Coolant doing a disappearing act

[chompster4runner]

So my coolant has been disappearing on me for years. Every other months I would check the reservoir and it is low. I replaced the radiator 2 years ago with denso. Also replace fan clutch, oem thermostat, aisin water pump and flush coolant with zerex(napa) pink/red fluid. Here's the kicker. I would always wipe the neck area of the reservoir because of crust. Pressure test the system and came out ok. No funky cold start. It did over heat once when I had it idle with ac on during 100 degree day for about 30 minutes. Kids in the car. So what am i missing here? Thanks!

 

[Seymore Butts]

The crust is left behind by this self-curing fluid when it leaks out. So, that's where the leak is happening.

The two places where it can leak without leaving a crust behind are into the transmission and through the head gasket.

 

[andreylights]

The crust is left behind by this self-curing fluid when it leaks out. So, that's where the leak is happening.

The two places where it can leak without leaving a crust behind are into the transmission and through the head gasket.

Or a radiator. I mean there will be spots of pink crust but they may be hard to notice.

 

[08TxRunner]

You've got an '05 V6, which makes the head gasket suspect.

 

[waypoint]

Before startup in the morning, turn off the radio and roll up the windows, listen for a "waterfall" sort of gurgling noise under the dashboard. This is air bubbles being pushed through the heater core, a good indicator of head gasket leakage introducing air into the cooling system.

 

[chompster4runner]

Before startup in the morning, turn off the radio and roll up the windows, listen for a "waterfall" sort of gurgling noise under the dashboard. This is air bubbles being pushed through the heater core, a good indicator of head gasket leakage introducing air into the cooling system.

I'll try that tomorrow morning. Thanks! Oh and my 4runner build date is 12/04.

 

[chompster4runner]

The crust is left behind by this self-curing fluid when it leaks out. So, that's where the leak is happening.

The two places where it can leak without leaving a crust behind are into the transmission and through the head gasket.

The cap is pretty snug. Surprised it doesn't come out of the tube end. I even got oem rad cap when I swap the rad out. Maybe just get my fluid tested lol

 

[gaber6]

Does your reservoir cap still have the tube going to the bottom of the container? If that tube falls off, the radiator overflows into the container, then when the engine cools off, can't suck it back into the radiator. That happened to me.

 

[chompster4runner]

Does your reservoir cap still have the tube going to the bottom of the container? If that tube falls off, the radiator overflows into the container, then when the engine cools off, can't suck it back into the radiator. That happened to me.

Yea the tube is there and pointed downward. Did the air sound check in the cabin and I hear nothing like any other days. Sooo back to just ignoring it and keep topping it off every other months. lmao

 

[waypoint]

No waterfall noise is good news. You can lose coolant via the radiator end tanks and not be able to readily see it on these vehicles, it puddles in the skid plate rather than leaving marks on the driveway. Consider dropping both skidplates and examining them and the radiator end tanks for pink crust.