Air bubble in heater core

This may be a silly question, but is the coolant level you're checking on from the radiator itself or the overflow? I'm leaning toward saying your head gasket is fine, but a compression test or boroscope would shed more light on that. However, you'd likely see low coolant at more than just the heater core and your climate would be exhibiting more and more issues with heating as the coolant got lower. Also, have you worked on the cooling system at all recently?

 

i use the overflow to see the level

 

Check the radiator itself. Sometimes that can be low and the overflow be fine. Again, you'd likely see other symptoms, but still. It doesn't make much sense, but I've seen it happen on 2 different vehicles

 

i could also bull the plugs and check if they are clean or dirty. do u think that would help?

 

Yes, it could help, but may not tell you everything. My suggestion is, after checking the coolant level, I'd do as another suggested and allow the truck to come up to temp and park it on a slight incline. Then let the truck run on full heat for a bit. Check the radiator level after that, although make sure you let the truck cool before you check the radiator lol.

 

Not silly, very possible. I had that problem on a different truck, overflow full but rad would get low. Small hose from rad to tank had a clamp on the tank end, but not the rad. Didn't leak coolant, but no vacuum to draw out of the tank. Small clamp fixed it. Then I replaced the water pump coz it was weeping, thus the low coolant.

 

coolant level fine in rad too. going to bleed the air out today and see if it comes back. I'm thinking I got air in the lines because of offroading, bouncing off of rocks and stuff will cause the coolant to slosh arround.

 

Because the bible (aka FSM) tells us to

 

Pretty sure on these trucks the WP has a weep hole and a little coming out isn’t bad nor does it warrant replacement

 

Different truck, same type weep hole. Refilling tank weekly does warrant replacement.

 

Pressurized cooling system, no way for air to enter even if the truck is upside down.

 

If it’s that excessive, sure. But, look up TSB 0117-11. Toyota claims these have an “ejection” port to weep temporarily, which - as stated above - does not indicate a failed W/P

 

But you need to understand what is happening.

 

Well it does tell you that the pump mechanical shaft seal is leaking.

 

Sure, it was a bit tongue in cheek. Just wanted to note that it says so in the FSM

 

don't care what the Toyota TSB sez, I WAS TALKING ABOUT A DIFFERENT TRUCK. Don't care if there is a TSB for any vehicle, refilling weekly is excessive. To me. YMMV.

 

If the coolant level is always spot on and doesn't drop slowly over time the headgaskets are fine

 

Curt much?
WHY ARE YOU YELLING AT ME?

 

i tried to bleed it with the funnel but the air is still in there

 

Coz I thought you were my wife. She is hx989 too.