[Whine not Walnuts]

This is long distance diagnostics so the more information we have the better chances we have at coming up with what to check on. Need some temperatures, the MINI will provide numbers in Celsius if you bring the information up.

[TBeast]

Hey, thanks. My thinking is that: since it's not overheating with the A/C on, the high speed is working. Nothing has changed since the resonator mod but current goes through the resonator (that I know because it's heating up when the A/C is switched on) so I wired it up properly. If it was a blown thermostat it would overheat despite A/C on or off. Also I remember reading somewhere that the A/C blowing briefly hot air when set to cold is somehow related to the malfunctioning low speed fan resistor but I can't find the quote. Oh well..

Yea, MINI will bring up the numbers if I let it sit still and overheat and wait to listen for the fan to kick in, which means it has to idle for 20 mins after it reaches normal temp, correct? All my neighbors will go crazy until I figure it out. I was kind of hoping that it would be one of these well known issues for the little buggers

[Jeff Cole]

Read every page of this thread, thanks to all contributors. My 1st stage fan was dead.

anyone ever think this is why so many have split header tanks and leaking hoses? Because they run too hot due to this fault?

anyhow, did it at the weekend and it's working. Thanks all.

[LAHills]

Originally Posted by TBeast

Hey, thanks. My thinking is that: since it's not overheating with the A/C on, the high speed is working. Nothing has changed since the resonator mod but current goes through the resonator (that I know because it's heating up when the A/C is switched on) so I wired it up properly. If it was a blown thermostat it would overheat despite A/C on or off. Also I remember reading somewhere that the A/C blowing briefly hot air when set to cold is somehow related to the malfunctioning low speed fan resistor but I can't find the quote. Oh well..

Yea, MINI will bring up the numbers if I let it sit still and overheat and wait to listen for the fan to kick in, which means it has to idle for 20 mins after it reaches normal temp, correct? All my neighbors will go crazy until I figure it out. I was kind of hoping that it would be one of these well known issues for the little buggers

It sounds like temp sensor, the fan temp sensor not the temp gauge sensor, is faulty. A/C on will activate low speed fan regardless of eng temp, so no overheating unless in very high amb air temp when the eng temp sensor would then kick in the high speed fan when eng temp goes above the target temp. Without the eng temp sensor working you only get cooling from forward movement of car or low speed fan due to A/C. A/C on only activates low speed fan.

[TBeast]

Originally Posted by LAHills

It sounds like temp sensor, the fan temp sensor not the temp gauge sensor, is faulty. A/C on will activate low speed fan regardless of eng temp, so no overheating unless in very high amb air temp when the eng temp sensor would then kick in the high speed fan when eng temp goes above the target temp. Without the eng temp sensor working you only get cooling from forward movement of car or low speed fan due to A/C. A/C on only activates low speed fan.

Hi, thanks for that. Where is the fan sensor? Is it replaceable? Never thought of that but sounds like it's worth a try.

[LAHills]

Oops, just looked it up. I take it back. There is only one sensor, it inputs to the DME (digital motor electronics control unit). That drives both the temp gauge and decides when to turn on the low fan or high fan. The A/C has a pressure sensor on the freon line and that also goes to the DME and triggers the low speed fan regardless of temp. I'm going to look back at your posts and re-think this.

[LAHills]

So looking around I found something I did not know, maybe you already did. But anyway, other posts report that the stock temp gauge is not linear. It stays at the mid (normal) point thru a wide temp range and only moves up when the temp has gone above the high speed fan temp point. So maybe with the chronopack you are seeing the engine move through its normal temp range. Engines do not actually sit at one temp all the time unless moving constantly at a speed high enough and at a modest and constant engine load. Once at fully soaked in at the thermostat temp the temp will go up from that and then back down depending engine load/fuel burn and on air flow through the radiator. At speed no fan is necessary with the high air flow and temp will sit at the thermostat temp. But at stop or low speed the temp will rise to the low speed fan point when it will turn on and if the temp rises some more then the high speed fan will come on. That is to say there is not one 'normal' temp and anything above that is abnormal or 'overheating'. With A/C on the low speed fan will stay on continuously replicating the car moving at a modest speed but more than 'stop and go', and so the temp will remain at the thermostat temp (so called 'normal'). So maybe it is just the chronopack is showing you what was going on all the time and is normal you just could not see it with the stock gauge. Per the Bentley manual low speed fan is tripped at 221F and off at 214F, high speed at 234F and goes back to low speed at 227F. And stock thermostat is 195F.

[TBeast]

Thanks both, it seems the low speed fan kicks in at 221F. So I now need to address the A/C issue

[Caterpillaraoz]

Hey! I'm having the same problem and I'm wondering..... Apart from the noise, will there be problems if I just bypass the broken resistor with a short circuit, effectively making the fan start on "fast" even when it should be at "low"?
The only thing I can think of is some "too fast temperature transient" but not much else....

[LAHills]

Just jumping from the low to the high speed wire will not damage anything. But it will put extra wear on the fan motor. The low speed handles cooling under all but the most extreme conditions so ordinarily the fan is sort of taking it easy. So wear is minimized. Adding the resistor instead of a wire jumper is not that hard.

[ChiggerPepi]

My resistor on my '03 R53 (dual plug) has been out for over 10 years, and my car still operates mostly fine... but that said, I am about to begin the dreaded supercharger overhaul process, (it's getting painfully noisy) and while I have it all apart, this is getting fixed too.

I found some 100w .33 ohm resistors on Aliexpress, and ordered a pair. (one spare)
https://www.aliexpress.com/item/2pcs...311.0.0.aHkJVx
If you order from this supplier, be sure to put a note on the checkout page and tell them you need 0.3R resistors.

I guess I'll figure out a splice and insert method once I get the radiator off. I haven't read the ENTIRE thread, but most of the helpful mods on here are related to the newer single plug version, and after looking at the wiring diagram for over two hours https://www.northamericanmotoring.co...ml#post3249121 I have realized I need to pull it all apart to fix anything on my version. (As previously stated by pretty much everyone.)

[Rich.Wolfson]

Originally Posted by ChiggerPepi

My resistor on my '03 R53 (dual plug) has been out for over 10 years, and my car still operates mostly fine... but that said, I am about to begin the dreaded supercharger overhaul process, (it's getting painfully noisy) and while I have it all apart, this is getting fixed too....I have realized I need to pull it all apart to fix anything on my version. (As previously stated by pretty much everyone.)

Here's what I suggest. Replace the fan with a Dorman replacement unit and be done with it. You are not going to get the resister to work right on your '03. The aftermarket resisters are better than the OEM ones. Check the pictures in Post #1289 and you'll see the differences. And also don't forget that the relays go bad too.

///Rich

[beken]

Is consensus here that the Dorman unit is better than the TYC fan motor? I tried to read through as much of this thread as possible given my limited amount of time on this topic. In Canada, a MINI fan motor got quoted to me at $606 CDN. The Dorman and TYC units are around $225CDN unless I get it from Amazon. Amazon (Canada) only has the TYC unit a reasonable approx $150CDN.

Given my original fan in my car has lasted 12 years, and I'm reading mixed reviews on the TYC and Dorman fans lasting about 2 years, I'm really hesitant in getting an aftermarket unit. If I just do the resistor fix (which no mechanic shop will do) I have no idea how much longer the original fan motor brushes are good for. So I am going to get a new unit regardless.

Has anybody kept their R53 longer than 2 or 3 years after changing out their radiator fan motors? I was thinking of keeping the old motor after replacement, and doing resistor upgrade, and keeping it as a spare.

Thanks for your advice.

[ChiggerPepi]

So I have my '03 R53 disassembled, and I assumed my resistor was going to be bad, but... after some measurements with the meter, it is actually just fine. The failure in my case is the shiny metal DF184 thermal fuse in series with the resistor. I could easily bypass the thermal fuse and have my low speed fan back, but I'm not sure exactly how safe this fix would be. The replacement DF184 is available all over the internet for next to nothing, so maybe I'll just do that.

Anyone else have this issue?

[gknorr]

Originally Posted by beken

Has anybody kept their R53 longer than 2 or 3 years after changing out their radiator fan motors? I was thinking of keeping the old motor after replacement, and doing resistor upgrade, and keeping it as a spare.

Thanks for your advice.

I replaced with a TYC fan many years ago and after about a year I think it was, the resistor had failed on it. I got the warranty replacement (from RockAuto and had to pay shipping), and the resistor in that TYC also failed after about a year. So when it comes to the resistor, you may not get much life out of the TYC.

I decided to do the resistor mod using that second TYC fan since I was tired of going through fans. I made a little change to the typical method and mounted two .68 ohm resistors in parallel to the front aluminum bumper structure. I also added weathertech connectors so that aluminum piece can be easily removed when servicing the car. The setup has been working well for at least 4-5 years I think, so the fan motor itself on the TYC seems to be fine. OEM is almost certainly better, but they're very expensive as you know. I kind of wish I had just done the resistor mod on my original fan looking back...

[Caterpillaraoz]

Originally Posted by beken

Is consensus here that the Dorman unit is better than the TYC fan motor? I tried to read through as much of this thread as possible given my limited amount of time on this topic. In Canada, a MINI fan motor got quoted to me at $606 CDN. The Dorman and TYC units are around $225CDN unless I get it from Amazon. Amazon (Canada) only has the TYC unit a reasonable approx $150CDN.

Given my original fan in my car has lasted 12 years, and I'm reading mixed reviews on the TYC and Dorman fans lasting about 2 years, I'm really hesitant in getting an aftermarket unit. If I just do the resistor fix (which no mechanic shop will do) I have no idea how much longer the original fan motor brushes are good for. So I am going to get a new unit regardless.

Has anybody kept their R53 longer than 2 or 3 years after changing out their radiator fan motors? I was thinking of keeping the old motor after replacement, and doing resistor upgrade, and keeping it as a spare.

Thanks for your advice.

I think going for the DIY resistor fix is the best way.

Rationale:
MINIs are also sold in places with all around hot climate, in a city in such places we can expect the a/c to be basically always on and the cooling fan to kick in really often.
Ballparking really conservatively, I`d say that on (60000 miles motored/20mph avg)=3000 hours the fan could be on for 1000 hours.
Having never heard of brushes failure I`d estimate the useful life of the fan at more than 1000 hrs, lets say 1500 at least.

So realistically brush wear itself is not a concerning factor for the life of the fan, dust and dirt ingress plus structural damage is. If yours sounds fine, spins free and has an undamaged frame I`d say keep it.

[pmanliu]

For those with the Mouser resistor, how long did it last before it failed? Installed mine back in July of 2017 and it seemed to potentially have crapped out after a short trip (2x 150mi trips in a day, few hours apart). Haven't had a chance to diagnose whether its the resistor, or something else.

[Whine not Walnuts]

Did you use heat sink paste on it? I have the ebay special in mine and after a year no issue. I have spare ebays and also bought a mouser that I have mounted on a computer heat sink with a fan. Have not gotten around to putting it in yet.

[pmanliu]

Originally Posted by Whine not Walnuts

Did you use heat sink paste on it? I have the ebay special in mine and after a year no issue. I have spare ebays and also bought a mouser that I have mounted on a computer heat sink with a fan. Have not gotten around to putting it in yet.

Hm i i did not... mounted it similar to this image [http://i.imgur.com/FbnHPwL.jpg] but just without the paste (told myself to get some but forgot! ).

Any advice on how i can go about testing the relay? I have a multimeter but am no means an expert on how to use it.

Also as a side note, checked the 30A fuses in the engine compartment and they all look in tact.

[Whine not Walnuts]

If power is going in one end and not coming out, would think the resistor is shot. With the resistor disconnected, you can take a ohm meter and see if you have a open circuit whereas the needle/gauge will to move, a closed circuit where the needle/gauge will max out or true resistance where the needle/gauge will move some what. You want the last.

[Whine not Walnuts]

Need to also check that the relays are engaging and sending power to the resistor.

[pmanliu]

Originally Posted by Whine not Walnuts

If power is going in one end and not coming out, would think the resistor is shot. With the resistor disconnected, you can take a ohm meter and see if you have a open circuit whereas the needle/gauge will to move, a closed circuit where the needle/gauge will max out or true resistance where the needle/gauge will move some what. You want the last.

Originally Posted by Whine not Walnuts

Need to also check that the relays are engaging and sending power to the resistor.

Thanks, going to give this a spot, appreciated your help.

Theres no 'click' from the relay when i turn on the AC to engage the low speed fan, but guessing its because the resistor is (most likely) dead

[pmanliu]

Just a follow up... turned out to be a faulty relay. Swapped it with high speed and the AC fan was circulating on/off.

At first i was confused that the AC fan was circulating on/off as when i first installed the radiator fix in the summer, the fan was constant on with AC. However now thats its much colder outside, it seems to circulate on/off and per earlier posts on this thread, is a normal function due to colder outside temps. Anyone have any insight on how it determines when to circulate on/off or stay constant on?

Also starting throwing a P0500 code when i was doing this fix (unplugged the first relay in the engine bay fuse and it might have triggered it?). The SES came on but went away after a few starts, but the code persists. No other lights though.

[Mike Gaviria]

I’m sorry for bringing this thread back to life, but recently my 06 MCS has had radiator fan problems. The temperature dropped severely last week and when I got my vehicle running I smelled a faint electrical burning smell. Popped open the hood/bonnet and saw that my fan was not on, its connector was hot due to the accumulation of resistance somewhere, and there was smoke coming from the fan area. I shut the vehicle off and noticed the fan was not freely moving. It had either been stuck, or frozen. Finally got it to start turning freely, but it never came back on after that. Yesterday I noticed my mini over heating while at idle for about 5-10 minutes and that’s when I saw one of my 50A fuses were blown. Replaced it, fan came on low, still making a sizzling noise as if it’s overheating, never kicked into high mode, connnectir kept heating up, and now the fan doesn’t come on. Yes the PS fan comes on. What can be wrong? Please help!!! 😞

[pnwR53S]

You fan obviously has seized once. By freeing it seldom lead to the fan not fail again. I would replace the fan if it were me.

What can be wrong?

It is called a part has passed its useful life.