E53 making bubbling sounds, only heats intermittently
 

As winter keeps coming around in Oklahoma, I still need my heater. For the most part, it is not heating. Just blows cool air, the temperature is running correct on the engine, but no hot air. Every now and then it will blow hot air, but for a little while and the quits.

Recently, I started hearing bubbling or gurgling sounds, that seem to come. right in front of the driver. Not sure what that means. I have checked the coolant within the last 3-4 weeks, will check again tonight. after it cools down. Thought maybe it might be low.

Any thoughts. appreciated.

E53 making bubbling sounds, only heats intermittently
 

Lots of cabin heat is one of the first signs of low coolant


Sent from my iPhone using Tapatalk Pro

bubbling sounds like air in the system, probably cause is low coolant level as suggested.

The two things may not be connected.

Bubbling sounds from in front of the driver was a dying vacuum pump on my 4.8iS.

The intermittent heat.... tons of possibilities, from aux to bowden cables

Sent from my SM-A730F using Tapatalk

On my 2001 3.0 M54, the coolant was slowly oozing from the ends of the two coolant hard pipes behind the oil filter. I swapped them when I did the head gasket and it's been good ever since. I did a pressure test and saw no coolant leak, only a very slow leak down of pressure that I chalked up to "probably the seal at the cap or quick connect on my Harbor Freight pressure tester". When I pulled off the hard pipes, the ends were bretty mucg disintegrated around the O rings where they enter the block.