Can anyone help? My 99 RX300 take much longer than usual to warm up. On a cold engine, I have to drive over 5 min @ 3K RPM before the transmission shift to 3rd and overdrive gear.

I think I got a stuck open thermostat. Can anyone tell me where the thermostat is located? I like to change this out as part of my coolant change. Thanks.

 

Welcome to Club Lexus.

That's normal what you describe and it is partially related to emissions reasons (warming up of cat converter). Everytime I run at the track, I have to wait at least 4 minutes before running from a cold start or I will be left in the dust.

I looked but I am afraid I don't have an exact picture of the location, but it is accessible on the right side of the engine block parallel to the air box. I'd have to wait until I get home to get a good shot of the area.

 

It is in a PITA location and unplug negative terminal of the battery and have a lot of patience. When you change the coolant be sure to open two drain plugs on the engine, as well as the one at the bottom of the radiator.

 

Thanks for the hints.

By the way, do you happen to know the thermostat part number?

 

I am not sure offhand. I switched out to a TRD T-Stat back in late 2005, and I could have sworn the old T-stat had the part number on it, but I don't have it nearby. In addition, as I have seen, part numbers can change over time. I'll try to take a photo of the location later today.

 

Make a distinction between engine temp and transmission temperature.

With engine COLD open the radiator cap and start engine. If the Thermostat is stuck open you will see/observe a flow in the radiator.

The transmission stays in low gear till it warms up [5 min is normal]. I tend to stay below 2500 till it warms up and frees up the higher gear.

Salim

 

Thanks, I will try the test when the engine is cold.

By the way, I know about the cold engine and transmission gear shift. It just I have been noticing it takes much longer to warm up; even in 80s/90s degree weather.

 

FYI. The location of the thermostat is behind this water inlet. Again, this is not something simple to do (and it is a little tougher in the RX than in other vehicles).