5vz cracked head. reman heads or junk yard engine?

You could also win the lottery, catch a 15lb bass and make a hole in one on a par 4.

 

After another weekend sitting in denial I did brainstorm one last idea and found a potential cause of issue I could be having. I had some AI analyze every single little symptom I could come up.

The 5VZ‑FE intake has a built‑in coolant passage (through the throttle body or a bypass tube) and thick lower manifold gaskets. If the rubber seals around the coolant ports fail, coolant can leak into the intake plenum or runners. Unlike a head crack, this tends to happen mostly when the engine is cold/cooling (as metal contracts around the failed gasket). Coolant pools in the intake or throttle body bore and is drawn into one cylinder on the next start, producing a brief white puff. Because the coolant is burned immediately, there may be no external leak and no measurable coolant loss.

I scavenged some more and came across this video here https://www.youtube.com/watch?v=ILPP5c35Uqg

I personally have seen forums on here of people having issues with the intake manifold gaskets leaking externally down the rear of the engine off onto the bell housing. I don't have major coolant loss, so its different there, however I feel like the two (cracked head, manifold gaskets or some other intake coolant related leak) is pretty indistinguishable without tearing into the motor.

I know my motor has miles racked up, and that its probably a cracked cylinder head after all. With all this extra class time I have being near the end of the school year, I have nothing else to do but sit and try and find reasons for what's happening with my truck.

Im finally sticking a borescope down in my cylinders today in shop class, so wish me luck!

 

Yeah, that bubbling is the intake manifold gasket leaking and pushing the coolant up. I think it's exhaust gasses pushing it up? It's a doable job, wayyyy better than removing heads.

The massive coolant leak down the back can be when the bypass pipe sealant fails which is a whole separate thing you can also access when taking off the intake manifold. It doesn't touch any air passages, so it's just dripping down.

A cheap salvage engine was probably a good gamble many years ago. But every year that goes by, knowing this is a common issue... I don't know, it sounds like the heads are in some phase of cracking on all of them.

 

OP, have you run a compression test or leak down test yet? Those would also be fairly easy (and fairly reliable) ways to rule out cracked head/head gasket issues and therefore rule in your new intake manifold hypothesis.

 

Compression test came out good and compression was fine