Hello!

Here's the deal and symptoms. 05 mcs
Car always bone dry on startup-have to refill everytime.
I drive with heat on in an effort to help.
Car will drive 20 min normal temp, spike real hot, and then go normal temp for 5 min, and then spike hot until I park.
By the time I park, the resovoir is boiling over. I have already changed t-stat, and bleed system on startup by lossening bleed screw and turning on heat, filling resovoir until bleed screw has fluid coming out.

I was told if the heater still works, then the water pump is NOT bad.
However, if the car is parked, and i simply put fluid in, there will be a puddle about 10 min later.

I was thinking of test running/idleing without t stat to check if the stat i bought was bad etc.



Thoughts?

 

From what you wrote in your post, it sounds like a bad thermostat, but I take it that it was acting this way before you changed it as you mention.

The water pump has a weep hole in it, when the water pump bearing is wearing out the seals begin to allow coolant through the bearing and then escapes via the weep hole, giving you an indication that the bearing is going.

I would do a compression test on your head, and then a leak down test, when you do the leak down test I would pay attention to the cooling system for indications the air is escaping from it.. I suspect you have a blown head gasket a small gap in the compression seal allowing gasses from the two upward strokes to be introduced into your water jacket, causing the issue.

The compression test and leak down test will show this if it is the issue.

Best of luck.

Motor on!

 

Thank you much and this does help. I guess its safe to assume it could be JUST the water pump, and worst case the water pump and head gasket.

I am a "newby" to minis, but I assume if I bought a new pump from Way motor works, that the pump has the bearing installed already?

Thanks again-I will do these tests, and hopefully just the lesser cost of the 2.

 

Don't mean to sound like a azz...
But you have to look....
You are loosing coolant...
You have a puddle after the car idles a bit...
If it is coming out the cap on the tank as a result of overheating, cause it has a it bubbles. It is one thing..but if it is leaking out, another...
So step one...
BLEED THE COOLING SYSTEM ..
The mini dies not self bleed just from filling...it has 2 bleed locations...fill the system, bleed it...let it run...
You symptoms might be from air trapped in the cooling system...
And be looking for where the coolant is going...
Cracked radiator tank, etc...
Running a 19% effective reduction is VERY AGRESSIVE....many tried...few stuck with it...
17% was the functional limit for many based on reliability....

 

P.S.
THE second bleed is next to the thermostat... Even dealers have issues...they can be a pain to bleed...
Any idea if the cap is bad...new cap comes with a new tank...they seem to leak at the seam every 40,000 miles or so....

 

I appreciate it and u dont sound like an azz, but I need the simple straight answer so thank you��.

I will do the leak and compression test and "look" as you say, and you're right, i had no idea of the 2nd bleed location! I did purchase a new cap as well, but still bubbles out.

Thank you all again

 

I'm willing to bet at this point the headgasket is nuked.

I cannot stress this enough: If it's overheating stop driving until the problem is fixed.

 

You're good. The car is parked and Ive been drivin the mustang.

 

I never updated this post, but I ended up changing the head gasket...still overheated, and then found a small pin hole in my radiator. Changed that out, bled at the 2 bleed points, and everything has been good for 1.5-2 yrs now with no overheating.

thank you all for your help

 

Good to know.