2001 Durango 4.7l V-8 issue after overheating
 

Hey all,

Longish post but trying to get as many details in as possible....

Been fighting with my '01 Durango all week. Last Sunday, everything was good with her...no major issues...Monday wife drove her to work and on the way home, it overheated. She got off the freeway when the "check gauges" popped on. She cranked up the heat to attempt to cool the engine off, strangely enough, no heat coming out of the vents. She parked and called me and AAA to get towed home. I got there about 25 minutes later and saw the check engine light was on. Pulled the codes and got P208 (cylinder 8 injector malfunction) and P308 (cylinder 8 misfire detected). I found a water leak at the auxiliary pump (was cracked and leaking after getting hot) so I figured that #8 got drenched,. Got her home (that's when I found the leak at the aux pump) and of course it was running rough as h*ll. Started looking closer at the engine (no apparent coolant in the oil) and that is when I found the snapped off crankcase breather element (passenger side, rear engine block) right near cylinder 8. Went to pick n pull to get replacement and ended up getting the wrong one and finally found one at O'Riley's. Replaced both drivers and passenger side breather elements, replaced the faulty aux pump (when I pulled the line off the outlet side it was trashed - corroded and cracked/broken fished all the pieces out of the line, I hope) and fired her back up. Still P208 and P308 and running really rough (duh Steve, your missing cylinder #8), Still not sure about the overheating issue the aux pump did not fix it...think it might be a t-stat or main water pump issue (both replaced about 2 years ago). At this point I am waiting for my mechanic to get back for further diagnosis,,,am hoping that I don't have a cracked head/blown head gasket...any suggestions on the misfire issue ??? Am I on the right track with the t-stat/water pump??? Any suggestions would be greatly appreciated.

Thanks

Steve

Likely dropped a valve seat in cyl #8, very common problem for these engines when overheated. Your wife sounds like she did everything right to try and protect it, but the 4.7 heads are the weakpoint and they drop valve seats far too easily.

Compression test cyl #8, it will likely verify my guess.

It's looking like you are 100% correct...compression test is coming up 0's on #8...I'm not too familiar with the valve seats but from the internet research, it looks bad...if the head has the valve seat issue, is the head still servicable or do I need to source a replacement head and rebuild it ??

Thanks,

Steve

If the coolant leaked out, there'd be nothing to carry heat to the heater core. So no heat. If you really want to know if your head gasket is shot, rent a block tester. Also, if you start the engine cold with the cap off, the coolant should not be turbulent in any kind of way. If it shoots out, you know the deal. The 4.7L hates overheating more than any other.

I get that if the coolant had leaked all the way out there would be no heat in the cab. The thing that was truly puzzling is it was perfectly fine the day before and as soon as the temp gauge began to climb she hit the heat to get some movement thru the system so she could get off the fwy. Seeings how #8 has no compression, I have to tear into it to figure it out...so I will be ordering the gasket kit and timing chain setup (just to be safe) and an oil pan gasket (want to clean out any crud and stop the minor seepage of old age on the pan)...I figure go big or go home...I've already upgraded the injectors to the 4 hole models, fresh plugs all the way around and if I play my cards right, she should be good for another 288k....

Thanks again,

Steve