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FINALLY got the project gl350 on the road. 2010 with 182,k kms.
Two lingering issues after getting my deletes done.
One: intermittent timing chain rattle.
So, when we first bought the vehicle about month ago. No rattle. After 20-30 startups. No rattle on startup. Nice and quiet as can be.
I changed the oil with castrol c3 (229.51) 5w30. Rattled upon initial startup for about 5-10 seconds. It has done that intermittently on cold startup since then.
Now, i got done with my deletes. I noticed in the garage that when revving, i can hear a rattle sound on the 'downrev' . Upon initial start, you do not hear it if you rev and let the revs come down.
Once its been idling and warming up for about 5-10 minutes. You can rev it and you'll hear the rattle when the revs come down.
KInda sounds like marbles being jiggled. Only on downrev for a second. Sometimes, it will present itself on idle for a second after revving, and then the idle is nice and quiet. No other hiccups.
Now, what have i investigated?. I have been looking at the chain tensioner through the oil cap. I see its a bit extended when i first bought the car (the day i brought it home). I was like, ok a bit extended, but still dont see the shiny part of it, so that means the chain isnt overly stretched. Is this true?
I have been opening the oil cap. I noticed the chain tensioner, wont "stay" where its at. It will either be where it is in the first pic (usually after driving), or back where the second pic is (when i can hear the cold start rattle and rev down rattle). One day, i opened the cap to check the tensioner position, it was where it was at in the first pic after sitting overnight. No startup rattle.
With the tensioner extended (1st pic), everything is good and smooth.
Now, i ordered and received an oem mercedes tensioner. I figured i might try and replace the tensioner and see if it resolves my rattle. Im leaning towards it being a sticky tensioner. What do you guys think? In my opinion, if the chain was badly stretched, id be seeing the shiny part of the piston = overextension. Right?
I feel like my chain might be a tad stretched, but might still get away without a chain replacment. For now.
2nd issue: my exhaust stinks of raw diesel and burns my eyes. Vehicle runs great, no excessive smoking (so far). My oil doesnt smell like diesel. Only present if i stand right behind the exhaust tips outside, or if its idling in my garage. Any ideas? Dpf, egr, swirl flaps have been deleted. Cat is still there. This smell was present before the deletes as well.
Thanks!
Warm engine after driving. Usual cold engine. I just changed the oil again, havent driven it yet. But the rattle is present with the tensioner here. I feel like its a bad tensioner that is bleeding out intermittenly and not holding pressure, causing my intermittent and now more constant rattle.
Well, to answer my own question somewhat, i replaced the chain tensioner.
Took about 10 minutes. Did it from the top by removing the air intake hose, and the wire harnesses out the way. Got a breaker bar with a 22 mm and got it loose. Threaded it out by hand. Getting the new one in was.a bit fun, as its "spring loaded". When you open the oil filler cap, you could see the relaxed chain guide now. Carefully got my dad to push the chain guide back inwards, while i threaded in the tensioner about 5-6 turns. Then was able to use a ratchet to get it tightened, and torqued to 80Nm.
Noise was gone for the first 2-3 startups and revs. Then it slowly seemed to come back. I imagine if i start it tomorrow morning, i might have some noise.
So, i believe my chain is stretched.
I also noticed upon holding revs at 3500k or whatever full throttle in neutral allows, the exhaust still stinks of raw diesel and bluish/white smoke. I think it might be due to idling so long and revving without load, as we havent even gotten the car on the road properly yet. I dont even know how old the diesel in the tank is. Think i might have a potential boost leak as well as i have whistle noise under load sometimes
Ill be calling around to get quotes for chain replacement, if its reasonable ill get a shop to do it. If not, ill attempt it myself.
Think I'm in the same boat: 200kms on an '07. Intermittent chain rattle on start-up, although I don't have the down-rev rattle.
For me, may just be tensioner, but I think - owing to the truck's age and kms (and can't see any notes about timing chain replacement in the logs) - I'd do the chain and tensioner.
From looking through guides and videos on the process, I think it's a reasonable DIY, and will furnish me with all the parts for less than the labour.
On the exhaust, have you checked if there's much oil leaking into the turbo intake from PCV? I recently did PCV and the PCV cover, which connects the PCV to the crankcase. The PCV itself was so busted, it leaked exhaust, and I'm sure, was not doing it's job at all. My turbo intake was getting hammered with oil-laden exhaust from the PCV inlet. I've replaced that, and all the red flanges and things seem better!
Think I'm in the same boat: 200kms on an '07. Intermittent chain rattle on start-up, although I don't have the down-rev rattle.
For me, may just be tensioner, but I think - owing to the truck's age and kms (and can't see any notes about timing chain replacement in the logs) - I'd do the chain and tensioner.
From looking through guides and videos on the process, I think it's a reasonable DIY, and will furnish me with all the parts for less than the labour.
On the exhaust, have you checked if there's much oil leaking into the turbo intake from PCV? I recently did PCV and the PCV cover, which connects the PCV to the crankcase. The PCV itself was so busted, it leaked exhaust, and I'm sure, was not doing it's job at all. My turbo intake was getting hammered with oil-laden exhaust from the PCV inlet. I've replaced that, and all the red flanges and things seem better!
Thanks for the reply. Have a look through the filler hole after a drive. See if the tensioner is overly extended. If so, might be a stretched chain.
Its always hard diagnosing without tearing ut all apart.
I did have the intake plastic housing off many times. Very minimal oil in my turbo and seal in good shape.
My 08 ml320 cdi has a lot more oil in the intake than this.
I took it for a first longer drive after idling a lot in the garage. A bitta smokey initialy but it cleared up and none for the rest of the ride.
I might just drive it for now and end up doing the chain in the next couple weeks
If it smells like diesel then you may have a leak. If you say you smell it at the back, that is where the fuel tank is, so I would check the feed and return line connections at the tank. Idk where hey connect in the back, buy in the front they are easily accessible behind (inward of) the left (driver) wheel
PCV Valve IS supposed to get exhaust out of the engine, the oil is just a side effect. That exhaust ends up going thru the turbo and intake and makes no difference at the back end.
If it smells like diesel then you may have a leak. If you say you smell it at the back, that is where the fuel tank is, so I would check the feed and return line connections at the tank. Idk where hey connect in the back, buy in the front they are easily accessible behind (inward of) the left (driver) wheel
PCV Valve IS supposed to get exhaust out of the engine, the oil is just a side effect. That exhaust ends up going thru the turbo and intake and makes no difference at the back end.
Sorry, i guess it wouldnt be raw diesel. I should say it smells like "unburnt diesel". Not actual liquid diesel.
Im starting to think if the chain is stretched, that would throw off the engine timing....causing the smell. Does that sound accurate? Im not sure.
Sorry, i guess it wouldnt be raw diesel. I should say it smells like "unburnt diesel". Not actual liquid diesel.
Im starting to think if the chain is stretched, that would throw off the engine timing....causing the smell. Does that sound accurate? Im not sure.
I don't know but I doubt it. Perhaps a bad injector then? It can sound pretty bad, and if it dumps tons of diesel then that could be it? Just a guess though. I have yet to find how to test injectors without pulling them out and sending to a shop though
I don't know but I doubt it. Perhaps a bad injector then? It can sound pretty bad, and if it dumps tons of diesel then that could be it? Just a guess though. I have yet to find how to test injectors without pulling them out and sending to a shop though
Yup, that was my next guess as well. No black death or anything yet. No weird noises apart from the chain.
Ill get to it eventually lol. I looked up and apparently there is a test that can be done with the injectors in the vehicle. You hook up clear tubes to some type of homemade cylinder apparatus. Not sure how it works, but i think it somehow monitors the "return fuel" or something. Im not Sure. You test one bank at a time while running the engine for a certain length of time, and check the amount of fuel. If one or more cylinders is more than a certain amount, the injector is bad.
Yup, that was my next guess as well. No black death or anything yet. No weird noises apart from the chain.
Ill get to it eventually lol. I looked up and apparently there is a test that can be done with the injectors in the vehicle. You hook up clear tubes to some type of homemade cylinder apparatus. Not sure how it works, but i think it somehow monitors the "return fuel" or something. Im not Sure. You test one bank at a time while running the engine for a certain length of time, and check the amount of fuel. If one or more cylinders is more than a certain amount, the injector is bad.
I did that on Friday on passenger side because I hear 2 of them ticking and it is not blowing by them. I can check the internal diameter of the tube for you btw if you want (I couldn't find it in video). I didn't follow any specific instructions, just waited around a bit, and as they were all rising fairly steadily at same rate, I figured they are fine. Btw, be prepared to catch a ton of diesel from the leak oil line that you disconnect I ended up with a good .5-1L. I think if you would do all the injectors at same time you would waste less. As it would only be coming from filter.
But that doesn't 100% guarantee the injector is fine still. Even if it is not blowing by, and not leaking off too much fuel, it can still be dumping too much fuel through the nozzle into chamber. And if it is not doing that, the spray pattern could be bad if it is fouled.
So as you've discovered, the timing chain rattling noise is almost never fixed by replacing the tensioner. In general, the chain stretches and you replace the tensioner "while you're in there" but not because it's bad. The OEM manufacturer actually sells a kit with chain, guides, and a tensioner for much cheaper than you could buy the parts individually.
The chain job isn't terrible, but requires some time and a lot of tools. It took me about 30 hours, but I've heard a pro mechanic familiar with the job can do it in less than 15.
The diesel smell sounds to me like you have a leaking injector. This is NOT uncommon on these things and can be catastrophic if the leak is large. I've seen numerous photos of bent connecting rods when the engine hydrolocked with a bad injector that filled a cylinder while sitting for a period of time. I'd check your injectors to ensure they are not leaking; it's not a difficult job to pull them but you will need either a crows foot wrench or a flare nut wrench as the nut that holds them is recessed.
I just had er idling today as i was cleaning the driveway. It idles with white smoke/watee vapor that smells like unburnt diesel. After idling for about 20 minutes, most of the smoke/vapor goes away. Smell remains.
Today though, i noticed it was puffing a tiny amount of blue smoke while idling. Very little amount. I took it for a spin driving hard, no smoke that i could tell while driving.
After parking back in the driveway, huge plumes of blue smoke coming out of the exhausts. Went inside to put my wallet away, came back outside and all smoke gone.
Took it for another quick drive, driving hard again. Got back, no smoke at all. Left it idling for a minute, no smoke. Shut it off and left it at that. I noticed by quickly smelling the smoke that it didnt smell like that unburnt diesel. But i didnt let it idle very long to see if it came back.
I have been monitoring my blowby, apparently you can do an oil cap test. If the cap dances it means too much. I loosed the cap and it doesnt dance or anything.
No weird noises that i can tell from the engine.
Im leaning towards injectors based on the stench. But im not sure. Could it be a turbo too?
I dont feel like its down on power or anything.
I have an 08 ml320 cdi, same engine. That exhaust actually smells like a 'normal' diesel, even though it still has its dpf
Also, after driving it for the last 3 days, my startup rattle and rev down rattle has disappeared.
Well i thought i'd post a bit more of what i have found over the course of playing with it. I was on holidays for 2 weeks so never got to tear it down.
The timing chain noise is not present anymore. After my deletes, i switched to 5w40 shell rotella t6. Chain noise is gone with my new tensioner so far.
The diesel exhaust smell is still present.. I will post what symptoms i see. The vehicle starts fine in extreme cold weather as well. it was -33 celsius the other night, started right up. I do get a puff of diesel haze, whitish grey smoke. I let it idle for about 10-15 minutes, still puffing white smoke/condensation mix. Smells like unburnt diesel. If i get in and rev, it will miss/skip at 2500 rpms. Nowhere else. When it skips, it emits blue smoke that smells like unburnt diesel. It burns your nostrils and eyes. If i take it for a drive, it doesn't smoke very much. No skipping or missing during driving. When i get back, it will chuff blue smoke that again, smells like raw unburnt diesel, but not as strong. After a minute, this smoke goes away as well. No more miss/skip at 2500rpms.
Now, if i rev, let off and immediately rev again, like blipping the throttle. It will skip/miss. Every skip/miss, it will puff blue smoke. The more i do it, the more smoke it emits. Smells strongly like unburnt diesel
Again, it clears up when driving.
No loss of power, or anything.
I am pulling the injectors to get them tested. Unfortunately no one in my town does them so i have to ship them out. I'll report back.
Also, basically. If i just ignore the smell/bit of smoke, and drive it normally. you wouldn't know anything was "wrong". It drives great, no issues apart from stink and some smoke. It doesn't smell like normal diesel exhaust, it smells really strong/unburnt diesel. It was there before the deletes i did as well.
Would an injector leak off test point me in the right direction? Or would that not help if say, the spray pattern was off or something.
Any other issues that can cause something like this?
Just as a side note, these two threads sort of relate to my symptoms. And they were both solved with injector replacements. Just for anyone who is interested/may be having similar symptoms.
Well diesel shop tested injectors. They said apart from above normal backflow, they are fine and passed testing. They said that excessive backflow would cause an issue with hard starting, not related to smoking at all. This starts right up no problem, even in -35 celsius.
They cleaned them up and i reinstalled them. Still have the white smoke that smells of unburnt diesel after i started it up and burns your eyes.
Any ideas?
It runs soo smooth and starts right up. Not losing coolant either. I havent driven it much honestly so i might button everything back up and give er a good solid run about and see what happens.
But if anyone has any thoughts of what it could be, please let me know!
Could a stretched timing chain cause this maybe? Or carbon buildup in the intakes? My swirl flaps seem jammed in place and we deleted them when we did the dpf, adblue and egr delete. I touched nothing when deleting except for removing the dpf
As its warming up ill rev it and it will stumble for a bit before increasing rpms. If i rev it more and rev up from beginning again, it wont stumble.
Let it idle for a 30s to a minute again and it will stumble again until it "clears up" and then rev fine.
It still smokes. If hold it at max revs in park it will smoke bluish smoke continuously. I stop revving and the smoke keeps coming but eventually clears. It doesnt smell as diesely, but as soon as you smell it it burns your eyes and nostrils.
It still stinks like unatomized diesel when idling.
Im at a loss. I have a mb 2 icarsoft scan tool but its not very helpful.
01-16-2021, 04:07 PM
