Well the day that i get my tranny working well is the day a new problem has came forward.

At idle my 2003 tl begins to climb on the temperature gauge(heat on or off). Its 10 degrees out where i live and it just started now that it got really cold. If i rev the engine in park, temp goes down. If i start to drive, temp goes down.

I also have the classic fan on for a while when car is
Off. Thats probably because the heat got all the way up though.

What do you guys think it could be? Coolant temp sensor? Thermostat? Low coolant?

Any help is appreciated!

 

Low coolant or air in the cooling system, also check the coolant switch its near the hoses that come from the radiator on the engine, might be unplugged.

 

Would that have been unplugged when
They did tranny work? If so its a good possibility

 

Do they need to drain (partially or fully) the coolant when replacing the transmission?

My car started overheating a few months after transmission replacement. We didnt notice it right after the replace because it was the winter, but the first warm day of Spring I needed to run the heat to keep the engine cool. Once I got home I took a look and we were short on coolant. Drained what was in there, replaced t-stat, hoses, etc and did the bleed procedure and all has been well since then.

I just assumed the dealer didnt properly refill coolant if they needed to drain it for the transmission replace.

 

^ Yes they need to pull the ATF warmer in order to flush it, Has 2 coolant hoses on top of the trans, once open theres air in the system.
Easiest way to tell if it needs coolant is open the radiator cap while the engine is cold or the reservoir level, if theres no coolant add as needed.

 

Brought to shop and they had to burp it. They did get air in the system. Good call man!!!

 

Glad it worked out and you posted back the results.

 

even though it was `fixed` ck the hose inside res cap- attached securely?

often the heater is left closed/off during burping--hiding air

for others: first thing to ck on temp raises is coolant level, the res cap and the fan temp sensor #1..thats a very common failure part if the rest is good
the fan runs after shutdown is a tipoff