Been trying to figure out what this is for a while now. The car drives fine. It burns a lot of oil, has for several years now. It has 300,000 km on it. I got my mechanic to replace the water pump last summer, but that made no difference. Sometimes it's loud, sometimes it's not so loud, but this rattle has been there for a couple years already.

My mechanic says it could be the timing chain due to lower oil pressure. Which I assume could be because sometimes I wait until the oil and check engine light come on before topping up the motor oil. But my mechanic replaced the timing chain with the timing cover in 2019. So it can't be the timing chain, right?

Here's how it sounds:

 

Knowing this I wouldn't spend any more money on that car. Are you trying to kill the engine?

 

Yes. But it won't die.

Normally I try to check the oil once a week and keep it topped up, but sometimes I forget and I don't do it until the oil light comes on. The engine is still powerful and runs smoothly at highway speeds

Any idea what the rattle is?

 

The best way to bring longevity to a Lexus/Toyota engine is proper maintenance. This always starts with regular oil/filter changes and making sure the oil level is topped off because oil is the life-blood of an engine. Waiting for the oil light isn't the same as the low-fuel warning light. You are... in effect... killing the engine as LeX2K has said. Oh... and Toyota/Lexus engines are built well but they will fail if you don't do proper maintenance.

If I had to hazard a guess that sound is either piston slap or some really worn out cam/followers. If you want to know more change the oil, save a little bit of the oil and send it out to Blackstone labs for an analysis.

https://www.blackstone-labs.com/

 

Thanks for the tip, I think I may very well do that analysis. Otherwise, I'm going to get a second opinion on this, probably at the Lexus dealership down the road from me.

I've scoured the web and the forums for Youtube videos of people with the IS model showing engine rattle, and I think mine sounds fairly similar to what I've heard, the prescription for which has almost universally been to change the water pump. But it can't be that, so it's a mystery.

 

Try running it for just a minute after taking the drive belt off. That will take all the accessories out of the equation of what could be making the noise.

If it's still there, you're likely looking at some sort of internal engine damage, especially with the attention your mechanic has given it.

 

Thanks, maybe I'll get my mechanic to try that.

 

It's weird, because some days you don't hear it much at all. Yesterday when I made that short video the clacking rattle was really loud, but today it was minor. I don't really know much about engines, but wouldn't that suggest it's probably not inside the engine block itself?

 

Now that you mention it. I had an 87' Toyota Cressida that made noise like that when I first fired up the engine after rebuilding it. It was the valvetrain clattering made by the new hydraulic lifters which had not pressurized yet.

If the sound is coming and going, my vote would be on collapsed and faulty valve lifters.

 

Take a long wood stick, stethoscope, or even a long screwdriver (24"), place your ear to the stick and the other as a probe along three spots of each valve cover high, then low by the exhaust manifold and you can pinpoint the location.

This is a good test for Idler pullies, water pump, and alternator bearings too. Pay attention and be safe.

 

I'd say its valve train noise based on the rate of occurrence. Change the oil completely this time with a new filter, and dump some STP oil treatment in it. Tell us how it sounds in 500 miles.

Keep oil with you in the car all the time and try to quit running it out of oil.

Long live the GR!

 

Engine died on the road. Got it towed home. With the holiday weekend, I guess I'll find out what happened when I take it to my mechanic on Tuesday.

 

Died as in it just shut off, or died as in it went KABOOOOOOOM!!!!!!?

 

As in shut off. All the dashboard lights came on and then the engine stopped. Wouldn't start again, would just ruh-ruh-ruh but wouldn't turn over. Seven years ago the same thing happened and I needed a new alternator. I'm no expert, but I'm guessing (hoping?) that this was what all the ticking was about. Otherwise the engine was fine for power, right up until it stopped.

Come to think of it, the drive belt was all dried and cracked back in 2015 when I needed a new alternator, so they changed it as well. That was about 175,000 km ago. Do drive belts/alternators start to go downhill after 150,000+ km?

 

Sounds typical when and Timing chain or Timing belt related problem is going on. Run fine, makes noise then just quits.