umermariner

Hello Guys,

I have had this car (2007 530 i with N52 Engine) for about three years now, and was planning a coolant flush anyway when I got low coolant warning. I thought, of just doing the flush instead of topping it off.

When got under the car and removed the lower shield, noticed a lot of coolant dripping. After some investigation, realized where the water was dripping for. I have two questions,

1. The water is dripping from the upper side of this joint and coming down. I only see three things there, rubber hose, plastic housing, and something inserted into the plastic housing from the top (is that a sensor)? Is this a common leak area? What needs to be replaced?

2. I was expecting drain plug to be blue, however; this is the only drain plug I saw at the bottom of the radiator.

Thanks again for your help and support.

Take care.

txag_530i

1. That is the lower radiator hose. You don't post the type of car that you have or the mileage, but, yes, that is a part that usually gets replaced at 100k+ miles. There is a temperature sensor plugged into the top of the hose. When you replace the hose you should either replace the sensor at the same time, or at the very least replace the sensor o-ring.

2. The red knob is the drain valve. Be careful when you turn the valve as it is subject to failure.

If you replace the lower hose then you should also consider replacing the upper radiator hose at the same time.

pcy

+1.
Don't use that valve for draining coolant. Simply undo the lower hose at the radiator and the coolant will drain.

umermariner

Thanks guys.

Car is 2007 530i, and I only have about 58K miles on the car. Thats what I was thinking, shouldnt have any of these issues at least till 80K miles. Car is about 7 years old though...

I was under the car looking into it, and am skeptical about doing it myself. Mainly bcz ramps only raise the car so much and other pipes in the way. What do you think? Is it an easy DIY?

So, if I go about it, you recommend changing both hoses and temp sensor?

Thanks.

twh

Coolant flush is easy. Mine is 2006 430xi. I used the red petcock to drain mine when I replaced the water pump and thermostat. Worst thing can happen is the petcock gets munged up and you need a new one. There is no block coolant drain. You just let it all out and then replace what went out. You'll need about a gallon of BMW antifreeze and a gallon of distilled water to refill what is lost.

Use the electric water pump coolant bleeding procedure when you are done. Can be found searching on this site.

But, you need to find the leak first. I'd hose the entire inside of the radiator down. Then run the car until it gets hot and all the water evaporates. You should be left with only the offending leak. It is possible the raditor itself has a micro crack -- wife's X5 is on radiator number 3