No compression in Cylinders 4, 5 and 6 Help

I would never trust a computer to tell me compression when there aren't even pressure sensors lol.

 

how does a dyno Not help diagnose 3 dead cylinders?
This simple and cheap tool could have given you the answer an about 6 seconds.
check the temp on the exhaust manifold at each exhaust port.

 

Simple. Don't need a $6k laptop to give the answer lol.

 

Stop at harbor freight and pick up a temperature gun. And measure the exhaust manifold temperature.

You might be able to find one that can park a truck somewhere close.

 

Did they do an actual compression test or just another BS one with a computer? Since they told you 40% and not an actual number in PSI I'm betting they didn't.

What did they do to determine the head needs a rebuild and that its not the cylinders?

 

Stop!

this is utterly insane, READ MY POST AGAIN!

if they put it on the computer, after being explained your situation than the mechanic is a moron.

they need to do a mechanical test, not a computer test and they have to check the valve adjustment of those two cylinder, the computer test is not to be trusted.