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JEEPOHOLIC · 01-16-2017, 05:36 PM

So a nasty lifter ticking sound has revealed its self to me, it started about 2 months ago, then it was just at a cold start up and would disappear, lately it's still at start up and sometimes stays around for a while, it's rather unpredictable the motor is a re-furbished 3126b rated at 300 hp in a 1999 Freightliner Sports Chassis with a 6 speed automatic, the motor has about 45K on it now, today I cracked the valve cover and made some very minor adjustments to the rocker arms, almost all were spot on according to the factory marks on the locking nuts, and the ticking continues, possible causes a hydraulic lifter that has failed, but one would think during the adjustments it might make its self clear by the slack in the rocker arm or the factory's marks on the locking nuts, any thoughts or comments on this ?

Unplanned Tourist · 01-16-2017, 05:43 PM

Injector?

Mr_D · 01-16-2017, 05:56 PM

Hydraulic lifter?I don't think you have them.

JEEPOHOLIC · 01-16-2017, 06:00 PM

Are they solid lifters ?

swampdog2 · 01-16-2017, 06:04 PM

My money is on exhaust manifold leak

twinboat · 01-16-2017, 06:08 PM

1, Probably solid lifters, so that's not it. Did you check the valve clearance with a feeler gauge ? They need to be set properly, if you moved any.

2, Did you look for a bent pushrod ? Self evedent by a very loose rocker.

3, Does the sound change after the compressor unloads ( blows off ) ? Failing compressor drive.

4, Does the sound go away while in gear ? Loose torque converter bolts.

Mr_D · 01-16-2017, 06:11 PM

Quote:

Originally Posted by swampdog

My money is on exhaust manifold leak

That would be my guess too.

JEEPOHOLIC · 01-16-2017, 06:41 PM

Quote:

Originally Posted by twinboat

1, Probably solid lifters, so that's not it. Did you check the valve clearance with a feeler gauge ? They need to be set properly, if you moved any.

2, Did you look for a bent pushrod ? Self evedent by a very loose rocker.

3, Does the sound change after the compressor unloads ( blows off ) ? Failing compressor drive.

4, Does the sound go away while in gear ? Loose torque converter bolts.

1)Rocker arms were adjusted at .015 on the intake and .025 on the exhaust side, rotated 360 degrees and did the other half
2) no rocker arms were more loose than the others I checked all the intake and exhaust before I made any adjustments and all the lock nuts ended up in the same marked positions
3) definitely not the compressed sound I know that sound
4) the ticking sound is definitely related to the engine RPMs
5) and just checked for exhaust leak sounds by using a hose to my ear listening for that rushing air sound and found none

twinboat · 01-16-2017, 06:46 PM

Get an oil sample.

JEEPOHOLIC · 01-16-2017, 07:01 PM

Quote:

Originally Posted by twinboat

Get an oil sample.

My last sample came back all normal and that was about 3 weeks ago, as I went out and listened for the exhaust leak, the ticking sound was gone, it's very random
And not consistent , but when it is there it is consistent with engine RPMs

Unplanned Tourist · 01-16-2017, 07:38 PM

I would suggest if it continues, you could get a Cat dealer to do a bit of checking. Take it to a shop and get a cylinder performance test done. It will have to be up to temp when they do it, so may be hard to see, but will pick up small differences cylinder to cylinder. Ever get a code come up? With the proper software you can do cylinder cut out tests also. Good Luck.

nosticks · 01-17-2017, 06:20 AM

Injector.

Podivin · 01-17-2017, 06:34 AM

You might try getting a mechanic's stethoscope so that you can listen to your engine, it really helps to pinpoint sounds that are coming from (or SEEM like they are) inside the engine. You should be able to get one at your local auto parts store or plenty of places online.
You might not be able to tell exactly what the problem is, but it certainly helps to narrow down where the sound it's coming from.

I had what sounded like a ticking lifter, but when I listened to the engine I could tell that everything sounded fine in there. In my case it turned out to be an arcing spark plug wire, clearly that's not the case in your engine.

JNSNWT · 01-17-2017, 08:22 AM

Here's a possible source of professional advice.

Search youtube for "Adept Ape". He is a Cat mechanic with several "how to" videos that are pretty good quality for freebies.

He does answer posted questions and I've seen him offer a 1 on 1 phone call consultation for $30 which is cheap to get to talk with a professional. IMO.

Just a thought. Best of luck. Please let us know how it turns out.