Rad Fans - Shift Points - Related?

[npye]

Just wondering if what I am experiencing is by design.

When the rad fans are running, my van (97 Voyager 3.8) won't shift into fourth gear until right around 78 KM/H. And then, when you coast down below that RPM / speed point, the van shifts down into 3rd gear. This does not happen when the rad fans are off.

Is the transmission being told to keep the RPMs up in order to power the fans, etc..?

Thanks,
Nial

[neon_rt]

The engine computer is thinking that the engine is overheated and runs the fans to cool down. It also selects lower gears to keep engine rpm up, mostly to circulate the coolant faster. You didn't mention it but in some models the air conditioning is locked off during overheat condtion. The question is: Is it overheated or is the sensor bad? I don't know about the newer models, but in older models you could test the fans by unplugging the water temp sensor while the key was in the run position (engine running or not). I assume that same test would work on newer models. The computer assumed full hot (overheated) if the sensor is not working or giving inconsistant readings. I would start there for a fix.

[npye]

OK thanks, I just wanted to make sure. That makes sense, keep the RPMs up to circulate the coolant more quickly.

I appreciate you confirming this for me.

Nial