reddtekk
Noob, but quickly learning!
I know this is old but I'd like to elaborate as we are coming into summer.
x2. We can get surprisingly hot here in CT and often have heavy highway congestion so you're sitting there in 105° ambient + solar heat on the pavement + added heat from all those additional automobiles around you...but GM designed the vehicle for that - kinda. Think of how our engines work...IDI engines have a lot of shrouding in the cylinder head because of the prechamber. You have most of your air getting compressed into that little pocket, then add some fuel and let it burn like a hell fire in there while it all makes its merry way out the little nozzle in the precup into the cylinder. DI diesels don't deal with this, so they belch out much less heat from their cooling systems. Even still, the truck was designed to deal with the extremes in stock form while handling its designed workload. The thing is that there seems to be a little less room for error in the cooling systems of these than in other vehicles so it's important to make it work the way it's supposed to.
I also like a previous post reminding us of the importance of keeping the radiator core clean. No one chimed in saying "Oh yeah I tried that and it really helped!" It bears reiteration - make sure your radiator core is clean and fins intact before going crazy with the cooling system. Fin combs are available in most auto parts stores. Tedious but necessary, especially if not careful with a potent pressure washer while trying to clean the core. Ask me how I know. :mad2:
Check specific gravity of your coolant - there is a myth among some that if it isn't going to freeze you don't need "antifreeze". Thankfully I haven't heard it mentioned on this post but I'll advise anyhow. It does prevent freezing and does actually slightly lower the specific heat of the water (that's bad), but you benefit from the anti-corrosive properties and lubricity of coolant. Fine rust particles can build up in the radiator cores and reduce heat transfer, water pump parts can suffer, etc. if this isn't present.
Make sure your thermostat opens. Yank it out and toss it in a pan of water with a thermometer. Bring it up to heat SLOWLY so your thermometer responds (keep the thermometer off the bottom of the pan to get an accurate reading) and observe the thermostat as the temperature approaches and passes its opening temp.
Regarding pressurization - I have a wood boiler and can go to about 230 before it starts to perk because I keep it under 15-20 psi of pressure. Lower that and you lower the boiling temperature. Same goes for a car. The reason they say not to open the cap when the engine is hot is because (a) the system is under pressure and will force some water out and (b) some of the water that remains could be above its boiling point @ atmospheric pressure so it will flash to steam, causing much more of the water to be ejected from the vented cap shortly thereafter. I also like the point someone made about the suction side of the water pump! Remember that if the boiling point rises due to increase in temperature, it will also DROP due to a decrease in pressure. So this localized area of decreased pressure could also be an area where boiling could occur.
Many great points have come up in this thread. To bring it all together, make sure that everything was as it was designed to be and you should be FINE. KISS, as one forum member suggested.
Happy trucking.:thumbsup:
