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Disappearing Anti Freeze Game!

Stomis

Stomis

Professional Amateur
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Roseland VA/PtPleasant NJ
I really cant figure this out. I was a gallon of antifreeze short. My truck was overheating as though the thermostat was bad. I do the tstat and pull the top hose and no anti freeze comes out. I go O jeeze and pull the cap off the rad. It took about 3/4 of a gallon of 50/50. I cant figure out where its going to. I get no residue or pools under the truck, no white smoke, no murky oil. The motor has 35,000 miles on it I really doubt its a head gasket. I mean its a possibility that the heatcore is shot.

The thing that really gets me is that the resovoire just doesnt work period. It wont push or pull antifreeze out of it. What could be the cause of that?
 
Bad heater core is my best bet on your missing anti-freeze.

In order for a recovery system to work you must have the correct radiator cap (should have 2 seals on the cap) for a recovery system (there are different caps for a recovery versus an overflow) AND you must also have a RECOVERY bottle not an overflow bottle (they are different).
 
Does it burn any oil at all? How long had it been since you last checked the coolant? It could be burning coolant in small amounts that would be disguised by burning oil.
 
Ditto on the correct radiator cap. If the system isnt sealed when it cools it will draw air in not coolant from the recovery bottle. It only takes a small chunk of crud or if somebody put alumi seal in the rad to screw up the cap and how it works. Also make sure the hose to the bottle is good. If is the core the floorboard should be soaked and when you turn on the defroster it probably will stink like coolant.
 
My boss' truck likes to play the disappearing anti-freeze game too. It's an '02 K1500 with the 5.3L and every couple of weeks it's low on coolant. We checked the overflow for cracks, the radiator, the heater-core, all the hoses... even the water pump but come up with nothin'... you can't see it leaking anywhere (the truck has 110,000 miles but it's immaculate under the hood and underneath) and I can't see residue on anything.
 
The 5.3 engine is notorious for the heads cracking around the inner head bolt boss. This will end up putting coolant in the oil. I don't know how many of those heads i've already found with this problem but just last week i did another set for the GM dealer and they were both cracked in that area.
 
I had this issue with an 01 Dodge 5.9l. Turns out I had a leaky freeze plug on the back of the block. Because of the location, I couldn't find any leaks. I guess it only happened when the motor was hot, because none ever dripped out, it just evaporated into this nasty goo..

rr
 
..

I had the dissapearing radiator fluid problem too. I dont' see any dripping or puddles under the truck. I lose about 1/2 to 3/4 of a gallon every week and a half or so.
I get out of the truck last week and notice a mist smaller than that of a fine spray bottle coming out of the front of the truck. I couldn't hear it and i wouldn't have seen it if it weren't for the way the sun was shinning in the early morning. Im replacing my radiator with a new one before the summer. What about having it pressure tested?
 
I agree, the pressure tester is the way to go. I've used it several times (used it just this past weekend) to find small leaks where I couldn't find any signs of fluid but still found the leak using the pressure test. You can use a spray bottle with soapy water to spray arround connections and check for bubble if there are no obvious leaks too.
 
Stomis said:
The motor has 35,000 miles on it I really doubt its a head gasket. I mean its a possibility that the heatcore is shot.
Click to expand...

Rebuilt motor? Did you rebuild the heads and have them checked for cracks? Your loosing too much anti-freeze to not notice puddles from any other location.
 
Your radiator ap itself could be bad. If it doesn't seal you coolant will just evaporate. I just changed my water pump and both radiator hoses to find out that my leak was in my heater hose. I could see my puddles though. If I had to pay for my brand new pump an hoses I'd of been pi$$ed!
 
I would have to agree with others that it is most likely the heater core. I had a water pump fail earlier last year and never saw the puddle under my truck. I only found it because I was doing my weekly fluid checks and the radiator was low. But, when I added antifreeze it started dripping from the pump.

I still lose a bit of antifreeze, but I know that I am losing it from my heater core, and I never see any drips or puddles, just a very occasional smell of antifreeze when the heater is on. Even the smell only happens once in a great while, I really should get it fixed.
 
I was lossing a lot of fluid somewhere, I would fill the rad and then next time I check the A/F was halfway down the rad. There were no signs of leaks on the ground under the truck. Turnes out to be the rear seal on the water pump. Must have only been leaking while driving and never left a puddle on the ground. The pressure tester revealed the leak.
 
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