Losing antifreeze

Just purchased 07 Tundra notice that the antifreeze reservoir was low on antifreeze. I filled the reservoir to the full line and drove about 50 miles. checked it again the next day and all the antifreeze I put in was gone. I see no sign of the leak on the ground or anywhere on the vehicle.

 

This happened on my Tacoma, never figured it out, traded in for my wife’s 4Runner, but I suspected a bad head gasket. You can get a test kit to determine if exhaust is coming through into your coolant.

 

I had signs of coolant being pushed out of the overflow. Yours may have just been low to start with.

 

How many miles do you have on the truck? Check around the water pump area, there may be a small leak there

 

Lets stick with symplicity first, sounds like a bad thermostat that can no longer regulate the cooling system. When the system gets to max pressure the radiator cap opens to relieve the pressure and allows the fluid to go to the overflow bottle and out the overflow hose on the bottle creating a venturi effect sucking the fluid in the bottle out as the tube is relieving the system. Most times you can't see fluid as the tube usually goes down far enough so you can't see any fluid leaking. The rig should not overheat until most of the anti freeze is lost. I take it you are not overheating yet right? You could rig up a hose from the overflow to a bottle to see if the bottle catches fluid.

 

Just did mine recently

 

Same thing happened with my tacoma but once I refilled it with new fluid, it hasnt happen ever since.

 

Generally....it won't show on the ground if it is the typical water pump leak. Right after I bought my truck I noticed my coolant level kept getting low, but no puddle. It would basically get blown backwards by the engine/cooling fans and dry as a pink crust on the lower part of the engine.

I'd check for white/pink crust - it is a very common problem with early 2nd gens.