A most VEXING Dodge Ram Hemi... Coolant LEAK

Status
Not open for further replies.
Joined
Feb 11, 2014
Messages
1,980
Location
Upper Midwest by the Lakes USA
The patient: 2005 Dodge Ram Daytona 5.7L Hemi, adult owner since new and driven sensibly, maintained regularly prior to my inheriting ownership. Runs good, operates at correct 201-207F temp, heater works great, no hop up parts no "tuner" parts, bone stock OEM.

The problem: Darn thing leaks coolant apparently ONLY when shut down (under little or no system pressure or perhaps during pressure bleed off simultaneous with underhood cooling after shutdown)

I run her up to operating temp, no leaks, doesnt even smell like coolant after a few minutes of warm up. So no leaks even 20min after shutdown laying under it watching. Somehow as she cools, particularly when sitting overnight in ambient temps of 40F or below.... she leaks some and it leaks reliably that way.

The moisture is not easily traced but i feel no moisture below the thermostat housing, but near it and below gets moist and finally forms drips in the main front crossmember. Some moisture on passenger side behind belt tensioner but no obvious source such as metal heater output tubes. Darn it!

I'm at a loss. Other than sitting under the truck for 8 hours looking for the first droplet to emerge.... I'm bewildered. There is ZERO coolant slinging on hood or other parts and zero crust by the water pump weephole.

These water pumps have a stout orange gasket that sits in a channel. Seemingly a nicely matured design and no monkeying with rtv as with Toyotas. But that is little consolation here fellas. Its hard to figure how a nice thick molded gasket in a channel .... "fails". Its not like it "goes" somewhere.

Anyone elso know of common failure places for weepy coolant leaks on these Hemi cooling systems?
 
Since it's leaking when it cools off, I'd check both the radiator cap and the drain tube to the reservoir. Each will have changes while it is cooling off....and if it doesn't leak any at first startup I'd inspect the reservoir tube first.
 
Originally Posted By: Kuato
Since it's leaking when it cools off, I'd check both the radiator cap and the drain tube to the reservoir. Each will have changes while it is cooling off....and if it doesn't leak any at first startup I'd inspect the reservoir tube first.


Will check that out! Thanks! And perhaps I should say it is leaking when cool or "as" it is cooling/depressuring. But never while I am watching it. Must be occuring over periods of hours and hours.

What a coincidence.... I ordered a spanking new cap just today for good mojo. Will double check the hose to overflow. So far no signs there over two days of looking. Just some mysterios drips on the bottom of that front "cradlle" crossmember and moisture near the pumps seems but very little and none visibly emerging. And zero drips when runnning.
 
Originally Posted By: Warstud
Intake Manifold Gasket. Not visible when running because it burns off.


That sounds really expensive.

Does that mean That the engine is breathing in coolant and getting ruined?
 
mine leaked out the timing cover, i would have that checked as well. had to tear it all down and put a new gasket in. also put a new chain and sprockets in while i was in there and that [censored] rips again
 
Originally Posted By: AntsinmyEyes
mine leaked out the timing cover, i would have that checked as well. had to tear it all down and put a new gasket in. also put a new chain and sprockets in while i was in there and that [censored] rips again


Ok, timing cover, will check it.

So at 99k, if i have the intake or timing cover gasket done (and water pump) .... should i "need" to do timing chain and gears or is that a lifetime item?
 
Well, we can rule out it wasn't driven hard by a high schooler and it uses superior water pump sealing than Toyota, so it baffles me, too.
This is when I suggest you do a UOA and not use oil with sodium in it.
 
Originally Posted By: SumpChump
So at 99k, if i have the intake or timing cover gasket done (and water pump) .... should i "need" to do timing chain and gears or is that a lifetime item?


no, shouldnt need too. it was only an extra $100 though in parts since i did the labor but the shop wanted $400 more to do the chain too. my chain that came out was definitely about half a link longer though than the new one.
 
I don't have the Hemi but I have a 2006 Grand Cherokee with the 4.7L.

In December I had similar symptoms as you're having. Turned out to be a broken radiator neck where the upper hose attaches. You couldn't tell anything was wrong by looking at it. I saw no evidence of coolant anywhere but just kept seeing the level in the overflow jug low every morning for several days. Hose/plastic radiator neck were not far from breaking off entirely. Caught it just in time! Needed new rad.

Hope this helps.
 
water pump on my 99 maxima did that , leaked when it cooled, but not when hot and not when cold, and leak was just a drop or two.

also had a 84 olds 4 cal the had a porosity in the block that did that (GM worst quality time) under warranty, dealer replaced the engine lock.
 
I'd put florescent coolant dye in it, run it for a week, then check with a black light under low light conditions-an external leak will be obvious, if you don't see one-then it's time to start running combustion tests on the coolant, UOAs, etc.
 
Had the same thing with my XJ, turned out it was the heater control valve. Not sure if Rams have those, Jeep got rid of them after 96, so I ditched mine and got the new style heater hoses.

x2 on the dye
 
Originally Posted By: bullwinkle
I'd put florescent coolant dye in it, run it for a week, then check with a black light under low light conditions-an external leak will be obvious, if you don't see one-then it's time to start running combustion tests on the coolant, UOAs, etc.


Florescent Dye.
This is what I would do also / and I have used it myself.
You purchase the Kit at Auto Zone or A.A.P. / Dye, Light and 'yellow' Sun-glasses
May not need a Week to find leak, I think 20 minutes of driving and I'd start looking.
 
Last edited:
Originally Posted By: skyactiv
Well, we can rule out it wasn't driven hard by a high schooler and it uses superior water pump sealing than Toyota, so it baffles me, too.
This is when I suggest you do a UOA and not use oil with sodium in it.
We have almost 750,000 miles on four Toyotas and have never had a water pump leak.
 
"Cold leaks" can occur at hose connections when the clamp isn't tight. Consider this especially if you have a screw clamp there instead of the usual factory spring clamp.
 
Originally Posted By: sasilverbullet
Originally Posted By: Warstud
Intake Manifold Gasket. Not visible when running because it burns off.


+1


I hear now that the Hemi is a "cold" manifold meaning no coolant in or near the intake gaskets. Could they therefore still be a cause of coolant leak?
 
Originally Posted By: SumpChump
Originally Posted By: sasilverbullet
Originally Posted By: Warstud
Intake Manifold Gasket. Not visible when running because it burns off.


+1


I hear now that the Hemi is a "cold" manifold meaning no coolant in or near the intake gaskets. Could they therefore still be a cause of coolant leak?


Sorry, late to the party. Yes, the HEMI has a dry intake, no coolant passes through it, so no, it would not be the source of your leak.
 
Status
Not open for further replies.
Back
Top