As of 2 weeks ago i noticed i began leaking coolant and thanks to my mechanics they filled me up again. then i took a good look at it and noticed the coolant level and the following day i did the same except i noticed that i lost more coolant. My R50 isnt affected but i keep losing coolant as the days go on.

So in my search for answers, i found out there is a common fault with these minis in which the there is a leak in the coolant temperature sensor housing. so im thinking its that but i dont know where its located to inspect it!

i was wondering if any of you guys have experianced this and where i could inspect for starters on my mini. id really love to get some input from you guys! much appreciated!

 

Ι repaired mine a few weeks ago, the thermostat gasket was leaking. Sadly, you have to buy a new thermostat as it is not sold seperataly. It's not a difficult job, the hard thing is to reach the bolts. I removed the battery, ecu and battery box in order to gain better access to the bolts, i just pulled back the thermostat housing without removing the water hoses, a bit tricky but possible.

 

The most common leak is the Thermostat, it was improved about a year ago to a new material.

 

Coolant tanks are a common place for leaks also. I replaced mine last year after looking for my coolant leak and finding the coolant bubbling though the tank seam after the car came up to temp and built up some pressure. If it is the tank they are only ~$40 on line and take about 10 minutes to replace.

 

36rodder it is common for the coolant tank to leak on the S, but the Cooper has a different tank, that isn't pressurized so they don't have problems leaking.

 

I had the same problem with my R50. The dealer replaced the thermostat under warranty. That is the most likely culprit!

 

Funny you mention that, my mechanic noticed the short hose going from the engine to the radiator fan didnt have any pressure. So its normal not to have pressure for the non s cooper (my r50) ?

I dont think my mechanic was aware of that.

thanks for the knowledge yall!

 

That overflow/expansion hose is just like 99% of other cars on the road...just a non-pressurized hose...not sure what type of cars your guy normally works on.....
The S is unique...it is uncommon to have thevoverflow tank pressurized.

 

oo man!!!

Get this guys, so I was on my way up a parking garage and there was a lot of brake, clutch, gas, action on the way up then when I get to my usual parking spot (lots of traffic this time). I smell hot coolant burning and I look @ my car temperature and its fine. Then I notice the car fans stay on when I turned off my car. So I pop the hood and I see coolant spewing out of the coolant tank!!!! (That morning I also happen to notice the tank was filled right above the minimum level (apprx 3/4 an inch above the minimum line)).

I'm worried and now I plan to fill it up with water until I figure out the faulty parts and replace them.

im not a auto guru but I do know how to signal trace and locate faulty components (I'm a navy electronic technician). Do any of you guys have an idea on what the faulty part is ?

i know it could be a leaky thermostat or fuse but idk if other components could be the culprit aswell.

 

I would also check the resistor for the low speed on the radiator fan. They often fail.
It should go on with a/c on or with coolant temp of 105 C. High speed comes on at 112 C.

 

If coolant is spewing out of the tank, it sounds like it was either overheating, and overfilled....you might have some air stuck in it from being low before...this and a bit of driving CAN cause overheating...
Or possibly a much more serious problem...
Over heating more than 1-2 times is a guarantee of possibly expensive repairs...head gaskets, warped heads, etc...the stress from overheating are huge, and very determental to the life/performance of the motor. If you want to drive it till it stoP's running in protest, and needs a new engine/head, that is your option...a $$$ one though!!

 

If the fan works..even if the lowspeed is failed, it should not overheat...
If it has a functional thermostat, and enough fluid, it should not overheat( well, a working waterpump, and unplugged radiator is needed too!)...the dammage from overheating is a bit cumulative, and not always immediately apparent...you may now have more issues...
Possible you just had an airbubble from being low before, but you are running you car on the edge of $$$ dammage...

 

Well the car never over heated according to the meter on the center dial where the speedometer is at. i thought that was the only way to tell overheating on a mini. the air bubbles story sounds about right since my coolant was low and my mechanic (of whom only works on base & S mini coopers) topped it off for me. then the fluid started to go down and all that and when i was on low and drove it it came spewing out as mentioned before. i believe it could be the thermostat and ill have to have the air that got in the system some way. well ill order the thermostat from WAYMOTORWORKS tonight and see how it goes upon installation. thx for the quick responses zippy & cristo

 

Idk how you check the temperature but this morning i turned on my mini let it heat up to its operating temp (in accordance to the interior engine gauge) and then turned on the A/C. I took listen as i heard sound activity comes from the passenger side where the belt began moving. i let it run for about 5 minutes and i noticed a high speed fan come on for 5 seconds then stop. that high speed fan came on again and off before i turned the engine off. could that be an indication of a faulty low fan speed resistor ?

 

If only the high speed fan comes on for a few seconds with the a/c on, the low speed fan circuit is probably open (broken). That's how mine was.

You can check the coolant temp by selecting menu 7.0 in the odometer secret menus as illustrated here (borrowed from mini2.com diy/fyi section):
It's also documented in the little Bentley book "MINI Cooper 2002 - 2006 Diagnosis without Guesswork".

How to show RPM, Fuel Level, Speed and more on your Odometer Digital Display
The information below is based on the account of a MINI2 member. Although MINI2 and the author of this thread believe this information is accurate,
using it as a DIY guide is done at your own risk. MINI2 and the author are not responsible for any damage, personal injury, or warranty issues that
may arise from the use of this information. Some information below may be specific to model specifications that are unique to certain countries,
and may not apply to your model of MINI One, Cooper, or Cooper S.
Do not undertake any DIY project that you are not qualified to perform. If you have questions about this project, you should consult with experienced
professionals and/or your MINI dealer before undertaking it. Always follow standard safety guidelines for car repair in performing DIY projects.

Seeing as I mentioned this in another thread elsewhere on MINI2, here's a quick how-to on getting a bit more information from your MINI's computer.

The information displays in place of your mileometer, so you DO NOT have to have the MINI OBC/Trip Computer option to see this.

A complete list of functions is below, this example is how to get into the menu number '7'.

1. With the key in the ignition, but in the off position, press and hold down the odometer reset button, while holding the button down, switch the key in the ignition to position 1.
2. The screen will say 'Test' and a number.
3. Scroll through, (pressing reset button) through to test 19 and wait a moment.
4. Wait and the message will say "log i-off" then "log i-on" and back to "log i-off" again. When "log i-off" appears, press again. You are now in the system. (Woooo)
5. You can (if you wish) start the ignition any time from now.
6. Scroll through to test 7.0 (or whichever from the list below) and wait a moment, after a pause you will enter the test 7.* range of information.
7. You can scroll through now (7.1,7.2,7.3 etc.) using the reset button.
8. You can exit each menu by pressing, holding for a few seconds, then releasing the reset button.
9. To leave the system scroll to 19 and leave it for a few moments.
   Switching off the ignition also exits the system.

Test:

1.0 Chassis number
1.1 Kilometer count
1.2 Parts number
1.3 Coding-, Diagnostic- and Bus-index
1.4 Production Date (Calender week/year)
1.5 Hard- and Software status
1.6 Injectorstatus, Cylinder count, Engine factor.

2.0 Combisystem Test

3.0 Service intervall counter

4.0 Actual fuel consumption in l/100km. eg.0154 = 15,4 liters/100kms.
4.1 Consumption in liters/100kms.

5.0 Distance consumption in l/100kms.
5.1 Actual rest distance with available fuel in Kms.

6.0 Actual amount of fuel in tank. eg. 123321 =12,3liters left 32,1 liters right
6.1 Total amount of fuel in tank.
6.2 Show value of Fuel guage. 1= both senders OK, 2= sender failure, 3=ti signal unplausible (no reading)

7.0 Actual coolant temp.
7.1 Actual outside temp.
7.2 Actual engine revs.
7.3 Actual speed

8.0 Hexadecimal readings of menu 7.0 to 7.3

9.0 Actual on board voltage (Battery)

10.0 Land codes

11.0 Unit codes

12.0 No funktion

13.0 Gong test

14.0 - 14.4 On board diagnostic codes. eg 000000 = no failures

15.0 - 18.0 No funktion

19.0 On/Off for Test menu.

20.0 Correction factor for Fuel consumption
Formula for correction:
Shown consumption x 1000 / user defined consumption
Push the trip reset button to begin the correction. Numbers count up from 0-9, when correct number shows push trip reset button.

20.1 Sets 10ths. for consumption factor
20.2 Sets 100ths. and 1000ths. for consumption factor
20.3 Saves the new consumption factor and shows new value

21.0 Software reset. (Same as disconnecting battery)

Notes:

I have not been able to get speed into MPH, if you can update me with how to do this (if it's possible), then feel free to do so.

Your MINI's computer may give more or less information than stated above.


minimarkcs for the complete list of functions, translated from German and typed by hand!

 

X2

 

im at 7.0 on the test checking the coolant temp and i heard that high speed fan go on and off for about 2 seconds in 89, 91, 93, 95 then it goes back down to 90 then moves back up to 91 and so on and the fan comes on at the same temperatures noted in the earlier part of this message. this seems to be normal, yes ?

(btw i have the car on with the a/c on full blast)

 

With normal driving and the a/c off, the thermostat will cause the engine to cycle
between about 85 and 93 in winter weather, as the radiator is being
cooled by ambient air pretty well. If you stop and idle, the temp will climb
above 95 once the radiator gets fully hot, and the low fan will come one at
105 and go off at about 101. If you rev the engine or drive hard enough to
get the temp to 112, the high speed fan will come on and then go off at 108.
If the low speed resistor is broken, then the temp will slowly increase during
idling until the high speed fan comes on at 112, and goes off at 108.

When the a/c is on, the fan comes on and stays on at low speed at a much lower temp,
and the high speed fan at a higher temp, but I'm not sure what the numbers are.
If the low speed resistor is broken, then only the high speed fan will come on
intermittently and briefly at temps you are describing.
I think a temp sensor in the a/c system is activating it under these conditions.

 

To answer the original question above, the fan should be coming on low speed and for a longer period of time with the a/c on.

See what happens idling with the a/c off and refer to the previous post.
Don't let the system get too hot or boil over, though, you don't want
to overheat your engine and risk damage.

 

So i went for a drive and came back with some results. I managed to re create the symptoms i described before and to what mr. cristo here has told me it seems i have a bad low speed fan fuse. i drove the car and cruised at right under 100 (degrees not MPH) untill i slowed down and did a little more stop and go driving. then temperatures came to a climb. when i arrived home i didnt arrive with the temperatures to activate the low speed fan. but i stopped checked the coolant level and saw it was spilling over the top again and i continued with raising the temperature. i came to 108 and the low speed fan still didnt kick in, or i didnt hear a difference in engine activity than in the previous temperatures. then i hit 112 and the high speed fan activated! i checked out the coolant level and it was like a darker yellow almost amber ish color and topped to the top of the cap and some spilled over.

So now i think i need to get a new low speed resistor and while im at it i think ill get the thermostat replaced. what do you guys think ? wise choice ?

 

Sounds like a good start. But . . . MINI doesn't sell the resistor, just the whole radiator fan assembly
(about $250-350, or aftermarket about $100-150 from non-MINI sources), although you can splice
a 0.33 ohm 100 watt resistor bought from Mouser or a similar electronics source into the wiring
harness to the fan. I ended up buying the whole fan assembly from Classic MINI in Ohio (20% NAM discount)
as the fan in my fan assembly was starting to go as well. Get the right fan assembly, though (they changed
part number and design approximately 3/2003 - early one has two wiring connectors, later one has only one).

See this very long thread: skip to posts 349-352 for this shortcut solution if the fan is good but the resistor is out.

https://www.northamericanmotoring.co...-solution.html

 

Great info on thermostat. I am working on a friend's 04 Mini and it was leaking, got a new thermostat/gasket, but was wondering if the housing was messed up as why would it be leaking in the first place? The thermostat has what appears to be a silicone rubber gasket material on the new part. Now I have ordered a DVD off Ebay of the service manual, but have not received yet. Is there a coolant air bleeding procedure listed? I'll have to search... Did not see much DIY on Mini2 BTW, everyone was saying "so I took it to the shop" at the end of their problems postings...LOL

 

Hey guys, so I took apart my front end today and heres what I noticed. On the drivers side by the radiator there was a cylendrical part connected to a frame. At the bottom there is leaking going on. Now im in a big sense of urgency to fix this very soon sometime next week. Do any of you guys know what all I should replace in concerns to coolant leak ?

1. Radiator Fan assembly (w/new resistor)
2. Thermostat Gasket
3. ? After market resistor ?
4. ? Thermostat Housing ?

I wonder if Waymotorworks can recommend something for me! *hint*

 

From the looks of your photo, the coolant is leaking from the driver's side radiator tank. I'm not sure of your level of experience but the silver finned thing in front with the silver pipes going to it is the Air conditioner condenser. The radiator is behind that. The frame just gives support, and the rubber between isolates the tank from vibrations.

The trick will be to figure out where the leak is coming from, just because its ending up on the bottom of the tank doesn't mean its coming from there, liquids flow downhill.

I'd start tearing into it (hope you an alternative driver) and check the hose clamps and hoses. If you have access to a radiator pressure tester tool you can put about 8-10lbs of pressure on it and see where leaks are pretty easily.

Its looking from the photo like a radiator needs replacing/repairing. Why did you list the other items on you post? I'd just fix what is needed at this time. The themostat housing I replaced (and that fixed it BTW) is not going to be easier at that time as its to the left of the battery in general, the only thing that would make it easier is that the coolant is going to have to be drained. Good luck.