Like some of the other threads recently, we're having a sudden coolant "leak" problem.

My wife got back from running errands, and within a minute of parking in the garage, the engine released a lot of steam and then coolant started spraying out inside the engine compartment and onto the concrete floor.

I asked my wife if any lights came on on the dash and she said 'no'. She couldn't remember if the fan had been running when she parked.

I looked at the engine compartment and noticed several things that may be of help. The coolant was sprayed all over the engine compartment, but almost all on the driver's side. The hose at the bottom of the radiator was loose (it had unfastened from its attachment point on the body of the car) but there didn't seem to be any hoses that had disconnected from each other. I couldn't find any visible leaks, but that was difficult to assess due to the coolant all over the place.

I've since ordered the coolant system pressure tester from ECS Tuning https://www.ecstuning.com/b-bav-auto.../b8800084~bav/

I'm baffled most by the fact that the car did this after the engine was already shut down. I had topped off the coolant last week, but didn't go over the recommended amount.

I'd be happy to hear your suggestions--I've read the other recent posts so I've got some idea of what I'm dealing with, but any comments regarding my specific circumstances would be greatly appreciated.

 

With a leak that big, you could start by refilling the coolant tank from the garden hose and watching for the leak source. Tap water can always be flushed when you repair the leak --- probably a damage hose. While waiting for the pressure tester, try to borrow a compression tester from your local auto parts store --- ensure there's no head gasket or cylinder damage. Yes, there's lotsa other coolant leak sources, but these are easiest to find without a pressure tester.

 

Bet its a crack on the thermostat housing? When mine leaked it sprayed and soaked the engine bay as the fine crack on the thermostat was like putting your thumb on the end of a garden hose. Fill it up and let it idle and watch it again. Or pressure test it. But if its the thermo it sometimes has to be hot to open up crack. Thats what mine did. closed up when cold, then finally went.

Here are the major areas to check:

https://www.northamericanmotoring.co...8-no-heat.html

 

Remember to replace water-pipe if you replace thermostat housing!

 

Likely the thermostat housing, or one of the many hoses connected to it. There is also a sensor on one of said hoses that usually weeps, but may have given up somehow. Lastly check your coolant tank overflow bottle and the crappy tube that is underneath it just to be sure it didnt somehow break.

 

WARNING WARNING WARNING

I agree that the thermostat is a likely source of your problem

BUT

I recently took my car in (under warranty) for a similar leak and it turned out to be the oil filter housing ... don't ask me why coolant flows thru this .... I was SURE it was the thermostat ... BUT!!!!!

all I'm sayin' is don't ASSUME it is a thermostat issue ... there's other stuff in the same neighborhood . . .

 

Have you had an oil change in the last 1000 miles?

Honestly, it is going to spray all over the place no matter. Why, because it is under 10-20PSI from the water pump. The pressure check only works for small leaks. If it is a massive leak, you need to be able to deliver alot of air quickly. What I found works best for large leaks is that you need at attachment to go into the expansion tank that will allow you to put 10-15 psi into the system quickly. Then you can "hear it". Once you can hear it, you can put your hand there and feel it. Now the pressure check kit does include that. However, you will really need a vacuum fill kit and that also has it in there. I used my air compressor. Water is hard to use as a source to find leaks because everything is wet.

As soon as I put an air source on my expansion tank, I immediately heard and saw my leak was coming from from the turbo coolant line T-fitting. That design is completely wack if you realize the expansion tank is in the way of being able to do an oil change. Every time you change the oil and undue to the expansion tank and pull that back out of the way to do an oil change, you will be putting incredible pressure on that fitting and it will eventually break as designed. I would venture to say it breaks within 20 oil changes. The way it breaks you can't see it is because it is 180 degrees from line of sight.

Before putting my new turbo coolant line fitting back, I reinforced the front and the back of the fitting with JB Weld so it can take a lot more stress in future oil changes. Also, I advise that you remove the bolt holding the aluminum coolant line to the turbo in the future when re positioning the coolant line. What that will do is spread the stress more evenly along the entire length of the line in case the hose doesn't bend.

Whoever designed the oil change routine on this car should be summarily taken out to the back yard and beat.

BTW, the Vacuum fill system you need to properly refill your coolant also will find small leaks. If the coolant system won't hold a vacuum, you will have a leak. It is just as easily to hear air hissing in as air hissing out if it is "small" leak. If it is a big leak, you will have the same problem. For big leaks, you need a jolt of air quickly and then stop and listen. Much easier to use your ear than your eyes for this. My leak was so big that all the 15 PSI was drained within 2-3 seconds.

 

My son and I spent the first two weeks of the quarantine going through the cooling system on is '09 hatch. To summarize our experience, I would strongly recommend you go through the entire cooling system as all these parts will all soon need to be replaced. The components are primarily rubber and plastic and have gone through heat cycles that cause them to fatigue over time.

We started with the water pump as this was the clear location of the leak. After successfully replacing it, we saw that the water pipe was now leaking. I think we caused it to fracture when we replaced the pump. While replacing the water pipe, we then had to replace the thermostat housing as the two are connected. As it had been two weeks of taking things apart and putting them back together so many times, I regretfully chose not to replace the hoses.

So, If I were in your shoes, I would do it all: T-stat housing, water pipe, water pump, and all associated hoses. Also, While you are in there doing the water pump, you might as well do the tensioner, crank pulley and crank pulley seal.

 

It is important to know the year and number of miles on your car. Although parts can fail at any time. There are certainly normal times. Like if you told me it has been 38 months since your last battery and when you click the car starter, you just hear a click and the lights in your car on dim. Dollar to a donut, your battery has reached the end of its 3 year guarantee...and consider yourself lucky because you got literally 2 free months

 

I haven't checked my '12 S but is that T fitting plastic? Seems the replacement version is now a metal T and the hoses connect to that. Stressing any part doing routine maintenance by design does qualify for backyard beating, I agree!

 

Yes. I just bought a new one. It is still plastic. I simply JB welded my old old and refurbished it for a backup.

 

Ahh, the metal one is for the N14:
https://www.pelicanparts.com/More_In...MN02&DID=12358

 

interesting, it looks like it could have worked with some modifications. However, the important aspect of that is the metal bracket on the T since that would lock it in place and force the rubber to bend. So the N14 is newer and better than the N18? lol

 

I guess that is one of the undocumented downgrades from N14->N18...thanks BMW.

 

There was a improvement in the margin.
$$$$
I guarantee you this cheap plastic T is probably stamped out in China by the millions and they just glued the hoses to it. I think the T's I use in my home irrigation are based out of higher quality plastic.

 

Found this in another thread:
Brass PEX 1" x 1" x 3/4" tee fitting and some clamps should do the trick
linky