Ticking only at warm idle

hjumper33

New member
2005 253k miles. Just noticed on my last trip that my engine has developed a tick only when at operating temp, and only at idle. Pulled the injector cover and nothing obvious, no puff of smoke when running, no deposits. The ticking increases in frequency with increasing RPM to about 1k when it disappears completely. Ive never done the injector seals, but the hold down bolts do appear to be newer, and i bought the van with 168k on it. It honestly sounds a little louder when listening from below than above, but that could just be it getting drown out by the top end. Also of note, used injector cleaner the last tank of fuel prior to the ticking starting, but that could be completely unrelated. Nothing noticed as far as drive ability or power.

Several specific questions.
1. Any issues with unplugging each injector separately to see if the noise goes away as an ancillary leak test, or will this piss off the computer?

2.Is anyone replacing injector seals as routine maintenance, or only waiting until symptoms occur? (I’ve got a lot of downtime currently and seems like a decent time to tackle this even if it isn’t the problem).

3. Any reason to try to get factory bolts with the captured washer for the injector cover vs just high grade M6 and a small washer? (Heads are rusty and starting to strip)

4. Any better ideas for what this noise actually is? (I went down an injector worm hole during my attempts to figure it out)
 

Nautamaran

2004 140” HRC 2500 (Crewed)
:idunno:

Are you hearing combustion clatter, metallic tappet sounds, or...?
The cleaner may have caused fouling to break up and progress downstream to now make something stick, but I’d then expect it across the board, not limited to warm idle?

The 2004-2006 om-647 engine will tolerate unplugging a single injector to help isolate a noise/misfire, or a shop-level scan tool can command injectors off individually for diagnosis.

A cheap stethoscope can help you isolate mechanical noises. Remove the round medical tip and jam a small bolt into the tubing, then place the bolt against the engine... this also works with a straight length of nylon tubing poked into your ear, but that’s far less comfortable!
(Common sense reminder: keep hair and clothing well clear of moving parts)

-dave
 

Nautamaran

2004 140” HRC 2500 (Crewed)
To points 2 & 3:
Some here suggest replacing seals preemptively... I subscribe to the “let sleeping dogs lie” school of thought. The hold-down bolts can strip their threads in the head, ao removing the injectors is not without risk, and TimeSert appears to have stopped making their repair kits for T1N engines (though asking them directly for the parts may get the tooling?) so repairs are less straightforward.

The captive washer is very handy for the two rear bolts against the firewall. Hard enough keeping the bolt from dropping let alone a small washer... Maybe dab a bit of grease on to help keep the washers in place on the bolts?

-dave
 
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220629

Well-known member
... Also of note, used injector cleaner the last tank of fuel prior to the ticking starting, but that could be completely unrelated. Nothing noticed as far as drive ability or power.
A tick is not generally fatal. Be careful that you don't introduce more problems in trying to eliminate something that may go away on its own.

... 1. Any issues with unplugging each injector separately to see if the noise goes away as an ancillary leak test, or will this piss off the computer?
Not on a NAS aka NAFTA 2005. Some scan tools have a program which disables one injector at a time.

... 4. Any better ideas for what this noise actually is? (I went down an injector worm hole during my attempts to figure it out)
Be certain to check for ticks coming from the serpentine belt system. It could be coincidental that the noise started after using an additive.

:cheers: vic
 

markxengineering

Active member
A sound recording or video might help. When are you due for oil change, and what weight oil is in there? It's a band-aid, but if thicker oil makes the problem go away, it's probably a bearing or piston, and something worth investigating before things get worse. The fact that it only happens hot and at low speed already makes me lean in this direction- something oil related. Oil pressure is lowest at hot idle.

If you can measure the frequency, you can figure out if it's an accessory, in the cranktrain, or in the valvetrain.

I have not seen any bearing failures (that I recall) after observing this forum for 2 years, so, hard to say at this point.

3. Any reason to try to get factory bolts with the captured washer for the injector cover vs just high grade M6 and a small washer?
Nope, I replaced a few of mine the same way.

For checking injector leaks- best to wait until it's hot and noise happening, then drop some liquid of your choice in each hole, and look for bubbles. Just don't use anything too too flammable.
 

hjumper33

New member
So played around a little more today. Unplugging injectors seemed to isolate the noise to #5. Put some simple green around the injector, and sure enough, small bubbles. Ive already got a new seal kit, I just wish I got to start with one that was a little more accessible. When inspecting closer with a camera, it does look like there is a little anti seize at the base of all the injectors, so very possible the seals have been replaced before. Going to let things soak in some pb blaster for a couple of days before attempting anything else. Interesting that the tick definitely was more audible from underneath, probably because it was getting drown out from the top, and reflected down by the firewall.

Anyone got any specific advise for removing #5? I feel like Ive done the prerequisite ready/YouTube video watching (get things hot, clean everything a ton, already have new hardware)

Are most people making a tap using the old screw? Any actual bad experiences with using the loosed and pop method? Anyone use an injector puller kit from an auto parts store?
 

markxengineering

Active member
Are most people making a tap using the old screw?
That's what I did.

Any actual bad experiences with using the loosed and pop method?
None I've heard of here. If injectors look like they have anti-seize, I'd try normal removal first (still while hot). You're in there anyway to loosen the tie down.

The injector puller I bought from Ebay was a POS. I had to grind it in multiple places for it to fit, and like most of them commercially available, the injector has to be rebuilt once you use it. Anything from the auto parts store is likely to be similar. You are far better off with the loosen and pop method or just pulling it out "gently" with whatever tools you have.
 

Nautamaran

2004 140” HRC 2500 (Crewed)
Hot means HOT... like the first five minutes of shutting it off after driving up a mountain.

Be careful not to pry against the valve cover. Pry ONLY against the “hard point” that the pawl pivots against.
Cap all fuel fittings with alum foil. Twisting the injector body with a wrench can help to free it up.
I made a DIY slide hammer to pop mine free using a 3/4” hitch pin and solid sprocket hub, and used a hook fashioned from hard steel wire to retrieve a stuck seal from down the bore (note the horizontal point, which is a key feature - hook design credit goes to Bodgit & Leggit Garage on Youtube)

Good luck,

-dave
 

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hjumper33

New member
Couple of days of soaking in pb blaster, a nice run around to get it hot. Bolt came out without a problem, and injector loosened by hand. Injector is pretty clean all things considered. Hope to finish the cleaning process tonight and hopefully my tick will be gone. Any more last minute tips or pitfalls for cleaning injector tube base? I’ve seen multiple methods online from 12 gauge rods to dowels with sandpaper on the end.
 

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220629

Well-known member
... Any more last minute tips or pitfalls for cleaning injector tube base? ...
A trained Sprinter tech once mentioned that if he didn't see any damage to the aluminum seat face in the head, he would just brush it clean with a special brass brush. Be careful that you don't screw up the seat face in the head during your attempts at prepping things.

Be certain to clean the clamp fastener threads properly and blow out any trapped debris/oil.

:2cents: vic
 

hjumper33

New member
Well job went well....still have the noise. Rechecked all the injectors with soapy water, no leaks. I’ll try to upload a video soon, but much more audible when sitting in the drivers seat or standing next to the drivers side wheel. Still going away at anything higher than about 800 rpm. Stethoscope didn’t really narrow it down, removing the belt didn’t change anything. Running normally otherwise. Good thing in home bound, and now I’m not so scared of changing injectors. Noise definitely decreases when power is pulled from injector 5, also seems to stop when I pull injector 1, but not 2-4.

Edited to add video

https://youtu.be/4X-UO0XeLUY
 
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Axiom

Mike from Florida Van Man
Pull the accessory belt off and see if the sound still persists with that off. It doesn't sound mechanical to me, it sounds like something is going around and slapping a little bit. It could be alternator pulley/clutch have had enough. If the sound stops with the belt off, you've found your culprit. Then it's just a matter of narrowing down which specific pulley is causing that noise.

Only other thing I could think of is something is banging around inside the cylinder but then you'd probably have smoking issues.
 
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markxengineering

Active member
What weight is the oil, and when is your next oil change?
Also would help to rev it up in the video so we can hear the change.
Right now it doesn't sound that bad to me, kind of like a heat shield rattling, but I can't tell which noise in there is the one you're concerned with. I'd try pushing on the shield over the turbo, any other components you can get access to, see if it changes.
 
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gs850gx

Active member
My van is making the EXACT same noise (knocking noise) and I hear it best by the drivers door just like you. When I pull the wire off no 5 injector it goes away 90%. 5000 miles on Mobile 1 European 0-40. Sometimes it seems cetane booster lessens the knock. I'm not going to drive it until I change the oil and see, might use something thicker. If it is still there I think I will order an injector and see again. Had thought about starting a new thread but we seem to be in the same boat, if I am intruding just tell me to bugger off. Watching this thread with much interest.

D
 

hjumper33

New member
Belt off, still knocks. Heat shield removed, still knocks. Using combo of mobile 1 and 1 quart of heavy duty oil stabilizer (have been doing this for over 50k). Only about 3k miles on this oil change. Going to do a leak down test today and poke around more. I’ll post another video of the change in sound at RPM.
 
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billintomahawk

Guest
Got a slight off idle knock with my '02 612 version on acceleration, then the sound is immediately and completely gone.
I thought that was normal?
No signs of leaky injectors.
Green Diesel tune.

Van runs great.
My Catalytic converter is gone(PO).

I don't know or have a frame of reference to know how the engine should?

Actually its more of a clack clack and then gone.
It's only on acceleration, not at steady idle.

bill in tomahawk
 
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markxengineering

Active member
If you were due for an oil change, I was going to suggest trying heavier weight this time, for debugging.
Since you're not, I suggest performing a "smooth running test" and checking the injection adaptation values for each cylinder. This is done with MB STAR diagnostic system and possibly others.

If you have a pilot injection issue, you will want to get that taken care of asap. I don't know what one sounds like because I've never had one, but one can imagine that it's a knocking. The smooth running test has a good chance to detect an issue, since the test is performed at idle, right where you have your problem. See discussion here:
https://sprinter-source.com/forum/showthread.php?t=83984&highlight=sticky

I don't know or have a frame of reference to know how the engine should?
Youtube!
 

owner

Oz '03 316CDI LWB ex-Ambo Patient Transport
My OM612 makes that same noise. Sometimes it seems worse than others. Mine has done over 430k km 270mi.

I run a 50/50 blend of 5w-40 229.5 and 10w-50 full synthetic. Penrite HPR5 and HPR10.

I havent done a smooth running test for a while, i should do one

Keep us posted on what you find.
 
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billintomahawk

Guest
My OM612 makes that same noise. Sometimes it seems worse than others. Mine has done over 430k km 270mi.

I run a 50/50 blend of 5w-40 229.5 and 10w-50 full synthetic. Penrite HPR5 and HPR10.

I havent done a smooth running test for a while, i should do one

Keep us posted on what you find.
If my sound was coming out of a gas engine we would have said it had a sticky lifter which is what it sounds mostly like.

It is very short duration and has never lasted beyond just getting the vehicle moving. I only hear it under load and it is momentary. Click clack and we are off. Never a stall or a hesitation.

Just Mercedes diesel music and a push from behind that is so assuring.


Rides like I stole a city bus.

bill
 
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Midwestdrifter

Engineer In Residence
If you think its one specific cylinder, send that injector to be tested. Poor control during the pre injection phase can cause knocking or tapping.
 

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