What are the probable causes for this noise, and is it repairable? The car has 117,000 kms and was lightly used by my wife throughout its life.

Welcome to TN.

Internet-distance diagnosis about noises pretty much requires a video or audio recording.

Plus, you really need two locations of recordings, one where the mic or camera is above the engine and one where it's below the engine. Ideally you pan the mic or camera across the engine to help pinpoint location (of course, secure or remove any camera strap and CLOSELY WATCH what you're doing around rotating parts or belts).

This is because knocking can originate in the valve train at the top of the engine, or in the "bottom end" (where knocking usually indicates too much clearance for the crankshaft and/or rod bearings).

There is even a mid-position possibility called piston slap, but usually piston slap happens at start-up and either goes away or gets much more quiet as the engine warms up.

Everything is repairable. The exception is in the US, where very high labor costs combine with very high repair parts costs AND impatience, all of which make a used or rebuilt engine more cost-effective. An engine swap can be done in a day. Rebuilding an engine can take several days, since you don't really know which components you need to replace until you tear the engine down.

By the way, what is your location? Are you in an area where major repairs are affordable and treated as the norm? (They aren't the norm in the US, where major repairs more often than not prompt the owner to throw the vehicle away).

 

Good mechanics are hard to find in Japan, too

Hello OleAvalon,

I live in western Tokyo. I'm at a disadvantage here because, like in the US, nobody likes to repair old cars anymore. Dealers will repair them for you only if they are covered under warranty, which my 10 year old car is not. Japanese generally don't keep cars longer than five years to avoid the very high inspection costs as they get older with some not even bothering to change the oil in that time unless their dealer happens to suggest it and it comes free of charge. Without even looking at my car my dealer said it would cost 300,000 to 800,000 yen (3,000 to 8,000 dollars) to overhaul my tiny little 1.3L engine which I consider outrageous for a car that only cost $12,000 new 10 years ago. They'd much rather we buy a new car which in my mind is wasteful and only adds to our throw-away society. Since when did cars become throw-away items? I guess I'm old fashioned. Years ago I'd have fixed it myself but I no longer have the space/time/tools/strength/patience for that kind of activity now.

I can buy a used engine which will cost, I don't know, maybe $2,000, but there's no guarantee it won't develop the same or a problem of its own a short time later. I know an independent mechanic who is cheaper than the dealers and is, as far as I can tell, honest, but even he doesn't like to overhaul engines. Used engines are apparently the preferred repair strategy these days. I'm also not intimate enough with the industry to know where the engine shops are and don't speak enough of the local language to be able to communicate my problem to any of the online car clubs.

My real purpose in contacting you was to learn the most probable causes for engine knocking in the 2SZ engine so I can speak intelligently about them with my mechanic. Back in the 70s low octane gasoline was the most common cause, and this sounds a lot like that though not as loud, but that shouldn't be the case now with computer controlled engines and I'd expect to see numerous fault lights or error codes pop up with other malfunctions but I'm not seeing any of that now. My informal research suggests that the timing chain or belt is a common culprit in the 1SZ and 2SZ engines, and that would match my personal experience with two past Toyota cars I've owned (with different engines), but I don't remember the knocking. The engines in those cars just simply quit when the belt broke, both at about 100,000 kms, as I recall.

It's not easy for me to send you a recording due to the noise occurring only under load when the engine is hot, though I could probably duct-tape an old cellphone to various spots in the engine bay and see how that goes. Is that the kind of thing that you were expecting?

Thanks for your help.

 

I live in western Tokyo.

I was hoping you were in mid-Europe, or Africa, India, or the like, where repairs are common and cars are treasures.

I'm at a disadvantage here because, like in the US, nobody likes to repair old cars anymore. Dealers will repair them for you only if they are covered under warranty, which my 10 year old car is not. Japanese generally don't keep cars longer than five years to avoid the very high inspection costs as they get older

My one trip to Japan (Nagoya and Tokyo) was so full of wonders that I never looked twice at what was on the road. A shame that it's a throw-away society there, too.

Since when did cars become throw-away items? I guess I'm old fashioned. Years ago I'd have fixed it myself but I no longer have the space/time/tools/strength/patience for that kind of activity now.

I'm in the same situation due to age, but as you can see from my signature, I don't throw cars away...

I can buy a used engine which will cost, I don't know, maybe $2,000, but there's no guarantee it won't develop the same or a problem of its own a short time later. I know an independent mechanic who is cheaper than the dealers and is, as far as I can tell, honest, but even he doesn't like to overhaul engines. Used engines are apparently the preferred repair strategy these days. I'm also not intimate enough with the industry to know where the engine shops are and don't speak enough of the local language to be able to communicate my problem to any of the online car clubs.

I hope that the $2000 you mentioned is the cost installed. Used engines in the US are anywhere from $250-900, and cost around $800 to install.

My real purpose in contacting you was to learn the most probable causes for engine knocking in the 2SZ engine so I can speak intelligently about them with my mechanic. Back in the 70s low octane gasoline was the most common cause, and this sounds a lot like that though not as loud

So it's a metallic, rattle-y sound? Did you mean that the knock in your engine is not as loud as pre-ignition knock?

My informal research suggests that the timing chain or belt is a common culprit in the 1SZ and 2SZ engines, and that would match my personal experience with two past Toyota cars I've owned (with different engines), but I don't remember the knocking.

If your engine's timing belt has a mechanical or hydraulic tensioner AND the sound is loudest around the "front" of the engine, it might be the tensioner. It might get louder under load, but probably not. "Front" in quotes -- the front of the engine is the section where you have accessory (alternator, air conditioning) belts.

It's not easy for me to send you a recording due to the noise occurring only under load when the engine is hot,

That would indeed make it hard to record. You need a chassis ear, a wired or wireless sound-gathering system that lets you clamp microphones where-ever you want. You might check eBay Japan to see if you can buy a reasonably-priced used set.

Take all of the rest of the stuff below with a grain of salt. I can talk only in general terms, not having heard the sound

A strong, pounding knock under load (not the delicate little rattle-y sound of pre-ignition) is almost always a main bearing problem.

Those are easy to fix... if you don't care about ultimate longevity. The first fix is to turn up the radio.

The second fix is to replace just the main bearings, which a mechanic should be able to do with the engine in the car. (This won't work if you have galled or un-smooth journals on the crankshaft).

The third fix: if you do care about longevity, then it's more complex: the mechanic removes the main bearing caps, the rod bearing caps, and the crankshaft. The crankshaft goes to a specialist re-grinder, where it is turned and polished. The mechanic then fits oversize bearings and puts everything back together. You would have to get local help in finding the right machine shops and mechanics.

A more delicate, rattle-y knock under load might be as simple as the CV joints in the drive axles, especially if the sound gets louder or changes considerably when you are turning the car under load. Even in throw-away situations, there should be low-cost rebuilt or aftermarket axles.

You feel a main bearing knock in the seat of your pants. You feel a CV joint problem most likely at the steering wheel.

But all this is guess-work without actually hearing it.

Can you give more particulars, such as the RPM when the knocking begins, or whether it happens also when you coast downhill in a gear lower than D (if you have an automatic -- if you have a stick shift, coasting downhill in 2nd gear). Does it always happen, or does the engine begin relatively quietly and get knock-y only when it reaches a certain temperature?

Just had a thought - listen to some YouTube noises and tell me what comes close to yours:

Main bearing knock:

Rod bearing knock:

(less pound-y; video ends badly, for the engine, that is)

CV axle clicking:

Lifter tap:

(should be easy, cheap fix; listen to the guy's explanation, he's good)

 

Even found a timing belt tensioner failure noise:

(Watch whole thing - unusual situation with a loose belt).

 

Good mechanics are hard to find in Japan, too

Thank you very much for these videos. My problem appears to be more akin to old-fashioned pre-ignition as it is a mild rattling sound, something like a bunch of ball bearings falling one by one onto a cookie sheet at quick, even intervals. It's not random or uneven like the loose belt sound, nor is it as loud as the crankshaft bearing and worn tappets sounds, nor does it sound like things are obviously broken like the rod bearing noise. It's about half the sound level of the CV joint knock but doesn't occur when turning the vehicle. It really only occurs on acceleration after the transmission up-shifts into high gear and when the engine is at full operating temperature. I should have said earlier that this car has a Constant Velocity Transmission. The sound appears most often soon after the car is in motion when the transmission adjusts itself so that the engine RPM and torque are at minimum. This of course saves on gas but it always makes me feel like I've up-shifted way too early. I don't have a tach so I can't tell you at what engine speed this occurs, but I can tell you the engine never stalls. The car has run like this since it was new so it is apparently normal for this engine/transmission combo to behave this way, minus the rattling sound of course which is new only over the past year or so.

A couple of events have occurred that may preclude our repairing this car. The first is that our mechanic has said that intermittent engine knocks are notoriously difficult to diagnose and he really recommends replacing rather than repairing the engine; the car also needs new tires to pass its next inspection; and my wife managed to just two days ago scrape the passenger side door and rear fender against the concrete wall next to our house, so we now have body damage to deal with as well. Seems that fate is really trying to tell us to replace this car despite its low 117,000 kilometer mileage. Sometimes you just can't avoid these things.

Thanks for all your help!

 

Glad that you aren't faced with the high-cost problems, anyway.

Since the CVT is asking you to lug the engine (make it turn perhaps a bit too slowly), maybe it IS pre-ignition.

If you have the option for higher-octane fuel, have you tried that? Over the years/kms, deposits and carbon can build up in the cylinder and on the piston. That can raise your compression to where pre-ignition can happen, especially when the engine is hot and under load.

If you don't have higher octane gasoline, maybe an "octane booster" might help -- if you can obtain it. Whether they really work, I don't know.

As for your long-term plans, good luck. It appears that your Vitz has served you well.

 

Follow-up

It appears that our Vitz was suffering pre-ignition after all. Thinking that regular gas was the same everywhere, we'd switched to a cheaper brand to save a few yen per liter about a year ago. It took a while for me to put two and two together, but it turns out that our "old" regular gas was 93 octane and our "new" regular gas is 87 octane. We went back to our old gas and our car is her happy old self again.

Though I'm relieved I don't have to buy a replacement engine, I'm annoyed as heck at our dealer who only wanted to sell us a new car. That's not taking care of the customer, IMHO. After driving Toyota cars for the past 30 years I think it's time we switched to a different brand for our next one.

Thanks for your help.

 

Simplest (and cheapest) is best. Congratulations.

And have pity on your dealer. He's there primarily to sell people new cars after all... I've had good treatment on two stops to my local dealer, but it's clear that the staff thinks I'm an invalid, a hopeless case in their primary crusade to sell new cars -- as indeed I am. My last new car was a 1972 Dodge Dart, which in many respects was the Corolla of the era, a bullet-proof, long-lasting, well engineered car.