Ok im dumb...but why is my overflow bottle not changing levels?

Had my radiator cap, thermostat, hoses replace last year. All Ive done to check coolant is to eyeball the overflow bottle.
Yesterday it dawned on me the coolant level has not gone up or down, even after driving for an hour. When the radiator cooled down I took the cap off and the collant is full to gje top. Radiator and hoses are hot, temp gauge is solidly in the middle. No whine from the water pump or any leaks. So am I crazy or just stupid?
The radiatot gets hot and expands the coolant into.the bottle, then when it cools down it sucks the coolant back in. So why is my radiator and hoses hit right now, but the coolant in tne bottle is ice cold. Wgat in the hell? Brand new cap, no leaks or coolant smell, no coolant leaks WHY is the coolant level not changing in the bottle, and why would it be i e cold in a hot engine and radiator?

 

Have you marked the coolant level when cold and checked when hot ?

 

Coolant level shouldn't change much with the engine off vs. running if the system is well bled.

 

The radiator cap only allows coolant to bypass it into the overflow tank when the pressure in the system exceeds the safe limit that it's designed to hold back. If the radiator is full and absolutely nothing is malfunctioning, then the system should not be moving coolant back and forth between the overflow and the radiator.

 

Yeah, at least on my 2.7 I can't say I really notice that it moves much between hot and cold.

 

Hmmm... with the coolant level at the full mark when cold it would be above the full mark when hot. The next day after it cooled it would be back to the full mark... My truck must be sick.

 

Physically the only time it can be sucked back in us when your coolant system pressure is over cap pressure but decreasing. This is a rare circumstance.

 

Thanks to all. Im thinking the cold weather means the radiator is just not getting hot enought to force coolant past the cap into the over flow bottle

 

I didnt read all the responses but something you want to check as its very common.....
the hose from the bottle to the radiator can get plugged with debris...

carefull pull hose of radiator side & blow through it....

if blocked, at the shop we clear it with compressed air pressure, blow / air gun...
if you dont have one....
garden hose...
maybe a coat hanger through the hose?
you can pressurize the bottle using the garden hose through the top & sealing the top using a rag & your hand.
You will need to add fresh coolant to the recovery bottle after that method...
But if blocked, should be flushed anyway removing at traces of debris.

 

From the internet : While you can't always believe what you read on the internet this is how the system works...

A coolant recovery tank, also known as an expansion tank, is a reservoir that stores coolant and allows the cooling system to discharge and recharge coolant as needed:
A coolant recovery tank's main purpose is to maintain the cooling system's full coolant capacity. It does this by:

• Capturing excess coolant
  When the coolant expands due to heat and exceeds the radiator cap's pressure limit, the recovery tank captures the excess fluid.
• Drawing coolant back into the system
  As the coolant cools and contracts, the recovery tank draws the coolant back into the radiator.

Coolant moves both ways, if it didn't when your engine/radiator was cool and you removed the radiator cap the radiator would be somewhat less than full. When I remove my cap radiator is full to the seat for the cap...

 

The radiator cap has a number on top like 0.9 or 1.0; this is the pressure rating. A lower rating means the cap will allow overflow at a lower pressure.

Did you replace the cap with an OEM one?

 

Working as designed

Overflow means when it needs some where to go. As in 100* day, excess expansion. Your cooling sysstem is perfect.

 

What kind of debris can accumulate?
Is it crusty stuff from Toyota coolant?
Thanks

 

Very common occurrence in some applications....
certain conditions like in an overflow bottle sometimes the coolant will get crusty on side of the bottle & then vibrations & what-not the crusty build-up will break-off & plug-up the hose causing a full on blockage.
Also alot of dealers that do coolant flushes......
Use BG products & a coolant flush machine...
Its a 3 part kit, chemical flush, water wetter / conditioner, & a sealer.....
Well that sealer is some sort of nonsense liquid mixed with what looks like sawdust....
Well, that sealer in itself will plug-up that hose even if the lube techs but the sealer in the radiator & not in the overflow bottle.

Just my experience as an engine, cooling system, manual trans , exhaust, heavy line tech for ford for 32+ years...
Seen a few things...

 

Yup I’ve noticed this happen in my truck, so this is the same crusty stuff that ends up in my radiator cap from time to time. thanks for the explanation!!