1992 400E - Timing Chain Issue - Broken Guide & Skipped Teeth

[Utah400E]

Just Joining the group! I had joined the W124 group on Facebook and everybody pointed me this direction.. I picked up a 1992 400E that I randomly found sitting next to a shop on a farm property here in Utah. Very random find, was actually at a kids b-day party with my 5yo... I will preface this with I have a couple of classics I regularly work on - one British, and one American, but no real experience with the this series of Mercedes, or this complicated of an engine.. I knew of the 400E and 500E and always thought they were amazing cars, so i couldn't pass on this crap shoot of a car for the $1.5k asking price.

The car hadn't run for approximately 7-8 years. The PO indicated it was a project car for him and is son, and they never found time to get it moving, but he thought it was a fuel issue. The tank was full of tons of sediment/rust which was the first thing I addressed - went through the entire fuel system, changed the oil, didn't see anything super concerning other than old dirty oil.. The car started on about the forth crank! It did idle a bit rough, but wasn't shocked given the amount of time it was sitting. I let the engine warm up a bit, checked the tranny fluid, and took the car for a spin around the neighborhood. I ran the car a couple of times that day just to get things moving again - on my third trip out around the neighborhood the car died very abruptly and refused to restart. Not only did it refuse to restart, but it was spitting and sputtering like something was significantly off. I towed the car home and threw a post on the FB W124 forum with a concern over possible timing chain issue. Most responded that there was almost no way it was a timing chain issue, and to instead focus on the ignition. Since I already had all the ignition parts on hand i went ahead and replaced plugs, wires, rotors, caps, insulators etc. Went to give it a go again, and absolutely no change, spit, sputtered and stumbled. I could also hear a bit of taping out of the passenger side valve cover....

At this point, i pulled the passenger valve cover - i found the snap on portion of the upper chain guide was indeed missing, pieces all over in the timing chain housing, and a few pieces visible between the chain and sprocket.. I pulled the plugs again and stuck a borescope in each cylinder and checked the tops of the pistons for scoring and didn't see anything obvious. I have read several posts on this forum and reviewed the process of a full chain removal and replacement, which looks to be a job that *may* be outside my ability...

My questions after this very long post:

1. I am concerned with the obvious debris between chain and sprocket that the timing may be significantly off, especially with it not even attempting to fire with verified fuel and spark.
2. Given that i cannot get even a sign of it attempting to fire, I am assuming the chain has jumped at least a tooth if not multiple, especially given the debris i have found between the chain and sprocket that is jammed in tight, and obviously lifting the chain.. Can i safely rotate the engine and attempt to remove all debris possible and then move on to removing the other valve cover/ pin cams and check timing as i have seen in other DIY guides and videos?
3. The chain itself looks to be in good shape, at least the portion that is visible. If one or more cam's are out on timing, is it possible to re-time cam's without removing all sprockets and cam timing advance mechanisms? I have seen a couple of videos where they removed the cams in tact with the exception of one where they removed the sprocket. Looks like a relatively straight forward process.
4. Maybe a dumb question, but if it is a single cam that is off on timing, is it possible to pull the chain tensioner and get enough slack to re time that cam?
5. It seems like everyone recommends just removing the cam's and replacing all of the upper chain guides - looks a bit daunting/outside my comfort zone, but i may be crazy?
6. Final question, and very subjective - I paid $1.5k for the car, it needs this issue address, full exhaust, tires, brakes, suspension work, a bit of body work and a re-spray, and a bit of interior work.. Is it worth it?? I have grown attached to the car.. It's not a necessity that I need to keep the car, I just hate to see it end up in the scrap yard... Other than the transmission possibly needing a re-fresh (it was shifting fine after the second run around the neighborhood following a fluid top off), I can do the balance of the work myself, including the exhaust, suspension, and paint/body work..

I know this is a long one, but any input on whether it is worth the hassle, and if so, any insight on best approach to move forward on the timing chain/guide rail issue given what I am seeing?

I have attached a couple of photos for reference - overall photos of head, and a close up of cam sprocket, as well as photo of debris that i have pulled out so far..

I appreciate any input on this and hope i have done my due diligence in reviewing similar posts..

Thank you,
Patrick

 

[R129 UK]

Welcome, I'm sure there will be far more knowledgeable individuals along soon to offer their advice but here are my thoughts:

Unlikely to be a chain issue, you can check the timing by rotating the engine with a 27mm socket on the crankshaft - you should be able to easily find the required resources on this site to be able to check this.

More likely it is something like a crankshaft position sensor issue which could cause a no start from an engine starting point.

Basically, start with the basics, spark, fuel and timing which are the fundamentals and I'm sure from your post you are well aware of this.

Check for a spark

Check fuel pressure (and fuel quality)

Check timing

Oh, definitely worth the hassle!!!


Good luck!!!

 

[Utah400E]

Welcome, I'm sure there will be far more knowledgeable individuals along soon to offer their advice but here are my thoughts:

Unlikely to be a chain issue, you can check the timing by rotating the engine with a 27mm socket on the crankshaft - you should be able to easily find the required resources on this site to be able to check this.

More likely it is something like a crankshaft position sensor issue which could cause a no start from an engine starting point.

Basically, start with the basics, spark, fuel and timing which are the fundamentals and I'm sure from your post you are well aware of this.

Check for a spark

Check fuel pressure (and fuel quality)

Check timing

Oh, definitely worth the hassle!!!


Good luck!!!

Hi R129 UK - appreciate the response! I pulled the tank, dumped all the sediment, replaced - had to soak it in muriatic acid/water mix for a few days to get it clean, replaced a couple of rotted fuel lines, new Bosch pumps, filter, pressure regulator, etc. fuel pressure at rail is right around 64 psi. Also replaced most ignition components. Checked again last night that I had spark and fuel, both good. No blink codes etc. chain was slapping valve cover towards the end of trying to get the thing to fire, lots of debris between chain and guides.. I am almost 100% that it skipped a tooth or two and the timing is too far off for it to fire.. No matter what I am sure I need to replace the rails on both sides, clean out as much debris as possible and drop the pan to do same..

Just not sure the best approach and how far to go...

Thanks again!

 

[R129 UK]

Post in thread 'M119 crank pulley out of time ?'

Aug 14, 2024

my M119 is faulty, I want to eliminate the possibility that it is a problem with the timing chain, how do I know if it has skipped a tooth or has broken rails ?

• E420 97 W210

• 

 

[R129 UK]

How many miles has the engine covered?

Mine has 124K and the chain is AFAIK the original and has not worn to any measurable degree.

If it had skipped a tooth, what you did since owning it is unlikely to have caused this so the issue is "new".

 

[gsxr]

Congrats on the new 400E, Patrick!

I am concerned with the obvious debris between chain and sprocket that the timing may be significantly off, especially with it not even attempting to fire with verified fuel and spark.

Yeah, best to remove all the plastic rail debris before proceeding. Use a flashlight to look below the intake cam sprocket, some stuff hides down there.

Given that i cannot get even a sign of it attempting to fire, I am assuming the chain has jumped at least a tooth if not multiple, especially given the debris i have found between the chain and sprocket that is jammed in tight, and obviously lifting the chain.. Can i safely rotate the engine and attempt to remove all debris possible and then move on to removing the other valve cover/ pin cams and check timing as i have seen in other DIY guides and videos?

Start by rotating the engine by hand. Assuming it turns freely and never "locks", pin 1 camshaft at a time and read the timing at the balancer. See post #4 at the thread @R129 UK linked above for details.

The chain itself looks to be in good shape, at least the portion that is visible. If one or more cam's are out on timing, is it possible to re-time cam's without removing all sprockets and cam timing advance mechanisms? I have seen a couple of videos where they removed the cams in tact with the exception of one where they removed the sprocket. Looks like a relatively straight forward process.

You can re-time everything WITHOUT removing the camshafts from the head.

Maybe a dumb question, but if it is a single cam that is off on timing, is it possible to pull the chain tensioner and get enough slack to re time that cam?

Depends on the camshaft. From memory, only the passenger side exhaust cam can easily be re-timed. I forget if there's enough slack to allow the intake cams to rotate.

It seems like everyone recommends just removing the cam's and replacing all of the upper chain guides - looks a bit daunting/outside my comfort zone, but i may be crazy?

No need to remove the cams, but YES you should replace all the upper chain guides. They are not expensive, but it's a slow, tedious job. Make sure to use the correct anaerobic sealant on the front head cover and intake cam solenoids (NEVER use RTV on these, they'll be almost impossible to remove again.) As mentioned previously, the chain itself is almost certainly fine and should NOT need replacement. Ditto for the tensioner. Main thing is replacing the guide rails. You may also need to replace all the PCV hoses on the intake manifold too, they are likely fossilized... only buy OE/Genuine, despite the painful cost (~$200 for all of them). Buy from discount dealers online like MB of Covington, Laredo, or Annapolis.

Final question, and very subjective - I paid $1.5k for the car, it needs this issue address, full exhaust, tires, brakes, suspension work, a bit of body work and a re-spray, and a bit of interior work.. Is it worth it?? I have grown attached to the car.. It's not a necessity that I need to keep the car, I just hate to see it end up in the scrap yard... Other than the transmission possibly needing a re-fresh (it was shifting fine after the second run around the neighborhood following a fluid top off), I can do the balance of the work myself, including the exhaust, suspension, and paint/body work..

It may not be worth a full restoration (depends on miles/rust/colors/options) but you should definitely be able to get it back on the road with minimal investment. Get it running properly first, then decide how much you want to invest in cosmetics. If you've never owned one of these, you may find that you REALLY like them. We have been driving 400E/E420's as daily drivers for 15+ years now. Best bang for the buck in the 124 chassis.


BTW - welcome to the forum!

 

[Utah400E]

The car has done 176k miles. It sat for a solid 7-8 years baking in 90+ deg heat for seven summers. My guess is that the heads, chains and guides were dry as a bone, I got the car moving again guessing the upper guides were brittle as heck, passenger side broke, wedged in between chain and sprocket and made it skip a tooth or two. I am going to try and pull the other valve cover off this week and see if I can check the cam timing per the guide above and others i have seen.

 

[Utah400E]

Congrats on the new 400E, Patrick!



Yeah, best to remove all the plastic rail debris before proceeding. Use a flashlight to look below the intake cam sprocket, some stuff hides down there.




Start by rotating the engine by hand. Assuming it turns freely and never "locks", pin 1 camshaft at a time and read the timing at the balancer. See post #5 at the thread @R129 UK linked above for details.




You can re-time everything WITHOUT removing the camshafts from the head.




Depends on the camshaft. From memory, only the passenger side exhaust cam can easily be re-timed. I forget if there's enough slack to allow the intake cams to rotate.




No need to remove the cams, but YES you should replace all the upper chain guides. They are not expensive, but it's a slow, tedious job. Make sure to use the correct anaerobic sealant on the front head cover and intake cam solenoids (NEVER use RTV on these, they'll be almost impossible to remove again.) As mentioned previously, the chain itself is almost certainly fine and should NOT need replacement. Ditto for the tensioner. Main thing is replacing the guide rails. You may also need to replace all the PCV hoses on the intake manifold too, they are likely fossilized... only buy OE/Genuine, despite the painful cost (~$200 for all of them). Buy from discount dealers online like MB of Covington, Laredo, or Annapolis.




It may not be worth a full restoration (depends on miles/rust/colors/options) but you should definitely be able to get it back on the road with minimal investment. Get it running properly first, then decide how much you want to invest in cosmetics. If you've never owned one of these, you may find that you REALLY like them. We have been driving 400E/E420's as daily drivers for 15+ years now. Best bang for the buck in the 124 chassis.


BTW - welcome to the forum!

gsxr - thank you for the detailed response! I will get moving on this in the next few days. cleaning out debris the best I can and then move forward with checking timing. To re-time the cam's it looks like I would need to R&R the sprockets - also looks like there is a special tool for this that is NLA?

 

[gsxr]

gsxr - thank you for the detailed response! I will get moving on this in the next few days. cleaning out debris the best I can and then move forward with checking timing. To re-time the cam's it looks like I would need to R&R the sprockets - also looks like there is a special tool for this that is NLA?

If only re-timing (not replacing the chain rails) this can be done without disassembling the intake cam advance mechanism.

However, to replace the 2 chain rails on the inside, below each intake cam sprocket... you either need to remove the intake cam+sprocket complete, OR leave the camshaft in place and disassemble the intake cam advance mechanism. The special tool for assembly (111-589-01-40-00) is still available, but isn't strictly necessary - but it will make the job much easier.

What tool are you referring to that may be NLA?

 

[Utah400E]

If only re-timing (not replacing the chain rails) this can be done without disassembling the intake cam advance mechanism.

However, to replace the 2 chain rails on the inside, below each intake cam sprocket... you either need to remove the intake cam+sprocket complete, OR leave the camshaft in place and disassemble the intake cam advance mechanism. The special tool for assembly (111-589-01-40-00) is still available, but isn't strictly necessary - but it will make the job much easier.

What tool are you referring to that may be NLA?

That was the one - 111-589-01-40-00! I would rather just remove the cam+sprocket complete, would feel much better simply removing and reassembling with the cam assembly complete. I'm working on getting an order together for the guides, just thinking it would make the most sense to do all of the (4) uppers on both sides for good measure? Looks to be tedious for sure, and a bit nerve wracking, but I think for a couple of hundred dollars it's worth a go. It looks like three is also a pin removal tool, is that worth purchasing?

And thank you so much for the assist and taking the time to give me your advice - it is much appreciated. I really don't want to give up on this car. It was an absolute blast to drive, even for the 20 minutes I had it running. I am by no means a mechanic, I am great with engine basics, full suspensions etc, but I won't deny a bit of fear when I pulled the valve cover off and considered this next step --

 

[gsxr]

That was the one - 111-589-01-40-00! I would rather just remove the cam+sprocket complete, would feel much better simply removing and reassembling with the cam assembly complete. I'm working on getting an order together for the guides, just thinking it would make the most sense to do all of the (4) uppers on both sides for good measure? Looks to be tedious for sure, and a bit nerve wracking, but I think for a couple of hundred dollars it's worth a go.

Click here and read that whole thread... make sure to look at the diagram attached at the bottom of post #3. Oh, also shell out for the OE/Genuine valve cover gaskets, don't use aftermarket. You can use the aftermarket copper washers on the bolts though.

Top vendors for aftermarket parts are FCP Euro, RM European, and AutohausAZ. Each can have slightly different offerings so you usually need to get the part numbers from the EPC, then search at each website. Avoid the junk brands discussed in this thread... they are false economy.

It looks like three is also a pin removal tool, is that worth purchasing?

You need a pin removal tool of some sort, either the slide hammer type, or the "threaded" type. I use the threaded design, there isn't much space for a slide hammer with the engine in the car.

And thank you so much for the assist and taking the time to give me your advice - it is much appreciated. I really don't want to give up on this car. It was an absolute blast to drive, even for the 20 minutes I had it running. I am by no means a mechanic, I am great with engine basics, full suspensions etc, but I won't deny a bit of fear when I pulled the valve cover off and considered this next step --

This engine isn't quite as complicated as it first seems, but you MUST use the factory service manual (FSM) and follow directions carefully. These cars, and engines, don't tolerate "winging it" like most domestic vehicles. If you don't already have a link to the FSM, click here.

 

[gerryvz]

Please check this thread, as there is a wealth of information in it (the first 10 pages or so) about removing the front cylinder head covers, replacing the timing chain guides, upper guides, timing chain tensioner, timing the cams (including when one cam slipped and had to be re-timed), and disassembling the intake cam adjusters (if you go that route). None of this is difficult work, just something you have to take your time to do.

Everything is well laid out with text, and illustrated with photographs.

If you don't have it already, you can also access the service manuals here, for the proper procedures.

With that level of mileage, you should also check your front crankshaft seal for any leakage/weepage, as well as checking your power steering pump and hoses for leakage/weepage (or tandem pump, if the car has ASR).

Please start an "OWNER" thread in the appropriate sub-forum, and I know any documentation of what you find, and what you do, will be very helpful and of interest to many people here.

 

[gerryvz]

Some shortcuts:

• Removing front timing cover: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Removing timing chain tensioner and top timing chain rails: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Pinning the cams: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• More on pinning the cams: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Removing timing chain tensioner (again) and cam sprockets: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Removing & disassembling intake came adjuster & replacing timing chain rails in cylinder head: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Intake cam adjuster assembly/installation tool: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Assembling and installing intake cam adjuster w/tool: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Passenger-side cam work: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Replacing driver's side timing chain rails in cylinder head: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Final sprocket install, lining things up, and top guide install: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Installing new foam under headlight buckets (this is for @Jlaa, because his car has been crying out for new foam here for many years): RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Re-installing front cylinder head covers, and rotating engine to ensure no interference: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Installing passenger side front cylinder head cover: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals

 

[Utah400E]

Some shortcuts:

• Removing front timing cover: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Removing timing chain tensioner and top timing chain rails: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Pinning the cams: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• More on pinning the cams: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Removing timing chain tensioner (again) and cam sprockets: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Removing & disassembling intake came adjuster & replacing timing chain rails in cylinder head: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Intake cam adjuster assembly/installation tool: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Assembling and installing intake cam adjuster w/tool: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Passenger-side cam work: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Replacing driver's side timing chain rails in cylinder head: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Final sprocket install, lining things up, and top guide install: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Installing new foam under headlight buckets (this is for @Jlaa, because his car has been crying out for new foam here for many years): RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Re-installing front cylinder head covers, and rotating engine to ensure no interference: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals
• Installing passenger side front cylinder head cover: RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals

Thank you very much for the shortcuts! I will start an owners thread as recommended, and will document what I find for others. I am still working on an order for various parts and pieces, so hope to get started on this in the next week or so.

Thanks again for the support.