I have a 2005 MCS R53. I consistently have to add coolant. I replaced the reservoir about a year ago, but it seems to need replacing again? I know they are junk, from what I've read, but two reservoirs within a year? Is that normal? The fan kicks into high when idling for longer than a few minutes.

Any other ideas, that may be causing it than I may not be thinking about?

 

they are junk, with random times of failure. are you actually leaking coolant? dribble dried up? or just finding the reservoir empty? cause you could need a head gasket if theres no visible drippage

 

Yes visible dried coolant all over the lower half. But might there be another cause? What's normal operating temp? Around 200? Mine stays halfway between 140 and 250.

 

Also my AC went out yesterday. I've read that this could possible be fan related issues if low fan speed isn't working.

 

When the resivior is overfilled, it tends to split/leak at the seam.....but you should see a residues around it...if it is clean, I would guess you have a leaking thermostat gasket, also very common....then again, on a 10+ yearold car,anything could be leaking with a pinhole sized leak....just have too look....

 

Possibly.... Many folks find that their AC compressor clutch fails after having a fan issue for a bit...seems that making the compressor work so hard against higher pressures can cause the clutch on the compressor fail. Might not be DIRECTLY related, but they certainly seem to be correlated. But before you jump to conclusions, I would get it diagnosed....could be low r134a coolant, it does tend to need to be topped off every 5-6 years in most cars, and there is a low psi swich that stops the system from running if low to prevent damage.

 

Thank you, that was going to be my first thing for the AC is check the refrigerant, before I go spend the money on the replacement parts. Also have to check the low speed switch on the fan, as well. Thanks for the Replies, I will more than likely go ahead and replace the thermostat. Is there a low temp thermostat for our cars?

 

A low temp thermostat won't cure your 250 degree problem. You have other issues. Stick with the factory temp thermostat and figure out the real cause of the problem.

 

+1
Running a lower temp thermostat tends to really kill mpg with a computer controlled motor....about 1.5 mpg of a hit...the car stays in "warm-up" mode" and sometimes will toss codes....the motor is machined to run a a certain temp...remember metal expands...so running cool can leave a tiny bit more clearance in some areas...
Some folks do it,but IMO it is more of an attempt to use an old school carbrated car trick on a computer controlled car....and things have come a long way since then.
Some folks take out the fan to change out the resistor that controls the lowspeed part of the fan....but IMO just getting a new assembly is a good option...the fan gets beat up, and filled with salt, sand and debris....
One suggestion...fill up the tank to about the baffles inside (about the same level as the seam on the side)...and clean up the outside....watch it for a few days....if overfilled, the tank vents through the cap...and you also get dried coolant on the tank....many folks overfill the tank...so there is zero room for expansion, and the tanks leak....

 

I changed out the resistor on my fan but if I had to do it again I'd just replace the whole assembly. It all has to come out anyway and it's easy to break the resistor housing.

 

I'd think you definitely have a leak somewhere as well. Sometimes if it's slight it can get burnt off before it makes its way to the ground. Make sure the hose on the bottom of the coolant tank isn't loose or leaking. There is a hose clamp that holds it on, so make sure it looks good. Just be sure to inspect everything closely. I like to do the water pump and thermostat at the same time, personally. If you decide to tackle everything at once, we have some pretty awesome super kits HERE that have just about everything you'll need. Good luck with the fix and hope you get it resolved soon.