I'm considering taking out the radiator to see if anything obvious presents itself. That's how desperate I am now.

Any thoughts?

 

Turn on the heater and temp. goes down is classic restriction or air in cooling system. The more incline [front of vehicle up] the better. I bought scangauge II and leave it hooked up always, great investment for me. Good luck.

 

Thanks Tony.
My next thoughts are, getting it pressure tested and possibly replacing the expansion tank (to weed that out of the equation).

 

What is the condition of the friction wheel? The friction wheel, which is driven by the serpentine belt, drives the water pump. If there is a failing friction pulley you can get a situation where the water pump is still being driven, but at much less power than it should. This results in less water flow through the cooling system than required. I had this problem on an r56 race car.

 

I didn't pay much attention to the condition of the friction wheel when replacing the water pump honestly.
All I did was release tension by pulling out the tension 'tab' and then replace tension by pushing the tab back in all the way when the pulley was tightened in place.

I'll give it a look now.

Thanks.

 

Ok.
Lifted up the car to get best access I could without removing the wheel well and tire etc. and I was able to loosen tension and replace tension by pulling the tab out and then putting it back in.
One thing I noticed was that I could still move the tension wheel with my thumb even when the tension tab was pushed back in.

Think it's not getting enough tension?

 

Went ahead and ordered a new expansion tank from ECS. ~$70

I'll just replace that, the friction wheel, and the radiator one at a time till it's fixed... *sigh

 

read this helpful guide:
http://www.pelicanparts.com/techarti...eplacement.htm

 

Thanks for that guide, Yesti.
Really liking Pelican Parts right now. I'll use their tutorials if I end up replacing the radiator.
Gonna take the car over to the shop around the corner here for a second opinion. I was told they could do a pressure test, verify there's no leftover air in the system and scan to see if there are any current codes etc. If that all runs well and they find nothing to look wrong, I'll keep moving forward with replacing the expansion tank, the friction wheel and then the radiator and related pipes.
All the pipes by the way seem fine to me but at this stage I'll replace them to be sure. That way at the end of this I'll end up with a completely fresh cooling system.

 

Quick Update.
The shop called after having the car for two days now. There's a tiny coolant leak somewhere. It's taking them a long time to find it and they want another day to keep looking. They're sure it's a coolant leak. (I'm kind of happy about that.)

Maybe it's a pipe, expansion tank... Either way it'll be nice to work on the actual problem vs. just replacing things the dealer "thinks" it might be. That's been a terrible experience.

More updates to come.

 

Bet its the water pipe or expansion tank hairline crack.

thanks for the update.

 

I'd hope not.
I just replaced the thermostat last weekend.

 

Not the thermostat, edit* meant the water pipe or expansion tank. Sorry.

 

Last Update, hopefully:
Shop called after diagnosing for four days.
They believe the car was fine all along. They couldn't find any leaks and after day four of pressure tests they couldn't get it to overheat.
Didn't charge me anything since they don't know why it's all of a sudden fixed.
Based on the recent work I put into it and the reading I've done here i believe it's trapped air after the thermostat replacement.
So now she gets up to 105,106c and then the second fan kicks on and it drops and stays under 90c in a matter of seconds.

I'm not sure what to think.
I might just return the new expansion tank from ECS. I'm afraid to touch anything now...

What do you think?

Thanks for all of everyone's input, advice and troubleshooting.

 

Gets to about 108c. driving around without AC. As soon as I hit the max button the temp drops below 90c. If I switch to just auto or non-max AC it goes back to 108 but seems to stay about there.

 

Thats great, glad its working now. Thanks for documenting it for us too.

 

So it was just not bled all the way? I bled mine 3 times start up, warm, then cool down, etc. I thought you bled it multiple times ? If you drive it a couple days and the level holds and the coolant holds the same temp. Then it could have been a stubborn air pocket. Thanks for the update, sounds like it working now. I would check the bottom of your expansion tank , if it has very small cracks , replace it with the one you have. That way you are fixing another possible leak down the road. If not , then send it back.

 

Yeah my guess is simply a stubborn air pocket. Yes, I personally lost track of how many times I bled it, but I know it was bled a couple times at the dealer as well. I'm wondering if all the pressure testing done at the shop nearby is what pushed it out...
The weirdest thing at this point is that I still haven't fed it but only 1.25 gallons of fluid. I was sure I read somewhere it takes 1.5.

I think I'll keep the expansion tank. At this point, I'm not touching the cooling system. But if something comes up or I build up enough confidence again, I'll replace it because it's one of only two things left to complete a new cooling system on this sucker.

Driving update: Freaking. Amazing. (for another thread but omg)

 

Great, I glad its working now. You might have not gotten all the coolant out the first time.