4.4 4.8 Timing Chain Guide

[x5Alpine]

I honestly have yet to see an 03 M62 with the updated TC tensioner fail. I have an 02 4.6is and the TC guides went at 106k, but everything was replaced and im at 129k as of now.

[Rockit]

Originally Posted by Roadkill

2 different interpretations of what was written. That's all. The point of the thread is change your tensioner if you think it will help no matter what V8 motor you use.

That is correct!!! I would change it, all V-8's. Just trying to help if you don't agree just click on to the next post.

I was doing a search on the subject on this board..4.4-4.6-4.8's were all effected...the years I posted was approx....

This tensioner only effects the lower chain and the guides. The upper tensioners in the head/cams are fine.

[dpbayly]

I just thought I'd share my experience with start up rattle.

After picking up my motor last April I noticed when it had been stood for a few days upon start up it would rattle for a split second but only after when it was shut down last at full running temp for example if I start it up from cold move it around the drive the shut it off while still cold then leave it standing even a week later it wouldn't rattle on start up but it would rattle if I'd shut it off after a 40 mile drive then leave it 2 days, so after looking into it I had stumbled on to the threads about changing the tensioner, so went ahead and changed and there was no change still made the noise.

Another thing to note is my motor had a service about 3k before I bought it and by now it was about 7.5k and I had noticed the noise becoming more frequent so decided to carry out an oil change and while I was at it I dropped the inspection panel in the sump and it was as clean as a whistle, it had previously had 5w40 oil used so thats what I used again and this made it go back to making the noise less often.

So I went on the search again and stumbled across this Wiki post talking about the M62 start up rattle on the BMW and Land Rover that use the engine and how it was known and regarded as acceptable by the main dealers and that the rattle comes from the Vanos unit and not the chain and sure enough when I had a friend start my car from cold I listerned and the noise was coming from the right head at at the front where one of the the Vanos units is situated.

Check it out:

M62 Startup Rattle - fullfatrr.com Wiki

After reading this I decided to swap out my oil from 5w40 to a good quality Fuchs GT1 5w30 so the oil is thinner at higher temps so when I shut it off after a long run the oil was thinner than before with the 5w40 and guess what I've had no rattle for 2 months.

So before writing off your guides or tensioner start with the basics check what oil your garage is putting in your motor and make sure its a good quality

[TiAgX5]

Not always the case. M62 4.4 with OE guides at over 175k miles here. I have the parts/tools for replacement ready to go in the garage. If they make it to 200k, I'm planning a total engine/heads/trans rebuild, the body/chassis/electricals/interior have worn like iron and look 1/10th their age.

[bobzdar]

Originally Posted by tmv

Haven't seen the TC Tensioner problem on N62 engine, not yet.
Fail TC Tensioner on M62TU -> fail TC Guide -> damaged engine.

If you catch it before it jumps timing, there's no damage. I had the guides fail on my e38 (m62tub44) at 214k miles but I heard it before they failed completely and the engine still ran fine, so no damage.

The heat is what kills them, and with the aging cooling systems what happens is the engines get very hot when a hose or similar blows (and this happens to all of them as we know), then the guides get damaged by the heat and fail shortly after. In my case, a heater hose went and the engine got hot. I replaced the hose and all was well, but less than a week later I started the car up and it sounded like a diesel at idle. I dropped the pan and sure enough chunks of plastic fell out. I bought the guides from the bmw dealer and replaced them that weekend, the PS guide was shot, DS guide broke into two pieces when I took it out and the center guide had the ends broken off. However, no damage to the engine as it didn't jump timing. I also did not need to re-time the cams as I zip tied the chain to the sprockets so it would not lose timing while I replaced the guides.

[AquilaBMW]

Hello Chaps -

So... the good ole Timing Chain Guides - the bane of existence to the M62TU engine.....

I have been around these engines for a few years now and have owned a few cars with this engine - both good and bad engines. Hopefully, it gives me a little bit of credibility on this issue.

The Timing Chain Guides on the M62TU engine and even the M62 (Non-VANOS) engine WILL FAIL at some point. It's inevitable. Past 100K is usually where owners have to start thinking about that repair job.

While replacing the Lower Timing Chain Tensioner is a prudent move, it only prolongs the life of the chain guides - if you are lucky to catch it before they start to deteriorate. It will however NOT prevent the eventual failure.

There are other corresponding things that contribute to this like the type of oil you use in the car and of course general maintenance.

The Tensioners come with a preload spring in them (This was revised at a later date) which is designed to pre-prime the tensioner at start up. This basically pushes the timing chains "off" the guides and once the car starts, the tensioner then operates using fluid pressure from the oil circulating in the engine.

As some posters have already pointed out - there are two types of start up rattles. The most commonly identified one are the chains literally slapping against the guides due to a failed or poor tensioner. This can be alleviated by replacing the tensioner. At the end of the day, replacing a $62 dollar part as insurance for your engine is worth it.

The second rattle is the VANOS rattle. This usually signals the start of the failure of your VANOS seals. Eventually, this rattle will turn into a constant rattling / dull clunking sound from the engine once warmed up. These days, you can get the Besian VANOS kit to replace your seals or replace the VANOS units at about $500 a piece + labor. The VANOS rattle will not kill your M62TU - it is just quite annoying to pull up to a light and sound like a diesel. Maybe just add a "D" to the car's model tag on the back and tell people it's a diesel

The issue with the timing guides is they are plastic - hard plastic, but plastic nonetheless. These will eventually failure through a number of reasons as mentioned in Bobzdar's post. However, it's not just heat cycles - it's plastic - it doesn't last forever. The chains are also metal and they DO rest against the guides (that's why they are called guides) and eventually the actually wear a groove into the guides which will eventually cause them to get slack and start slapping against the guides and then - BOOM! Eventual failure.

However, as importantly pointed out by Bob - they do tell you before they go. You will hear them rattle or start slapping around prior to catastrophic failure. I have never heard of any case where they JUST failed out of the blue. So, keep an ear out for that dreadful noise and if it does happen - stop driving the car and get it fixed.

I am happy to tell you that the M62TU engines themselves are quite sturdy and robust engines. If you intend to keep your car for a while it is worth the effort and cost to fix the guides and enjoy another 100K or more miles of driving pleasure. A dealer once reported a case where a lady brought in a 740i M-Sport with 198K miles when the guides failed. They fixed the guides for the owner and during the job, they took a peek at the short block and noticed barely any scarring on the cylinder walls - AT 198K MILES!

As far as your VANOS, I think they belief in the past was to use thicker oil or engine snake or voodoo oils to alleviate this - wrong! The issue with VANOS was a lack of oil around the seals and units at start up and during running. As we know, thick oil does not flow as well as thinner oil. THe better solution was to use lighter weight oil - and synthetic. Owners have had great success with oils like Mobil 1 Synthetic 0W/40 or 5W/40 or 30 oils. They leave a coating on the moving parts at shut down and flow tons faster at start up to help protect your moving bits and the VANOS units.

Eventually those seals do fail though and if you can't stand the noise, then you can acquire the Besian kits for a fix.

Cheers,

Michael

[StephenVA]

Thanks for the insight as it coresponds to what I call "Good Practices" of vehicle maintenance. Replace and repair as required before total failure occures. Always cheaper than the alternative results. (ask me how I know...did wheel bearings once on another vehicle, after I egnored the squeeks, creaks, and noise. Welded bearing races on the spindles, trashed the rotors due to heat warping, had to replace the spindle, brearings, rotors, brakes, ball joints, tie rod ends, etc. Out in a driveway while it was snowing. What fun that was. Lesson learned the hard way.)

Keep up the great posts as it help us all to do preventive repairs to avoid the death rattles.

[TiAgX5]

Originally Posted by AquilaBMW

.....The Tensioners come with a preload spring in them (This was revised at a later date) which is designed to pre-prime the tensioner at start up.....

When exactly was the revision of the tenisioners? Having one of the last '03 MY M62s with over 175k on OE guides, I wonder if the revision could have been sometime during the '03 MY production run.

[x5Alpine]

I have the same question.. I've yet to see an 03+ have chain guide failure.

[e30cabrio]

I ordered the tensioner today and will replace it.