I opened the coolant tank cap when the car was cold. I did not hear any pressure being released. I noticed the res tank was almost empty. After I fill the reservoir tank, do I need to Re-pressurize the system?

Car is a 2004 Non-S

 

The pressure will increase automatically as the engine heats up when you drive the car. The pressure will drop back down as the engine cools down after your drive.

This assumes, obviously, that you've put the cap back on after filling the reservoir!

 

The Mini is rather odd in that the coolant tank is part of the pressurized system, not an unpresssurized overflow tank like on most systems. As such, you never want to remove it when the engine is hot, but it is fine after it cools down. You want the coolant to be between the min and max lines - there are some fins on the bottom of the tank that are at the min line so you want to keep it so those are submerged.

- Mark

 

you should be fine.....
One word of warning....use the same coolant you have in your car. Do not add any universal fluid....it does not meet specs for compatibility. The green, the orange, the yellow and the pink are all chemically different than what is in your car if it still has fluid from the factory/ dealer. BMW/mini fluid is blue, and is a hybrid technology fluid...zyerx g-05 I think is the aftermarket compatible stuff. But BMW/mini sells it undulated for about 18$ a gallon...just mix it with de-mileralized water...otherwise known as distilled water is recommend.
Since you only added a cup or so of water/coolant....you should be fine...you might want to get a jug for future use!!

 

Great, Thanks for the info. Seems to be running fine. I drove it to work and back (160 miles) round trip and no temp change.

 

Since you have a Cooper and not an S the coolant tank is NOT pressured on your car, it's just an overflow tank. So your fine with opening it and topping it up. Don't worry.

 

Way,

Is it true you can remove the cap on the cooper s only if it is cool? Also are there any other no-no's when dealing with the cooling system in the cooper S?

 

I swear all I did was top off the coolant in the tank and in the fill port and now I seem to have a small leak some where, I noticed a small drip under the car today when I was replacing my spark plugs.

 

If you overfill the tank, it is possible that excess fluid will be vented.....cold it shpuld be at the full cold line, or hot, at the full hot line....above that and when it expands, it will drip out.
Also it is strongly recommended that you use a torque wrench to tighten down your spark plugs...and only install the plugs in a cold car.

 

You should let it cool down before opening on an S, but if you let it cool a little and open it slowly to release the pressure that will work most the time. Other than that the only other NO NO is don't trust the coolant temp gauge. It will stay at the half mark until over 230 deg before it moves, by then the car is overheating. I suggest the ScangaugeII for using as a temp gauge.

 

Well I put the car on the lift and climbed around the engine bay, the coolant leak or drip seem to be coming from the thermostat area. The 3 bolts seem to be a little bit loose, So I tightened them up and we will see how the leak goes.

 

That is a very common spot to leak...a revised thermostat with an improved gasket is available. If you buy a new one...just be sure to get the newer one...they changed the color of the gasket...so you can tell the new stock from the old stock.

http://www.waymotorworks.com/thermos...t-r50-r53.html

 

Is this a good one to use?

http://www.autozone.com/autozone/cat...&parentId=63-0

 

I personally would not use anything other than the OEM thermostat....I've heard a few folks say the universals don't fit due to the housing shape or that the gasket on the aftermarket must be notched to fit....IMO not worth the effort to save a couple buck...especially if you have to go through the hassle of doing it AGAIN!!

 

I'm not trying to poke fun at you by saying this....but swapping out the thermostat might be over your head a bit....I'm sure you could do it...but it might be wise to get a pro to install it, or a good friend who knows what they are doing at the very least. When you are done, the system must have the air bled from it, and you must get the right type of antifreeze to refill it. None of it is especially difficult, but it sounds like you might need a buddy that can show you a few things about your car.

 

Hahah....Um what gave you the opinion that I don't know how to work on car?
I have a full shop with a 10K lift. Current projects are a complete fram off restoration 55 Chevy belair wagon, and a 1965 VW bug. I just finished a rebuild on my 96 jeep cherokee + installed a 4.5" rubicon superflex kit, and even painted the darn thing. Not to mention a whole plethora of other vehicles I have built. I just like comming here for advice and other opinons. "Mesure twice and cut once" I always say. But thanks for the vote of confidence..

 

I had a recent overheat issue on a 2007 mcs. The dealer replaced the thermostat housing which corrected the issue. They said a common problem.

 

Yeah soon as I get a chance, Ill order the new "updated" thermostat. Maybe Ill do a DIY thermostat replacement with photos. If it has not been already done.

 

Sounds like you know what you are doing no problem....just the line about do I need to " Re-pressurize the system" made me think you were a bit green...we see a lot of that around here!! Have fun...it is an easy job!!

 

Yeah I hear ya, Thanks take care!