First- I can't tell you how impressed I am with the knowledge base and interaction found on this site. Being new to Mini's I have spent countless hours in the last month soaking up information pertaining to my early 03 R53 S (36K) . I have only put 150 easy miles on it to date as I know there are things that need to be addressed. Very old tires were first- then an oil change - radio repair and I ordered an expansion tank for starters. Unfortunately, I was Baptized with a split tank the same day the new tank was delivered. I caught it early and was able to limp home without incident. The pseudo temp gauge stayed at the middle mark during this episode. . I replaced the tank- added fluid and bled. (I think I did) Researching the tank and overheating issues lead me to the low speed fan problems Mini's have. I learned that the low speed fan and PS fan should spin when the A/C reaches pressure. Armed with this tidbit of knowledge I found that the low speed fan does not engage and shortly after starting the engine (a/c on) the high speed fan (quite loud) comes on and cycles on for 7 seconds and off for 15 seconds continuously. I then confirmed that all fuses are in working order. This early model has two connectors for the fan wiring. I saw 12V at both pins in the connector feeding the fan. I applied 12v directly to the low speed fan and got zip/nothing. 12V applied to the high speed fan worked well. That monstrous 13 year old thread on the fan is a doozy- A few questions to move forward.

Can I safely assume the fan needs to be replaced ?
Are there alternatives on the early models ? Any new resistor hacks for this models- ?

Is the high speed fan cycling an indication there is air in the system ? or is this normal.
Threads I have read say the high speed fan will come on in lieu of the low speed fan but no mention of cycling.
My fan cycles with a/c on before the upper radiator hose is hot.

Will the PS fan spin at all if the low speed fan is out of commission ?

Thanks for looking-
Sto

 

I couldn't agree with you more to point out your initial comment. The community/contributors have been fantastic at filling in the holes from what the Bentley leaves out.
They have helped me a lot!

I'm not a seasoned Mini guy so I'll let the well informed give you the more valuable knowledge to your early model cooling fan issue.
The one thing I would advise (if you don't already have one), is to invest in a good BMW/Mini OBDII scanner that will also allow you to turn on various electrical and computer driven modules.
I purchased a Foxwell NT 510 elite. It has pretty darn good Mini specific scan/code abilities in addition to enable things like: ABS pump, low & high speed fan, A/C (HVAC) functions etc...for troubleshooting purposes.

 

Yes, it sounds like your low speed resistor is toasted but it's best to confirm by activating it via a scan tool as Here2Go suggested. If it's bad, you don't necessarily need to replace the whole fan assembly, you can splice in an off-the-shelf replacement resistor. I've never done this myself so I can't offer advice on how to do it.

High speed fan cycling is normal when the AC is on, even if the engine is cold. It needs good airflow across the condenser to operate.
Without the AC on and the car not moving, the low speed fan will cycle on/off and the high speed fan will only engage if the low speed operation isn't sufficient to keep the engine cool. If the low speed fan is not operational, then you can expect the high speed fan to cycle since the engine will eventually get hot enough to activate it.

The PS fan will still operate if the low speed fan isn't operating. When the DME commands the low speed fan to come on, it also triggers the PS fan. They're (kind of) wired in parallel, not in series

 

As the previous poster said you can replace a bad resistor if that's the (probable) culprit. My '03 also has the two connectors for the fan, so you can't just add a resistor in line as you can with a single connector. You'd have to remove the fan and put the resistor in. If you go to the detroittuned.com website they sell the resistor and have directions on the repair. Since it's a bit of work to remove the fan assembly I chose to just replace mine with a TYC brand fan. I didn't want to open up the front end and then have the fan itself die in fairly short order, and the TYC wasn't nearly as expensive as a MINI branded one. Also I assume that you PS fan is in fact turning because that can cause issues with the engine fan too. Best of luck in your repair!

 

Gentlemen I thank you all. Suspicions confirmed. I can see that a scan tool would be a handy addition to the tool box. Is the Fox a good starting point or is there another to consider ? I think it's best to replace the entire fan as there is not much savings just replacing the resistor and I certainly don't want to do it twice. Glad to hear that the high speed cycling is a normal condition. Eases my mind. I'll try to get under the hood again this weekend.

I read a thread recently where it was stated that elevating the front end aids is bleeding the system. Any truth to this ? Then there is the very interesting thread on using a shop vac on the expansion tank- sounds easy, but hard to understand how it could get an air bubble from the deep to the tank.
Thank again.

 

Best bet is to do the Mouser Resistor Mod. I did this 5 years ago and haven't had an issue since. if you replace the OEM one with a similar Resistor, IT WILL FAIL AGAIN! There should be a Thread on it in the Forum.

 

USNAF2- Do you think that is best on a 20 year old fan rather than replacing the entire fan assembly. All thing will fail sooner or later. This is the fan with two connectors and didn't think there was a resistor relocation. I read a bunch of the long fan thread but don't recall seeing the Mouser Resistor mod. I will search for it. THX

 

I preformed the "Mouser" low speed fan resister mod on my single plug, pre-facelift '04 R53. It's been 3years since then and - I have to say it is one of the best decisions/mods I've ever made/done.
However If I recall; I think (I think) this particular mod only pertains to cooling fans that have the single plug and not for the early 2plug version.(?)....

Edit: I believe this is the discussion in question Low Speed Fan Resistor - we need solution
Perhaps you might jump to this part of the discussion pertaining to the early 2 plug version/ alternative mod.
Although there maybe more info on the 2 plug mod in the preceding pages/comments.

Edit: With respect to OBDII scanners in general; you definitely want to invest in one specific to MINI/BMW.
I started out with a reasonably low cost ($65) Creator 110+ BM code scanner (notice "BM" and not BMW) which worked just fine for clearing an airbag light fault after I fixed a blown resistor squib (BST) at the battery.
After realizing the C110's limitations; I found a really good deal on a brand new Foxwell 510 elite ($124 including shipping) on Amazon.
I am not that proficient with computer aided modern cars and not yet at the level of utilizing higher end diagnostic tools. I am sure there are many contributors here that might suggest more current or advanced OBD and diagnostic tools...
As for my current needs; all I can say is that - the Foxwell is smarter than me and has served me well over the past year.

 

For a 70 year old shade tree mechanic, these Mini's are a bit intimidating. I haven't had to do much wrench turning on an auto for many years. The Min's seem to have more than their fair share of quirky, hard to diagnose, impossible to get to issues. It could keep me young or add years in no time. :-) I'm sure I'll be back for guidance.

Thank you all

 

The last couple months have been hectic with little time for the Mini. Following recommendations, I did purchase a Foxwell NT530 OBD scanner. It confirmed that the low speed portion of the cooling fan was indeed out of commission. I picked up a TYC fan on Amazon and installed it without any hiccups. Having little to no time in a Mini I don’t have a baseline of some operations. Using Mini’s own OBD info and the Foxwell I have found the following. Warming it up at idle (760rpm) to 2000rpm - the thermostat opens at about 94C – it cools a few degrees and then climbs - at 105C the low speed fan starts – at exactly 101C the fan stops and then goes through the same temperature/fan cycle. This seems to match the specs I have read on the site so this a good thing. I also found that starting the A/C does start the low speed fan - another good thing. I put a few miles on it and she runs fine with temps between 90c to 96c with no fan interaction. A few hours later I took it back out with the A/C on and it too ran cool with the help of the fan. I turned OFF the A/C a few miles from home and watched the temp stay put at low 90s. Once home, I realized the low speed fan was still on with temps far below the 105-101C needed to active it. It appears that once the A/C actives the fan it does not release it when turned off. In testing this I found that quickly turning the engine off and restarting does not stop the fan. If I turn it off and let the car sit for 10 minutes or so the fan does NOT come on when restarted. I can’t imagine this is standard operating procedure. Could lead to a bunch of needless hours on the fan. SO - What is keeping the fan running after the A/C is turned off and temps are below the trigger temp ?

If the Power steering fan is only activated when the high speed fan turns on at 112C it must not run very often (at least in a temperate climate)at the operating temps I’m seeing in the mid 90’s. Is there a way to easily turn off the low speed fan to test the 112C activation? I know it worked with the old fan w/o low speed. I can run it with the Foxwell but that’s not quite the same.

THX

 

Was hoping someone with a R53S 02-03 would chime in here. Under normal operating temperatures below 101C, does your slow speed fan turn off when you shut the A/C down ? I'd love to cross the cooling system off the list of repairs and move on to the next issue.

Regards

 

I have a 2002 R50, which for that purpose should be identical to a R53 (it is indeed the 2 plugs variant). What you described is also what I observed, up to the "low-speed fan doesn't turn off when AC is off and temps are low". To the best of my memory (I don't use AC much, it's not that hot here), my low-speed fan properly turns off after using AC.
Note that my R50 does not have a power steering fan, so I can't offer any input on that part.

P.S. : the temperatures you're seeing are correct, though the thermostat opening can be a bit higher or lower. I'm sure of it because I obsessively checked those before and after changing my fan (which also had a toast low-speed resistor).

 

Fradow- I'd like to thank you for taking the time to post. This is a step in the right direction but I'm not sure I have enough solid information to trouble shoot this issue if it is indeed an issue at all. I have spent hours searching all forums and haven't been able to find a word about what process might shut the fan down. I inquired with the local Mini mechanic and he just scratched his head like I have. I still have hope that other 02-03 owners can assist.