Troubleshooting noisy/knocking engine

[smash]

Hi all, original owner of a 2009 Base Vibe, 1.8L engine. 70K miles, mainly in-city driving, with a 25 mile/65mph run a couple of times/month.

Last month, my oldest got back from taking it on a camping trip, and when I went to start it up, I was surprised at the engine producing more noise than I'm used to - I had to check that I wasn't in a Diesel Jetta! At startup & at initial acceleration, I hear knocking, and a bit noisy. At speed, it is less noticeable, but maybe just covered up by tire/wind noise.

So far I've done the following:
- Checked oil - was 1/2 qt low, changed it
- Added a bottle of gas treatment (in case they got crappy fuel), have run 2 tanks of "known good" (Costco) fuel, noise remains. In-town mileage is still at 29 mpg, so whatever this is, is not affecting mileage
- Checked air filter, ok, cleaned MAF sensor.

ToDo: Clean throttle body once I get a replacement clamp for the air hose as the original clamp is rusted shut.

Asking the community for ideas on "next steps" to try to troubleshoot what this might be, or whether this is just normal wear-and-tear for an 11+ year old engine...

[andrewclaus]

A little more description of the noise would help.

Valve train noise will be tapping from the top of the engine. Louder knocking noise from the engine block could be from a piston or connecting rod. An exhaust leak will be a rapid series of muffled explosions. You can narrow down the location with a mechanic's stethoscope. My dirt bag version is 2' piece of heater hose.

How long was it between checking the dipstick? How long ago was the previous oil change?

Have you checked the coolant level and condition?

Throttle body isn't causing this. I'd find this issue before you do any more work.

[Caretaker]

These oil burners hate being low on oil and aren't especially fond of freezing temperatures. Having nursed mine through many winters, I know. The car sounds eerily loud at startup ESPECIALLY when it is moist/high humidity in winter mornings. Once the oil sloshes around, it quiets down. Only if you hear very loud knocking (like a diesel Mercedes), and as long as the noise gets noticeably quieter after 2 blocks of driving in freezing temperatures, I would not worry about it. Welcome to the world of a 1.8 liter engine that Toyota strung out over 4+ decades with few enhancements.

[zbyers]

These oil burners hate being low on oil and aren't especially fond of freezing temperatures.

The 1.8L doesn't burn..Well, at least not like the 2.4L.

[Caretaker]

They do and all three of mine have, but as Pat Goss and the Car Guys told me, its within specs.. There are tons of videos on youtube showing the issues with the poorly designed oil rings which get clogged up and the oil return holes which are too small and too few. That aside, the longevity of this proven Corolla engine used in a multitude of vehicles and trucks around the world demonstrates why it has been such a workhorse all these years. That aside, now that it is 2020, the engine is very much "long in the tooth" and pairs only so-so with automatic transmissions. Toyota and Subaru have a tendency to stick to what works for too long a time (the 1.8 and the 2.0 for example), and get passed up by the Mazdas and Koreans who seem to benefit from those who endorse slow change.

[smash]

Thanks for the replies. The oil level was last checked about 6 months before, and had last been changed 1 year (~5000 miles) before . Coolant looks fine.

I recorded the engine sound at idle from within the cabin & have uploaded it. https://imgur.com/BlsVNix.

I'm in Charleston, SC so we don't worry so much about freezing temps, but we usually have plenty of humidity...

I won't have a chance to try to pin down where the sound is coming from exactly before the weekend.

[Caretaker]

I believe there to be a boatload (not scientific) of heat shields on these cars. It is possible one of them has become loose. The one atop my Fit's manifold had a poorly designed bolt which allowed for separation and rust over time. I had to jam a "C" clip under the bolt head to get the vibration noise to stop

[zbyers]

That video to me does sound kinda like a heat shield. How does it sound at the front of the car vs. middle vs. rear? What about if you lay on the ground near front/back and listen.

[smash]

Loose heat shield vs something engine related makes sense as my power/mpg haven't suffered. I'll try to track it down during daylight this weekend. Thanks!

[smash]

Rattle seems to be coming from the alternator or close by.
https://imgur.com/a/ZHyNkqx

Given that I've only done tires, brakes, battery & headlamps in 11 years, I guess I can invest a little more to keep it going...

[Caretaker]

that was an excellent video/audio. Now you may have to focus on the noise being the belt tensioner or the water pump. I had a noisy water pump on mine 6 years ago. My mechanic thought I was nuts. I made him take it off. Once you spun the wheel, the grinding noise was obvious.

[SSizler]

Sounds like the belt tensioner.
I was able to use a long screwdriver and pry against the tensioner while the engine was runnung, and the noise ended.
I replaced the belt at the same time.
They recommend also replacing the idler pulley, but I did not do that.

[smash]

Just to wrap this thread up - it was bad bearings on the alternator allowing the pulley to vibrate. Replaced alternator & belt and sounds brand new.

[Caretaker]

Great work smash. Thanks for letting us know.

[jolt]

It was most likely the pulley clutch bearing on the alternator that was bad.

https://www.rockauto.com/en/moreinfo.ph ... 94&jsn=846

https://www.rockauto.com/en/catalog/pon ... ulley,2448

A lot of people change out the whole alternator but these pulley clutch and the bearing in the pulley go bad. Chrysler mini vans have these go if you get noise from the alternator / belt area. Most people do not realize that it is not just a pulley but a clutch and bearing in the pulley.