2004 Mini Cooper S JCW 188000 miles

Two days ago I had let the Mini idle while I swept the drive before putting it away and when I parked it I noticed steam coming from under the bonnet and there was coolant on the aluminum tray under the expansion tank. I wiped up the coolant and let it cool and then opened the tank and found it empty. I filled the tank to the top of the baffles with Dex-Cool orange coolant.

Today I checked the coolant and The coolant level was just below the top of the baffles in the coolant tank and I added a bit more Dex-Cool to just over the baffles before driving 118 miles. The engine temp varied between 199F and 205F on the drive at freeway speeds and in stop and go traffic. At home I checked it again after it cooled down there was again some coolant on the aluminum tray under the tank and the tank was empty again.

So....maybe a crack in the coolant tank that leaks under pressure? Bad pressure cap? Should I refill it and try to pressurize the tank to see if any comes out?

 

.

Dex-Cool is bad juju in my opinion, I would never trust it or use it, do a search here on NAM to see what people have said/experienced.

I like the Zerex blue stuff, but as with oil choice, it's personal preference really, so whatever floats the boat.

In your case,
first I would comprehensively check the tank --- is it the original unit?

Aftermarket replacement?

The aluminum versions are bulletproof and a worthy investment.

That said,
OE MINI caps also regularly fail and are also dubious in quality, sometimes it is necessary to cycle through "bad ones" until you get a "good one".

I've had this experience myself but thankfully out of the 3 was able to find a "good one".

GTT in uk did a pressure test thingamajig once:




Would also closely inspect the radiator itself for any signs of cracking/leakage because if cracked then it simply will not be able to maintain the correct system pressure.

Should I refill it and try to pressurize the tank to see if any comes out?

Yes!

Do a pressure test if you have a tester, that would point you in the right direction.

 

Thanks for the reply, Oldboy,
The picture is helpful. I had not thought of pressurizing the tank with the cap on it. I didn't see any coolant on top of the tank, but that does not prove the cap is OK. The tank is yellowed (or maybe actually oranged) plastic so I assume it is OEM. Good to know that aluminum ones are available.

I didn't know Dex-Cool could be a problem. I thought it was recommended for aluminum engines. But then our Honda Odysseys specify Honda Blue coolant exclusively.

 

Wasn't there a class-action lawsuit over Dex-Cool and gasket failures? Or maybe it was intake manifolds.

I believe the conventional wisdom is to never mix Dex-Cool with anything else, but I'm no chemist.

 

Orange or brown = Time to switch it out. Either new OEM or as widely preferred here/posted aluminum/metal - Your choice.
Since my Mini is the first water cooled I've ever owned, I didn't know any better. I too just kept adding coolant as I kept seeing a loss. I never expected the tank. It was brown...and eventually, literally exploded one day while pulling up the drive.
Besides the cap failing, these things are notoriously prone to bursting at the seam with age and neglected inspection.
Either way - Time for a new tank.
Trust me.

 

Definitely your plastic tank. It won't leak until it's hot and under pressure. R53s run near boiling so it's time for a new tank. My opinion: a new plastic one will last you years and they're a LOT cheaper than aluminum.

 

I have a 1986 Daimler double six with the jaguar aluminum V12 and I once forgot which anti-freeze was in it and added green glycol to Dex-Cool and it formed a gelatin like mass. It was a real mess. Now I keep tags on the filler caps to remind me not to mix them.

The eBay aluminum coolant tank was around $50 and a plastic one (not OEM) is about $10 less; OEM plastic is $100. The OEM tank has those curved baffles inside which I took to indicate the fill level by filling to their tops. Do they serve another functional purpose? I suspect the aluminum one I ordered will have no baffles. I saw two you tube videos on tank replacement and both used $50 eBay aluminum tanks and said "so far so good" afterward. I thought the polished aluminum would compliment my stainless air intake box.

EDIT: Oops. I ordered it from Amazon, not eBay. Undoubtedly both from China anyway.

 

Update: New coolant tank came and installation went well. The one adjustment I made was to put washers behind the top mounting tab to space the upper hose away from the bracket holding the tank and the PS reservoir. So far so good.




However, now the bad. I took a long slow drive around my rural neighborhood and the temperature on my UltraGauge varied between 199 F and 204 F, so same as before the new expansion tank UNTIL......
Driving maybe 30 MPH I heard flapping sounds that I thought was something caught up in a wheel so I stopped but the flapping continued briefly and then stopped and the UltraGauge went dark and the battery light came on. I continued slowly 3/4 of a mile home and at home after shutting down, the cooling system was making gurgling sounds and there was a stream of coolant from under the Mini. I opened the bonnet and the fan was running and continued for a couple of minutes while I turned the key on and coaxed the UG to display and it showed the temp then was 230 F. I did not see any coolant at the new expansion tank nor on the heat shield under it and I had been too surprised to notice the Mini’s temperature gage.
I looked underneath and there was a coolant puddle that began near the back of the engine approximately in line with the front edge of the door and ran forward down the slope of the drive from there. I could also see belt stings hanging below my Rennline skid plate. The belt is (was) a Gates K060535 installed 2.5 years and 1850 miles ago. Darn! I hope the Alta belt tensioner stop saved my ATI Super Damper this time, but I'll have to check it later - I'm just too bummed to do it right now.

 

bummer

Sorry to hear the bad news, but at least you were at home so be thankful for that, it totally sucks to be stranded with a broken belt --- mine snapped and the tensioner totally trashed the 2 coolant hoses for the oil cooler but thankfully my ATI damper only suffered mild scratching...

https://www.northamericanmotoring.co...t-failure.html

...still,
it was a very inconvenient unexpected out-of-pocket expense for me, time-consuming nightmare, loss of income because I never got to the job I was travelling to, as well an excruciating psychological torture.

I swear these cars get so much love from us yet often still conspire to be hateful beasts, I have developed a love/hate relationship with mine! LOL currently at 165,000 and it's been one thing after another and although somewhat painful (especially in my older age with creaky bones spinnin' spanners at it), the reward is ultimately very great and totally worth the time investment in my opinion.

Anyway,
hope your damage ain't too bad and you can get it fettled in fine order.

Love the Tweety Bird by the way!

 

1st Dex-Cool is an absolute NO in our coolant systems, and if used needs to be completely flushed. It has been known to really gum-up the system (as mentioned above) which also helps to create areas prone to air pockets, even worse than normal.

2nd With the new expansion tank, you need to treat the radiator cap as a consumable maintenance item, you no longer have the benefit of the plastic expansion acting as a failsafe from an over pressurised system. (The plastic expansion tank acts as a safeguard/weakest link prior to popping the much more expensive plastic radiator tank ends) and quite often our radiator caps fail in the absolute "wrong way", they choose to close up completely instead of weakening, opening up and not holding pressure anymore as you would expect.

 

Thanks for the condolences, and yes the one good thing this time is that the belt didn't let go a few days earlier when I was doing 80 on the freeway. That did happen to me 130 miles from home in September of 2020 and resulted in a birds nest of belt fibers, broken tensioner, and a trashed ATI damper. I had to have my wife come get me and go back with the car trailer to haul her home. I had to send the Super Damper to ATI to have the outer ring replaced because it was totally trashed by the broken tensioner. I never knew if the tensioner or the belt broke first (and I don't know yet this time), but I did learn that if you order a Gates tensioner from Rockauto it will be the same Litens 765000-1 tensioner in a Gates box. I added an Alta tensioner stop to it at the time so I hope it worked to save the damper this time.

Now for the belt. I bought two Gates K06053 belts and carried one as a spare, but I didn't expect a new Gates belt to fail after just 1850 miles. Also, I experienced the belt tensioner jumping and making a clacking sound for several minutes on start up for the first 500 miles with the new gates belt which some said happens if the belt is too stiff. After 500 miles it did stop jumping and clacking on start up so I assumed the belt had finally "broken in". I skimmed your link and see discussion of a Gates Green belt and maybe another brand (I need to read it more thoroughly), but what is the best belt for our Minis to alleviate or at least reduce the chance of catastrophic failure? Or do I need to proactively replace the belt on a strict time or mileage schedule?

BTW, one of my British Car Club buddies named her for me when he asked if I was going to drive "that Tweety Bird" to a club event, so she's been Tweety Bird ever since. I had to settle for a "Tweety2" license plate because Tweety was already taken.

 

The PO of my Mini used Dex-Cool in it so I have continued to use it. This seems to be a controversial issue although most comments are against Dex-Cool. I have Prestone Dex-Cool in my 85 Daimler Double Six V12 and have not had a problem except when I forgot and added some green Glycol which caused a gelatin like formation. Is it that the Mini has plastic parts that are not compatible with OAT coolant?

And are you saying the plastic tank itself would expand if the system was over pressurized? or that it would fail before the radiator if the system was over pressurized? The aluminum tank has a pressure cap on it that will release excess pressure, which I assume it did when the belt broke and I drove a short distance. I didn't see coolant at the new tank but I had added a hose to the bib at the pressure cap and I think coolant was released through that hose to the back of the heat shield and to the ground. When it had cooled there was 1/2" of coolant in the aluminum tank which had been filled up to the center seam similar to the OEM tank.

 

have you checked the other pulleys -- AC, alternator, supercharger, idler -- to see if any of them are seized / compromised, between them and the tensioner / ALTA thing something could/must have seized up and eaten that belt. Would also check crank pulley and make sure no issues there, since it was rebuilt and reinstalled.

 

I checked the other pulleys and replaced the idler pulley, even though it seemed OK, when I replace the tensioner and damper. I spun the alternator with a rope and turned the others by hand and checked the seating of the damper to make sure it was where it was supposed to be on the crank shaft. The supercharger was making more noise than I would prefer, but a Mini specialist listened to it and said he had heard much worse and was not concerned by it.

I'll be jacking it up today and removing the liner to see what the damage is and I will check the other devices again. I also plan to search the archives for belt suggestions. I am a bit belt shy now having gone through this twice in 1850 miles.

BTW, Cravenspeed says of this Gates K060535 belt, “Since your R53 probably has a few miles on it already why not take this opportunity to install one that will last you at least another 100,00 miles”.

 

Yes, the plastic tank itself will start leaking at the seam (its failure point) before the radiator if the system over pressures.

I have a fully aluminum system, expansion tank and radiator, using the factory pressure release cap.
My cap went bad, but instead of it leaking, it closed and would not allow pressure to escape. It ended up finding the weak point between the core and tank of my all aluminum radiator, a much more expensive to fix.

Simply replace or test the cap as a maintenance item when using an aluminum expansion tank. Cheap insurance.

 

Something else may be a factor. Your car is a JCW. If you're running the stock diameter ATI crank pulley / dampener (and not the +2% oversize one) and the original JCW 11% supercharger pulley you should be running the K060539 belt, not the K060535.

https://www.rockauto.com/en/catalog/...rive,belt,8900

https://www.summitracing.com/search/...d=ATI%20damper

 

My Mini does have a 2% over damper and a 17% under super charger pulley and with the the Gates K060535 half of the hole in the tensioner metal strip was showing when the belt was new; I had not checked that hole recently.



Now for the good news. I removed the right fender liner and there were a few pieces of the belt on the skid plate and one continuous strand still in the pulleys but most of the belt was gone. The rubber channel that had been on the inside edge of the Alta tensioner stop was also laying on the skid plate.
The Super Damper is dirty on the face but the grooves are not damaged, The tensioner does not appear to be broken and did not contact the damper so the Alta limiter seems to have done its job and I don't see any other damage done by the flapping belt. The AC, alternator, and both idler pulleys spin freely, and the SC pulley turns by hand with some stiction as it did before.




That is all of the belt that I could find.

I'll see if I can glue the rubber channel back on the limiter without taking it off again. It was like this when installed.


So....It appears that I may get by with installing another belt, but I am reluctant to put my spare Gates belt on. Other threads recommend a Goodyear Gatorback 4060537. Any other suggestions for a belt that will last more than 1850 miles?

 

Pretty sure I'm running a Gates right now, about 4K on it, no issues, knock on wood. Have run them in the past on this and other cars without incident. Any oil or other fluid(s) on the damaged belt or pulleys you can see?

 

I have the Gates K060532 that I bought with my Detroit Tuned supercharger (17% pulley). No problems with my belt since installation about 11,000 miles ago.

I don't think a faulty belt is the problem here.

 

There's not enough left of the belt to tell, but I felt no oil or other fluid on the pulleys. I decided to put my spare Gates belt on so I could move the mini if we get any hail in the coming storm. It was difficult to get on and I had to get my wife to push the belt under the idler pulley while I pulled on the tensioner tool as hard as I could and once on, the first hole was 1/4" above the tensioner casting. However after I started the engine and let it get up to operating temperature, the first hole was just above the tensioner casting and the belt seemed to run OK. Now I have to decide whether to run this belt or buy a Goodyear Gatorback 4060537 to replace it. Or does anyone have another belt I should consider?

Spare Gates belt




tensioner when Gates K060535 first installed.



tensioner after running up to operating temp.

 

I'd have to agree that the belt isn't the problem.

Phil,
did you check all your pulleys to make sure that they are all freely moving and not binding?

All pulleys lined up in parallel correctly?

:

That said,
I can relate to you wanting to change brands of belt --- I had the same sway when my belt broke even though I knew it wasn't a faulty belt, my allegiance was to Conti and I never liked Gates because I despise their stupid fractional inch measurement methodology, but switched to their team and've been using the green FleetRunner belts with good success and I'm happy with them, same Gates part # as whatever length you're using but add an HD at the end, in my case it's K060539HD.

Regarding the Gatorback,
that brand seemed somewhat popular on NAM a decade and a half ago but haven't heard much chatter of it lately, then again NAM isn't as heavily populated nowadays either so our survey sample size would be smaller...

...looking back on the NAM archive, people said that the Gatorback was loud (despite being marketed as the quiet belt), and another thing to consider is that the design itself doesn't have as much surface area as a normal belt, but I've never tried one so have no real world experience to offer.

Here's an old pic of one that broke, found on an older NAM thread...

 

Thanks for that info and related anecdote. I think I understand you...
My limited knowledge: had always assumed that the factory cap could fail in 2 ways - e.g:
1)_The cap would leak allowing coolant and pressure to escape through the cap threads.
- and/or -
2)_The cap may loose it's ability to release pressure and cause the reservoir to bear the "load" and eventually pressurize 'til it leaked or burst at the seam.
So the factory plastic tank leaking could be the "fail safe" for the radiator (as someone also stated), (?).
Does my understanding correlate with your analogy?
Thanks.

 

Hmmmm. There was a lot more of that Gatorback left than my Gates, and when I lost a belt on the freeway 2-1/2 years ago I think there was even less, but I don't know what brand it was then. I didn't know if the belt or the tensioner broke first that time but the tensioner was in several pieces. This was less then 6K miles after I purchased it in Dec 2017 from a BMW nut who had recently rebuilt it with New Clutch, Pressure Plate and Flywheel, New Struts, springs, shocks and ball joints, New Radiator Support, All new engine gaskets, New Battery, New belts and hoses, New Belt Tensioner, New plugs and wires, New Supercharger and Water Pump, New Motor Mounts, New Starter, New front axles, New Windshield, New Clutch slave cylinder, New Hood Struts, New Brake Calipers, Alta 17% Undersized Supercharger Pulley, ATA 2% Oversized Super Damper, Alta Intercooler gaskets, and M7 Speed Cold Air Intake.



When I put it back together in 2020, the tensioner , damper, and idler pulley were new as was the belt. Looking back in my notes, I thought I had noticed an increase in engine noise just before the ill fated trip when the belt failed at speed, and it still seems a bit louder than I would like but not the "box of rocks" sound that I've heard describing a bad SC. When I put the Gates belt on in 2020 I got my stethoscope and checked the flat idler pulley, the alternator, the supercharger, and the pivot end of the belt tensioner, and the tensioner was making the most noise, and for about the next 500 miles on cold start up the tensioner would jump and make a knocking sound for several minutes before quieting down. Someone suggested this was caused by a stiff belt and it eventually went away and I assumed the belt had finally been "broken in", but now I wonder if I had a bad belt from the git go.

The Gates belt this time has not caused any tensioner jump or knocking sound and it seems to be running more smoothly than the previous one did, so maybe I did have a problem belt the first time. I just ordered a Gatorback 4060537 on eBay (or maybe I did because the listing shows both the Gatorback and a Continental Elite) to either replace the Gates or carry as a spare if the Gates is doing OK, but I am still tempted to get the Gates fleetrunner HD or the RPM if I can find them in the 535 or 537 length. Some in the archives said the fleetrunner was more prone to stretching but I've not found any reports from anyone running the RPM. I do find it confusing that sometimes the effective length is listed and sometimes the outside length is listed and sometimes no length at all.

In any case Tweety Bird is back together and I'll drive "him" with the Gates belt for now and hope for the best. Guess I'll consider an annual belt change from now on to be on the safe side; it's not that hard to change and might save me from this again.


.Just had another thought. These belts aren't directional, are they? There are no arrows on the Gates that I saw. Could they still have a "preferred" direction to run?

 

Yes.

Might have been me. whether designed that way or not, it works that way.

Again, nothing at all wrong with the aluminum version, just replace or test your cap when you do your maintenance if you use one, it's simply the best chance to possibly save you a costly repair.
​​​​​​​

 

@BlwnAway As always - Thank you again for your courteous and informative insight