sexylexy19

Hey all. My 98 es300 will most likely need new o2 sensor soon if not already. I will be checking them this weekend. My questions were what o2 sensors (parts #) do I need and where is a good guide (with pics) on how to replace them?

tbmobiledj

There are two O2 sensors on the vehicle. The easiest one is right up front on the exhaust manifold. Take a wrench to get it off, but it might take a little effort to get it out. Be careful though, from experience, there is a bolt holding the fan in right up front that I have a nice scar down my arm from running it across that bolt. Lot of blood and a little grease got that one completed in about 5 minutes. The tough one is way down at the bottom of the other side of the engine on the exhaust manifold next to the firewall. Easiest way I found to get to it is from the drivers side and leaning over the fender. A good wrench will get it out also.
I got the replacement O2 sensors from AutoZone, but they are about $200 a piece. Good luck.

sexylexy19

Do you by any chance know the part # on those. I want to see if I can get them cheaper online.

MikeLex

Both Federal spec (not Cali)
Front: 89465-06100
Rear: 89465-06020

CUMan

Rock Auto has Denso oxygen sensors for a 98 ES for $66.79 each. Denso was likely the manufacturer of the original oxygen sensors in the car.

I would assume that you will need two of the "upstream" sensors and one of the "downstream" sensors.

sexylexy19

I read elsewhere on CL that the downstream sensor is not important and does not affect the way the car functions. Is this true?

Also, thank you, MikeLex.

CUMan

That could be true, but I would guess that it would set off the check engine light if it malfunctioned. The code you could retrieve should indicate if the sensor is bad. You certainly don't want to change out this sensor unless it is absolutely necessary. I have never had a problem with the downstream sensor in my wife's 94 ES, but I understand it is very difficult to access. I recall reading something about removing the seat inside the car to get to the connector.

The two upstream sensors are not too difficult to replace. The one between the back of the engine and the firewall is somewhat difficult because of the small space you have to work in. The front one is easily accessible.