Throughout all the questions about the MCS cooling system, one thing has bothered me. Sooner or later almost every car overheats. Usually this just involves steam coming from the radiator, letting the car cool off, adding some water/coolant, and then driving on.

Since the MCS doesn't have a pressurized cap, it seems like the only possible outcome for an overheating situation is a blown hose, coolant tank, or some other cooling system component, and then you're stuck.

Isn't there any pressure release mechanizm in the cooling system that will allow for recovery from such a situation without creating a permanent leak in the cooling system, and stranding me?

 

Good question. I thought (perhaps incorrectly) that the pressure in the system was such that overheating was extremely unlikely; and thus, if you ever did "overheat" bursting a hose would be a relatively minor side effect of much more serious damage. In other words, something else would have gone first.

BTW, I haven't driven a car that's overheated -- boiled over the radiator -- since my 1972 BMW (which did it on a very regular basis...perhaps that's not a good sign )

 

I've had a few cars that have overheated because of stuck thermostats or slow leaks in the cooling system (water pumps and such). I think I've only had one that actually steamed out of the radiator cap, the rest I've caught by paying attention to the temp guage, but you can't always be on top of that.

I'm hoping that someone with knowledge about the engineering of the cooling system might chime in here.

IF it doesn't have any type of pressure release, I hope that its coolant capacity, radiator size, fan design and such make it *highly* unlikely to overheat. Also, I'd hope its going to warn me in some way that's hard to ignore (is there an audible alarm for this?), before it pops the coolant tank or something else in the system.

Anyone know about these things?

 

Is there a solution as simple as a pressure regulated cap that would allow excess pressure to escape in these times? Seems pretty simple really... maybe another BMW has a cap that would thread right on.

 

>>Is there a solution as simple as a pressure regulated cap that would allow excess pressure to escape in these times? Seems pretty simple really... maybe another BMW has a cap that would thread right on.

I looked at the cap in the coolant overflow tank and it does appear to have some metal device in it which I guess is an overpressure relief valve.

M.

 

Yes it is a pressure cap just a different setup than most cars.
which have two one on the resevoir one on the radiator itself