Hi all. I just bought a 2006 rx330 with 187k miles on the odometer and no service history (carfax didn’t help). Everything works well. I’m getting ready to replace the spark plugs and timing belt kit, and I also want to check the valve clearance. Any ideas on what to check/replace additionally when I dig into these areas (side and rear of engine)? I attached the spark plug condition for example. The condition is not so good, but the gap is good: .043”

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Last Aug I was in the same shoes as yourself, bought a 2004 with 169K miles no service history so figured "do things right" so I'd have a great car for many more miles
Before starting this work go pressure clean entire engine compartment top and bottom (I recommend spraying engine with Castrol purple cleaner or Simple green in a cold engine, let it sit for maybe 15 mins, rinse with a hose then go to a self washer adn use their pressure cleaner this way you'll start wtiha clean slate and know what make be leaking and how much and it makes working on the engine much more pleasant

While doing rear plugs-
Spark plug tubes
PCV valve ($10 at Amazon)
I recommend changing the coil pack connectors as they get very brittle. Costs @$6 for all 6 you just pop out the end and attach new plastic end very quick and easy
Many like to replace the valve cover gasket while it's apart, I didn't when doing mine
Depending on your mechanical aptitude I cleaned my fuel injectors by sp[raying them out with brake cleaner

Timing belt-
If so the water pump and thermostat too, idler pulley and any barings in that area.. Aisin makes a complete kit I believe that includes everything plus they are the right brand to buy

Other things-
Brake fluid
Trans fluid- drop the pan check the magnets for shavings
Transfer case fluid
Rear diff
Check all suspension rubber bits as they are highly likely in need of love also check struts for leaks
Check brake pads and rotors
Replace power steering fluid
Check radiator for leaks
Replace engine oil and filter, v engine and cabin filters
Disconnect battery for at least one minute (If I remember right this was done when doing the plugs too), this will clear the old drivers habits from the ECM and take a few miles to learn yours however it will also require you to reset the windows, sunroof, and rear hatch
Lastly - spray clean off your MAF (do not touch it with anything) and both upper and lower O2 sensors... very easy, quick, and cheap job this gave me much better gas mileage, do this at the sme time as the battery disconnect so it learns your driving style

Good luck! Hope this helps

 

To add onto Leeper's list, I would also change the PCV valve, clean the VVT-i filters (one per bank), remove and clean the VVT-i solenoids, and clean throttle body as well. Taking the two Phillips screws holding the MAF lets you really spray clean it well vs. it being in the intake tube and only having proper access to clean the front of it.

 

Thank You! Yes, the throttle body, MAF, PCV valve alongside O2 sensors were on the list to clean. I didn't think about VVT-i solenoids and filters, thank you for pointing that out. Coincidentally the ASIN TKT026 kit & PCV are already on the way from RockAuto although Amazon has them too. Thank You guys for your advice!

 

When its time to do your brake's, great time to do the gen3 upgrade, pads/rotors & a pr of reman calipers, also great time to swap out the oem brakes hoses since your there. One look at the gen2 #1005 pads to the gen3 #1324 pads as well as single piston calipers to the gen 3 twin piston calipers.....Direct bolt on. Trans fluid, I used a gallon of Maxlife & a Wix filter(clean both magnets) for the transfer case/pto & rear diff, I went w/ 2 qtrs of 75/90 Royal Purple diff oil.....