[byebyev8]

Would Replacing to old timing chain tension the updated one prevent the timing chain problems on the pre 14s before they start?

[Billfitz]

I've got to figure there's a reason why they changed it.

[sspade]

If I were going that deep... I would DEFINITELY change the guides as well and most likely the chain too.

[rjd_F30]

Probably, but as long as you catch it before your engine grenades, you're better off waiting until it's necessary and upgrading to new ones at that point. The issue is still fairly rare, and it's not too terribly likely you'll be affected.

[Billfitz]

Originally Posted by sspade

If I were going that deep... I would DEFINITELY change the guides as well and most likely the chain too.

The tensioner is a fairly easy swap out that doesn't involve delving into the innards of the engine.

[sspade]

Interesting...

Appreciate the heads up.

I say this loosely but "usually" the tensioner is located behind the timing cover. This is my first German car and all of my prior experience is with GM/Cadillac products, specifically the 3.6L global V6 that is also known to have chains stretch/guides break. Luckily, that engine is non interference so catastrophic damage is unlikely to occur (unlike the N20/N26).

Considering the tensioners on our vehicles is easily replaced and cheap (~$60)... do you think it is a good preventative measure for those of us driving vehicles with the "older components" that are more prone to failure?

[Billfitz]

I've seen it recommended on other sites.

[rjd_F30]

Is it something that can be done in the garage? I was under the impression a timing chain (tensioners too) job was a fairly involved process.

[Billfitz]

Replacing just the tensioner is a fairly easy job.
https://www.newtis.info/tisv2/a/en/f...shaft/HtiBPV3K

[rjd_F30]

Originally Posted by Billfitz

Replacing just the tensioner is a fairly easy job.
https://www.newtis.info/tisv2/a/en/f...shaft/HtiBPV3K

Pardon my novelty, but I'm not sure what I'm looking at there. Aren't we talking about the chain and tensioners that are run along the backside of the engine, up against the firewall? Is that what's pictured in that link? If it is mind explaining a bit?

[BunkerJ]

The issue isn't so much of a tensioner issuer as it is the guide itself. The guide is made of a faulty material that degrades much quicker than expected. I'm at 89k with no issues on my 2013. Biggest solution to this is coding out auto stop/start.

[BunkerJ]

Have fun with that install haha. Definitely doable but would take a day or two depending on experience: https://www.newtis.info/tisv2/a/en/f...shaft/HipcnQuO

[Billfitz]

Originally Posted by BunkerJ

The guide is made of a faulty material that degrades much quicker than expected.

Maybe, maybe not. Which broke first, the chain or the guide? The characteristic whine that presages the failure of the chain indicates that it's likely the chain that breaks first, taking the guide out when it does. What's in question in this thread is whether a bad chain tensioner might be the cause of the chain failure, and whether changing the tensioner might prevent that. If BMW knows they're not saying, but they did change the tensioner, didn't they?

[BunkerJ]

Originally Posted by Billfitz

Maybe, maybe not. Which broke first, the chain or the guide? The characteristic whine that presages the failure of the chain indicates that it's likely the chain that breaks first, taking the guide out when it does. What's in question in this thread is whether a bad chain tensioner might be the cause of the chain failure, and whether changing the tensioner might prevent that. If BMW knows they're not saying, but they did change the tensioner, didn't they?

They've gone through like five variants of all those parts apparently. According to BMWs statement on it and reports of those with bricked engines, it appears to be the plastic guide wearing down too quickly leading to slack and eventually skipping a tooth. A lot of those engines see completely cracked guides or pieces broken off that caused it to skip. They did update the tensioner as well, but the root cause as far as I understand was the guide primarily. By keeping AS/S turned off, you're reducing the number of times the car rubs the chain across the guide without oil/fresh oil and prolonging the guide. I check mine every 1k or so for a whine and to check the slack. I've also been told that in most cases you can hear the whine well in advance to it breaking. I'm personally going to just keep checking until my CPO is up in 11k. To replace the entire guide/chain/tensioner is either a costly fix with a shop or a longer one with you doing it at home.

[rjd_F30]

Originally Posted by BunkerJ

Have fun with that install haha. Definitely doable but would take a day or two depending on experience: https://www.newtis.info/tisv2/a/en/f...shaft/HipcnQuO

That guide is more like what I was expecting to see. And it looks like it's way more difficult than what my mechanical inclination would allow me to do.

Originally Posted by BunkerJ

They've gone through like five variants of all those parts apparently. According to BMWs statement on it and reports of those with bricked engines, it appears to be the plastic guide wearing down too quickly leading to slack and eventually skipping a tooth. A lot of those engines see completely cracked guides or pieces broken off that caused it to skip. They did update the tensioner as well, but the root cause as far as I understand was the guide primarily. By keeping AS/S turned off, you're reducing the number of times the car rubs the chain across the guide without oil/fresh oil and prolonging the guide. I check mine every 1k or so for a whine and to check the slack. I've also been told that in most cases you can hear the whine well in advance to it breaking. I'm personally going to just keep checking until my CPO is up in 11k. To replace the entire guide/chain/tensioner is either a costly fix with a shop or a longer one with you doing it at home.

I understand the opening the oil cap and checking the chain for slack, but how do you check specifically for whine? Isn't that something you'd just hear under normal conditions? Or do you do an open hood, specific RPM sort of deal.

[rjd_F30]

Originally Posted by Billfitz

Maybe, maybe not. Which broke first, the chain or the guide? The characteristic whine that presages the failure of the chain indicates that it's likely the chain that breaks first, taking the guide out when it does. What's in question in this thread is whether a bad chain tensioner might be the cause of the chain failure, and whether changing the tensioner might prevent that. If BMW knows they're not saying, but they did change the tensioner, didn't they?

Like you alluded to, it sort of seems like a chicken or the egg sort of debate. If the chain breaks the guide while it itself is breaking, then it's effectively impossible to tell which part really failed. That being said, it makes more sense to me that the guide is the more likely part to fail, as is the case with other automakers with similar problems. Audi had/s a similar but more prevalent problem with the timing chain systems on the 4.2L engines, and in those cases, it's always the guide that breaks. The guides are essentially a regular 75k mile maintenance item on those engines, while on our cars it's not a guaranteed failure. I know its apples to oranges, bringing in the Audi issue, but I thought it was relevant.

[sspade]

On the reverse side of the coin, the guides rarely break on the GM 3.6L I spoke of above. The chains literally stretch and jump timing. This motor is in just about all GM vehicles and product lines currently, no exaggeration. They have also "corrected the issue" like BMW on newer models. Luckily, the valves do not smash into the piston and destroy the engine (non interference).

The photo below is a Cadillac CTS.

[BunkerJ]

Originally Posted by rjdnyy224

Like you alluded to, it sort of seems like a chicken or the egg sort of debate. If the chain breaks the guide while it itself is breaking, then it's effectively impossible to tell which part really failed. That being said, it makes more sense to me that the guide is the more likely part to fail, as is the case with other automakers with similar problems. Audi had/s a similar but more prevalent problem with the timing chain systems on the 4.2L engines, and in those cases, it's always the guide that breaks. The guides are essentially a regular 75k mile maintenance item on those engines, while on our cars it's not a guaranteed failure. I know its apples to oranges, bringing in the Audi issue, but I thought it was relevant.

Good BMW Tech blog that showed a guide snapped: https://bmwtechnician.com/2016/08/07...g-chain-issue/

Article regarding the lawsuit against BMW that mentions the material used: https://www.carcomplaints.com/news/2...g-chains.shtml

It's also evident based on a design AND material change in the most up to date timing chain guide. It sounds like multiple issues in the system and the AS/S is a huge catalyst for it.

[Gen13 F36]

Originally Posted by BunkerJ

The issue is so much of a tensioner issuer as it is the guide itself. The guide is made of a faulty material that degrades much quicker than expected. I'm at 89k with no issues on my 2013. Biggest solution to this is coding out auto stop/start.

Nice 89k miles already.....not bad....I will be keeping mine around 150k - 200k or longer of the interior and exterior is not bang up or look old or outdated....if you know what I mean😁

[sspade]

Originally Posted by Gen13 F36

Nice 89k miles already.....not bad....I will be keeping mine around 150k - 200k or longer of the interior and exterior is not bang up or look old or outdated....if you know what I mean��

Im with you on that. Im definitely keeping this car as long as possible. Part of the reason Im so interested in learning about this platform. Unless I win the lottery of course.

I owe about $5k more this car than its worth. Im not ashamed to admit it, consider myself a realist even if it hurts a little

Ive taken a bath on a car before. Not worth it unless you are truly loaded. Pick a car and enjoy the shit out of it.

Like you said, as long as the body is ultra clean and you've taken care of the interior... should still be a sweet ride for years to come.

[rjd_F30]

Originally Posted by sspade

Im with you on that. Im definitely keeping this car as long as possible. Part of the reason Im so interested in learning about this platform. Unless I win the lottery of course.

I owe about $5k more this car than its worth. Im not ashamed to admit it, consider myself a realist even if it hurts a little

Ive taken a bath on a car before. Not worth it unless you are truly loaded. Pick a car and enjoy the shit out of it.

Like you said, as long as the body is ultra clean and you've taken care of the interior... should still be a sweet ride for years to come.

You're guys' outlooks have me wondering what the highest mileage N20 out there is. There's gotta be some with 200k right? I'd love to hear that person's experience thus far. I'm hoping not to cross 100k in my 328i (at 68k now; 3 mile commute to work and she only comes out once a week during the school year so I think it's doable), only because I'm hoping a 335i will be in my garage in the next 3 years.

[Gen13 F36]

Originally Posted by rjdnyy224

You're guys' outlooks have me wondering what the highest mileage N20 out there is. There's gotta be some with 200k right? I'd love to hear that person's experience thus far. I'm hoping not to cross 100k in my 328i (at 68k now; 3 mile commute to work and she only comes out once a week during the school year so I think it's doable), only because I'm hoping a 335i will be in my garage in the next 3 years.

We have BunkerJ....he is going to hit that 100k soon and his car is modded...so its taking punishment.😁