Changed my thermostat and now the car won't idle properly and it seems as though thermostat isn't opening. The nose going into the radiator at the top is nice and warm and the hose coming from the bottom is cold (could be air in the radiator?). Biggest issue I need resolved is the idle.

 

Might want to check to ensure that your thermostat is not installed backwards (reversed). This could cause it to not close/open properly. The portion with the spring should be pointed toward (inside) the engine block.

 

The thermostat housing only fits one way.

 

Not the housing. The thermostat can be turned the wrong way.

 

The thermostat is molded into the housing. You can't move it or adjust it.

 

I second double checking the thermostat. All the ones I've put in have the thermostat and housing as two parts. Make sure it is installed with the correct side outwards / inwards. The thermostat housing will fit over the thermostat even if the wrong side is facing outwards / inwards. You may just need to flip it over.

Also... I have found that the bleed valve by the radiator is good for detecting if the thermostat is opening. Mine did not bleed until the thermostat opened and let the coolant flow.

 

This is the thermostat and thermostat housing. It's for a 2013 R55 with the N16, naturally aspirated engine. The housing is fused together, with the thermostat itself sandwiched in between.

 

Oh sorry for the confusion. I clicked into the wrong generation forum. I have a r53. Good luck

 

All good. I'm actually kinda jealous that you guys have the ability to change just what needs to be changed.

 

My bad. Thought you had an R53.

 

Guess it's possible that you have a bad thermostat even though it's new. You could test it by submersing it in really hot water to see if it opens/closes. Of course, you would need to remove it which may be a PITA (I'm not familiar with your model). If after testing it shows to be operating properly then you could at least eliminate it as the issue.

 

Yeah like Cooper 48 mentions, to fully test the thermostat you will need to put it in a pot of water and start heating it up. Once it gets to 190F, I believe, it should open up.

I, too, have an some experiences with the thermostat. Can you state which brand and where you get yours? i buy most parts from ECStuning and let me tell you. There's this brand, Bremmem, DO NOT BUY!!! Stay the heck away from it. I got so pissed off with it I had to go on ECStuning and put a bad review on it. I had it installed on my wife's car, running good for almost a year, then all of a sudden, it failed causing overheating problems. It was stuck close, or didn't respond to rising temperature. Whatever the case, the overheating problem constitutes a bunch of other failed parts on the belt side. The friction wheel's plastic housing got melted off and finally broken into pieces and jammed into the belting and pulley assembly. The belt got all sorts of burnt rubber on it, the friction wheel itself is toast. I had to open up the water pump to check it's health. But the water pump pulley wheel is also bad. Rubber was full of uneven extra burnt plastic, so that has to be replaced. I had to remove the water pipe to check and remove any possible debris, had to change those o-rings.

I later bought a Dayco thermostat. When I compare them side by side, I find Dayco's unit has all sorts of printing and markings on it, just like the factory one (I kept the old factory piece in the shelf). The Bremmem unit has no prints on it, not even their own branding. I also have put a Dayco's thermostat on our old N12 cooper 4 years ago, no issues to this day. Just saying, watch who and what brand you're buying from. You may have gotten a hunk of junk if you don't be careful.

 

I don't remember the brand right off, but I got it from www.autohausaz.com . It's an OEM thermostat.
Things have actually settled up. Found out it was the breather tub was broken. Got it replaced and all is well.