Bubbles in the coolant recovery bottle

I'm having a problem with air bubbles in the coolant recovery bottle. When I shut of the engine when its hot I could here an audible BLIP, BILP, BLIP coming from under the hood. Opened the hood and noticed tiny bubbles coming into the recovery bottle from the overflow hose. I noticed the coolant getting lower in the bottle over a week or two.
Yesterday I poured in a bottle of Bars stop leak. Waiting to see what's going to happen. The truck has 217k on it. Anyone else having an issue like this?

 

Sounds as though the Head gasket has given up on you my friend. Is the expansion tank dirty as well? Might be exhaust gas leaking into the coolant via failed head gasket.

My '05 4.0 is doing the same thing. I'm gearing up to tear it apart and replace the head gaskets (along with just about everything else that has to come off) within the next couple of weeks.

I've seen a couple 4cyl threads on here replacing the head gasket but did not look into those too much as I was hunting for a 6 cyl write up.

https://www.tacomaworld.com/threads/2006-4-0-v6-head-gasket-overheating-rebuild.609265/

 

edit - didn't see that OP has a 4 cyl

 

2.7's had the same issue?

 

Good call I didn't see that under his avatar. To my knowledge they did not

 

FLUSH THE STOP LEAK OUT IMMEDIATELY!!!

Pull the tstat housing, pull the tstat out and flush the truck, PLEASE... that stop leak stuff just gums up EVERYTHING.


Its likely as simple as a worn out radiator cap.

 

I used to do many head gaskets in small Diesel engines. Snap On had a solution and suction device that would turn the solution a different color if you were getting exhaust gasses in the radiator. Among several other things to check, this was a quick painless check that worked.

 

I would stay away from the Bars Stop Leak until you know what is going on with your engine.
It is not unusual for coolant to be pushed into the overflow bottle soon after shut down. The engine goes into hot soak and briefly increases in temperature.
I recommend closely monitoring your coolant level going forward. Be sure to check it on a regular basis, and account for engine temp's when checking levels (always check it near the same temp). If you are losing coolant, pressure check the system and repair any leaks.
If it were my truck, I would replace the radiator cap and thermostat.
If you tighten these things up and are still losing coolant, check for exhaust gasses in the coolant (reveals head gasket leak). it is easy to check with the following kit:

 

You said you had noticed coolant level getting low over a few weeks. That's a sign, bad rad cap poss but not likely. Have you seen any visible signs of coolant leaking? No, ohh oh, head gasket.