12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

Losing Water

Old Feb 10, 2010 | 09:29 AM
  #1  
joey's Avatar
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From: rockport texas
Default Losing Water

Ok every 2 weeks or so i check my radiator fluid and it is a gallon or 2 low. It never runs hot but is always low. Problem is i cant figure out where its going. Its a 97 2500 dodge with ac and heater. Just today my heater quit blowing hot and its low on water again. Could it be a bad heater core because i cant find it leaking anywere.
 
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Old Feb 10, 2010 | 09:40 AM
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ArizonaRedneck's Avatar
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you cant smell the coolant or see any where its leaking i would pressure test it if i was you
 
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Old Feb 10, 2010 | 09:50 AM
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No water in the oil right? It could be a back heater core, but you should be able to see where it was running down, coolant dosnt dry really so you should see something i think. Wouldnt hurt to pressure test the system, could be a stupid hose leaking or something.
 
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Old Feb 10, 2010 | 10:01 AM
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There is a leak somewhere. Hope its not a HG. As stated pressure test is the way to go, but also check the cap. Also make sure your oil level is not going up.
 
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Old Feb 10, 2010 | 11:48 AM
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Bypass the heater core for a few weeks and see if that cures your problem. Mine did the exact same thing. I could never find where it was leaking but my heat sucked so I bypassed it now I don't loose any more coolant.
 
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Old Feb 10, 2010 | 02:34 PM
  #6  
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how do i pressure test i have never done that before.
 
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Old Feb 10, 2010 | 02:36 PM
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they sell a tester for it
 
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Old Feb 10, 2010 | 04:21 PM
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I'd bet if you took the right side door sill molding up and lifted the carpet you will find the place its at.Sounds like a heater core to me,especially if your not finding any coolant in the oil or smelling antifreeze in the exhaust.

Another notorious place to look is inbetween cylinders 5 and 6 where the heads are known to crack.If it has cracked there it will leak out and run down the back of the motor over the bellhousing and then be all over the underside of your truck without you knowing it.
 
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Old Feb 11, 2010 | 05:35 PM
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I use here in Spain a coolant, you can see if is leaking with UV lamp, is a practical thing. Maybe you use the same.

---AutoMerged DoublePost---

I use here in Spain a coolant, you can see if is leaking with UV lamp, is a practical thing. Maybe you use the same.
 

Last edited by gdizama; Feb 11, 2010 at 05:35 PM. Reason: Automerged Doublepost
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Old Feb 12, 2010 | 01:54 AM
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From: Willis, Texas
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My truck does the same thing. I found a hole big as hell in the radiator. Mine wouldn't leak until i got the rpm's built up. Pressure i guess. Hope you have the same bad luck as me. I got a can of stop leak (i'm fittin to do a rebuild so i can that stuff out of everything) fixed it right up.
 
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