I have gone through the maintenance recommendations in my Toyota 2011 rav4 manual and it never mentions replacing the timing chain. The closest thing is that it tells me to inspect drive belts regularly, but I don’t think you can really inspect the timing chain, can you? What’s the recommendation for a 2011 RAV4 timing chain? And why isn’t it mentioned to replace in the scheduled maintenance of my manual?
Because it’s a timing chain and not a timing belt.
The manufacturer assumes that the original owner is going to replace the vehicle after 100,000 miles. So why include another service interval in that period?
But timing chains/tensioners don’t last forever.
After 100,000, the timing chain system should be checked for wear.
Tester
@Rockjock
Ordinarily, Timing Chains Aren’t A Maintenance Item. (I Don’t Know Of A Manufacturer Specifying Its Replacement.)
I have never had to replace a timing chain on any of my GM cars and one is nearing 300,000 miles. I will say that the chains on these 3.8Ls (and the 3.5Ls and 3.6Ls ?) is just a short single loop and I’m sure that helps (KISS method). On some DOHC engines the chains are more convoluted or are multiple chains and possibly more problematic.
Most people will tell you that a worn chain will usually begin giving an audible warning, unlike a timing belt.
Keeping clean oil in the engine will assure long chain life.
CSA
…because routine replacement of a timing chain is not a part of anyone’s maintenance schedule.
Timing belts need to be replaced on a specific schedule.
Timing chains typically last for the life of the engine, IF the engine is maintained properly, with oil changed at least as often as the mfr specifies, and as long as the engine is never run very low on oil.
And, it is typical that timing chains give you some auditory warning before they need to be replaced. If you ever hear what sounds like–Guess what?–a chain rattling against a metal casing, that is your signal that the timing chain most likely needs to be replaced. However, if you maintain the engine properly, and as long as you don’t intend to drive more than…let’s say… 250k miles, it is very unlikely that you will ever need to replace it.
NOPE!
You can’t give me that timing chains/tensioners will make noise before they fail.
I can’t tell you how many vehicles were towed to the shop with these problems that never made any noise.
My 95 Nissan pickup is one!
Sitting at a light waiting for it to change, when it does, take off and the engine stalls.
Hit the ignition to restart the engine, and there’s that fast spinning of the engine like there’s no compression. Pucker factor ten!
Sure enough, the plastic timing chain tensioner took a crap and the timing chain jumped time.
Lucky for me, no valves were damaged.
Oh!
This was with 140,000 miles on the engine.
And I maintain my vehicles.
Tester
“Sure enough, the plastic timing chain tensioner took a crap and the timing chain jumped time.”
I could see checking a chain and finding it worn and replacing it, but a plastic part as you describe “taking a crap,” that could happen to just about any plastic parts.
Once I go through the trouble of checking a timing chain at a measly 100,000 miles then I might as well replace it.
Since I have put 100s of thousands of miles on many cars and never had a chain problem then I will continue with regular oil changes and plan on no chain inspection or replacement.
CSA
^
…so do you proactively replace timing chains and tensioners?
@VDCDriver I’ve only ever replaced one timing chain, on a 1984 Impala V8. The thing started rattling like a diesel at about 200,000 miles and we replaced it with a heavy duty double sprocket set for about $250 at that time.
That’s being PROACTIVE since you could always drive it till it breaks. By that time the noise would probably drive you batty!
Chains normally aren’t replaced. Mechanics told me that the GM 3800s that I had tended to need timing chains and gears at about 250,000. That’s about what I got. One developed a noticeable rattle but the other one just stripped the plastic gear at a stop light with no warning.
By the time a timing chain is worn out the rest of the engine attached to it is also worn out or headed that way.
Hmmmm?
I wonder why https://www.rockauto.com/en/catalog/ sells timing chain sets for just about every vehicle?
I mean, if timings chains/guides don’t wear out, why would they list them?
Tester
@Docnick
By “proactive”, I meant…Do you replace your timing chain before it gives any auditory indication of impending failure?
Since you did replace it when it was making a racket, I don’t consider your action to be proactive, and instead I would consider your actions to be…very timely.
@Tester
Do you routinely replace timing chains (and guides) at a certain mileage, before they start making rattling noises?
“Hmmmm?
I wonder why https://www.rockauto.com/en/catalog/ sells timing chain sets for just about every vehicle?
I mean, if timings chains/guides don’t wear out, why would they list them?”
I’ll bet they sell head gaskets and piston rings, too. Do you ordinarily replace those at 100.000 miles?
Why do they sell them? Because if somebody is tearing down an engine for some reason, like damage from overheating they may feel it’s prudent to replace other parts that are much easier to access at that time…
… or sell them to people who think they are maintenance items.
CSA
The timing chain system is designed to last the life of the engine.
HOWEVER, there absolutely is something you can do to support that intent. That “something” is to ensure that you keep your oil above the FILL level and don’t put off oil changes. Timing chains will wear prematurely from neglecting your oil maintenance.
I learned this lesson many years ago
http://www.1aauto.com/content/articles/timing-belts-chains
Tester
Good article, Tester. Thanks for the link.
From 1A Auto’s: Timing Belts Vs. Timing Chains Article
http://www.1aauto.com/content/articles/timing-belts-chains
“Most vehicle manufacturers recommend that timing belts are changed between 60,000 and 100,000 miles, though there are exceptions, both higher and lower.”
“The beauty of the timing chain is that it typically lasts a very long time. Some car manufacturers recommend replacing it at certain mileage or time intervals, while others claim that the chain is good for the life of the automobile. It really depends on the make and model of the car or truck.”
My Chrysler cars had a timing belt replacement interval of 120,000 miles.
My GM cars have a timing chain replacement interval of never.
That definitely is the beauty of a simple, short, single loop timing chain running in clean oil.
CSA
The T-Chain warning debate is valid. It all depends on the type of T-Chain system that is implemented on the engine. There are several types of T Chain designs.
Many times when theres a lot o miles…and the plastic chain guides (if used) give way…the extra slack that is created can cause a lot of noise. But its possible that the plastic can break…and then IMMEDIATELY after that the chain jumps time or worse…with no warning…bc it never had time to give a warning. The guide breakage and chain hopping occur almost at the same instant if you will…
Then there are those that have a hydro or spring loaded T-chain adjuster/tensioner that are at the end of their throw and no longer able to remove chain slack. These are usually the noise makers because all else is fine, the guides etc…the chain is now just too loose. It all depends on how the system fails for sure
One type of chain system that sneaks up on you is the type like the Ole Chevy 350…there is no guide or adjuster…its just a precise fitment of chain and sprockets when new. These like to stretch slowly over time and when they do…there is most often no warning sounds to go by at all, but there can be from chain contacting the metal cover…but more common for Zero sounds. These chains present symptoms in a SLOW and insidious nature…the engine just slowly slowly runs worse n worse because it is literally getting out of time…mechanically. A very gradual decline in performance is your only clue. Ive personally seen a lot of Dodge Ram trucks suffer from this…at 60-75K miles !!! Which is EARLY ! From what i see on the Dodge forums…they complain about it all the time. The solution is a more Robust chain design instead of the single roller type. The more robust chains usually require different gears also.
So the T chain warning or no warning really depends on what type of system is used and how it was designed. Some are more prone to noisy failure, others cannot make noise if they tried, while others still present themselves in the slow decline in engine power and performance which can be discovered when you try to time the engine…and you cant because you ran out of distributor radius…or have to induce too much rotation on it…a HUGE clue.
All depends…Ive seen examples of every type because they are out there…
Blackbird
I havw replaced timing belts a few times, head gaskets a few times, but never a timing chain. I never neglect my oil but am disturbed to hear they have gone to plastic parts for tensioners and guides. Plastic is a lousy structural material and it is a shame to see something as robust as a timing chain imperiled by a piece of plastic.
@VDCDriver As a maintenance consultant I sometimes use different terms than those commonly used. Yes, some things are PROACTIVELY replaced because failure would be catastrophic or expensive. In aerospace that is often the case. Same with timing belts.
Since timing chains start getting noisy their replacement would fall under the term “condition-based” maintenance since the activity is not time-based or proactive, but related to impending failure… Such maintenance is usually the most cost-effective.
I agree you are right with respect to the term PROACTIVE of often called preventive.