HELP COOLANT ALL DRAINED OUT WHILE DRIVING

[IgotBMW]

There are clips under the electrical box that attaches it to the injectors. They're a pain to get to, but all you need is a long skinny screwdriver and just try to get one side off. I've also read you can just yank the electrical box straight up.

[benfbuilder]

Ok thanks, I'll try it.

[benfbuilder]

Mam4.6 you were right it is that hose you were talking about. How fun. Anything else to replace while I've got this torn apart? Also thanks for all the support and input from everyone!

[J.Belknap]

When you pull the water manifold in the rear of the motor you're going to need new 4 o-rings in addition to the head water gaskets, two o-rings for manifold, two orings for water pump.

[mam4.6]

Originally Posted by benfbuilder

Mam4.6 you were right it is that hose you were talking about. How fun. Anything else to replace while I've got this torn apart? Also thanks for all the support and input from everyone!

Lucky guess... I had an underlying issue that caused mine to rupture under pressure. Does your have a pinhole leak, or a whopping tear in it. I took the inside cowl cover off, then the whole cabin air filter assembly. Only 4 bolts holding that on, and it comes right out... Gives you good access to the back of the engine. I didn't need to do anything other than that, i.e. other hoses, gaskets, etc... Took the old hose off, put the new one on, bled the coolant system, and everything was good...

[benfbuilder]

Mine has about a 1.5 " tear in it. Water was pouring out of it when I poured it into the expansion tank. And yeah that's what I did is removed the cabin air filter housing. I've been having an issue with my expansion tank cap, it will bleed out coolant little by little like the system has too much pressure. Even with a brand new cap from the dealer so I have to add coolant once a month or so. Any ideas what could be causing that? Do you think that's what could have caused my ruptured hose?

[mam4.6]

If your hose had a small leak in it, that could've been what was pressurizing your system, and the hose weakened over time, finally rupturing. I'd replace the hose, and keep your eye on it. If your still getting excessive pressure in the system, diagnose further...

[benfbuilder]

I don't think it ever had a small leak because I'm under this thing quite a lot and never noticed any dried up coolant on the backside of the engine/around the bell housing area. But who knows. Hopefully the dealer will be open today so I can get the hose and some more coolant.

[bcredliner]

Unless the expansion tank cap is defective, even though it is new, or you are overfilling the system, bleeding coolant indicates the system is overheating enough to reach the pressure release point for the cap. That could be because of a leak where the coolant got too low or a thermostat or waterpump problem. All of these should have caused the temp to run higher long enough to be noticed before a hose bursting.

I would fill it with water after replacing the hose, let it run until it has been at operating temp for 30 minutes and check for leaks or white smoke out the tailpipes before filling with coolant. It could also be the expansion tank leaking giving the appearance the leak is coming from the cap. I would get out my handy dandy auto stethoscope and put the probe on the water pump and listen for a growling noise. Look for indication coolant is leaking from the pump. Replacing the hose may be all you need to do but since you are losing coolant from the expansion tank I would check for a contributing problem causing overheating.

You never saw any indication of coolant on the ground after having driven at operating temp for 25 or so miles?

[benfbuilder]

No, none of that. That's why this doesn't make any sense. The temperature gauge has never risen above halfway since I've owned the car and I've driven it 1000 miles through 115° heat in the desert with ac on max. The coolant is definitely leaking through the cap and not the tank. And never any coolant on the ground or from anywhere elese. Just the cap.