Hello,

I have a 2005 MC-S that has been overheating at idle, but not while in motion. I found on other threads several possibilities for what this could be. I have noticed low coolant so I started there and thought I would flush (first time I've tried this) and didn't have the best results. Raised front driver (US) side on a jack, disconnected the lower radiator hose, opened Expansion tank cap and bleeder valve on top hose. Only had a little under a gallon come out. Flushed with hose for a while, turned engine on, turned heat on, let it flush out. Turned engine off, turned water off, let drip. Reconnected lower hose. Added fluid (maybe too fast?), nothing came out of bleeder valve opening but tank was full. Started engine and let it run a little- tank volume dropped a little but then expanded back up. No heat coming from vents
So then I was a bit stumped. Replaced bleeder valve screw, replaced expansion cap. lowered vehicle back to ground. Drove home (about 20 min). Let car cool. Checked tank, volume was lower for sure. Didn't see dripping. Opened bleeder valve and fluid came out- seemed like a good sign. Added more fluid to reservoir to max line. Idled car with heat on until car came to normal temp and then for a few minutes more. Still no heat.

I feel like I missed something and somehow there is air or something preventing fluid from going to the heat thingy. (technical term). Can't find directions on how to solve this.

Side note- fan did not come on at all during this time so I'm guessing my original problem with overheating is a bad fan and not the coolant system but now I've gone and fudged up my heat. Any help would be greatly appreciated. Thank you!!

 

There is a second bleeder by the thermostat....

 

Does it look the same as the one on top? Plastic? I think the thermostat would be to the right of the engine, if facing the car from the front, a little bit down, is that right?

What should I do? Open the thermostat bleeder on its own? with the reservoir cap on or off? Sorry total newbie here. Thanks for responding!

 

The lower bleeder screw is a metal screw and it's way down low under the MAP sensor bracket. You'll need a long reach screw driver and a good flashlight to see it.

 

http://www.pelicanparts.com/techarti...ant_Change.htm. They go into detail on how to bleed the system with both bleed screws. Good Luck.

 

Thank you buzzsaw - I read those instructions but have a question - as I am alternating bleeding the two screws, do I leave the reservoir cap off or should it stay on the whole time? I assume off?

 

https://www.northamericanmotoring.co...g-coolant.html. Check step 5 and 6. Good luck!

 

Surprisingly this morning, I had heat! So hopefully the air worked its way out... Any thoughts on if I need to do anything further to ensure no issues in the future?
BTW, I ordered a new fan and a new intake snorkel boot since I found a crack in the boot.