I used to use Barr's Stop leak until I had to replace a new radiator because it clogged up. The heater I should have replaced was a whole lot cheaper.

 

Sooo, what are you doing Monday?

I picked up a new heater core today, I'll be doing it this weekend - weather permitting (no garage). I'm gonna flush it out good to try to get rid of any stray Aluma-Seal. I also ordered a new thermostat from Cummins to see if that helps with the wandering temp gauge. While the system's drained, I might as well put it in.

The truck had a new radiator put in it right before I got it, and the shop that did it put in Dex-Cool. I think I'm going to change it back to green. I don't think the Dex-Cool is neccessarily to blame for the bad heater core, it is 13 years old and who knows how well the cooling system was maintained before. I would just feel better with normal looking coolant in there.

 

I got it all apart in a couple hours. It seems the heater core the girl at Advance (who is usually very good) ordered for me is the non-A/C style. The good news is they can have the right one for me tomorrow by noon. The bad news is that it's supposed to rain tomorrow.

The directions in the FSM were pretty helpful, but they left out a few things. I had to pull the radio out to get access to the vacuum connector, which meant that the dash bezel had to come out. I had to drop my tach and my FP gauge, too. The whole dash is in pieces. The big thing the FSM left out is that you gotta pull out the ABS computer. I spent 20 minutes wiggling the HVAC unit around before I figured it out. I pulled the RWAL computer and the HVAC unit practically fell out.

The one thing that did go well was the thermostat change. I found I did have the really old style thermostat in there, so it was probably the original.

Well, hopefully the rain will confine itself to the morning hours tomorrow and I can get this thing put back together before I forget where all the pieces go.

 

congrats on the taking apart, now good luck putting it all balck together. Hope it all works out for ya.

 

It is not that hard really, but it is one of the hateful jobs. Don't envy you. I did mine a couple of years ago.

When I was using bars leaks for the head gasket in large quantities it plugged my thermostat up, just a heads up.

 

Congrats on the disassembly. You are a hardier man than I am. The thought of having to attempt that outdoors in the wonderful winters of PA gives me heart problems. I used to live not to far from there when Nixon was in office. Murphies Law is not forgiving when it comes to wrenching.

 

Dave
I dont remove the vacuum lines from the controls, I remove them from the vacuum motors just for that reason.
As far as the non A/C heater core, thats what happens just about every time I order one too

 

It was 43 and sunny. No hardiness required.

I think Dave Barry said "hardy" means "not exceptionally bright".

 

I have to agree with Dave Barry, I just crawled out from under mine chasing that steering problem that is totally elusive. Steady rain and 50 degrees. Intelligence not required.

 

Well, I decided not to be "hardy" in the face of steady rain and 41 degrees. I'll be driving the Heep tomorrow.

On the plus side, my brother (he fixes electron microscopes) lent me a spare vacuum pump and some plumbing bits so I can evac the A/C system once I put the truck back together.

Wednesday is supposed to be nice.

 

Sure can't fault you for that. Why ruin a perfectly good day with something you can do tomorrow?

 

43 and sunny this afternoon, I got home from work at 3 and dove right into it. Had it running by 5:30. No leaks, no coolant smell, and good heat. The old core was aluminum and about 3/4" thick, the new one is brass and about double the thickness. It also looks like the fin pitch is much wider on the replacement. I'll see how it is in colder weather.

I only ran it about 3 miles, so I can't say how stable the new thermostat is/isn't. I'll know tomorrow.

Tomorrow's project is to vacuum the A/C and recharge it.

 

Were you able to fully disassemble and reassemble without refrigerant evac, or is that a mandatory step? My AC doesn't work anyways.
I need to tackle this one before winter (which will probably be in about 3 weeks).

 

It's probably already winter there!
I may need to do the same; does not heat up very well.

 

I have great heat. It's been freezing at night here lately and when I fired up the heater, the smell of coolant and steamy windshield reminded me of the issue.