carguy75

I do my own oil changes on my 2011 Lexus RX350 AWD in my garage. The job is very easy as oil changes go.

I was able to find this part which is the large oval rubber weather strip that goes on the body frame itself that seals the rear hatch. I am not sure of any other seal for the rear hatch. However, I have the 2011 model. https://www.lexuspartsnow.com/parts/lexus-weatherstrip-back-door~67881-48050.html?Make=Lexus&Model=RX350&Year=2014&Submodel=JPP&Filter=()

I changed my 2011 RX350 AWD cabin filter in about the same time as you, and I also do not see why it would cost $140 to exchange one at the dealership. I purchased an aftermarket carbon filter for about $9 on Amazon.com, so the filters are cheap even carbon embedded ones. Lexus labor cost is insane. Note: The 2011 RX350 cabin filter is the easiest to change in any car I have owned. Just open glove box, remove a panel, open the filter door, swap filters with arrow pointing up, close door and replace panel. Too easy.

The tech is correct sort of. The transmission is filled with transmission fluid that would last about 150k or so before completely breaking down therefore many original owners would sell the RX350 before any major issue occur in theory hence the lifetime claim. However, the fluid should be changed before 100k miles to prevent the start of transmission failure for vehicles running more than 100k miles. The transmission also has a filter that needs changing as well after 100k miles. So if you are going to trade the RX350 in at 100k miles or soon after then the fluid is lifetime and no change is necessary. However, If you buying a used high mileage RX350 with 60k miles or more; or keeping your current RX350 well past 150k miles then I would change the fluid ever 60k miles and the filter at 120k miles to reduce the change of a transmission failure. The transmission has a drain plug,level plug and a fill plug or just a drain plug with level tube and fill plug. However, the level is determined by a level tube located over the level plug that only allow certain amount of fluid to drain out based on fluid temperature expansion. The video shows how to it works on a seal transmission without dipstick. Similar to the RX350.

I would check under the seat to check the hoses that feed the seat cool air. The hoses may have ripped or came loose. I repaired a cooled seat on my 2015 Genesis by using HVAC tape to repair a torn hose that was loose. The seats started to cool again. Hopefully, the issue on your RX350 is a similar easy fix.

The short answer is yes a owner should follow the maintenance schedule. Manufacturer recommended services are usually needed for the car to provide dependable service. Will the car stop working and break down if the recommended service is not performed? Maybe not, however I believe that cars that are properly maintained per the service chart is more dependable as time goes.

To my understanding you will have to remove the intake manifold to access the rear plugs, so no easy way that I have heard of. My wife's 2011 RX350 AWD have hit 98k miles so it is time for me to tackle this job as well. I have done a similar difficult spark plug job on my wife's old 2006 Nissan Murano AWD which required more work due to having to remove the wiper motor and cowl section in addition to the intake manifold. I will use this video to help me do my wife's 2011 RX350 sparkplugs. The 2010+ highlander is very similar to our 2010+ Rx350 so same method more or less.