High temperature reading, warm A/C output?

GABRIEL ABREU

MEMBER
2004 TOYOTA SIENNA
3.3L
V6
2WD
AUTOMATIC
281,763 MILES

Vehicle has new water pump, thermostat housing, thermostat, aluminum radiator and cap. When idling, temperature rises well over operational (above 3/4 mark). Radiator fans do not hold high speed when temperature gets to operational (1/2 mark). Radiator fans engage on high speed briefly and suddenly disengage to normal speed although temperature keeps raising. Engine compression test passed. Vehicle lowers temperature when accelerated. Fan relay terminals 1 and 2 do not have continuity when pulled out of the box but do when installed and battery connected. I guess it is an “Normally Open Relay”? Might be the relay or the Coolant Temperature Sensor? Any help or suggestions will be greatly appreciated. Thanks in advance.

Thursday, July 13th, 2023 AT 8:01 AM

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
54,144 POSTS

It sounds like the A/C condenser fins are clogged; I would use a high-pressure garden hose to blow out the cooling fins in the condenser.

Here is a guide you can go over as well:

https://www.2carpros.com/articles/engine-overheating-or-running-hot

There is a cooling fan ECU that might be going bad as well, to be sure we can run a CAN scan to see what comes up. You can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon.

here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

Here are the radiator cooling fan wiring diagrams so you can see how the system works. Also here is the coolant sensor if you want to try a new one to see if that makes any changes. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.

Images (Click to make bigger)