Leaking coolant tank and reduced pulley

[QQQ]

Brought my MCS to the dealer cause I smelled burned coolant when I drove it this morning. As I'd guessed there's a leak on the joint between upper and bottom hlafe of the tank.

I know this is a known problem, but could it have anything to do with the reduced SS pulley, since this pulley also drives the waterpump or does the leaking coolant tank also occur with standard MCS and Cooper/ONE?

Any input welcome

Cheers

[Nic D]

Doubt it, JCW has a smaller pulley too

[ananiou]

That's bad news but fear not as writen above. I've changed the damn thing twice allready and i'am still running a stock S, even though here in Greece temperatures run quite hot..., I think that this was a bad in design and build part from the start.
Be well.

[QQQ]

Cheers guys, was a bit worried for warranty issues as I drive a rental car for 3 or 4 days on BMW cost now. Dealer said he was gonna claim it with BMW though, glad he's not making to much trouble as he knows about all the mods on my car

So is there already another design tank ?

Thanks

Ananiou, still haven't got a quote for the Suoersprint header/cat, will let you know if I do. The EUR 1800 for Pegasus was only header + cat, not the full system

[obehave]

Quote:

Originally posted by QQQ
Cheers guys, was a bit worried for warranty issues as I drive a rental car for 3 or 4 days on BMW cost now. Dealer said he was gonna claim it with BMW though, glad he's not making to much trouble as he knows about all the mods on my car

So is there already another design tank ?

Thanks

Ananiou, still haven't got a quote for the Suoersprint header/cat, will let you know if I do. The EUR 1800 for Pegasus was only header + cat, not the full system

Designs the same. Materials seem different. Yellowish color. To be honest though, you guys in Europe get updates well before we seem to. At least compared to what I get.
My new tank:

[DerekR]

Had the same tank issue. Dealer said they'd replace it under warranty and admitted it's a problem with most cars and would probably re-occur. So I asked them to plastic weld the new one along the seam before putting it in. SInce then I've had no leaks.

Also, there's an alloy tank available from one or two of the U.K MINI aftermarket suppliers.

Beware of removing the tank yourself - the system is pressurised and needs to be bled after the tank is replaced. Not difficult but it is necessary to do it correctly.

[s3-mk20116]

I had mine replaced two times. On the third replacement, my dealer explained that the yellowish tank was to indicate the updated design. They also said that it was the cap that caused the problem. I don't know if anyone else had the same explanation.

QQQ
If they replace the tank for you, see if the tank is white color. It might leak again if it is the white colored tank.

[QQQ]

Thanks everybody, I'll keep an eye on whether I get the yellow-ish coolant tank next week

[QQQ]

I wouldn't wait too long fixing it Max, the tank is under pressure, if the joint breaks further you'll be running without coolant in no time

[ananiou]

Mine, the second one, is also in different colour and definately of a different material, the design looks the same.
QQQ
it would have been a real bargain to get a full system from them at only 1800eur. I'll be waiting for SS though.
Thanks

[Tonyt3]

QQQ,
reducing the pulley on the SC can't have anything to do with this - the pulley wheel is reduced in size, thus upping the gearing effect on the SC, making it spin faster. However, to achieve this they would need to reduce the lenght of the pulley drive belt itself, and doing so should have no effect on the speed that the other ancillary parts run at. The drive wheel would still rotate at the normal speed, and the ancillary units are then driven by this directly.

However, there is a tuner out there (can't remember who) that actually increases the diameter of the driven pully gear - the one thats directly connected to the engine. This is a poor design as it does exactly what you have been worrying about, increases the speed of the SC, but also increases the speed of the ancillary components. This design for cheap power does not seem to have been popular, thank goodness.

Max,
Seeing blue crystalisation on the seems of the tank is NOT indicative of a split header tank. As has been said, the system is under pressure, and runs normally under pressure. However, like all things that run under pressure, there is a pressure release valve that is designed to keep the pressure at a set maximum. When the system needs to exceed this maximum (due to higher than normal temperatures) the valve opens and let some of the fluid out. If it did not do this, the system would over pressure, resulting in a failure of the weakest point in the system. The weakest point in the system on the Mini would appear to be the header tank. If the release valve does its job properly, there will be a small discharge fronm the unit. The release valve is I believe part of the cap on the header tank. As the fluid is released normally, it will naturally run down the outside of the tank, probably along the seam of the tank itself, and the fluid will evaporate leaving behind the residue that you see. If you had a split in the tank, believe me, you would know all about it. The stuff stinks when it is sprayed on the engine, and your car would suffer from over heating. Sonia's MCS had this three months ago.

With the increased engine heat output from your car caused by the hard driving of your GGR conversion, I myself would be surprised not to see the valve releasing some pressure occasionally. Interestingly, if you were to fit the Stainless Steel header tank as suggested here, you would in fact just be removing the header tank as the weakest point in the system. I don't think that this would be a good idea. If your pressure release valve were to fail, and pressure exceed the maximum, where would the new weakest point be? Some gasket in the engine? No idea, but you would create a new weakest point somewhere. At least the plastic bottle of the header tank is easy to replace and cheap......

Hope this makes sense...
Tony

[jlm]

the water pump is direct driven from the back of the blower, not the belt.

the blue crystals are what is left when the leaked coolant evaporates. I'm on my third tank, the yellowish one now, no leaks.

[QQQ]

Quote:

Originally posted by jlm
the water pump is direct driven from the back of the blower, not the belt.

the blue crystals are what is left when the leaked coolant evaporates. I'm on my third tank, the yellowish one now, no leaks.

My thoughts exactly. Max I agree with John, the crystals are evaporated coolant. Normally an expansion tank would only release air when pressure is too high and not the coolant itselfe. Do you ever smell burnt coolant when driving? Take a look at the cover plate of the exhaust header to see if it has coolant on it.

[Tonyt3]

Quote:

Originally posted by QQQ
My thoughts exactly. Max I agree with John, the crystals are evaporated coolant. Normally an expansion tank would only release air when pressure is too high and not the coolant itselfe. Do you ever smell burnt coolant when driving? Take a look at the cover plate of the exhaust header to see if it has coolant on it.

QQQ, as I stated, seeing the coolant residue on the tank is not indicitive of a split. Let me explain what I meant in a little clearer detail. What I meant is that its not absolute proof of a split, as seems to be believed by some. The top of the coolant header tank has a built in pressure valve. True, this is mostly there to release the air pressure, however, it can just as easily release fluid if necessary. Max has had this residue on his tank since it was new. He has since had his engine upgraded, and thus we can expect that on occasion it will have run quite hot, for instance on his Dyno day, or when he has be demoing his car to others (or indeed when I gave it a good thrashing at Max's insistance). If his header tank was really split, you would have expected him to lose a lot of coolant, therefore you would have expected his car to over heat during this time. My wifes car (MCS) sufferred a header tank split. She does not 'cane' it, she is a sensible woman driver who mailny uses her car to comute to and from work. Her car started overheating on even sensible drives, for instance at 70 mph on the motorway, in WINTER. Yes, when we looked, she had residue on both the tank and the plate beneath it. But she also had substantial fluid loss and overheating, which max has not had. So although max may well have residue on his tank, it does not prove that his tank is split (although equally, it could be). After my wifes MCS had its header tank replaced, I made sure to check my own MCS to see if this was a problem. Although I saw no splash residue, I saw that the fluid level was very low, below the Min mark on my own car. So I put a bit of water in with the intention of taking it back to the garage sharpish. When I checked the next day, after some 'spirited' driving, there was evidence that some fluid had come out of the header tank. I guess that I should not have added fluid, it will after all expand when hot and 'boil' off if necessary. I had suspected that I had the same problem as my wifes car, but, 6000 miles later, still no problems, and the levels remain the same. I still have some residue on the plate beneath my header tank.

So, although Max should keep an eye on the situation, and if he is at the dealership, he should have it pressure tested to see, but he should not panic about it, unless he suffers any overheating. I stand by my opinion that he should not bother replacing the header tank with a stainless steel one. At least, if the plastic one is split, he can have it replaced under warranty in just an hour or so. If you were to put a non BMW stainless steel tank on it, and then he had some other part of the coolant system fail, it could be disasterous in terms of warranty claim. Pressurised systems will always find the 'weakest point' and fail at that point. Thats why they have a 'false' weakest point, namely the presure release valve. I would suspect that cars that suffer from a split header tank actually had a faulty pressure cap, which did not releive the prssure correctly. Maybe its a design fault, I would be interested to see if Mini has looked at replacing this part.

Just one other point. Most people who check their fluid levels do so incorrectly. For instance, most people will check their oil level before starting up their car (ie, when the engine is cold). This is not correct. The car should be run until it is at its normal working temperature. The car should then be allowed to sit for a few minutes ( at least 5 I think) before you check the oil level. This will give an accurate level during normal usage. As the coolant level disappears below the Min mark when the car is cold, I can only suspect that it is the same for the coolant system. When the car is at normal operating temperatures, the fluid level should be somewhere between min and max.

[QQQ]

Hi Tony, totally agreed, with the remark "my thoughts exactly" I was reffering to jlm's remark that the waterpump is driven by the SS pulley Further I just wanted to indicate, as Max himself said his coolant tank was leaking and this a well known problem with MINI's, that I wouldn't wait too long getting it to the dealer as the leak might expand. Anyway Max is checking every day, he's in total control and probably doesn't need our well intended advices anyway. It's just too make sure it's being looked after, you never know.