Hello, I have a 2001 RX300 with 180,000 miles and need to replace the knock sensors after getting the related check engine lights and error code. I've read through previous posts about replacing the knock sensors and have some questions about what other replacements it would be smart to do at the same time given work will have already been done to provide access.

1. Which gaskets does it make sense to replace? I read of three that are associated with the intake manifold, two are labeled 'Manifold Gasket' (OEM #17177-20020, #17178-20020) and a third is labeled 'Plenum Gasket'. (OEM# 17176-62030) Is access gained anyway to all three of these when replacing the knock sensors? Which one or ones should I replace?

2. I replaced the spark plugs at 120,000 miles 4 years ago with OEM Denso SK20R11 Iridiums. I think I would get another 60,000 miles out of them but does it make sense to replace them now anyway? If i do should I replace the spark plug gaskets at the same time? (OEM#11193-70010) What about the valve cover gaskets? If it makes sense to replace them what are the OEM part #s for those?

3. Should I replace the water bypass hose?

4. I'm already planning to replace the Knock Sensor Wire Harness. Anything else I should ask the mechanic to do?

Thanks very much for the help.

 

Per your #1, I've been able to reuse all of the mentioned gaskets. Any that are bent upon removal, replace.
IMO, it doesnt make sense to replace your spark plugs that early but it would be wise to pull them out for inspection. Any fouled plug will determine there is something wrong with the gap, plug installation or coil pack.
Replace the valve cover gaskets the same time as your spark plug gasket seals. I prefer the Felpro set due to the material vs OEM. While the intake manifold is off, it would be a good time to replace any old vacuum hoses. They all lose their flexibility with the exposure to heat. Good luck!

 

I am just getting ready to tackle this myself. I am going to change the spark plugs while I am in there....I really have no clue how old the plugs are! I am wondering about the fel-pro vs OEM gaskets...why do you prefer the fel-pro over the OEM? In the past, when I've used gaskets that were aftermarket they always seem to never fit right. I am not criticizing you for using them, its nice to get to hear experience from some one who has actually used them.

 

I just did my valve covers last month. I like felpro but i noticed the spark plug tube seals did not fit tight in the valve cover openings. so I added some RTV before seating them. I ended up ordering 3 OEM seals for the rear cover and there was a better fitment. Some here had different results with felpro so be your own judge but the basic difference is price. Felpro is a quality product but its not OEM. You can save money by using felpro for the cover and oen for the tube seals.

 

The key feature i liked about the Felpro's is the sealing bead on the mating surface of the gasket that seals against the head and through testimony of friends that used them in other applications like the heat resistance. I noticed immediately how dried up, how much the OEM gasket shrank and lost its elasticity from the heat exposure when i removed my old gaskets. I had no issues with fitment with my gasket set and tube seals during the freezing temperatures of last february. I had expected them to be extra rigid during my install.