Hey everyone,

So about two weeks ago I went on a camping trip. I was heating up a bit on the highway mountain roads here in CO, like I usually do...

On the way back home I started up the Disco and let her warm up. Started my trip off the mountain with no issues. It was about 20 to 30 miles before I got to the on-ramp.

Once I got on the on-ramp I was trying to accelerate and noticed I was losing or did not have the power to do it. Right then I saw the temp gauge start to climb fast till it peaked and and the red warning light went off.

I quickly pulled over and shut the engine off.

After popping the hood there was coolant coming out of the expansion tank cap. It looked the the coolant was boiling?

So I got her towed to a parking lot where I let her cool down and added coolant to the tank to replace what came out. I started up the truck and let it slowly warm up.

I went for a drive just to see and almost after 1 mile the temp gauge went right to red. Again I pulled over quickly and shut her off. And again coolant leaked out from the cap and overflow hose.

So I go her towed back home where she is sitting now.

Is this a blown head-gasket or could it be a simple replacement of the coolant cap?

I am not sure what to expect when a head-gasket blows. but from what I read it seems like its the head-gasket and exhaust is escaping into the coolant?

I have been planning on doing a rebuild so this seems like the time to do it but want to make sure I am not missing something here...

Thank you!

 

I had the same symptoms and it was a cracked block. Do you have any misfire codes? Try a new cap to rule that out, but you are probably looking at new head gaskets at a minimum. Sorry. Best of luck.

 

Unfortunately, whether the initial overheat was a result of a bad gasket or not, letting it overheat twice has more than likely resulted in just that, or worse.

 

You need a scangauge or ultragauge (everyone does) to accurately monitor your Temps. It was overheating before you ever saw the gauge move.

 

A cooling system pressure test is in order.

If, using the tester, you pump it up to 15 pounds and it holds with no problem that's a good sign, albeit inconclusive. If it doesn't hold pressure and there is no evidence of coolant leaking to the outside that might indicate coolant leaking into a cylinder, the reverse of what happens if exhaust gases are pressurizing the cooling system.

After you refilled the reservoir and it again overheated quickly was the reservoir again empty?

While it's true that overheating can cause the headgaskets to fail I'm not as quick as others here to say you're two, short incidents caused that to happen to your truck.

Do you have any idea how old your coolant reservoir cap is? If not, spend $15 for a new one and see what happens. If you don't know how old it is you would want to replace it even if you end up needing to do the headgasket job.

 

Some great advice given to me was to check the hose temps pre and post T stat as well as pre and post heater core. Failure or blockage in either of those two can cause what occurred to you. You can do this check with your hands and letting the truck warm up. More importantly, it doesn't cost you anything

 

You can do a fast and cheap test to be definitive. Go to the parts store and get a combustion gas tester. It will tell you if you have exhaust in the coolant.

 

This will work for the heater core but is inconclusive for the radiator. Even a clear radiator will take awhile to heat up the bottom hose, probably because of the bypass design.

 

I'll defer to KingKoopa. Just get the combustion gas tester. If that test is negative replace the reservoir cap. If you still have problems do the pressure test.

 

I had that event several times but not with the cap. Still have the same truck still strong and tick gone. In an event of overheating as severe as yours, it will take a while longer before it cools down at first. I assume that 2nd time, mile drive theres not much coolant in the system yet and because of the faulty cap and a lot of air in the system from boiling it will overheat again faster. Good it was towed. Just get a new cap and go from there. But yes, get an ultragauge.