Hi guys.
My Toyota 4Runner 1988 first gen 22RE has 140000 miles on the clock, it was used but well maintained by the PO. I have the maintenance history, but I don't see anything about the timing chain or chain dampers (guides) replacement.
The FSM, in the EM-48 section: Engine mechanical - Timing Chain - Inspection of components, says the check those parts need, but the FSM doesn't say anything about when it's the recommended moment to replace them.
So my question's when I should do that. When is the recommend moment to check/replace the timing chain or chain dampers. Suggestions please.
Thanks!

 

i'm not sure there's a definitive answer. on the one hand, good maintenance history would extend the expected life of those parts. there are numerous examples of original timing chains and guides delivering 350,000 miles of service. on the other hand, 30 years is a long service life for the factory plastic chain guides. they might be brittle, or they might give you many years of service.


there are a lot of proponents for switching to metal guides. i'm not one of those; the oem plastic guides deliver excellent service in miles and years with good vehicle maintenance. no need to alter that. i'd be surprised if most earlier guide failures were not due to poor upkeep or non-existent care, ie, not regularly changing oil, filter, overheating from lack/loss of coolant, etc.

 

I think there are really 2 wear items, the guides and the tensioner. Obviously if the guides break, the chain can slap around in there and eventually will wear a hole in the cover. If you pull your valve cover at every oil change and look down there with a bright flashlight and see that your guides are intact then you can just keep doing that every 3000 miles and stretch things out. As for your tensioner, I would assume that if your truck is running well, then the tension is ok. My truck developed a rattle, so I knew it was time for a new tchain, probably around 160 or 170k miles I can't remember. I did have grooves in the cover, but they did not wear a hole (although I found it had a big crack in it so I had to buy a new one). This question is one for debate, you'll probably get responses from people who got 200k out of their original tchain, and many people with less. There is a bit of a piece of mind, knowing a fresh tchain, guides, tensioner are in there, it's pretty cheap if you do the work yourself, but it's a fair amount of work.

Edit: Wally has great points about the service life. Probably a lot of us on this forum sort of lump maintenance items together, such as, oh I have some oil leaks, so might as well do the tchain and guides while I'm in there sealing up the cover and chaining the front main seal...so people on here might lean more toward early replacement, I seem to follow that trend myself.

 

I would definitely pop the valve cover off and take a look. My guide cracked at 120,000 miles and the truck was very well maintained.

I have used metal guides in the past, but I went with an OSK kit with plastic guides last time. I think I will stick with OSK kits for any future 22RE timing chain jobs. The components are Japanese and of high quality.

My reasoning for using OSK plastic guide kits in the future is that the chain and the tensioner wear out regardless of whether or not the guide is metal backed or plastic. The plastic guides should last 100,000 miles and by then it is probably time to replace the other components anyway. The OSK kit is only $64 on amazon and includes everything you need.

 

how old were the components when they failed? ie, when did you hit 120K miles? 1990? 2000? 2010? it matters relative to what i stated, ie, for failures in the first 10 to 15 years after the date of manufacture, i wouldn't be surprised to find that most of the failed guides were directly related to poor maintenance. in the same way, getting 400,000 miles is possible, but only if that happened during the first 10 to 20 years. much less likely to happen as the vehicle ages, even with excellent routine maintenance. they are wear parts, and should eventually be replaced. how you feel about the when is up to each owner.

 

My truck is a '94. I noticed my guides were broken in 2003 or 2004.

 

That's good to know, thank you for your answers.
My 22RE's running very good at the moment. If it's not broken don't fix it, but the timing chain's the only thing that worries me because we plan to do a 3500 miles summer trip (plus 2000 miles in a ferry) with our 30 years old 4Runner, so in this case the preventive replacement'll give me peace of mind, I guess.
Dilemma.

 

Until I read this comment I would have said wait until you are servicing it for some other reason like the water pump or radiator when you would have to remove a bunch of stuff for access anyway.
But since you planning on a road trip far from home, I would address the timing chain while you have the time, along with any other common failure issues for 140k miles...alternator brushes, starter brushes, h20 pump, thermostat, tires, brake inspection, etc.