Coolant Bubbling

Teenone · 05-17-2022, 06:06 PM

My bus has been sitting for some months, and I need to move it about 1000 feet into the shade since it's getting hot... so I started it up, walked around for a about 5 minutes or so to let it warm up and came back and there was some water shooting and spraying out of my radiator! I ran to turn it off and came back to the engine and my coolant was bubling like crazy for a while... I could find where the coolant is coming out of the radiator... looked into a thread that had a similar issue and saw that my air compressor IS connected to a coolant line on top... it looks like a small amount of water is actually leaking out of the air compressor so I'm guessing it has a blown head gasket or cracked block...? Also it has a bit of rust so it looks like it's been leaking out a small amount for a while... I checked my oil and it seems fine... coolant level is topped off... I'm wondering what to do next, and if it would be okay to just start her up real quick and move her into the shade while I try to figure this out...
I'm thinking it could be either a thermostat, air compressor headgasket/block, head gasket in the engine or a cracked engine block.... Pic 1 is showing the air compressor where the water is leaking out its kind of sideways...
Pic 2 is the coolant line connecting to the air compressor...
Pic 3 is the air compressor
Pic 4 radiator
Pic 5 engine model

cadillackid · 05-17-2022, 06:15 PM

in my case when my compressor was bad my coolant was bubbling after i shut the engine off until the air bled down a good bit... an Engine head gasket or cracked head will result in the coolant bubbles stopping within a very short time of the engine being turned off..

Teenone · 05-17-2022, 06:33 PM

Thank you for your reply.. Okay so I guess I need a new air compressor... I'm hoping I didn't mess up my radiator...

cadillackid · 05-17-2022, 06:40 PM

fluid should never come from the radiator unless there is a pop-off on it... in my case the fluid came from the pressure relief on the cap and boiled over the bottle and onto the ground... if it came from the cores of the radiator and not a pop-off or hose clamp then your rad is probably shot.

Teenone · 05-17-2022, 07:12 PM

Thank you.. Yeah you're definitely right. That sucks ... well guess I need a new radiator now too. I'm thinking the pressure got too high and blew the radiator

cadillackid · 05-17-2022, 07:15 PM

it likely wouldve gone anyway... be sure to have the cap tested or replace it.. if it truly didnt pop when it was supposed to and ruined the rad you dont want that happening with normal operation.. but if the rad was weaker than the cap and it blew the rad, the cap might still be good.. I wouldnt take the chance personally..

Oldyeller · 05-18-2022, 09:43 AM

From the picture of the compressor, it looks like it's been leaking for quite a while.

Teenone · 05-18-2022, 01:05 PM

Yea you're right since it's rusty, but I I think maybe since it sat for a few months the head gasket might have gotten dried out and failed? Or maybe I just didn't notice it before... but it put a pinhole leak in my radiator from the pressure of the air going into my radiator, I'm going to change the head gasket and see if that helps since it should be the cheapest option.. also going to try and Sauter/braze the pinhole leak in the radiator since it's not in the actual radiator core it's just the top piece. Thanks for the response... also I'm wondering if I need to flush my air brakes system if there's a possibility that coolant got into my air brakes and how I would do that? Or do I just need to drain all the air at the air tank? ��

Tin Roadtube Vagrant · 05-18-2022, 02:45 PM

Could have.... PSI charged air going into coolant when running and PSI charged coolant into cylinder when shut off. I would test the motor oil. If no coolant in motor oil then no coolant in air brakes. If you show coolant (usually also high sodium) in the motor oil, drain tanks, drive a fair size charge of low % water isopropyl alcohol into the air system (quart) via discharge line of compressor and operate service functions repeatedly as soon as you hit 30PSI on dash. Air dryer will dump most of the alcohol if you allow it to achieve a discharge cycle. Dump another dose of alcohol in, ramp up to governor cutout and operate all park brake releasing functions repeatedly, then service brakes. Drain tanks when done to eliminate pooled alcohol.

Air dryer check valve may require you to make discharge line swallow alcohol by using a rubber tipped blow gun.

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