Coolant bubbles

[MrLinsky]

If I've got bubbles coming into my overflow tank when my engine is running. I don't know for sure that my cooling system is completely burped yet, so it could just be pushing bubbles out that are already in the system. It's after the system has been running for a few minutes, it's pressurized (upper radiator hose is taught). I get a small bubble coming up from the overflow about once every other second or so. My guess is it's got a head gasket issue. I've been hoping to be lucky and have been replacing everything that isn't the head gasket so far. I picked up a coolant funnel (thanks to White Stripe) and am going to let it burp tonight to see. Anyhow... If the head gasket is bad (or the head is cracked) does the frequency of the bubbles sound about right? or would it change with a change in RPM? I don't have a leak down tester, but I do have a hose I've modified for replacing valve stem seals I could use to pressurize the system to see if it's pushing air into the overlfow (and possibly narrow down the cylinder with the issue).

 

[Output Shaft]

Get THIS kit. It'll tell you if exhaust is ending up in the coolant.

 

[txnight]

Autozone will loan this tool out as well. You will need to purchase the fluid from autozone for about $10

 

[roscoFJ73]

I would try a new radiator cap before anything else. Getting all the air out is as simple as disconnecting one of the heater hoses (with the controls on) and filling there. Being the highest point in the coolant system, all air will go there

 

[Nutoreeus FOB]

your head gasket is shot...the kit Output Shaft mention above should indicate that there is co2 in your coolant...good luck

 

[sggoat]

if this issue is ongoing(it keeps happening over time) I would guess you have a head gasket leaking. Unless you have recently opened up the cooling system for some reason, any air would have long since dissipated( if you did open it up, the air would have either gone, or you would be seeing overheat issues). One easy thing to do would be a compression check-(you should see 140 psi on all the cylinders)If you do the check when the engine is cold, anything below 90 is suspect.