Bubbling in Radiator?

[TCruiser93]

I have bubbling in my radiator after an average drive. The coolant in the reservoir has decreased slowly. I have replaced my fan clutch, thermostat, radiator, hoses and had a pressure test done to check for other leaks, so by all accounts no leaks and HG should hopefully be ok although I know it's possibly hurting. Any ideas would be greatly appreciated! Thanks!

 

[TCruiser93]

Tyler, is your dash temp gauge showing an elevated temperature when this happens (as with an overheating engine).

Did you check for bubbles in the RADIATOR with the cap off (engine cold upon start up)?

When you are driving....are you running your A/C then parking and turning engine off (and then hearing the under hood noise)?

I ask because I wonder if you are hearing the 'normal' noise of the high and low side of the A/C system 'equalizing' after shut down.

The guage is reading normal. Although I have had one time, maybe 2 that it elevated. That’s been a while ago.

I’ve gotten bubbles out of the radiator before by running the motor and squeezing the hoses. I haven’t really seen bubbles just opening the cap I don’t think.

I believe it happens no matter if I’m using the a/c or not

Idk. Speaking of A/C. I have a long standing issue where it stops blowing cold while driving , I put the button off, drive idk 5 min, press the button and it’s cold again. Trying to figure that one out.

 

[flintknapper]

Idk. Speaking of A/C. I have a long standing issue where it stops blowing cold while driving , I put the button off, drive idk 5 min, press the button and it’s cold again. Trying to figure that one out.

^^^^

Most likely:

Your Evaporator or TXV is freezing up. Cooling stops then resumes when it thaws out.

Cause: Refrigerant level low, moisture in refrigerant or both.


Less Likely:

The thermistor on your evaporator is not working.


Suggest: You have the system pressure tested. If low then you have a leak someplace, A/C refrigerants are not a 'consumable' like engine oil for example. So a leak is the only way you can have 'loss'. A slow leak (top off system once every season or two) is generally not worth chasing down. More than that....find the leak and fix it.

 

[TCruiser93]

^^^^

Most likely:

Your Evaporator or TXV is freezing up. Cooling stops then resumes when it thaws out.

Cause: Refrigerant level low, moisture in refrigerant or both.


Less Likely:

The thermistor on your evaporator is not working.


Suggest: You have the system pressure tested. If low then you have a leak someplace, A/C refrigerants are not a 'consumable' like engine oil for example. So a leak is the only way you can have 'loss'. A slow leak (top off system once every season or two) is generally not worth chasing down. More than that....find the leak and fix it.

Makes sense. Someone told me once it could be expansion valve.

 

[TCruiser93]

Now in the cooler weather I’m having. I’m not getting the bubbling noise. Should that make a difference in the issue? Mean it is overheating a little when it’s hotter?

 

[DSRTRDR]

Regular coolant loss is only by a leak or a HG.

It took me 3 months of regular checking to find my coolant loss and it turned out to be the 3 o-rings on the bypass pipe by the thermostat.
I happened to catch a bit of coolant before it evaporated to define where the leak was occurring.

I cleaned that up and installed new o-rings and all new hoses, including the PHH and rear heater hoses.

Then it opened a leak on my 8 YO OEM radiator. That's the last part in my system now.

You may encounter similar things in tracking a coolant loss.

If you cover all these bases, then check the radiator for exhaust gases.
Then a compression test on each cylinder.

he hasn't told us what radiator or radiator cap he has

I found that a mismatch between them can get the water to boil under some circumstances (in our case high altitude), because the mismatched cap doesn't properly seal - a cheap auto-zone aftermarket radiator cap solved the problem on our 80 while on a trip through Yellowstone National Park in 2019

the symptom was hearing bubbling after the truck was parked (shut off) - no evidence of overheating on the factory gauge or aftermarket radiator fluid gauge

this was a Koyo radiator with an OEM cap, and the mismatch problem only ever reared its ugly head at over 8000-9000 ft altitude on our attempt to run the Beartooth Highway (which turned out to be closed before the Continental Divide, due to too much snow on a June 6 or so )

so, we let the radiator cool down, coasted down to the intersection, turned onto the road to Cody, WY, and babied the truck to the next autocrats store . . . new radiator cap, ready to go

before that trip, the truck had only ever been in "flat" country, like TX, AR, LA, and low altitudes of southern AZ

 

[KC masterpiece]

My guess is the rad cap is not sealing well on the new radiator. Might need a new cap or need to bend the tabs down. Bad cap will keep the system from pressurizing. It will run at okay temp then boil and bubble when turned off. I spent a long time diagnosing that on mine and mud paranoia made me keep looking for bigger issues.

 

[jsloden]

Forgive me if I missed this but, he said he just had the radiator and coolant replaced. Are we sure the mechanic bled the system properly?

 

[baldilocks]

I've never know about the PHH, that's interesting. And maybe I will see about a compression test. Thanks!

You can learn a lot about your 80 by doing randomly worded searches through google. This is how I researched 80’s prior to purchasing one 9 years ago. Many of the results will lead you to Mud where the best answers are but the Mud search feature itself isn’t as good. I post this due to the fact that you’ve never heard of the PHH, an infamous Achilles heal of the 80 and very high on every new owners baselining priority list.

 

[TCruiser93]

You can learn a lot about your 80 by doing randomly worded searches through google. This is how I researched 80’s prior to purchasing one 9 years ago. Many of the results will lead you to Mud where the best answers are but the Mud search feature itself isn’t as good. I post this due to the fact that you’ve never heard of the PHH, an infamous Achilles heal of the 80 and very high on every new owners baselining priority list.

Believe me I’ve done a lot of research. And I’ve had it for 18 years. Somehow never heard that that heater hose is an issue. Probably because I don’t do major wrenching on it myself. I appreciate everyone’s input!

 

[TCruiser93]

My guess is the rad cap is not sealing well on the new radiator. Might need a new cap or need to bend the tabs down. Bad cap will keep the system from pressurizing. It will run at okay temp then boil and bubble when turned off. I spent a long time diagnosing that on mine and mud paranoia made me keep looking for bigger issues.

I replaced the radiator cap. And he did bleed it.