New Corolla timing chain - "Interference" engine?

gnicholasw

I want to buy a new Corolla, but the salesman told
me it has a "lifetime" timing chain which does not
require replacement. Does the Corolla have an
"interference" engine, where the valves and pistons
occupy the same space at different times in the
cycle? If so, a broken chain would at least bend
the valves, and perhaps require a new engine
altogether. If I plan to keep this car for a long
time, is this a realistic risk? A friend had this
happen to his Nissan and it cost him $2,500.

gus

I don't think that the Corolla 4-cylinder engines have an interference fit. I'm not sure, but I don't think the 6-cylinder is an option on the Corolla. If it is, I couldn't tell you whether it's an interference engine. Camry 6-cyls. are not.

Also, the Corolla engine has a belt, rather than a chain. Unless Toyota is changing their procedures, all recent model Corollas need their belts done at 60k, although the belts are often good for 80-100K.

mazda323

The 1.8L engine in the 1998 and 1999 Corolla has a chain, not a belt. I don't know if it has an interference fit, but the chain should last for the life of the car. Older models with the 1.6L engine used a timing belt (I don't know about pre-1998 with the 1.8L)

gus

Thanks for that info! I also tried looking this up. The motor in the new cars is classified as the 1ZZE, or something like that (older corollas had the 7AFE or the 4AFE engine). The Toyota fast-moving parts book has everything for the newer models except the timing chain--so it must be lifetime (duh)! I'll try calling toyota to see if it's interference or not.

richie1

Thanks for the info on the timing chain.
I am a first time user. I think this town hall is great.

autoexams

checked with toyota this engine is a problem if belt does break. remember car companies are saying timing belt do not need replacement now until 105,000 miles. your lifetime of an engine is now 250,000 miles on imports if you keep up good oil changes. but that has nothing to do with the timing belt it is not lubed. age is a factor in it life because it is like any other rubber belt it dryrots. if it breaks expect severe engine damage. and a lot of money to fix thats how your dealers make money.

gus

I think that we established that this engine had a chain, rather than a belt. Yes, belts on interference engines can cause a lot of damage if they go bad, but chains go bad infrequently, and they are lubricated by the engine oil. Furthermore, chains will give signs of going bad. On the pre-Tacoma Toyota Truck engines (as well as early Celicas), the chain will loosen up and make a rattling sound, which is a pretty good indication that the chain needs to be done. On these models, even with just the beginnings of a rattle, you're a far way from chain failure.

I doubt that manufacturers try to mislead people for the sake of replacing entire engines. This seems far-fetched to me. I'll grant you that some manufacturers are mis-judging the length of time that their belts last, but is it intentional? Doubtful.

Manufacturers know that a greater replacement interval for t-belts will shake out as a lower estimated annual repair cost on their vehicle. It's a selling point. If a car is on a 60,000 mile t-belt schedule, then in 250,000 miles the car is due to have four t-belts. If the car only gets a t-belt at 100k, then that car will have 2 t-belt replacements. Let's say that timing belts cost 500 dollars to replace (mostly labor). Well, if you buy the car with the 100K t-belt schedule, then, over the life of the car, you'll save $1000 in maintenance over the car on the 60K schedule! This is in theory. In practice, it's likely to be different.

epoe

I have an '89 Corolla withe the 4AF engine. I had the first belt replaced @ about 80k miles. It just broke @ 190k. I want to try and replace this belt myself for ($35) but i don't know if it is an interference engine. Would anyone know? I guess i could pull the head off and find out? Thx!

gus

I don't think it is. This engine is the smaller version of the 7AF-E that's in the '93 and newer. That engine isn't an interference fit, and neither is the engine that preceded the 4AF-E.

Replaceing the timing belt on these models is not an easy job, mostly because of the space between the front of the engine and the inside of the engine compartment. Furthermore, if you do the job, you need to remove an engine mount, and you should have some way of supporting the engine. If you've only done your timing belt in the past, you may want to think about having your water pump done as well. 180K is a lot of mileage to put on the water pump. Use official Toyota replacement parts, they last longer than aftermarket parts.

epoe

Thanks gus! I will do the water pump when I do the belt, good suggestion! I wonder how many miles I can get on this engine. I have about 130psi in the cylinders (Of course this figure is from a month ago when i tuned it up)!

acorn1

I also need to replace my Corolla's timing belt when it reaches 60k miles. The workshop manual says that to remove and replace it, I will first have to remove the starter motor and lock the engine by holding a screwdriver against the ring gear, and then I have to undo the the crankshaft pulley bolt before I can get the lower timing belt cover off. This looks difficult to do for a home mechanic. The starter motor is buried underneath the air plenum on the firewall side of the engine -- so how can I get it out? Secondly, how can I undo the crankshaft pulley bolt when it is torqued up to the recommended 118 Newton-meters torque? Will I be likely to crack a tooth on the ring gear when trying to undo the crankshaft pulley bolt? Do I need special tools? Has anyone done this job and can advise me on this?

gus

acorn, what year is your Corolla?
I don't think pulling the starter is necessary on any of the models. What manual are you using?

acorn1

Gus, thanks for your response. My Corolla has the 7A-FE engine. The manual says that the purpose of removing the starter motor to gain access to the ring gear, so that the engine can be locked by jamming the ring gear with a screwdriver in order to undo the crankshaft pulley bolt which is apparently done up really tight. However today I got a look at a proper Toyota workshop manual, which shows a long lever bolted to one of the crankshaft pulley bolts to hold the crankshaft pulley still while the bolt is undone. I guess my real question is: how difficult is it to get the crankshaft pulley bolt undone?

gus

What you might try doing, short of using an 1/2" drive impact gun, is holding the crank pully with large channel locks, using the old drive belt as an insulator. You don't want to mar the grooves in the pully at all, so be sure that you have some sort of insulation between the pully and whatever you're using to hold it. The old belt works well becuase it's a perfect fit, and you can really clamp down on it.

You can also try sticking a rag between the two cam gears once you have the valve cover off. If you turn the crank pully, the rag will bind up the gears, and you should get enough resistance to break loose the crank bolt. I can't remember now if turning left (off) will bind up those gears, but it's worth a try.

I'd try #1 first, and then #2. Remember to support the engine when you remove the motor mount at the front of the motor. There is no way to remove the timing belt without taking that motor mount loose.

Good luck,
Gus
Conference Host

acorn1

Thanks Gus, I will try those options you suggest.

gus

Well, hopefully, all goes well! Good luck!

jonathan75

I am getting my new 2000 Corolla from a dealership 75 miles away! How do I drive it home? I can't go over 55 during the break in period and I only have the freeway. Plus I need to change my speed around all under 55! Do I just put my hazard lights on and pray that I don't get hit? The freeway is like the only way to go home!