So i was driving the other day and noticed my check gauges light come on all of the sudden. which made me notice my engine heat was damn near the H! which got me worried. I used the old trick of turning the heat on to lower the engine level but now I'm curious why this happened.

here is a quick picture i snapped as it was dropping back down.


it rose up really fast and than dropped down really fast. Any ideas guys? for the moment being I'm not gonna drive the D. So I'll be stuck driving a little 2000 Malibu! any ideas or advice would be great guys.

 

First I would check the level of your coolant and then if that checks out I'd replace that thermostat. Likely it got stuck and turning on the heat unblocked it for the time being but I'd get that replaced.

 

Yeah. i'll check the coolant level. tonight. and yikes i hope its not the thermostat. those are a pain on the 4.7l's!

Any other ideas guys? i noticed this small plastic tube on the side of the coolant cap. it looks like it should have a small hose attached to it but it doesn't. its odd. I'll get a picture of that up tonight as well.

 

kinda sounds to mel ike your low on coolant, and if its the spot i am thinking of it should be connected tot he overflow, if its not then your definitely low on coolant, ill wait for a pic to say for sure

 

yeah sounds like air in the system so most likely low ont coolant and it caught an air pocket

 

well here is the small plastic tube i mentioned. its that little piece right next to the cap on its right? i don't think its supposed to be connected to anything. also i think it might have leaked out from there. it does look like there is some coolant spilled out onto the side and down under. i can see coolant on the floor in the garage as well. very small amount on the floor. maybe a 3 inch circle. its just damp not a pool or anything.




Also how high is the coolant supposed to be? the measure on the dipstick reads full and the whole dipstick was covered but its damn near to the top in the container. maybe just 2 inches from the cap. maybe 3 inches?

 

The little line from the radiator cap (on the right) is supposed to connect to the coolant reservoir. Now if that hose is leaking (which you indicated) then the overflow is going on the ground when it gets hot instead of going into the reservoir.

When coolant gets hot it expands and is pushed into the reservoir, when the hose is broken or cracked the fluid spills onto the ground. When the system cools off, the coolant condenses and with a cracked hose it sucks in air. Well air in a cooling system won't cool and therefore over heats the motor.


Replace the cap and hose.

 

Hydra how would it connect to the reservoir? there is no loose line or hosing laying around under there. And yeah i know it expands due to temp and pressure. So you're saying to replace the cap on it as well?

Ok what ever needs to be done right? a cap and a line not a big deal.

So where does that reservoir line come up from? i dont recall there ever being anything attached to that. though i never looked that closely i guess.

 

Well I am reading this, and though I have the 5.9, your set up looks the same as mine, and I have been having similar problems, and now I need a new radiator.
Are you talking about the molded pipe that comes from the plastic expansion tank, just R of the yellow square filler cap ?, I thought it was just an overflow, and nothing is connected to mine either, which does not seem right, and I have been struggling to keep my D cool for quite some time, even before the rad took a dump, keep getting air in the system evan if I burp her like a baby !

 

that is NOT supposed to be connected, its the overflow for the resevoir, the hose coming off the radiator cap is probably blocked up only allowing coolant to flow out of the system into the overflow, and not allowing it to be pulled back in, i would replace the cap and that hose, the little one that connects to the bottom of the overflow