Small Coolant Leak

[1SickEuro]

If you guys haven't seen my last post, I was leaking coolant really bad. So I replaced my radiator with upper and lower hoses. That did not solve the problem. I then thought it had to be the water pump, so I took out the old one and it was completely locked and didn't spin. So I just replaced my water pump as well as thermostat and topped it off with coolant and no more overheating. My "check coolant level" on the OBD also went away. But Im realizing that over the last two days when I check my car in the morning that I'm slowly losing coolant on the drivers side. It doesn't leak when the car is on rather when it is parked and I see a small puddle of coolant in the morning. What do you guys think it could be? I know the only possible thing left is the head gasket. Looking forward to hearing from you guys. Just want to get this coolant issue solved for good.

[r33p04s]

Drivers side or passenger side? Either way the hose going into/out of the radiator is leaking...happened when I changed mine and didn't put on new hoses

Sent from my thumbs to your eyes.

[Sleepyhead97]

Hello, Sorry to hear that. I went through the same thing.

My advise: Go buy OR Rent a pressure tester for the coolant. Hook it up, pump it up to about 25 psi (or what is stated on your coolant reservoir cap) and look for leaks. Harbor freight has one on sale right now 89.99, plus if you print a 20% off coupon online and take it into the store, it will be around 70 out the door. There are so many places coolant can be leaking, you will replace everything before you figure it out. If you are thinking head gasket, get the pressure tester first and be sure.

[Daniel Ocean]

Hello, Sorry to hear that. I went through the same thing.

My advise: Go buy OR Rent a pressure tester for the coolant. Hook it up, pump it up to about 25 psi (or what is stated on your coolant reservoir cap) and look for leaks. Harbor freight has one on sale right now 89.99, plus if you print a 20% off coupon online and take it into the store, it will be around 70 out the door. There are so many places coolant can be leaking, you will replace everything before you figure it out. If you are thinking head gasket, get the pressure tester first and be sure.

Exactly, just get a coolant pressure test done. Just throwing parts at it can get expensive.

With that being said, have you checked the part (not numbered) below #7 here:

http://www.realoem.com/bmw/diagrams/d/m/6.png

It's plastic, and a common leak.

[Auto Parts Guy]

Check the small hose going from the reservoir to the driver side radiator. I just went through this, rented a pressure tester and found that small hose to be leaking at the radiator on the driver side. You also have lines going to the throttle body and air box so check those carefully too.

[1SickEuro]

Drivers side or passenger side? Either way the hose going into/out of the radiator is leaking...happened when I changed mine and didn't put on new hoses

Sent from my thumbs to your eyes.

The small overflow hose going from the expansion tank to the radiator had a small hole in it so I replaced that. The leak is coming from the drivers side of the car

- - - Updated - - -


Check the small hose going from the reservoir to the driver side radiator. I just went through this, rented a pressure tester and found that small hose to be leaking at the radiator on the driver side. You also have lines going to the throttle body and air box so check those carefully too.

already replaced the small overflow hose as it had a hole in it. Ive driven the car every night for 3 hours or more at a time and no overheating. If the head gasket was gone wouldn't I notice it by now?

[r33p04s]

I just went out and poured some coolant in my cold engine and can spot coolant leaks at almost every connection to the radiator...if you have old hoses go back in and replace (I won't be taking my own advice because I don't want to do all that again after doing it last month)

Fingerblasting my iPad

[15Michaeljoseph]

depending on the radiator, sometimes cheap plastic cracks. on my moms e36 the upper rad hose connector had a crack in the bottom, leaking coolant on the drivers side. it can happen if you overtighten clamps too much

[r33p04s]

depending on the radiator, sometimes cheap plastic cracks. on my moms e36 the upper rad hose connector had a crack in the bottom, leaking coolant on the drivers side. it can happen if you overtighten clamps too much

Not sure if re: me

But my radiator is a brand new oem replacement. Didn't over tighten, 18yr old hoses molded to the old radiator and dried out seal on the temp sensor are my issue

Fingerblasting my iPad

[15Michaeljoseph]

okay sorry i wasnt using my head haha

[Auto Parts Guy]

already replaced the small overflow hose as it had a hole in it. Ive driven the car every night for 3 hours or more at a time and no overheating. If the head gasket was gone wouldn't I notice it by now?

Not necessarily depending on where/how it fails. I would rent a pressure tester so you can find your leak. I doubt it's a head gasket, more likely it's a coolant hose or connection regardless if it's new or old. A pressure tester pumped to ~14psi will tell you where it's leaking. There are several hoses on the driver side as I have already mentioned. A few months ago the plastic piece that goes into the airbox that has 2 coolant lines on it spontaneously busted on my car. That is also on the driver side. pressure tester...

[1SickEuro]

Not necessarily depending on where/how it fails. I would rent a pressure tester so you can find your leak. I doubt it's a head gasket, more likely it's a coolant hose or connection regardless if it's new or old. A pressure tester pumped to ~14psi will tell you where it's leaking. There are several hoses on the driver side as I have already mentioned. A few months ago the plastic piece that goes into the airbox that has 2 coolant lines on it spontaneously busted on my car. That is also on the driver side. pressure tester...

Will let you guys know what happens as soon as I do the test. Any suggested places to get a pressure tester from?

[Sleepyhead97]

Harbor Freight Special. It is a decent tester

[Auto Parts Guy]

Advance Auto Parts rents them as well. $200 but you get it back when you return it.

[TheDurk]

I like my HF tester, too. Orange adapter fits perfectly.

[Sleepyhead97]

I like my HF tester, too. Orange adapter fits perfectly.

haha. Yup