Throttle Body Thermostat Missing Hoses (1 Viewer)

[Tan DaMan]

Hi all,

I'm new to the forum here and just purchased a 2000 LX470. When looking at my engine, I noticed a couple of hoses are missing from the throttle body thermostat. I've searched all over and cannot find an answer as to what hose needs to go there and where it needs to be routed to. I hope someone here has an answer. I found a picture below and I've circled the two nipples on the thermostat where there is no hose connected on my vehicle. Thank you!

 

[Tan DaMan]

Looking at these photos, I can see that the forward facing port is supposed to have a hose connecting it to the back side of the throttle plate. However, what does the other port (circled in red) connect to? Both ports on my vehicle have nothing connected to them.

 

[awesomeissquid]

Okay, so I was procrastinating from doing actual work so I dug into this for you since I kinda remembered, but I wanted to be sure.

As you found, the front facing port connects back to the throttle body itself. As explained in your snip from the FSM, the thermostat uses it to bypass coolant based on temperature.

The remaining connection should be the coolant return from the throttle body to the front water bypass joint (circled in red). That hose should be PN 16261-50090.

Having said that, are you sure you have this hose (circled in blue)? This is the coolant supply, and if you do have it, I am not sure how your system is functioning without the return as well since either coolant would be leaking out or your throttle body is not allowing coolant to flow through.

 

[Tan DaMan]

Thanks for your reply! I do have that coolant supply hose. The vehicle runs fine and does not leak coolant, so I suspect that without the hose connecting the back of the throttle body to the front port, it is not allowing coolant to run through the throttle body? Is the coolant functioning to cool the air coming into the throttle body or warm it up? The FSD wording is unclear to me. Also, do you have the PN for the hose that runs to the front port from the throttle body?

 

[awesomeissquid]

Very weird, I am not sure if the system would be able to shutoff flow like that. Maybe I had the flow direction backwards, but I would think it would just leak so maybe there is something else going on. From reading the FSM passage again I think it's function is to preheat the throttle body/air. I do not believe the other hose is available separately from the throttle body, but check out Partsouq.com. You can enter your VIN and find all the parts diagrams and prices are usually not that bad.

 

[Tan DaMan]

Thanks for your help! Yea s you can see from my picture, there doesn't look to be any coolant leak, so this is quite odd. Also wondering if I should just leave it alone and not worry about buying the hoses because I live in central Texas and don't need the intake air to be preheated?