[PlugNickel]

My 19yo boy called me on his way home from work to say he might need me to pick him up. His 1998 Durango (4x4, 5.2L) had overheated and steam was coming out of the hood. So I load up with some coolant and headed his way. As he explained to me, everything was normal and the check gauges light came on and he noticed he was hot. so he pulled over and shut down and steam was coming from the radiator cap. When I got there the cap was cool and was loose and there was a little spray in the engine compartment, but not coated. He said he hadn't touched it, so I guess it had gotten loose somehow and blown coolant out. Plus I think he has a slow leak in the heater core, so I've told him a million times to keep the fluids checked until we can repair it. The radiator was practically bone dry...not sure how much it actually had in it, but I dumped right at 2 gallons of coolant into the radiator. When he started it back up, it was idling rough. No check engine light but I pulled the codes and he had 3 pending misfires, cylinders 1,3,7 and then the check engine light came on. I checked the oil and so far there's no coloration and there's no smoke coming from the tailpipe, so hopefully he hasn't warped a head. But I don't know what could be causing the rough idle and misfires. Could he have fouled a plug or three? I can't think of what else might cause this besides a blown gasket, but so far that's not indicated. Hope you folks might have some ideas on which way to go next. Thank you for your time!

 

[MWeed]

He could have water in the ignition system or in the wires for the injectors from all the steam. Remove the distributor cap and spray it with WD40 even if you have an air source available as it will displace water. You should also do the plug and coil wires and the injector plugs for the same reason.

 

[Chase300]

It would not loosen on its own. 2 gals. is basically bone dry.
Yup, it seems the head gasket is blown...assuming it ran smooth up to the overheating point.

 

[Robfrmny21]

Did you do compression test and leak down ?
Pull the plugs and inspect for some coolant

 

[that_guy]

Yeah, I'd definitely do a compression check, as suggested above, before jumping to conclusions that it's a head gasket. Checking the plug wires, distributor, and the plugs themselves as MWeed suggested would be a good starting point.

 

[PlugNickel]

Thank you folks for your suggestions. I'll see if I can locate or rent a compression gauge tomorrow and we'll check out his distributor, wires and plugs for anything abnormal. Still no signs of smoke. Oil still looks good. The vehicle runs fine at anything but at idle. Doesn't seem to have lost power or anything else. Just a rough idle. I appreciate everyone taking time to offer help. Hopefully we can nail this down.

 

[Chase300]

...and that is a sign of a blown headgasket.
I drove a 4 banger from Ohio to GA with one. Had miss at idle, but otherwise ran fine.
No mixing of coolant and oil, it would just consume coolant as I drove and more when a load was put on the engine.
I kept a jug of water with me and when it started to heat up I'd stop and put more water in it.

 

[that_guy]

I'd take a look at the throttle body and the IAC solenoid, when they're dirty they can cause a rough idle. Take the throttle body off and give it a good cleaning. There might have been a rough idle there before that you're just now noticing or paying attention to due to a paranoid mind. It is rare to blow a head gasket on these motors.