coolant reservoir

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lt403

SILVER Star
Joined
Aug 10, 2003
Threads
97
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417
Location
miami, fl
where is the coolant in my reservoir going?
It keeps emptying when i fill it. radiator level is fine.
 
Smell the tailpipe....No I'm serious.
 
If you still have the heater hooked up under the passenger seat you may have a leak in the lines running to that core. My truck was doing the same thing, i kept adding coolant, and the level just kept going down. What i found was the heater lines running above the cats were leaking, so when i replaced all my heater hoses i just capped off those two lines to bypass that core. Having those lines leak, or having a leak in that heater core seems to be a common problem on our trucks. Replacing the rubber heater hoses, and hard lines above the cats and transmission is a real PITA, so since i live in Arizona i just opped to bypass that heater.
 
How fast does it disappear? Could be a really small leak that can be really hard to locate.
 
Mine was the radiator, a small leak.
 
Smell the tailpipe....No I'm serious.
As Hornd said, if your able to smell coolant at the tail pipe, it's time to do a compression test to see if you've got a bad head gasket. Another test you can do, is the dye in your coolant system test. If the dye turns color then that means you've got exhaust gases leaking into your coolant system, and that too means it's time for a head gasket.
 
The reservoirs themselves can also leak. I had disappearing coolant, and that's where it was disappearing from.
 
Another vote for a pressure test. This should help you find your leak.

John
 
Whilst pressure testing (I used whilst again!) I found a small leak was landing on the exhaust manifold/heat shield. Though I could smell it I didn't find it till pressure test.
Another possibility for you.
 
thanks everyone. I'll be taking my truck to the dealer soon and i have a feeling it will be getting a new head gasket along with all the other things while they are in there.
i recently purchased a y pipe that also needs to be installed.
 
All of the above however, a pressure test of the cooling system will not always show up a leaking head gasket, whereas the dye detection of gases in the coolant will almost certainly will. The reason is the gasket 'fire ring may be just 'letting by' with 250+ psi of pressure behind it but, the other direction from the cooling system is only around 20 psi and not make it across. Also might be worth checking your transmission dipstick if you have an auto, a high level there with the oil looking like a strawberry milkshake will mean the trans cooler in the bottom of the radiator has failed.

regards

Dave
 
All of the above however, a pressure test of the cooling system will not always show up a leaking head gasket, whereas the dye detection of gases in the coolant will almost certainly will. The reason is the gasket 'fire ring may be just 'letting by' with 250+ psi of pressure behind it but, the other direction from the cooling system is only around 20 psi and not make it across. Also might be worth checking your transmission dipstick if you have an auto, a high level there with the oil looking like a strawberry milkshake will mean the trans cooler in the bottom of the radiator has failed.

regards

Dave

And the dye test will not find all head gaskets leaks, none of them are 100% definitive.
 
The dye test is sort of negative confirmation - if it detects combustion gasses you have a bad headgasket. If it doesn't detect them, you still might have a bad headgasket.
 
And the dye test will not find all head gaskets leaks, none of them are 100% definitive.

Only found it does not work if the coolant has been replaced diluting the dye.

regards

Dave
 
The dye test is sort of negative confirmation - if it detects combustion gasses you have a bad headgasket. If it doesn't detect them, you still might have a bad headgasket.

Agreed, and a good point.

regards

Dave
 
The dye test only detects combustion gases, a head gasket can leak without going into the combustion chamber. A pressure test will find most leaks, including combustion chamber.
 
It must have been missed in my earlier post? A small leak from the combustion side (250psi) into the coolant jacket will not always allow a pressure test of circa 20 psi to cross back into the chamber. The fire ring will often open under engine running conditions but close when you switch off, the pressure test is thus limited. No test is 100%, you need to weigh up all the diagnosis test information.

You do not always get oil in the water or the other way around.
You do not always get combustion gases in the coolant.
You do not always get low compression from a head gasket starting to fail.
You can get an oil leak out of the head gasket down the side of the block.
You can get a water leak out of the head gasket down the side of the block.

Did I miss anything? I am sure there will be other contributors along to add to this list.

regards

Dave
 

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