Silverado, need some wisdom, please

Scalded Dog · 08-20-2015, 12:06 PM

2002 Silverado 1500, 2WD, 4.8L, auto trans... about four years ago, water started leaking from my heater core. I replaced the heater core, problem solved.

Incidentally, on some vehicles heater core replacement is a piece of cake, light work... on this vehicle, one must disassemble the entire vehicle, piece by piece, part by part, component by component... the only thing that did NOT require disassembly was to actually remove filaments from bulbs... but every other damn thing on the entire truck has to be reduced to its molecular base. I will set the truck on fire and push it off a cliff before I will do another heater core replacement on this otherwise decent truck.

So, a few months ago, damnit, it started dumping cold water into the passenger footwell. I simply assumed it was the heater core going bad again. However, instead of repairing it, I simply bypassed it... it is now completely removed from any water/ coolant source. I disconnected the hoses (the output/ intake hoses from the water pump just make a simple U-turn, with nothing passing through the heater core). The heater core itself sits isolated, with nothing feeding it.

However... cold water keeps pouring onto the passenger footwell, at seemingly random times! I can't find any predictor of why/ when it's going to do so, but every now and then, slosh! Here comes a deluge.

It's not rainwater, as we haven't had rain since the Reagan administration (ok, THAT might be a slight exaggeration, but, really... rain has been scarce, and this does it even when we've gone weeks without a drop, with daily temps in the 90- 100s). Washing it is not a cause, as I haven't put a hose to it in a long time. The water seems fresh... no coolant, although, admittedly, my coolant levels are pretty thin right now, and it is possible that there is coolant in the water that I just cannot detect.

Can anybody tell me if there is some other water source that could be dumping this into my footwell?

JantzenOKC · 08-20-2015, 12:12 PM

Check the drain where the ac evaporator water drains out. A lot of times a leaf or other trash will block the hole from the inside and the condensation backs up until it finds somewhere to leak out. I usually find the drain (usually on the firewall below the heater hoses and a.c. lines) and blow some compressed air through the drain. That usually unblocks it and all is good.

willhe64 · 08-20-2015, 12:23 PM

Quote:

Originally Posted by Scalded Dog

Incidentally, on some vehicles heater core replacement is a piece of cake, light work... on this vehicle, one must disassemble the entire vehicle, piece by piece, part by part, component by component... the only thing that did NOT require disassembly was to actually remove filaments from bulbs... but every other damn thing on the entire truck has to be reduced to its molecular base. I will set the truck on fire and push it off a cliff before I will do another heater core replacement on this otherwise decent truck.

LOL. Look at the assembly line and you'll see the first thing down it is the heater core, then they build the rest of the truck around it.

It's the drainage for your AC condensation.

Scalded Dog · 08-20-2015, 05:21 PM

Cool, thanks for the tips... will check that out!

Scalded Dog · 08-22-2015, 12:26 PM

You people are the best!

I really had no idea that a clogged AC evap line could back up so that it dumped water into the passenger footwell... without your suggestions, I would have left the heater disconnected, and sold the truck for cheap, letting the new owner know that the heater core was bad (although, admittedly, I might have omitted the part about how it is a 10,000- hour job, by qualified technicians with specialized tools...). But... I followed your advice: Sure as hell, that line was clogged, backed up with a lot of water! I ran a soft wire up the line, and unclogged whatever was in there.... it dumped a half gallon of water on the ground.

I've now reconnected my heater core hoses correctly (damn sure don't need the heater now, but in a few months, it WILL be appreciated!), and everything now seems great!

Thank- you!

08-20-2015, 12:06 PM	#1
Scalded Dog Drives: 2011 1LT Join Date: Mar 2012 Location: Crestline, CA Posts: 3,029	Silverado, need some wisdom, please 2002 Silverado 1500, 2WD, 4.8L, auto trans... about four years ago, water started leaking from my heater core. I replaced the heater core, problem solved. Incidentally, on some vehicles heater core replacement is a piece of cake, light work... on this vehicle, one must disassemble the entire vehicle, piece by piece, part by part, component by component... the only thing that did NOT require disassembly was to actually remove filaments from bulbs... but every other damn thing on the entire truck has to be reduced to its molecular base. I will set the truck on fire and push it off a cliff before I will do another heater core replacement on this otherwise decent truck. So, a few months ago, damnit, it started dumping cold water into the passenger footwell. I simply assumed it was the heater core going bad again. However, instead of repairing it, I simply bypassed it... it is now completely removed from any water/ coolant source. I disconnected the hoses (the output/ intake hoses from the water pump just make a simple U-turn, with nothing passing through the heater core). The heater core itself sits isolated, with nothing feeding it. However... cold water keeps pouring onto the passenger footwell, at seemingly random times! I can't find any predictor of why/ when it's going to do so, but every now and then, slosh! Here comes a deluge. It's not rainwater, as we haven't had rain since the Reagan administration (ok, THAT might be a slight exaggeration, but, really... rain has been scarce, and this does it even when we've gone weeks without a drop, with daily temps in the 90- 100s). Washing it is not a cause, as I haven't put a hose to it in a long time. The water seems fresh... no coolant, although, admittedly, my coolant levels are pretty thin right now, and it is possible that there is coolant in the water that I just cannot detect. Can anybody tell me if there is some other water source that could be dumping this into my footwell?

08-20-2015, 12:12 PM	#2
JantzenOKC Drives: '13 2LT/RS Twin Turbo Join Date: Aug 2012 Location: Edmond, Oklahoma Posts: 3,073	Check the drain where the ac evaporator water drains out. A lot of times a leaf or other trash will block the hole from the inside and the condensation backs up until it finds somewhere to leak out. I usually find the drain (usually on the firewall below the heater hoses and a.c. lines) and blow some compressed air through the drain. That usually unblocks it and all is good. __________________ 3.6L Twin Turbo V6 Garrett GT28 turbos -- Jacfab forged connecting rods -- Diamond forged pistons(10.5:1) -- Alky Control Methonal Injection -- CircleD 2E triple disc torque converter -- BMR suspension 10.75 @ 131mph

08-20-2015, 05:21 PM	#4
Scalded Dog Drives: 2011 1LT Join Date: Mar 2012 Location: Crestline, CA Posts: 3,029	Cool, thanks for the tips... will check that out!

08-22-2015, 12:26 PM	#5
Scalded Dog Drives: 2011 1LT Join Date: Mar 2012 Location: Crestline, CA Posts: 3,029	You people are the best! I really had no idea that a clogged AC evap line could back up so that it dumped water into the passenger footwell... without your suggestions, I would have left the heater disconnected, and sold the truck for cheap, letting the new owner know that the heater core was bad (although, admittedly, I might have omitted the part about how it is a 10,000- hour job, by qualified technicians with specialized tools...). But... I followed your advice: Sure as hell, that line was clogged, backed up with a lot of water! I ran a soft wire up the line, and unclogged whatever was in there.... it dumped a half gallon of water on the ground. I've now reconnected my heater core hoses correctly (damn sure don't need the heater now, but in a few months, it WILL be appreciated!), and everything now seems great! Thank- you!