Car Overheating...

[nonick]

So I had my car towed on Friday night because it was flashing red warning lights about overheating.. Of course BMW won't even look at it until Monday so in the meantime I'm left wondering how much this will cost me. I shouldn't complain too much, 115k in 3.5 years and its been 100% trouble free so far, something was bound to break eventually!

Anyone have any guesses to what it might be? I'm hoping something simple like the thermostat is wonky, but I'm sure with my luck it'll be something big.

[ColinAndrews]

Re: Car Overheating...

There are lots of things it could be. Do you have the ability to scan the car yourself or are you leaving it completely to the dealer?

Thermostat is a possibility and not bad at all to change. At least not on the VAG products I've had. Could be your coolant pump is broken and not circulating. Were your fans operating correctly? If they broke your car would have trouble cooling as well.

[PRY4SNO]

Re: Car Overheating...

That's tough to diagnose with out an OBD-II scanner to pull codes... barring a puddle of coolant from something busted.

GL! Hopefully it's something small and cheap like a sensor or coolant flange or such.

[longsock]

Re: Car Overheating...

most likely the thermostat, hopefully..

[aliencurv]

Re: Car Overheating...

bmw driver.... prob no coolant

[The_Jerbel]

Re: Car Overheating...

Thermostat is a possibility and not bad at all to change. At least not on the VAG products I've had.

LOL, just wait until you change the t-stat on your S4...

[The_Jerbel]

Re: Car Overheating...

98% of thermostats fail in the open position, meaning that the engine runs too cold. There is still a chance that the T-stat is your problem, it's just unlikely.

Does it overheat on the highway, in traffic jams, or what? Or did the car just scream at you with a warning light- have you even noticed the temp gauge getting too high?

[ColinAndrews]

Re: Car Overheating...

LOL, just wait until you change the t-stat on your S4...

Other than changing the oil there's pretty much no job thats "easy" on the 2.7T I've come to decide.

[RONDAL]

Re: Car Overheating...

bmw driver.... prob no coolant

audi driver.....prolly 100% water instead of coolant

[J-hop]

Re: Car Overheating...

audi driver.....prolly 100% water instead of coolant

100% water actually has better heat capacity than when mixed with antifreeze!



the jerbel brought up some good questions to consider, could be several different things.

[RONDAL]

Re: Car Overheating...

100% water actually has better heat capacity than when mixed with antifreeze!



the jerbel brought up some good questions to consider, could be several different things.

to a point, you have better cooling, but you're more prone to boiling and rusting.

[aliencurv]

Re: Car Overheating...

to a point, you have better cooling, but you're more prone to boiling and rusting.

lol!!!!!!!!!!!!! WHAAAAAAAAAAT? BOILING? WHAAAAAAT?

[The_Jerbel]

Re: Car Overheating...

Yeah.....

Water boils when you heat it up. Didn't you know that?

RONDAL,

I think what DJ is trying to say, is that in a properly sealed system, your coolant is under such pressure that it will not boil whether you're running straight water or a water/coolant mix. When you relieve the pressure in the system by removing the rad cap, the water/coolant boils immediately, and you get dangerous steam coming out. While the system is pressurized, it would have to far exceed normal operating temperatures to boil over.

[J-hop]

Re: Car Overheating...

to a point, you have better cooling, but you're more prone to boiling and rusting.

true about the rust as anti-freeze contains corrosion inhibitors, however according to a conversion chart a 50/50 mix will boil at 107 degrees as opposed to waters 100 degrees at standard conditions (1 atm) now I believe most cooling systems run at 15psi above atmospheric, according to google this raises the boiling point of water to 121 degrees c and 50/50 mix to 129 degrees c, sure if you are strictly looking at numbers you may be slightly more prone to boiling but if you are reaching coolant temps of 121 degrees c during normal driving you've got something seriously wrong with your engine/cooling system (especially when, as mentioned water has a higher heat capacity than the 50/50).

[aliencurv]

Re: Car Overheating...

Yeah.....

Water boils when you heat it up. Didn't you know that?

RONDAL,

I think what DJ is trying to say, is that in a properly sealed system, your coolant is under such pressure that it will not boil whether you're running straight water or a water/coolant mix. When you relieve the pressure in the system by removing the rad cap, the water/coolant boils immediately, and you get dangerous steam coming out. While the system is pressurized, it would have to far exceed normal operating temperatures to boil over.

what i'm saying is in vegas, my 90% water and 10% coolant boiled and my car was towed to the dealershpi to get raped by a lambo mechanic that re-used my intake manifold gasket, didn't hook up my maf, and broke 3 vacum connectors. it was awesome. oh yah, i paid $600 for it