05 4.2
Car was blasting full heat with a/c so I changed the heater valve, made sure all the hoses went back on the correct was as I marked them all.
Parked the car on a incline so as to have the coolant tank at it's highest point.
Filled the tank with coolant & let the car run with cap off.
The tank spewed coolant out after awhile. i refilled to just below full mark & it's bubblig inside the tank. The bubbling does subside for awhile but starts again.
It's managed to take only 3/4 gallon of coolant after running 45 minutes.

Any suggestions? The heater is ON full blast & the air is barely warm.
The cooling fan only came on/off once in 45 minutes. Ambient temp is 73

Should I keep it running?

 

Do not run the car with the cap off for an extended amount of time. The system needs the pressure to move the coolant and cool the system.

Is it bubbling because it is boiling?

You have a bleed screw on the coolant res. do not over tighten because they are easy to brake

 

+1 on the bleed valve, not available separately from the tank but i found any old ac o-ring kit from autozone has a new oring that will replace the old one for pennies, as for the bubbling i'd look up the purge procedure perhaps some air got in the system ??

 

I just drove it about 2 miles & it got HOT so I pulled over & released the pressure from that bleeder on the tank.

I too think it's a air in system problem as I have no hot air inside the car

 

if you are getting an endless amount of air out the bleeder and over heating temps, its time to get a block tester and make sure you don't have a blown head gasket.

 

I tried the o-ring once and it didn't hold well under 10lbs of pressure so I used some teflon tape and it sealed very well.

 

I susect a "air in system" issue as I just felt the 2 heater hoses going to the core at the firewall & they are barley luke warm after 55 minutes of operation.

 

sounds like a good amount of air in there somewhere, short of a block tester have someone rev and hold the rpms at around 1500 rpm with the bleeder cracked and the heater at full (engine warm of course) see if they can get that air out, if that doesn't work I'd rent a coolant system tester and block tester as stated above and test for gasket issues.

 

I replaced my tank prior to testing the system, turned out to be the blasted cap that was shot wouldn't even hold 5 psi caused all sorts of problems

 

kicker is, car ran fine yesterday, just did a 200 mile trip Saturday. Only reason I drained coolant was to R&R the heater valve

 

We this morning I popped the hood & the coolant tank was empty, the hot/cpld cycle seem to have sucked all the coolant in overnight. I added about 3/4 of a gallon & drove the car. The heater was blasting HOT air after about 5 minutes.
Drove about 30 minutes to work, No issues. Checked coolant tank, still full & no more bubbling. Seems as though there was tonnes of air in the system.

Thanks guys.

 

Excellent news!

 

It's great when they heal overnight. It just doesn't happen often. :-)