nirvanaor

Leak is getting worse (more than a tablespoon a day) . I have 67k miles on the car . The Temp sensor was replaced last year. I checked the hoses under the hood but didnt see any leaks there. The only place I see the leak is at the bottom where it is dripping from the bottom of the "Module Carrier" RealOEM.com * BMW E60 525i MOUNTING PARTS F RADIATOR

Since the "Module Carrier" is hiding the leak I dont know if its the Radiator itself or is there a hose running in there.
See attached pic where I am pointing towards the leak. You can see the coolant drain plug in the background.
Drain Plug and all the hoses from the bottom looked dry .

Looks like I need to get the Fan and the radiator out to see what is going on inside the Module Carrier.
Does anyone has a link I can follow to see what needs to be removed and in what order ?

twh

I've seen a number of people on the forum say the o-ring on the drain plug failed. That would be a cheap first try. Get one from BMW, unscrew the plug and put the new one in before too much drains out. Take the car to the car wash with an undercarriage wash. Check back in a couple days and see if the drip is back.

nirvanaor

It is indeed a radiator seep (not a fully developed leak) . An Indy shop mechanic pressurized the coolant system and didnt see any drop in pressue so he thinks I have some time to order and replace the radiator.

I did notice that the only time I see a tablespoon of the coolant on the floor is over the weekend when the car is not driven for two days.
At work the car was parked at an angle for 8 hours and I didnt see a drop in the coolant level.

I am going to continue to look for a complete DIY with pics on how to replace. I have seen a few links out there that gives you an idea on what needs to be done but havent found a complete step by step DIY with Pics for 525i .
If I dont see anything in a week or so I probably will take a stab at it and document it.

BimmerFan52

You might want to check your vent tube (runs from top of radiator under a metal shield over the electric fan to the coolant reservoir).

(#4 in diagram) - RealOEM.com * BMW E60 525i Cooling System Water Hoses

It is a plastic tube that tends to start leaking around the age and mileage of your car, and the coolant can run down the side of the electric fan or in the holding bracket for the fan that you mention.

Coolant runs through the vent tube mainly after you turn the car off and the coolant begins to expand and needs somewhere to go.

Take the metal shield off, warm up the car, turn the car off and see if you can discover a pin hole in the vent tube.

E60I

I have this problem today. The rubber hose (see attachment) that connects to the radiator appears to be leaking. Should I buy BMW OEM part or is there a better alternative?

At a little less than 82,000 miles, it looks like my car (bought it brand new) is starting to fall apart. Below is a list of what I replaced this month and car is still running sh#tty.

1. Bosch Starter
2. Oil separator and three hoses that go with it.
3. New MAF sensor (Centenial, VDO); they said it's OEM
4. New BMW OEM injector for cylinder #4

When they said a car is the worst investment, I think they meant BMW. The car is too delicate, I am afraid to abuse it like all the cars I had. lol

Thanks!

pcy

Hey Dan,
That leak from coolant return hose is a known issue. I have replaced that hose with new one (I think I bought it from RMeuropean). Original clamp on that hose (radiator side) is a crimp type; so, you can't reuse that clamp. Get a small hose clamp and tighten.

About the issues you are having... You haven't even started with cooling system overhaul (water pump, thermostat, radiator, coolant reservoir, hoses, etc).

By the way, 530i (Inline 6 engines) are supposed to be more reliable than V8 engines. :-)

E60I

Hey Pcy!

Hope all is well!

I am going to get that replaced soon! I wonder if I should go to Home Depot and just replace the rubber hose only. I don't think the plastic part of the hose can break or leak.

By the way, the bad idle and lack of power/sluggishness on acceleration is gone (I think) after I replaced the oil filler cap.

Thanks!

pcy

the plastic part is known to become brittle and crack due to age+heat. Some people have replaced that plastic part of that hose with copper tubing and attached it to the rubber ends.

I just bought a new one, it's around $36 on RMeuropean. Coolant leaks can bite you at the least convenient times.

E60I

You're right, if this thing lasted 82,000 miles, what's $36 if it can buy you peace of mind.

After the starter problem I had, I replaced the oil separator and hoses because I told myself I don't want to be stranded again. That part and a few other things are being processed and shipped as we speak. :-)

Thanks for the wisdom, Mr. Sage. lol

losblancos

So, I’ve got the same issue as OP — a consistent coolant deep and I cannot spot any wet/leaking hoses and the like.

What I CAN see is coolant collecting on the forward part of the splash shield, and on the underside of the radiator carrier.

Any thoughts? Is there anything within the carrier that could leak other than the radiator itself? The thin line up top referred to earlier seems fine.