Folks,

OK so for my near daily concern with the '85 I have landed on a random engine noise that occurs only when cold.

- At one particular accelerator pedal position (2k rpm ish) , it sounds like something in the engine bay is loose or an injector is nailing. Not rhythmic or constant. When it starts it will happen fast for like 3 to 5 times, then stop as I move the pedal higher or lower.

- It goes away progressively as the engine warms up, until it is non-existent above 80C.

- This has occurred before and after I swapped in new injectors from bgkast, so Im fairly sure its not an injector issue.

I am going to poke around at it tomorrow. I have been ignoring it while I have worked on other stuff over the past few months.

Any ideas? Im hoping this sparks a 'oh, i had that, its this' response from someone Vac pump? Loose EGR or ARV?

Thanks, as always!
dd

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

Poked around a bit this morning, no luck locating the source.

It seems to be front, passenger's side. It also sounds 'internal'. Maybe not to the engine, but not a loose bolt.

As soon as the thermostat opens, it's gone.

Hopefully this rings a bell for someone...

dd

Went to advance auto and they did not have a stephoscope...and I left mine elsewhere...doh.

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

Mine quiets down when it warms up. Maybe what you are hearing are "cold engine" sounds.

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1993 W124 300D 2.5L Turbo, OM602.962
2000 Chevrolet Cavalier, 2.4L DOHC
2002 Ford Explorer, 4.0L SOHC
2005 Toyota Prius, 1.5L

http://www.fuelly.com/sig-us/40601.png

Thanks oldwolf...

Maybe...but they are loud enough (the noises, that is) that my girlfriend notices them - my threshold for whether or not a noise is normal.

Once warm completely to 85C, it sounds fine and the noise is gone.

Even left for an hour or so, the noise comes back until the car warms back up to 85C.

Could it be something to do with the thermostat opening or closing? Haha, I really need the stephoscope :-)

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

I actually had developed a tapping noise that sounded like something was loose until the car warmed up right after I added a plate under my EGR valve. I had removed the vacuum lines as well. I just put a block plate on and removed the whole valve and the tap is gone.

I figured it was the piece inside the valve tapping on the plate until things warmed up and expanded.

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Chad
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys

Chad,

Thats just the sort of story I have been looking for. It sounds like it's coming from that area, although I haven't isoloated it to there yet. I removed the EGR valve once to check the tensioner spring and it may have developed since that point.

When I get a chance i will take a look and maybe make a plate. 330 mile trip today from Boston to Wilkes-Barre PA, so the engine won't be cold again until tomorrow morning.

Anyone have a spare EGR blocking plate kick kicking around

dd

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

I havent had a chance to get into the engine yet, but I have put another 750 miles on it and the noise seems to be getting a bit worse if anything.

Chad, was this sound you heard a light tapping that you had to strain to hear? I am hearing something louder.

If I didnt just put in new injectors (noise existed pre injector change), I would suspect them 100%. It sounds like nailing except it sounds like a part is loose and random.

Tuesday I will get a chance to look into this in a nice garage. Any more ideas? Can the ARV do funky things?

dd

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

Thanks to Brian Carlton, I put in the EGR 'delete' kit for some offroading

The noise is still there, but much better. Could it be somehow the EGR was amplifying it?

So I guess it's time to figure out how to make a video or a recording of this thing, or nobody will be able to help...

Front of the engine, sounds like a ping or knock, happens on acceleration only when cold. Not normal cold diesel engine sounds...

dd

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

Have yout tried listening with Mechnics Mtethoscope; sold cheap at Harbor Freight to pin point where the sound is comming from.

Loosen 1 Injector Hard Line Nut see if the noise goes away or changes; tighten it back up and do the same to the rest.
If the noise goes a way or decreases on one Cylinder that is where you are having the problem.
If you find a problem Cylinder remove and swap positions of 2 Injectors and see if the problem follows the Injector from the Bad Cylinder.
If the Bad Cylinder is still making noise you have a problem in the Engine.

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84 300D, 82 Volvo 244Gl Diesel

Diesel911 - I replaced the injectors with bgkast rebuilds, and the noise has persisted through that. And the noise doesn't seem connected to a single cylinder. I have two of the HF stephoscopes :-)

I had a mechanic listen to it today, who admittedly does not have much mercedes or diesel experience, but he thought it was the chain tensioner with how it was so erratic and only happening cold. He agreed it seems to be coming from the right side of the engine.

I have checked the chain stretch cold, its 4 degrees.

How can I check the tensioner? How big of a deal it is to change it out?

dd

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

OK, I have read a bit back and located the chain tensioner article in the FSM, 05-300.

I see that this isn't exactly an 'easy' procedure. Coolant has to come out, thermostat housing has to come off. Definitely a daylong adventure.

Would it be worth it to try changing just the spring initially?

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

Just throwing out ideas, but I had the same issue with my 96 Kia Sportage gas engine. Bought the car brand new, and at about 59,000 miles, a noise as you described started to rear its ugly head. From my prior experience on gas engines, I knew that it could be either of two things. A piston slap, or a rod or main bearing. In my case, the noise only occurred within the first five minutes of starting the engine, and then diminished once the engine got up to temp. The car was still under warranty, and I left the car at the dealership overnight, and returned the next morning to be present for a cold startup. The noise was evident, and the dealer had his mechanic use an optical camera inserted into each cylinder, and it was evident that the number 3 cyl. wall was scored. Apparently, there was too much clearance between the piston skirt and the cylinder, and the noise was being caused by the excessive rocking motion of the piston skirt hitting the wall of the cylinder. As the engine warmed up, the clearance diminished, and became less noticeable. Over time, this condition would have gotten to a point where the engine would have to have been rebuilt or replaced. In my case, I was still 1,000 miles within the warranty period. Good luck !!

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96 E300d

Thank you for the ideas...I really hope you're wrong

The engine only has 150k on it, so I am hoping for something fixable. If it weren't for the noise, the engine is perfect. No blowby, less than 1/4 quart per 1k miles, starts in 0 degree weather, gets 28 mpg highway.

dd

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

Don`t know if the problem I had is anything related to yours.

This was back in early 07. In the morning when first starting the engine I heard this ticking or slapping sound in the r/f of the engine. (pass side)
when the engine warmed up, it went away. wasn`t real loud, but could be heard.

Then in July 07 is when the timing chain let go at 65mph. not sure why, I had it replaced 70,000 prior to this.

your problem may be unrelated, but check things out reeeeel good.

500 miles was a loooooog way to push the car home .

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Charlie,

This is exactly the type of noise im getting. Mine only occurs under light load / acceleration. Like going from 0-10 mph slowly.

OK, I think its time to take the valve cover off for an inspection.

What can I take pics of or report on?

Ill re-measure chain stretch (4 deg ~3k miles ago w/2mm valve lift method), take pics of the tensioner / guide rail.

dd

__________________
-------------------------------
'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car