2000 LS V8 - Heater blows cold

I've read through a few other threads on this topic and am still not sure what's going on.

Here's my story though: 3 months ago I had to replace the engine in my car (did it all myself) because of a broken timing chain that broke a few valves and put dents in a piston. After putting it in the heat worked fine after a few months.. fast forward about 2 months and one day it got a little low on water/started to over heat (maybe 1/8" over "normal" temperature on the gauge). I make it to work, wait for it to cool off..add more water and it hasn't overheated since.

Unfortunately the heat also hasn't worked since. There are no error codes in the auto diagnostics on the DATC and the water lines going to the cabin are hot (although them being right beside the engine makes it hard to tell for sure--but I think they're hot). Today I tried leaving the ignition in the on position w/car turned off in hopes that the water pump in the cabin would get things moving but it still blows cold.

Any ideas?? I was thinking air at first but after a month I figured I'd at least get a LITTLE water flowing by now if that was the problem.

I'd run through the process for bleeding the air from the cooling system before getting too excited. I think the process has been posted on here a time or two.

-Rod

Will do.

Nevermind..found it. Here it is for anyone looking:

BLEEDING THE COOLING SYSTEM

Here is the procedure from the factory service manual:

1. Remove the engine fill cap.
On 3.0L engines
2. Open the engine air bleed.
On all engines
3. Open the heater air bleed.
4. Add coolant to the degas bottle allowing the system to equalize until no more coolant can be added.
On 3.0L engines
5. Close the engine air bleed when coolant begins to escape.
On all engines
6. Replace the degas bottle cap.
On 3.9L engines
CAUTION: Care must be taken to ensure the accessory drive belt does not become
contaminated with engine coolant.
7. Add as much coolant as possible to the engine fill. The heater air bleed will remain open.
8. Replace the engine fill cap.
On all engines
9. NOTE: The heater air bleed remains open.
Start the engine and turn the heater to MAX position.
10. Close the heater air bleed when a steady stream of coolant comes from it, during engine idle.
11. Allow the engine to idle for five minutes, add coolant to the degas bottle as needed to maintain the
cold fill MAX mark.
12. Reopen the heater air bleed to release any entrapped air and close again.
On 3.9L engines
13. Maintain engine speed of 2,000 rpm for 3-5 minutes or until hot air comes from the heater.
14. Return to idle and verify hot air is still coming from the heater.
On 3.0L engines
15. Maintain engine speed of 1,500 rpm for 3-5 minutes or until hot air comes from the heater.
16. Return to idle and verify hot air is still coming from the heater.
On all engines
17. Set the heater temperature setting to 24°C (75°F ) and allow the vehicle to idle for two minutes.
18. Shut the engine off and allow to cool.
19. After the engine has cooled, add coolant to the degas bottle to bring the level to the cold fill MAX
mark.

FULL VERSION WITH PICTURES CAN BE FOUND HERE:

http://www.carsonparris.com/ls/bleedcoolingsystem.pdf

Well, during my lunch break I decided to play with the bleed screws a little.. I loosened the one for the heater that is beside the radiator reservoir on the drivers side of the engine compartment. Antifreeze immediately came out and I saw no air. I didn't want to get antifreeze all over the work parking lot so I closed the valve before much came out.

When I get home I'll let it run out a lot more to be sure all air is out..but there is definitely pressure pushing antifreeze out from that bleed screw and from what I've seen so far no air is in that part of the system.

Any thoughts?

Last update :)

Dug down to the auxiliary pump tonight and there was infinite resistance between the terminals. That leads me to believe the pump is bad.

Will replace and report back--I'm guessing the short run without water/overheated water fried it. It has 200K miles on it so I guess it was about that time :(

Interesting find. Please report back with results.

-Rod

Does anyone know where I can buy this pump from?? I can't find one in any of the online catalogs or eBay...