Unsolvable?

[MojaveJoe]

Have a low temp coolant leak. Stops leaking at operating temps. Mechanic befuddled. Refilled coolant reservoir now making leak 10 times worse. Need help.
Any and all advice and experience welcome.

 

[Ozymandias]

You have a leak but can't see any traces of coolant around the engine?

 

[MojaveJoe]

Coolant spray around fan cowling when it leaks. Wet numerous places behind fan.

 

[p-Bar]

Check the waterpump. Take the tension off the pump pulley and see if the shaft is sloppy.

 

[MojaveJoe]

Mechanic checked water pump. No problem noted. But said he saw some evidence of minor leakage where pump contacts block. Drove on vacation 200+ miles with no further leakage. Will replace water pump and radiator when I return home to prepare for a heavy hauling RV summer season.
BTW, these unfindable leaks on warm up started when I had cooling system flushed and all hoses replaced. Will update after next service. Im thinking it had previously been treated with coolant sealer and flush reopened previous leak. Iam second owner (at 130K, Have 160K now.).

 

[p-Bar]

How many miles on the pump? also where the radiators seem to go bad is at the mounts at plastic end caps.

 

[seafish]

Could well be from the WP weep hole which indicates that the WP bearing seals have failed and the bearings will also fail soon...time for a new WP.

There ARE also one, or even sometimes two (depending on transmission configuration and MY) hoses that run from right behind the alternator to the heater core. These hoses very often begin to leak due to heat degradation from their proximity to the exhaust manifold. There are updated silicone hoses available from Genos or Cummins, but that being said, these hose(s) are a b*tch to change due to EXTREMELY limited access. If they are in fact the source of your leak, you will definitely want to remove the front passenger wheel well liner and perhaps even the alternator in order to change them!!!

 

[petersonj]

Has anyone pressure tested the radiator when the engine is cold? A simple hand pump type pressure tester should easily make the leak show. I have found many intermittent leaks using this method.

- John

 

[Timd32]

Since its low temp leak, could you pull the fan and run it and check??? Would that cause any issues on a 04? It would take forever to get hot and you could run an external shop fan. This way the airflow is not spraying the leak everywhere.

If you have the budget Mr Bob's has IMO the best set of hoses going.

https://www.mrbobsdistributing.com/dodge.htm

I dont see how just filling the bottle would make it 10x worse at low temps unless the bottle is cracked or something, the coolant is just sitting in the bottle. Unless the entire "system" leaks to such a low level below where the Rad is broken, and they refilled the "system" above the leak.

On the line of odd coolant leak stories...
For 3+ years several oil change place including one dealer would tell me my '11 Traverse had a coolant leak, bottle would be empty by the time I was due again for oil change, you could smell coolant once in a while but no leaks on driveway ever. It never ran hot, pressure tested several times nothing showed up. Finally I figured I needed to do some research on good ol'Google, turns out that specific bottle has a "FULL COLD" in large letters at the top, so folks fill it to that level, what they fail to notice is the small arrow from that word that is about 6" long down to the bottom of the bottle, it only hold a few oz of coolant, when you fill to the top it spills out when you make a turn, eventually gets to a lower level where it never spills out, then the next person would fill to 6" above the real line and repeated the process, so there was never a leak but it would smell since it was spilling out.

Pic from another forum.....

 

[Ozymandias]

Check the hoses to the radiator barbs, i had it leak at that connection especially when cold.
The use of springloaded hose clamps solved it for me.

 

[Wayne M.]

Has anyone pressure tested the radiator when the engine is cold? A simple hand pump type pressure tester should easily make the leak show. I have found many intermittent leaks using this method.

- John

The mechanic hasn’t pressure tested the system cold?

 

[Timd32]

Will replace water pump and radiator when I return home to prepare for a heavy hauling RV summer season.

Sometimes the OEM Radiator is much better than aftermarket. So before you just swap that out make sure its part of or is the issue. Also check the posts for your year, the new even OEM might not be as good as what you have installed for number of cores and the side types.

Obviously you don't need a breakdown if its leaking now its no good.

 

[EDankievitch]

Coolant leaking where the water pump meets the block is a sure sign the water pump is on it's way out. The weep hole on some pumps is in a small slot machined in to the casting face that is against the block.

 

[MojaveJoe]

That's a bunch of good ideas to check out buds! Thanks so much for your input.
RE: Radiator pressure check done 0.5-1.5 hrs after I drove in towing my trailer. Radiator was cool enough to remove the cap but cold? No Way. My leaks were at near freezing temps in the AM. More followup to come.

 

[Ozymandias]

That's a bunch of good ideas to check out buds! Thanks so much for your input.
RE: Radiator pressure check done 0.5-1.5 hrs after I drove in towing my trailer. Radiator was cool enough to remove the cap but cold? No Way. My leaks were at near freezing temps in the AM. More followup to come.

That would speak for what i had, with the cold the plastic shrinks and let out some water.
Check this connection on the top right of the cooler, because if it leaks there the Fan sucks in the coolant and sprays it all over the engines front.
If you have screw hose clamps, retorque them, if you yave the OEM Spring clamps check that the are in the same position on the hose as they have been.
BTDT

 

[Motorhead]

Have you looked at the pipe plugs on the passenger side of the engine, on the top of the head? Mine seeped when cold on my '07, 5.9.

 

[Wayne M.]

if you yave the OEM Spring clamps check that the are in the same position on the hose as they have been.
BTDT

I have seen the OEM clamps rot away and break, leaving a leaky joint.

 

[MojaveJoe]

Well...........
Replaced my radiator with OEM radiator. Boy are they expensive. But at 160,000 miles was due anyway.
Old one only leaked when bellow freezing in the am while engine warming up.
Water pump and hoses replaced a year ago, and never leaked.
Thus, may not know until next serious freezing morning to see if former leaks are gone.
Followup next winter if I remember ...LOL

 

[MojaveJoe]

So finally had service tech replace the upper radiator hose clamp with a high end one. That eliminated any seeping as in the past. Just did 5000+ mile trip cross country without a leak. Final test next winter when temps drop below 32F.

 

[Ozymandias]

Like i said, the upper hose clamp.