78 Chevy K10 AC condensation issue

[DSS]

I have a 78 Chevy K10 pickup with factory AC-  While the AC still functions very well, after running it awhile, condensation starts dripping in onto the passenger side floor. Any suggestions out there on how to fix this?  Thanks!

[AZ87V10]

Check to make sure that your condensate drain at the bottom of the evaporator housing isn't plugged. If you don't have condensation dripping from the drain while running your a/c but it does drip into your interior, then the drain is plugged and your evaporator case is overflowing to the point that it drains back into your cab.

[DSS]

Thanks for the info!- I'm not very familiar with the AC system- just confirming evaporator housing on left/passenger side of engine compartment and drain is on bottom of this?

[AZ87V10]

That is correct! The evaporator is in the big black plastic box on the passenger side of the firewall. The drain tube should be on the bottom of that either facing the front of the truck or pointing straight down to the ground. Check that first and confirm operation of the system. Report back if you're still having issues. Also verify that it is indeed water only and not coolant! The heater core is also in the same vicinity and if it's leaking, then you have a bigger problem on your hands!

[DSS]

OK- hate to sound stupid, but I have been looking all over/under the evaporator box and can't seem to find a drain??- pretty sure this is the problem as when moisture does come in to the passenger floor there isn't any coolant smell to it- Any suggestions on how to find the drain?  I attached a pic of the truck- Thanks!

[roundhouse]

It will be on the bottom.....


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