Last week, heading home from work my 03 Durango was hissing when I got home. I popped the hood and it was my radiator. I figured it was a weak hose, and since I had half of yesterday, today and tomorrow off I figured I'd find the problem.

Saturday I noticed the hissing stopped. I figured the leak had clogged... Which wasn't good. But I knew I had Sunday to check it. On my way to work Sunday (literally a ten minute drive), about 2 miles from work, my gauges started dinging, and I noticed my temp was hot as could be. (At this point, I figured the hose blew and I was loosing coolant). Since I was so close to work, I turned my heat on (windows down) and made it to work, without stopping. As I pulled in I shut her off. Smoke everywhere. I only had a four hour shift so I let her sit.


At the end of my shift I popped the hood. The pressure cap was blown off, and I had grey gunk all over the engine bay. Great. Blown head gasket.


Here's where it gets weird. My D has had an impeccable service record. Oil changes every 3-5k, all fluids done at 100k or 115k, new water pump at 100k, and literally an oil change 3 weeks ago!

I checked my oil. It was light brown, as it should be. No metal bits, no dirt, and it wasn't low. Next I checked the coolant. Yellow, sweet, and absolutely clean. (Did I mention it wasn't the hose - my coolant wasn't even low!!)

I'm still sure it was the head gasket, but my question is why?! And how?!

I'm absolutely baffled. For reference, I have an 03 4.7l SLT, with every option. Except the leather interior. It's been sitting at work since 10am yesterday. I'm considering getting it towed but not until I know what's the deal.

 

So your radiator or hose wasn't actually leaking and it overheated? I don't know much about the 4.7, so I don't really know what to say. Maybe your waterpump failed or something like that. All I do know is that the 4.7s are way less tolerant to overheating than the 5.2 and 5.9.

 

No, my radiator is fine. The water pump didn't seem to be leaking. All of the fluid under my hood seemed to be coming from that one spot - and it wasn't a lot of fluid. It was just grey and gunky. Just like it would normally be if the head gasket is blown. It just doesn't have other normal signs like dirty oil, or dirty fluid in the reservoir so that's why I'm confused. My mech seems to think it's done, because I drove it that short little distance (literally <2 miles) to somewhere I could safely stop.


It wasn't knocking or anything so I would like to disagree. It had JUST gotten hot as I was getting to work. I don't know a TON about these engines but I drove my cousin's car with a blown head gasket ~20 miles to a repair shop and it was repairable. So I don't see how 2 miles would kill a younger/ well kept engine.

EDIT: typo

 

I don't know what to tell you without seeing things in person, but like I said modern engines such as the 4.7 are built to much tighter tolerances and are much more prone to damage when overheated.

 

You could have had the Water Pump go out, or a bad Thermostat, or worst case....both?

When our Water Pump went out last summer, it leaked fluid around the engine bay (in front) and then the fan sprayed it everywhere, but then it never leaked the rest of the 4-day weekend and never got hot above 1/2 way on the gauge.....even on the 150 mile drive home.

I have an 03 SXT with the 4.7L

 

Alright, I'm heading up there in about an hour and will post some photos this afternoon when I am home. Hopefully they will help.

I'm almost certain it's not my water pump based on the location and what I see. It'll all be dry now, and I'm not starting it up, but I will post pictures and explain what I saw when I opened the hood yesterday. Hopefully that will help.

Thanks for the input in the meantime.

 

I meant maybe the waterpump failed internally and caused it to overheat.

 

Not sure how to post photos in mobile....
I can confirm I have oil from the radiator gunked up. My mech suggested the old head gasket test- take the belt off of the water pump, cold start with rad cap off and look for bubbles. With these 4.7s being so finicky I wanted to see if anyone had an opinion on that test.


Thanks guys.

 

Of course he thinks it shot, he wants the $$$ to fix it.



As far as the issue goes i think that_guy is on the right track with the water pump.. I know it is new but, new parts DO fail, that's why i don't shop at Autozone with there duracrap parts anymore.

Bottom line is something is preventing a proper flow.. If it be the new water pump, sticky thermostat, or a clog in the radiator i can't say but its something. Also you have the 4.7L, when you did the water pump and added new fluid did you burp the system? IIRC, the 4.7L required a good burping so you may just have large air pockets in the system not allowing coolent to get where it needs therefore creating overheating. Just my


Per FSM:


STANDARD PROCEDURE - REFILLING
COOLING SYSTEM 4.7L ENGINE
(1) Tighten the radiator draincock and the cylinder
block drain plug(s) (if removed).
CAUTION: Failure to purge air from the cooling system
can result in an overheating condition and
severe engine damage.
(2) Remove the cooling system bleed plug from the
radiator upper hose inlet housing. (Fig. 11)Fill system
using a 50/50 mixture of ethylene-glycol antifreeze
and low mineral content water, until coolant begains
coming out of the cooling system bleed hole. Install
the cooling system bleed plug. Fill radiator to top and
install radiator cap. Add sufficient coolant to the
reserve/overflow tank to raise level to FULL mark.
(3) With heater control unit in the HEAT position,
operate engine with radiator cap in place.
(4) After engine has reached normal operating
temperature, shut engine off and allow it to cool.

When engine is cooling down, coolant will be drawn
into the radiator from the reserve/overflow tank.
(5) Add coolant to reserve/overflow tank as necessary.
Only add coolant to the reserve/overflow
tank when the engine is cold. Coolant level in a
warm engine will be higher due to thermal
expansion.

 

Actually, my mechanic is a good friend. He always charges me cost, of the parts that is. Labor is always free, and if he needs a hand I'm always there. I can fix most of my own issues, usually diagnosis is what he's for. The oil from the radiator is what I was seeing. So, looks like I was right. Now we just have to wait and see if there's any severe damage. I'm leaning towards no, since I pulled the lower radiator drain plug and also got clear yellow 50/50 from the lower reservoir.

Anyways, I did mention to him that it could be my water pump. It was burped, actually twice - I didn't have coolant when we installed the new water pump (two years ago now) so I used water. And we burped it again 5 miles later at my local shop when we filled her with 50/50. Actually, we used 60/40 since we have harsher winters. But it's always run fine. He said he'd check it, but it may be my tstat clogged, since we have clean fluids all around. It could've been the buildup that spewed out.