I was driving my TL last night on a rural road and had to pass a semi hauling produce. Not too long after I noticed that the temp gauge was creeping up to 3/4 of the gauge. I dropped my speed and RPM's down and it returned to normal. Arriving at a traffic signal, it started to creep up again util I got going. This behavior happened at each stop. Once in town it was hovering more and more at the upper 10% of the gauge. I made it to my destination and popped the hood. I found some coolant had leaked down below the right (drivers) side of the radiator. It was dark and late, but I didn't see an active leaking of the radiator. I really couldn't tell if it had come from the overflow or not, but when I opened up the radiator cap, the level wasn't there to be found. A few months ago I had the timing belt/water pump done, so it's possible the system wasn't bled properly. I've never noticed coolant though under the vehicle or the smell of antifreeze. I had the car towed home and will work on it this weekend. I did check the oil dipstick to see if it was milky at all. Oil looked pretty clean

I plan on starting with the easy stuff, replacing the thermostat, and filling and burping the cooling system. Does anyone have the proper procedure for this? I see various references for the free downloadable shop manual, but those are no longer available it seems.

Any help appreciated.

 

This is what i do whenever i need to burp the cooling system. Raise the front of the car on ramps or jackstands, let it idle with the cap off the radiator. You will see the bubbles come out the radiator cap opening, keep adding coolant as the level goes down. Do this for 40 mins or until majority of the bubbles stop, rev it to maybe 2k to 25k rpm and hold it there for maybe 3 or 4 minutes, at this point you should feel the heat start to kick it, add coolant as needed. Turn the car off and let it cool down, than top off again, as you drive, the system will bleed itself of the remaining air. This is the way i bled the system on every car i owned and it always worked. Someone else may chime in with a different way, but i believe thats the best way. Good luck.

 

But make sure you fix the leak first or new air will be introduced into the system.

 

Well, looks like I'll be doing a complete drain and fill on the cooling system. The overflow bottle was full of green coolant, and I know the mechanic who did my TB/Water pump topped it off with the Blue stuff since I provided the fluid to him and he returned an almost full bottle. Don't care much for the mixed coolants and it's probably due for a drain and fill anyway.

Also, it looks like the plastic 90deg fitting on the overflow bottle was broken. So I'll be replacing that as well. I believe it may have been where the coolant in the engine bay came from when the system was under pressure.

 

So today I drained the radiator and engine block today. I replaced the broken overflow bottle elbow (~$2.99 at local dealership) and refilled the system. Did the burping procedure and it took pretty much all of 1.5 gallons. Went for a drive and the thermostat stayed right where it should be the whole time. Had to add a small amount to the overflow bottle, but the radiator was at capacity. Looks like the combination of not having a full cooling system, coupled with the broken elbow on the overflow bottle, caused the overheat in my case. I'll monitor the levels over the next couple of weeks.

 

Nice!