[Ssleeping]

Over the past week or so, I have noticed my radiator fan is on full blast while driving. Today while driving my car flashed a yellow then a red coolent light before cutting power at an intersection. About a minute later I was able to move to a parking lot where I popped my hood and noticed coolent around the coolent cap. Below is an attached picture, any idea whats causing this?

Car is a 2008 335i.

[madmantwo]

Originally Posted by Ssleeping

Over the past week or so, I have noticed my radiator fan is on full blast while driving. Today while driving my car flashed a yellow then a red coolent light before cutting power at an intersection. About a minute later I was able to move to a parking lot where I popped my hood and noticed coolent around the coolent cap. Below is an attached picture, any idea whats causing this?

Car is a 2008 335i.

My guess is you have a crack somewhere either in a coolant line or the reservoir, and because it is no longer pressurized it caused your coolant to bubble out of the cap?

Sounds like your coolant isn't circulating properly through the radiator, in turn, allowing your car to overheat...wonder what the cause of that could be

[madmantwo]

Originally Posted by FCobra94

Sounds like your coolant isn't circulating properly through the radiator, in turn, allowing your car to overheat...wonder what the cause of that could be

Lol yes as FCobra is hinting at, most of those symptoms are common when the water pump fails. The spilled coolant leads me to believe that something else could be causing it, but that may just be a coincidence.

If you want to test your water pump, I think you can put your key in the ignition, press Start, turn the fans onto the lowest setting, crank the heat all the way up, then hold the gas pedal down for 10 seconds. This should start the bleed procedure, and if your water pump is working then you should hear a humming sound as it spins up. If you hear nothing, then the pump is dead.

[Ssleeping]

Well the heating certainly works, however the AC has been iffy lately. A few days ago, the AC would cut out for a split second during gear shifts, also the AC does not seem very powerful.

[MR.BLUECOLLARMAN]

Originally Posted by madmantwo

Lol yes as FCobra is hinting at, most of those symptoms are common when the water pump fails. The spilled coolant leads me to believe that something else could be causing it, but that may just be a coincidence.

If you want to test your water pump, I think you can put your key in the ignition, press Start, turn the fans onto the lowest setting, crank the heat all the way up, then hold the gas pedal down for 10 seconds. This should start the bleed procedure, and if your water pump is working then you should hear a humming sound as it spins up. If you hear nothing, then the pump is dead.

Yes this is the correct way to pump out all of the bubbles from the coolant. The caps for the reservoir need to be replaced every 5 years as they lose the ability to hold pressure causing coolant leaks/air pockets which are no good. I would do a coolant flush, do this air purge procedure and then go for a drive and see what happens.

[Ssleeping]

Originally Posted by MR.BLUECOLLARMAN

Yes this is the correct way to pump out all of the bubbles from the coolant. The caps for the reservoir need to be replaced every 5 years as they lose the ability to hold pressure causing coolant leaks/air pockets which are no good. I would do a coolant flush, do this air purge procedure and then go for a drive and see what happens.

Sounds good, I assume the way to remove bubbles from the coolent system is the same for BMW as other cars (pull radiator cap and idle engine)?

[Miller335]

Originally Posted by Ssleeping

Sounds good, I assume the way to remove bubbles from the coolent system is the same for BMW as other cars (pull radiator cap and idle engine)?

The 335 has an electric water pump so there's a way to run the water pump and clear all the air without starting the car, it's pretty slick.

[MR.BLUECOLLARMAN]

Originally Posted by Ssleeping

Sounds good, I assume the way to remove bubbles from the coolent system is the same for BMW as other cars (pull radiator cap and idle engine)?

Close the reservoir cap, turn the engine to ON, do not start the engine, turn the temperature to 84 degrees with the fan on the lowest setting (1 bar) then hold the gas pedal for 10 seconds and then let go. Should take roughly 12 minutes to vent the bubbles. You can stick your head into the engine bay and hear a quiet whirring noise, that's your electric pump. When it's all done it should be quiet and all you have to do is open the cap and top the fluid

[theweebabySeamus]

Originally Posted by FCobra94

Sounds like your coolant isn't circulating properly through the radiator, in turn, allowing your car to overheat...wonder what the cause of that could be

+2, very common issue and sypmtoms match the water pump fairly well.

[muncie21]

He'll be back..OP that is.
The WP mistress shows no mercy

[CanadianTSi]

If the fan comes on as soon as you start the car water pump is dead.

[MR.BLUECOLLARMAN]

Make sure it's ON, put in FOB and press the start button with the brake pedal not being depressed, all your lights should light up as if you're about to start the car. Turn your knob temperature to max inside the car (84). What part are you having issues with?

[Ssleeping]

Originally Posted by MR.BLUECOLLARMAN

Make sure it's ON, put in FOB and press the start button with the brake pedal not being depressed, all your lights should light up as if you're about to start the car. Turn your knob temperature to max inside the car (84). What part are you having issues with?

I got it figured out, its currently doing something under the hood (pulsing sound coming from coolent reservoir).

[MR.BLUECOLLARMAN]

Originally Posted by Ssleeping

I got it figured out, its currently doing something under the hood (pulsing sound coming from coolent reservoir).

That's your pump, let it run for about 12 minutes. When it stops running you can open the reservoir cap and you should hear it hiss a bit from the pressure and then top up the fluid. You should do this one more time the next day (which reminds me I have to do this tomorrow haha)

[Ssleeping]

Sounds good, just did that, I fired it up and the radiator fans instantly went to max. That commonly a result of a faulty water pump? Thanks again for help.

[Jeff@TopGearSolutions]

You should have codes? Do you have any method to read codes? Tune?

IF you have 70K miles or more then that on your vehicle it's time for a water pump regardless.

[Ssleeping]

I do have a CEL that's on constantly for idle being slightly high (its likely from a custom tune on the ECU). I will check and see if there are any new codes at Autozone tomorrow.

[madmantwo]

Shouldn't drive it, you run the risk of blowing a head gasket. Also I don't think the CEL is for a high idle, find someone local who can pull the codes for you and post them here, if possible

[Ssleeping]

I have P0507 Idle air system RPM higher then expected, it has been this way since I bought the car.

[madmantwo]

Originally Posted by Ssleeping

I have P0507 Idle air system RPM higher then expected, it has been this way since I bought the car.

Ah, alright that isn't a BMW-specific code. If you want to get the BMW codes, you'll need something other than a generic OBDII scanner. There may be some other codes causing your CEL, one of which may be something to do with your water pump