Changed oil now engine sounds like it's about to explode

There is no low oil light.

There is a low oil pressure light. Usually when you see that you have a few seconds to shut down before permanent severe damage sets in.

 

When there's work you've recently done, it does make good sense to think first about any way a new problem might be related to that.

But you don't have to rule out the chance that the new thing is just some other thing that has happened. To always think "there are no coincidences" means missing things when there are.

 

I've been saying that all my life, and it's certainly true about a Gen 2, but I'm going to have to be more careful in the future, because somebody posted back in March about their 2021 Prime giving a low oil warning, and sure enough that car has an oil level sensor! The part number crosses to 34 Prii and Corollæ going back to 2016.

 

I was delighted to discover that my 2020 Mazda has a low level indicator.

...until I caught it lying to me once.

Dipstick still works great.

I don't know what mechanism my Mazda uses for its level sensor.

I have read that Porsche did very well early on with a stack of thermocouples arranged vertically on the oil pan. The system looked for a gradient between thermocouple outputs held over time and when that gradient hit their threshold it would throw a low level error.

This with no moving parts, crankcase penetrations and associated seals or anything like that. Pretty nifty.

 

Yeah, when I saw the picture of this one that looks like a float, I figured less of the magic is in the float itself, and more in how the ECU firmware teases a real oil level out of the bouncing and sloshing.

 

That often comes in above the plug through a leaky valve cover gasket into the plug well, rather than getting past the plug from inside.

 

I guess if people pretend something exists for long enough it finally can exist...

 

I bet someone stole your catalytic converter... Did you look under the car yet?

 

Actually for the spark plug o-rings that keep your spark plug wells dry you should be able to just look down that hole where you pulled the plug out your spark plug would be almost flooded like at least up to the hex that you're turning to get it out so that's going to put oil on the bottom of your spark plug wrench or socket when you pull it up and an engine with deeper wells like that I tend to wipe the socket off as I pull plug number one out then go to number two pull it out look and see if I got oil and whatnot wipe the socket off and so on and so forth. I very rarely seen the one NZ engine with failing spark plug seals or spark plug well seals. Very rarely and I've taken quite a few apart but anyway you should be able to see this with a flashlight look down that hole It should be a silvery brownish color at best if not just silver If it's getting oil regularly you'll see the blow by sticking in the walls of that circular hole that you're sticking your spark plug socket down Good luck.

 

It gets asked, because cat theft is so common for Prii, and it's funny how different people describe the sound. To me, a pipeless engine really doesn't sound like anything else but a pipeless engine, and I would know the sound the instant I turned the car on. But we get a lot of threads that start with "so I turned the car on and it makes this really loud noise it didn't make yesterday...".

 

Just wanted to make sure we eliminated that one because cat theft victims have some strange and quite similar ways to describe their symptoms.

 

I like the ones who say: "Why does my car suddenly sound like a race car?"