Well, I'm nut sure what happened but yesterday on the highway the engine started making really distinctive knocking noise, almost like hammering, metal which depends on the RPM. So i parked the car, and now trying to figure out what it is, my guess it would be the timing chain? water pump? I'm clueless. And the dashboard doesn't have the check engine light on. Am i still okay to drive it like that to the shop? or that would kill the engine completely?

 

How many miles you have? My water pump went last month at 95k more of a grinding noise which got louder when I pressed gas. I would get it in right away you have warranty?

 

150+k miles but they did the recall engine rebuild or something like that about 12k miles ago, i think that they had the warranty for that for like a year, which hasn't passed but i think the warranty was 12 months or 10k miles

 

Definitely TOW it back to the dealership; no sense on causing MORE damage on driving it any further. If you'd like to check it yourself, I'd start by draining the motor oil and checking for metal flake in the oil. Can you tell if it was coming from the front end of the motor or inside the motor?

 

water pump for sure, if it was anything else u would have mil illuminated. I do 1 a week on these.

 

Water pump would cause that metal noise? Its pretty damn loud and scary.

 

What happens on these cars when the water pump goes? Is it a simple bearing failure? Or something more? Older BMW water pumps were notorious for having their plastic impellers shatter, sending shards of plastic through the engine's cooling system. Not good.

 

yep happen to me not a good sound.

 

water pump bearing is bad....

 

How I see it is that the WP bearing can goe (which can cause noises by itself), but then that causes the WP impellor to "walk" around perhaps causing metal-to-metal contact and additional noises itself. Not a good position to be in.

 

Just came back from the dealer. They told me i need a new motor that the knocking is coming from the bottom part, so i would need a new short block. I was also told that when they opened it up, there was no oil in the motor.
I didn't have any low oil pressure or low oil warning lights not before not during the time that this happened.
The piston and ring job that they did before is warrantied for 1 year (which hasn't passed) but they are saying that they can't do anything with that and that they will have to charge me 16.5 for the new motor…
Suggestions?

 

Is this a 250 or 350?

 

Piston and ring job? Are you referring to the carbon build up campaign?

 

Did you not check the oil level when you started having these noises? Where you park every night, is there not a puddle there? I assume in-between the time Lexus did their work and today someone somewhere did an oil change on the car...yes? Whom? Check the under engine cover for oil; if there is oil residue all over the place from leaking, then the car was not properly filled with oil last oil change.

Find a used, long block and get a local shop to swap it in for you; you'll save thousands.

 

250
Yes, so basically they rebuild the engine.
The oil was not supposed to be an issue, I change it regularly, and i checked, that was the first thing i did check, the dip stick showed normal levels, on top of that i would assume that some kind of warning light or CEL would come up indicating a low oil pressure or low levels of oil. I checked for leaks - none, and 6 liters of oil don't just disappear, the oil pan is also intact. The whole undercarriage is clean.