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Internal combustion engines rely on a cooling system to regulate the engine temperature as well as provide heat for the climate control system (HVAC) and the mechanics of it hasn't changed …
That's basically how cooling systems have worked for a long time since Fords Thermo Syphon System
"Apoplectically Complicated" - so the cooling systems themselves are filled with rage? 
So....plastic in critical areas, in addition to finicky electronics. This is why they are problematic. Got it.
More modern BMWs have a plethora of operating modes to meet various cooling goals. They use sophisticated electronics to control the operation of the thermostat and water pump to oversee internal engine and accessory temps.
aircooled said:More modern BMWs have a plethora of operating modes to meet various cooling goals. They use sophisticated electronics to control the operation of the thermostat and water pump to oversee internal engine and accessory temps.
The essentially means speeding up the electric water pump.
That doesn't really explain all the failures.
z31maniac said:aircooled said:More modern BMWs have a plethora of operating modes to meet various cooling goals. They use sophisticated electronics to control the operation of the thermostat and water pump to oversee internal engine and accessory temps.
The essentially means speeding up the electric water pump.
That doesn't really explain all the failures.
Germany has yet to figure out how to make viable plastic or rubber.
The pressure cap on the cooling system establishes system pressure, not the water pump.
The most recent and just about only major change I've noticced is the t-stat now controls flow from the radiator not to the radiator.
Knurled. said:z31maniac said:aircooled said:More modern BMWs have a plethora of operating modes to meet various cooling goals. They use sophisticated electronics to control the operation of the thermostat and water pump to oversee internal engine and accessory temps.
The essentially means speeding up the electric water pump.
That doesn't really explain all the failures.Germany has yet to figure out how to make viable plastic or rubber.
I agree, for what they charge and the maintenance costs, it's not reasonable, even given how well they drive.
In reply to z31maniac :
Depends on the BMW in question. You can replace the entire cooling system (radiator, water pump, thermostat, idler pulley, hoses) for an M50 powered car for $400-450. If you are really worried about a failure you would do that every 60,000 miles. Do other cars have to deal with cooling system repairs as frequently, no, but the cost is less than $.01 per mile. Not exactly what I would call unreasonable cost, but I guess people have different ideas of what is reasonable.
Because Germans can't make something simple that works.
I blame beer.
ChasH said:The pressure cap on the cooling system establishes system pressure, not the water pump.
The most recent and just about only major change I've noticced is the t-stat now controls flow from the radiator not to the radiator.
The water pump establishes system pressure. The radiator cap just establishes the pressure in the radiator.
Put a pressure gauge in your cooling system between the water pump and thermostat and do some experimenting. I've seen 45-70psi in properly functioning cooling systems.
As far as cooling system operational changes are concerned.... suction side thermostats are old news. The new hotness is computer controlled partitioned cooling systems. Ford has some Ecoboost engines that are partitioned off enough that on a cold start, coolant only goes to the exhaust side of the cylinder head. Then it is alloed to go to the intake side of the head. Then it is allowed to flow through the block. Then, and only then, after everything has been allowed to come up to temperature at an even rate like that, is it allowed to circulate through the radiator.
I know they are right proud of the 2.0 Ecoboost being able to go from dead cold to operational temperature in 90 seconds.
MTechnically said:In reply to z31maniac :
Depends on the BMW in question. You can replace the entire cooling system (radiator, water pump, thermostat, idler pulley, hoses) for an M50 powered car for $400-450. If you are really worried about a failure you would do that every 60,000 miles. Do other cars have to deal with cooling system repairs as frequently, no, but the cost is less than $.01 per mile. Not exactly what I would call unreasonable cost, but I guess people have different ideas of what is reasonable.
It’s completely unreasonable to have to rebuild your cooling system every 60k. This is the problem.
Patrick said:MTechnically said:In reply to z31maniac :
Depends on the BMW in question. You can replace the entire cooling system (radiator, water pump, thermostat, idler pulley, hoses) for an M50 powered car for $400-450. If you are really worried about a failure you would do that every 60,000 miles. Do other cars have to deal with cooling system repairs as frequently, no, but the cost is less than $.01 per mile. Not exactly what I would call unreasonable cost, but I guess people have different ideas of what is reasonable.
It’s completely unreasonable to have to rebuild your cooling system every 60k. This is the problem.
Ex boss's sister's boyfriend had a 330xi that had all that stuff still original at 200k.
Scratch that - it needed a thermostat at one point, as it was setting a P0128.
Honda K-series have a ton of plastic in the cooling system (water outlets, radiators, etc). Actually probably a majority of modern cars have a lot of plastic. Somehow it is only BMW that seems to have a problem. I think being on the Internet is the root cause...
In reply to Patrick :
First off, you don't have to overhaul the entire system every 60,000 miles. That was an extreme example to illustrate that the cost isn't as big a deal as people make it out to be. Obviously, it's a weak point on the cars, but for most people it's a one time repair. If you intend to keep the car well past 200,000 miles you might as well invest in an aftermarket radiator that deletes the plastic end tanks.
Most modern cars have plastic bits in the cooling system. Outside of early Mercedes plastic radiators, most cars seem to kill the radiator somewhere around the 10 - 12 year / 100k mile mark due to the plastic running out of fatigue life from heat and pressure cycles.
Some of the BMW plastic bits do have a shorter life, although there are non-plastic replacements available for some. In the case of my E38, the radiator and especially the expansion tank are the big weak points that tend to fail suddenly and without much warning. Having an engine where normal operating temperature is 220 - 230* (in the name of efficiency) and a stupidly high system cap pressure of 29 psi (to give more safety margin at the higher operating temperature) leads to a lot of stress on those plastic bits. Certainly more than a lot of other cars have placed on them until very recently.
MTechnically said:In reply to z31maniac :
Depends on the BMW in question. You can replace the entire cooling system (radiator, water pump, thermostat, idler pulley, hoses) for an M50 powered car for $400-450. If you are really worried about a failure you would do that every 60,000 miles. Do other cars have to deal with cooling system repairs as frequently, no, but the cost is less than $.01 per mile. Not exactly what I would call unreasonable cost, but I guess people have different ideas of what is reasonable.
That should be, "you can buy all the parts" for that price. The dealer will charge you an ungodly sum for labor.
Therein lies the problem. BMWs are built to maximize profit for them and enjoyment for the owner over a 36-month lease. I'd argue that they do a great job at achieving those goals. They are not designed, or built, for easy long-term care. If you want that, I'll sell you my 2000 Silverado 5.3.
In reply to Dave M :
But at the same time, if you're DIY-inclined, not all BMWs are terrible to work on. I found a radiator swap in the E38 to be slightly faster and significantly easier than doing the same on the Jeep, for example. A little more stuff to remove on the E38, but the process was more logical and with the appropriate bits removed, had more room to work as well. Now getting the front sway bar out / in, we just won't go there...
In reply to rslifkin :
Fair, although I've never tried to wrench on my i3. I need some more electrical engineering classes before I start fooling with that one!
I guess the adage would be, every manufactured is capable of making dumb design decisions. Heck, changing the oil on my Odyssey makes you wonder how Honda ever got a good reputation.
In reply to Dave M :
Of course a dealer will gladly take whatever organs you are willing to donate. I don't think that's exclusive to BMW. I wouldn't recommend that anyone own a car from a "premium" brand if they don't intend to do the work themselves or have very deep pockets.
I agree that your statement about leases applies to the more modern BMW's, but the older cars are not hard to work on and are relatively sturdy.
In reply to MTechnically :
Fair point! I was thinking of post-financial-crisis BMW, which has seemingly turned into a high-end finance operation. Seems to be a much better choice for them than a low-end finance operation like Nissan!
The "newest" BMW in the family is a 2005 X3, 3.0 and we will not be purchasing anything newer than this one. Yes, that could mean an E46 but only if it has a stick. The cooling system has a weak link, the key is that thermostat that is at the bottom of the external reservoir that connects the thing to the mother ship of hoses and the motor.
I wounder how many different plastics, with and without metal parts are snapped into place that might have different heat cycle "until" failure you can work into one system. Reminds me of those interference motor cam belts that suggested 60,000 mile changes. That is a 5 hour, plus, job that always suggested you really should refresh everything on the way into getting to the cam belt.
Like on the '94 Nissan Pathfinder 3.0 I am doing now.
Careful what you complain about.
MTechnically said:In reply to z31maniac :
Depends on the BMW in question. You can replace the entire cooling system (radiator, water pump, thermostat, idler pulley, hoses) for an M50 powered car for $400-450. If you are really worried about a failure you would do that every 60,000 miles. Do other cars have to deal with cooling system repairs as frequently, no, but the cost is less than $.01 per mile. Not exactly what I would call unreasonable cost, but I guess people have different ideas of what is reasonable.
You may not realize I'm one of the biggest BMW fanboys here. Built swap cars, had new ones, etc.
I've never heard of a Ford Focus needing a cooling system rebuild like any other cars than BMW. Or window regulators, or, or
For what they cost to buy and maintain, it's unacceptable.
z31maniac said:I've never heard of a Ford Focus needing a cooling system rebuild like any other cars than BMW.
at least they fix them for free ...
Slippery said:z31maniac said:I've never heard of a Ford Focus needing a cooling system rebuild like any other cars than BMW.
at least they fix them for free ...
One particular car (had I used another example, ugh) with problems is very different from an entire brand.
It's cool, I know you're just giving mean hard time :)
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