Coolant Fluid Leak Question?

[Garrcus]

Hey guys,

85 Chevy K10

So I replaced my heater core a few weeks ago, my truck does have A/C but is currently not hooked up. The two hoses that hook into the heater core through the fire wall are brand new and from my understanding is a closed system for the coolant. However, there is this little hose(Shown in the pics) underneath both of these main hoses that seems to be a vent or drainage possibly for the A/C? Whenever I drive the truck everything works great but after I park it for a couple of hours when I get back out to the truck there is a little pool of coolant on my driveway. This coolant is coming from that little hose somehow.

Do you guys know what this hose is/does and how I might be leaking coolant from it?
Is it supposed to by plugged or hooked to something else?

Thanks for any advice guys.

[bd]

That's an evaporator housing condensate drain.  Did you wash all the old coolant out of the heater/evaporator housing when you replaced the heater core?  If it was clean and dry when you assembled it, either your heater hoses are leaking (loose clamps), OR you have a faulty heater core, OR the core was damaged during assembly (usually during reinstallation of the housing as the core bibbs are stabbed through the firewall), OR you're over-pressurizing your cooling system (blown head gasket). 

Check your coolant level, then check the pressure building in the cooling system with the engine running.  Any "white" smoke blowing out the exhaust?  If you installed an aluminum heater core, check for electrolysis with a voltmeter.  Make sure you reinstalled any engine and firewall ground wires that were removed.  Why did you replace the core?

[Garrcus]

I replaced the heater core after cracking one of the bibs changing an old cracked and leaking heater hose, it flooded the passenger side floor with coolant which was really fun. Anyway I removed the entire housing and cleaned it all out before installing the new heater core. Couple of questions...

If I did damage the new bibs wouldn't it be leaking down my passenger floor again? 

It is an aluminum heater core and I do have a voltmeter but I don't know how to check for hydrolysis, any tips or solutions?

Also I do get a little white exhaust when it is really cold outside but only until it gets up to operating temperature and then nothing, I get none while driving the truck when it has warmed up. I am still learning this stuff but I assume that's just due to the difference in temperatures, am I right on this or do I need to let my wife know that our trip to vegas is now paying for an engine rebuild.

Thanks again for your help.

[bd]

If I did damage the new bibs wouldn't it be leaking down my passenger floor again? 

Depends on how badly damaged and where the damage is.  If the bib connection to the core is cracked, it will probably leak into the housing... and drip out the tube.

It is an aluminum heater core and I do have a voltmeter but I don't know how to check for hydrolysis, any tips or solutions?

Take some time to peruse the following site...

http://www.sancarlosradiator.com/VoltageDrop/education.htm

...and realize there are a lot of excellent links nested within the text of the document that will redirect you to detailed explanations and exact testing procedures.  Test for both types of electrolysis.  And, look at the images posted on the site under "Heaters," "Radiators" and "Wiring," and compare them to your vehicle. 

Also I do get a little white exhaust when it is really cold outside but only until it gets up to operating temperature and then nothing, I get none while driving the truck when it has warmed up. I am still learning this stuff but I assume that's just due to the difference in temperatures, am I right on this or do I need to let my wife know that our trip to vegas is now paying for an engine rebuild.

From what you posted, I think you can safely assume for now that you don't have any engine damage.  Your Vegas trip is Safe!  White "smoke" (actually moisture) on initial startup is normal.  I would be concerned if you noticed profuse amounts of moisture from the exhaust when first starting the engine on a warm day. 

I suspect you have a faulty or damaged core.  But before you go pulling it all back apart, do you smell coolant inside the cab?  Make sure the radiator is full of coolant then pressure check the cooling system for 15-20 minutes with the engine off.  Does it hold pressure?  Do you notice an increase in coolant dripping from the drain?

FYI:
In the future, when you replace coolant hoses, wipe a small amount of McKay brake assembly lube inside the hose before slipping it onto the nipple or bib.  It's an excellent lubricant that won't damage the rubber and makes future removal much easier.  Just don't use it on silicone hoses.   

[454Man]

Simple test that may just work. Let the engine warm up to normal operating temp. Turn the heater on and fan on high. Put your nose close to the vent and see if you smell antifreeze. Are you using antifreeze?
If you smell antifreeze/ a sweet smell that you have a leak:(

[frotosride]

Simple test that may just work. Let the engine warm up to normal operating temp. Turn the heater on and fan on high. Put your nose close to the vent and see if you smell antifreeze. Are you using antifreeze?
If you smell antifreeze/ a sweet smell that you have a leak:(

+1 It really does almost smell just like it taste...

[firefighter]

Not sure what state you're in or how warm it is where you are.
If you had a chance, just remove the two hoses from your new heater core and join them together with a pipe nipple or something. This will obviously bypass the heater core and eliminate the leak possibility. You may even take an air hose and blow some of the remaining antifreeze out of the now unhooked heater core.
If the leak goes away, you have a bad NEW heater core.
Just a thought.

[Garrcus]

Hey thanks guys,

I live in Colorado so the heater is a necessity but I will try both the "sniff test" to detect and then "bypass" test to see if the leak goes away. I am going to be a little irked if I damaged the brand new heater core on installation. They are not the funnest thing to replace.

Also bd thanks for the link I will definitely read up on this topic. If I did damage my new heater core should I avoid the aluminum for the replacement? If so what would be the best alternative?

[bd]

There's nothing wrong with aluminum.  The 'sweet' smell will be obvious if there's a leak.  If you bypass the core, 'join' the lines as firefighter said, DO NOT plug the lines, as this may cause overheating on some models.  Both are good suggestions and cost nothing.

[beastie_3]

Not related, but you said you have AC? That firewall doesnt look like it...unless its aftermarket.

[454Man]

Hey thanks guys,

I live in Colorado so the heater is a necessity but I will try both the "sniff test" to detect and then "bypass" test to see if the leak goes away. I am going to be a little irked if I damaged the brand new heater core on installation. They are not the funnest thing to replace.

Also bd thanks for the link I will definitely read up on this topic. If I did damage my new heater core should I avoid the aluminum for the replacement? If so what would be the best alternative?

You didn't damage it.... it was like that when you opened the box. You installed it and it leaked:)

[bd]

Not related, but you said you have AC? That firewall doesnt look like it...unless its aftermarket.

Sharp eye!  The 'bypass test' may be the best approach.  One will have to look under the dash to see if/how the A/C & heater housings are interconnected.

[Garrcus]

Yeah, not real sure if the truck originally had A/C or not? But it does have the condenser and compressor as well as the dash lever option to turn on the A/C. The previous owner said that there was a leak and that he just never recharged the system.

I haven't had a chance to try any of the previously mentioned tests yet, too much going on, hopefully this weekend sometime. I'll let you guys know.