Overheating?! Not Again!!!

[DaveVoorhis]

i bought a new fan clutch like a month ago.

So? I once bought a new master cylinder for a Ford truck that leaked fluid out as quick as it was poured in. When I returned it, the parts jobber said, "Oh yeah, we've had a whole crate of those do that." I went through two aftermarket clutch slaves in six months on an E28, before I bought one from BMW and it lasted. Sometimes new parts suck.

[Jehu]

Are you sure the Coolant /Water mix is at 50/50? I just had mine overheat last night after five hours of hard highway driving and after i let it sit for about 40 Minutes and added a half gallon of H2O i was able to drive it home another 70 miles home with no temp rise. I bypassed my Heater Core last week and didn't refill the system with a 50/50 mix , just used all Anti Freeze.... big error in judgment .

[///Sniper535]

I had my car on ramps nose up and let it run for sometime and no overheating. Fan clutch seems to be in perfect working condition.Definately no air in the system. If this happens again ill look into a new thermostat.

[filip00]

thermostate is the cheapest part of the whole cooling system, so just replace the damn thing.

btw, the coolant - water/antifreeze mixture is not important, as long as it's at least 20% antifreeze, 80% water, it's good. no need for the 50-50. it is important that you don't have more antifreeze, because water is a better heat isolant

[Jehu]

thermostate is the cheapest part of the whole cooling system, so just replace the damn thing.

btw, the coolant - water/antifreeze mixture is not important, as long as it's at least 20% antifreeze, 80% water, it's good. no need for the 50-50. it is important that you don't have more antifreeze, because water is a better heat isolant

Interesting and the gyst of my thrust was that I had more coolant than water which I hope was the one and only cause of My overheating. As i noted i did drive it after a cool off period after adding over a half gallon of water and again today got it hot and up on the highway and not a hair over Twelve O'Clock High so I assume that was the only thing. I started dreading it was the Thermostat while i was sitting in a dark and empty rest area in the way out wilderness of northwestern Massachusetts letting it cool. I hate spending money on long tows.. If I brought the car into a BMW dealership and asked them to flush and refill you think they'd do it 80/20 water to coolant?

[nbeckius]

thermostate is the cheapest part of the whole cooling system, so just replace the damn thing.

btw, the coolant - water/antifreeze mixture is not important, as long as it's at least 20% antifreeze, 80% water, it's good. no need for the 50-50. it is important that you don't have more antifreeze, because water is a better heat isolant

The antifreeze/water mix really depends on where you live. 50/50 is the recommended in many areas. Remember the water does the cooling, the antifreeze just does what it's name implies and has very poor cooling properties.

I've never heard of going more than 60% antifreeze in a system and if you live in an area where you never see below freezing temps you can not use it at all and go 100% water.

Distilled or purified water is best as it prevents corrosion. 75 cents per gallon at the market and it'll make the cooling system function better.

[Adnan]

Distilled or purified water is best as it prevents corrosion. 75 cents per gallon at the market and it'll make the cooling system function better.

Hi,

One reason to use coolant is that it usually contains lubricants for the water pump. Otherwise, I agree that water does the best job of cooling. If you do use just water, consider adding a wetting agent to it, such as Redline's Water Wetter. The change in surface tension offers a noticeable improvement in cooling.

Regards,
Adnan

[E34 530]

If you bought a Behr fan clutch, it could be bad. I bought one last year and it was bad right out of the box and they sent me another one which I think is going bad again.

[Chris'91'525i]

The antifreeze/water mix really depends on where you live. 50/50 is the recommended in many areas. Remember the water does the cooling, the antifreeze just does what it's name implies and has very poor cooling properties.
I've never heard of going more than 60% antifreeze in a system and if you live in an area where you never see below freezing temps you can not use it at all and go 100% water.
Distilled or purified water is best as it prevents corrosion. 75 cents per gallon at the market and it'll make the cooling system function better.

Theres a reason auto makers recommend a antifreeze/coolant mix.
Recommending 100% water is not good advice IMO.

Antifreeze/coolant besides the obvious it raises the boiling point of water, it does not evaporate like water does, it prevents rust and corrosion, and it lubes the moving parts in the cooling system.
Thats why you want to flush the system periodically, as the additives get depleted after a couple years.

[filip00]

Distilled or purified water is best as it prevents corrosion. 75 cents per gallon at the market and it'll make the cooling system function better.

it's so much easier to simply COOK the water at home, and have it distilled in a few minutes instead of buying it



2 Jehu - i don't know what mixture they'd give you in a bmw dealership, but i usually use the 80-20 and i'm satisfied with it. temperatures here are from -12 to +45 C and no problems whatsoever.