ok my 1999 Lexus RX300 AWD has 223000 miles on it and I'm using a quart about every 4-500 miles. looking at swapping the engine. can I swap an engine from a 01-03 Toyota Highlander AWD in it?

 

welcome. An engine from a 01-03 highlander is virtually the same but the accessories are mounted differently. It is not an easy task for a swap. Consider it a last resort if you have confirmed low compression via damaged piston/rings.

Search the threads regarding oil consumption. Early year 1st gen models can benefit from upgrading the rear valve cover to the latest revision found in the rx330.

 

I have no sign of oil leaking I haven't done a compression test because it's freezing and I don't have access to my garage which isn't heated and has a 71 c10 that is waiting for the snow to melt so I can fix it as well (wide hard tires makes for crappy snow traction) but I'm at the point where I fill the oil and check the gas. If it's valve guides I can get a set if rebuilt heads for 500, but then what if it's the rings I suppose if its 40 like they say it might be I can check compression

 

Welcome to ClubLexus.
It seems you are not ready to do any real work in these conditions .. so its the best time to do the homework. As fastnoypi, stated there can be subtle variations. Based on that I would suggest going the route of identical swap (down to AWD/FWD) or find the alternate local so that you can choose to return it.


Salim

 

oil leaking via the valve covers typically does not contribute to high oil consumption in these cars unless the seals are severely damaged. Its the design of the integrated baffles in the rear valve cover which can be blocked overtime due to gelling of oil mist and condensation during short drive time intervals and some cold weather conditions. Once semi-clogged, it causes a high pressure situation that literally pumps your oil into the intake tract for consumption. It is a less than $300 job for a DIY.

 

Dumping oil into the intake would explain the top mileage of 17mpg. should I buy the updated valve cover or just clean it out? I'm willing to try anything cheapest engine I've found is $1200 says it's from japan with 60,000 miles but also from a Toyota highlander , local yards have 180,000 miles wanting $2200 but I could have a rebuilt long block for that

 

its is more a personal decision based on downtime and effort you want to spend. Should you be content with your RX and you are blessed with longevity, you will most likely be revisiting the valve cover at a later date sooner with a cleaned out 1st revision valve cover than the updated design.

 

So the covers for a 04 rx300 with a 3.3l fit my 3.0? that's all I can find for the rx330 engine

 

from my invoice part 11201-0A060

here's a thread that may prove useful in your decision making and research to tackle the rear valve cover https://www.clublexus.com/forums/rx-...lve-cover.html

 

Just an FYI, but I was experiencing similar problems with my RX and I swapped the valve cover out 2 years ago. Oil consumption imediately dropped. There are a couple of great threads on the rear valve cover swap. I would read through them and you can decide if it's worth the effort to replace that VC.