Mysterious Rumblings

[hydrogin]

Been noticing a rumbling sound coming from the right corner (passenger side) of my 94. It is most noticable when I drive on the freeway for 10 minutes, then pull off. After I stop, I sometimes hear a deep rumble for 3-4 seconds. It sounds like an old steam radiator cooling or heating up. At that point, my ear tunes into the noise and if I get back on the freeway, I can sorta hear that rumbling on top of the regular road noise.

 

I had all kinds of theories ... creaky motor mount or bushings, maybe a bad right-front strut, maybe ABS was going nuts. But couldn't figure out why the rumbling can happen when stopped. Having the clutch in/out when stopping didn't matter.

 

Then yesterday, I noticed water coming out from under the glove compartment! Never seen that before. Long story short ... I can now drive on the freeway for 10 minutes, come to a stop, hear the rumbling start then stop, then go to a parking lot and drive in fast counter-clockwise circles (left-hand doughnuts) and water will come streaming out from under the glove box. I was able to repeat this over and over through 30 miles of test driving last night. During this test driving, I made sure the A/C button and fan slider were in the off position. However, I also turned on the A/C a few times (the button's green light goes on) and verified A/C is operational.

 

Putting the rumbling noise and mysterious water together ... could I have a bad A/C compressor? Or something related to the A/C system that causes it to be on (even with the A/C button off) creating condensation somewhere, and creating the rumbling noise? Wherever the condensation is being pooled, driving in tight circles seems to force the water out from under the glove box.

 

Thanks for listening to my story.

Edited March 29, 2013 by hydrogin

[Leo94]

Sounds like a heater core to me. The rumbling would be your water bubbling kinda like when you try and open your radiator cap on a hot engine.

[adamzan]

The drain for your evaporator is clogged. Easy fix. Shoot some compressed air or stick a coat hanger up the pipe to clear it. You'll see the hose under the truck near the firewall.

[gv280z]

I agree with Heater core also. During your 30 mile test drive, you said you only turned on the a/c just briefly, was there still water coming out of your glove box even though there should be very little to no a/c condensation built up to actually "slosh" out...? If you drive it today and run the a/c the entire time, get out and look under and see if you can see any wet spots on the ground where the a/c would be draning, maybe see it dripping. If YES then your not plugged up but have something going on with the heater core...I guess it would be air in the lines maybe...it all goes back to your radiator, I wonder if your radiator cap is old and needs to be changed, because that would mean that your boiling your water/coolant away, therefore providing space in the heater core to allow boiling water to "rumble" The cap would be the problem because when it no longer holds pressure, the boiling point of water/liquid drops. The higher the pressure, the higher the temp at which your coolant will boil away. And that is how you loose coolant even if you don't have a leaking radiator or hoses. Replace the cap and refill your radiator.

[adamzan]

If it was the heater core it'd be coolant, not just water. Unless the OP is running straight water in his cooling system.

[Slartibartfast]

A bad heater core dumping coolant into the vents would probably make itself more obvious (and the title of the thread would be something involving skin grafts). My bet's on the clogged air conditioner drain.