I noticed that my coolant was low the other day and I topped it off, while I was doing this I saw that the coolant in the overflow was bubbling a little bit. I've checked periodically for a few days and sometimes it is bubbling and other times its not. The engine runs great and has no white smoke coming out. I'm really hoping its not the head gasket. all input is welcome. thanks

 

Has the coolant level been stable or is it dropping?

Can you smell exhaust in the coolant reservoir?
Home kits are available which test for exhaust in the coolant.

 

[QUOTE=Georgeandkira;2238210]Has the coolant level been stable or is it dropping?

Can you smell exhaust in the coolant reservoir?
Home kits are available which test for exhaust in the coolant.[/QUOTE

The coolant smells fine and I dont think I've lost any. I checked the overflow again today and no bubbles

 

Additional thoughts from me, a non-expert on cooling systems.
Being a 2002 -aka 24 model years old- the radiator caps pressure spring might be weak, allowing the coolant to boil.

Can an aged, perhaps failing, thermostat be causing this?

What's the overall condition of the cooling system? ...weak, filthy coolant?, ...encrusted radiator and engine passages?, ...eroded-away water pump impellor?

 

The coolant is clean and everything seems to be in good shape. I’m wondering if air got trapped in when I filled it up and I was just bubbling out because I haven’t had any issues with the coolant bubbling for like three days.

 

And you're not overheating...and the heater works...It's Miller time.