Potential Blown Head Gasket

I pulled back into my driveway after a 20 minute drive through the country where I was "racing and high-revving" my truck quite a few times. Anyway, the truck smelled like coolant and you could hear the coolant overflow reservoir boiling after the truck was shut off.

Fast forward a few weeks, I had a coolant flush completed as well as the thermostat replaced, and radiator cap. The truck still overheats after a little while.

Exact symptoms:

After driving the truck around for 5-8 Miles, you will see the Temperature gauge slowly rise to in between the 'H' and the "Normal operating temperature hash mark". The temperature will drop after idling at a stop sign for about 15 seconds. Thena after take-off, it will start to heat up again. The truck does not overheat from sitting at idle.

The shop has block tested it three times and it has passed all of them. They did say on the last test there was a slow decrease in pressure but was still in spec. The motor oil is clean and not milky, the exhaust does not smell like coolant, and there are no obvious coolant leaks anywhere, including the water pump and the block.

At this point I am thinking there are only a few options:

1. Blown head gasket
2. Failing water pump or some time of idler pulley causing friction on the serpentine belt
3. Semi-clogged radiator or collapsing hose

What do you all think?

 

Air in the system?? My celica would boil coolant due to air in the system until I bleed it, but that is apples to oranges..... Ensure your cap is still good to go and not missing pieces to it.. Double check all your hoses and ensure no cracks or leaks... Not sure what your mileage is, but my water pump blew up at 25k mi. more or less and has been flawless ever since.....

 

Does your recovery tank smell like exhaust?

 

Well, the shop figured out the issue. the exact same issue as detailed here:
<https://www.tundratalk.net/threads/2011-5-7-coolant-leak.657346/>

Essentially the valley plate gasket is leaking coolant into the valley of the motor. So the coolant is losing pressure and getting air into the system further making the coolant loss more exasperated.

 

Interesting, does the valley plate experience pressure from the intake at all? Wonder why beating on it caused it to fail.

 

I am unsure if it receives pressure from the Intake.

 

probably because heating up to high temps fast and then cool offs a lot just caused it to give way just like any other sealer would.