sure we don’t do an overhead as part of our bus maintenance regimen.

 

[Sdhntr]

Yeah, that’s good. Thanks for the responses. I just happened to notice this maintenance recommendation in the manual. Says to adjust valve lash at 135k for the A schedule and at 150k for the B. I’m about to hit 150k and I don’t exactly baby this truck. It has lowish miles for its age, but most of those miles was towing something or other.

 

[Learjet]

what about the 4th gen 6.7...valves are good past 150,000 miles?

 

[Topzide]

I had pulled valve cover for a valve adjustment check right around 150k. Everyone was within spec! Listen to your truck, it'll tell you when it needs it. We tend to be on top of our trucks as far as maintenance. I think your good to go as others have stated.

 

[Sidewayzz1969]

I pulled my cover at 150,000 also. I checked each on. They were all spot on. As others have said, listen to her. You will know.

 

[Darkbloodmon]

If you're paranoid about it or have a valve cover gasket leak that needs to be addressed you can go ahead and check it. When injectors are installed is typically when a lash adjustment is done (valve train removal for installation) I forgot which rocker arm pedestal comes out, but that's when I did my lash adjustment.

Otherwise just take what you hear as a baseline of healthy engine noises/operation and go from there.

 

[Topzide]

@Sdhntr, By the way, Welcome to TDR! Hope you enjoy the forum and are able to get the answers you need for your truck!

 

[p-Bar]

Yeah I had 220k on the clock and did nothing other than ojl filter transmission changes.

 

[sag2]

Here is another thought if you just want to check. You will need a set of feeler gauges, the angle style seem to be a little easier, and worst case a baring tool. You can always use the generator nut just rotate the engine backwards so the belt doesn't slip, and a valve cover gasket.
Remove valve cover, rotate engine to TDC on cylinder #1.
Measure clearance on half the valves. (just Google which ones to check)
Rotate engine one full rotation and measure the other six valves.
If within a couple thousandths of specification put cover back on with new gasket.
If not, put cover back on with old gasket and make appointment with your shop to adjust.
It isn't rocket science, it is as easy as inserting the feeler gauge between the valve and bridge. If unsure if it is right on or close, use a feeler gauge .001-.002 smaller or larger to see if it goes in or not. They should all be fairly close to the specification. Too loose is better than too tight, so if the feeler goes in you are probably close enough.

 

[06 Dodge]

When I had mine done on my 06 after 10 years & 100k I was very surprised how quite they were after being adjusted being I did not think they sounded loud and saw a 1 mpg improvement in city driving....

 

[AH64ID]

At 150K they are often in spec, but no longer at the set point.

I always adjust mine back to the setting if I take the time to remove the valve cover. Equal airflow makes for a more balanced running engine.

 

[Dieseldemon]

2006 5.9. Running great. No engine or drivetrain issues at all. About to turn 150k. Manual says to adjust valves at 150K. The only good diesel shop I trust is a ways away and will be rather inconvenient to take the truck to. I think this is over my DIY ability. So my question is, if truck is running well, do the valves really need adjusting? Any real downside to going another X amount of miles or waiting until I hear clicking or lose fuel mileage or something indicative of an issue?

After a lot of miles the intake valves wear tight and the exhaust valves wear loose the intake will wear far enough they will hold the valve open then it will run rough