I'm happy to report that I no longer have a HG leak. I ran the K&W stuff through it twice, with the second time doing the trick. The first time, I let it idle with the stuff for about 20 minutes (as per the instructions), but it didn't work. I don't think the instructions are good for a tiny leak like I had.

The second time, I left it in the radiator for a week and drove with it for 500 miles before draining. The whole time, I had the heater core disconnected. I also removed the shroud/overflow tank and ran the overflow hose directly into a glass bottle (so it would stand the temps). The KW doesn't stick to stuff until it's dried, so I flushed the radiator with a hose before letting everything dry. All this was to minimize any clogging issues it may cause. So far, so good and coolant is staying in the neck now.

 

Glad to here it worked for you are you thinking of pulling the heads in a few years? Your Dak still looks great maybe swap in some HO cams and new timing chains at the same time put a little more pep in her make it worth the hassle.

New lifters would be good also

 

Those sound like great ideas, but I don't think I'll be digging into it unless I'm forced to.

Right now it's running like a well oiled sewing machine. I haven't done a leak down test, but the engine seems to have loads of compression. The only noise I get is the ubiquitous cold start clatter for a few seconds, until the oil circulates. It's really hard to believe this thing's got 267K on it, because with the new front end components, it drives tight in every way... almost like a luxury car. Oh and I just performed an oil change on Sunday. I ran it for 6K and didn't have to add a drop of oil.

Oh and for you guys chasing down parasitic losses and maximizing gas mileage... While I had the shroud out and serpentine belt off, I spun every component by hand and found that the AC idler and belt idler pulleys were pretty dry. I was able to score a smooth spinning AC pulley from the junkyard a while back, so I installed that. Pulled it off with a a Harbor freight 3 jaw puller. The belt idler...I pulled off the grease seal with a pick tool and injected grease into the bearings via a grease needle. She's running smooth again. So, it's not just swapping out the mechanical fan that you can do (I still have my fan), just make sure all pulleys are fully greased. With the right tools and care, your pulleys can last forever.

 

I've read through the better part of this thread and the answer to your question as to why it happened it simple, its a 4.7. They are prone to head gasket blows, cracked head and worse of all, seizing up for no reason. For whatever reason, Mercedes Fiat used two different metals on the head and block. Which has proven time and time again that's a bad idea. Look at the Toyota 3.0 v6. 4.7's 8/10 are just ticking time bombs.

Glad you got it fixed for now. But keep a close eye in it. Imagine your engine is frort Knox and Russia is coming for its gold.

 

Well, with almost 300K, I can't complain about this engine. The cracked head possibility is why I didn't want to pull it down. When I first got it, previous owner had it running low on coolant with a leaky rad, so he may have overheated it at some point. BTW, Fiat and Mercedes had nothing to do with this engine. It's a Chrysler product, thru and thru.

 

OK. But its still not a magnum. really it isn't.

 

The 4.7 has some flaws if you are aware of them like don't overheat it ever things are good I have seen many a 4.7 last into the high mileage zone with ease.

Condemning them is wrong

I wish they had a 190 or 185 temp stat available as even my 2.5 gets a little hot with a 195 but a 180 makes it run too cool in the city.

The 195 stat is too hot for the 2.5 that cools only with an efan that dose not turn on till a temp of 210 is reached. What makes things worse is in the summer running my A/C keeps my engine from warming up at all except on long drives.

Best would be to not run my A/C till the engine warmed up BUT THAT WOULD SUCK as I would be covered in sweat in the 160 hot cab in no time.

 

Glad that's important to you. Like I said, I'll be at 300K on original drivetrain soon and running superbly. You?

 

Just wanted to revisit this thread as I was reading through some articles the other day and I think I may have come upon the reason for my HG leak. To repeat, I'd had the truck a few years with no issues, no overheats when it started losing a small amount of coolant. When I first got the truck, I had performed multiple radiator flushes and when I refilled, I used Supertech coolant, mixed with distilled water. Well, that coolant is free of most things and is great for Japanese cars, but check this out....

http://www.allpar.com/fix/cracks.html

"Genuine MOPAR antifreeze, recommended in Chrysler owners manuals, contain a small amount of sodium silicate to stop internal leaks as they develop. Hence, leaking head gaskets and cracked heads are usually only a problem if you haven't been using genuine MOPAR antifreeze as Chrysler recommends."

Also of note: http://articles.sae.org/11284/

"Chrysler, the last of the Detroit 3 car makers to use a silicated antifreeze, has switched to an organic acid technology (OAT) formula for the 2013 model year. The change to an “OAT” might have been anticipated with the acquisition by Fiat, but the Chrysler-selected OAT formula, although it shares a major inhibitor, is not the same as used by Fiat."

"The new antifreeze replaces G-05, a low-silicate BASF formula (called a “hybrid OAT”) made in the U.S. by Zerex (Ashland Inc.) and that also had been the Ford choice until 2010. Silicate inhibitors have been used for many decades, and antifreeze chemists still may admit there is no equivalent substitute. It forms a durable coating on the walls of the cooling system, and because it works so quickly, it re-establishes protection within the water pump if the surface becomes pockmarked by imploding coolant bubbles from cavitation. The pockmarked surfaces, if left unprotected, would corrode."
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So, to summarize, I may have done it to myself with the flushes and not using silicated coolant. I'm still using the Supertech, but I've now got the K&W block seal in there. I won't ever run a flush through this system again (no need to), but I will change coolant on schedule and use distilled water to keep things clean. I may even go back to using a silicate coolant, but then again, I wonder if this is why we have so many heater core clogs. Could the OEM coolant have been contributing to those due to silicate buildup?

Thoughts?