GMC Sierra 5.3L Final Assembly

This week in class, with permission from my instructor Jeffrey Starkey, my team worked on my GMC Sierra 1500, which was in the shop for repairs originally as part of another class which I helped with. It has a 5.3L gasoline engine, but for the purposes of our class it is very much "electronic engine controls," even if not a diesel. It had been my hope to get the truck finished that day and pulled out of the shop.

Most of the engine work had been done, all that needed to be finished on it was valve covers, the radiator fan, coolant hoses, and of course... electrical connections to sensors and other electrical components. Final step was engine oil and coolant (which we used water to flush the system).

We got everything hooked up and started the truck. Whoops! Coolant leaks everywhere, and a bad idle. What did we do wrong?

This engine has four blocks with little nipples that go into coolant passages on the heads, two on front and two in back. The front ones are passages for the "coolant air bleed pipe" which connects under the throttle plate to the intake and allows air to bleed out of the cooling system. The rear two are simply there to block the flow of coolant out of the heads.

In my haste to get this vehicle finished, I had put the gaskets to these on wrong, and coolant was leaking out of all 4. Lesson learned! We luckily just had to take them back off, put the gaskets on correctly, and we also put some RTV silicone on them just to be sure of correct sealing.

I drove the truck onto our alignment rack, and found it died on me several times. On Thursday, we found this was due to the MAP sensor not being plugged in.

On Thursday, we fixed these issues and finally got the truck running decently and pulled out of the shop.

First ignition after we fixed the leaks and the MAP sensor was plugged in.

Reflection:

Don't get in a hurry. It's not a race. Take the time to go through your work and ensure it is all correct and up to spec. I made some mistakes through being in a rush and learned well from those lessons

The truck still has some issues which need to be ironed out, such as a misfire. However the big work is done. Just a matter of working out the kinks that were probably not related altogether with the crack in the head we fixed, and as always the learning will continue.