96 Fleetwood Brougham w heat issue

vacadillac · #1 (**permalink**) 11-07-09, 09:37 AM

I just inherited my mothers 96 Cad w 45,000 miles which sat in her garage for a long time. My wife and I drive it only on Sunday's. After my first 1000 miles on it, the AC compressor failed. Had it replaced. Mechanic said it through a lot of trash but flushed it good and often before putting on new compressor. Now the heater is not working. Fans blow but know heat. Faint heat near the duct can be felt when fans are off. Engine comes up to temp but only one of the heater hoses going into the firewall warms up - the other one remains cool. The engine does not overheat when driving. Coolant level OK. Any direction here would be much appreciated. Thanks.

phastlt1 · #2 (**permalink**) 11-07-09, 09:57 PM

First, check the pass. side floor board and make sure the carpet is dry. You have a clogged heater core. If it's not leaking yet, it can be saved. I had this happen to me on a LT1 Caprice. The way I fixed it is I pulled both the heater hoses off the core at the firewall, and put a garden hose on one side. Once it built up pressure, some nasty crap shot out the other side and I kept going untill I saw clean water running thru the core. After that, hook the hoses back up and refill any lost coolant, and bleed the system.

Or you could flush the whole cooling system, which it probably needs anyways after sitting for so long. But if you are going to do that, I'd do the core flush first anyways, and remember, your car has the LT1 which has a reverse cooling system...it's a bit funky if you're not accustomed to working with it. Good luck.

**Ranger** · #3 (**permalink**) 11-08-09, 08:20 PM

Quote:

After my first 1000 miles on it, the AC compressor failed. Had it replaced. Mechanic said it through a lot of trash but flushed it good and often before putting on new compressor.

I hope he replaced the accumulator and the condenser or you'll likely have another failure in the future.

Quote:

Now the heater is not working. Fans blow but know heat. Faint heat near the duct can be felt when fans are off. Engine comes up to temp but only one of the heater hoses going into the firewall warms up - the other one remains cool. The engine does not overheat when driving. Coolant level OK.

What engine? If it is a Northstar, follow phastlt1's advice. If it is a 4.9, was the T fitting removed? It has a restrictor in one leg and that leg MUST go in the proper orientation or you'll have heat problems.

phastlt1 · #4 (**permalink**) 11-08-09, 10:28 PM

Quote:

Originally Posted by Ranger

What engine? If it is a Northstar, follow phastlt1's advice. If it is a 4.9, was the T fitting removed? It has a restrictor in one leg and that leg MUST go in the proper orientation or you'll have heat problems.

The '96 Fleetwood Brougham has a 5.7 Chevy LT1, and it's rear wheel drive. I know the guy posted in the wrong section, but since it's something I'm familiar with, I went ahead and tried to help as best as I could. In all actuality, the '96 Brougham has more in common with the Buick Roadmaster, and Chevy Caprice/Impala SS (GM B-Body platform) than any other Cadillac. I'm sure there is a section on this site pertaining to this car, but I've not looked for it...there is much info on the mechanical aspects of the Lt1 Fleetwood on the Impala SS Fourm, 9C1.net, or the Buick Roadmaster fourms.

**Ranger** · #5 (**permalink**) 11-09-09, 11:23 AM

Right you are. I'll move it to the correct section where he may get more help.

thefleetwoodguy · #6 (**permalink**) 11-09-09, 11:42 AM

Quote:

Originally Posted by Ranger

I hope he replaced the accumulator and the condenser or you'll likely have another failure in the future.

What engine? If it is a Northstar, follow phastlt1's advice. If it is a 4.9, was the T fitting removed? It has a restrictor in one leg and that leg MUST go in the proper orientation or you'll have heat problems.

Im surprised a moderator doesnt know you have the LT1
sure he missed something
anyway, this is COMMON on these models
I fixed one last week same issue!
the garden hose method mentioned above will work
a good way to test out if the core is blocked, feel the two hoses
one will be hot the other not so much
I find the best way is, disconnect the two hoses
drain out as much coolant from the core as possible, then with a funnel
pour a bottle of radiator flush into the h/core, have both hoses up
so you dont just drain it out
let it sit like that for an hour, then hook your garden hose up to it
in the REVERSE direction that it would normally flow
now let the hose run for 10 minutes at full blast
also reverse flush the two heater hoses back to the w/pump
that will clear the restrictor
put it together and enjoy your heat!!

vacadillac · #7 (**permalink**) 11-09-09, 09:09 PM

Thanks everyone. Sorry about posting in the wrong place, being a newbie and all. I flushed the heater core with a garden hose, lots of rust colored then cleared, both directions. I then flushed the lines, both directions. Would have flushed the radiator but the *&#^$% tab part of the plastic drain plug broke. Anyways, I got heat. Both lines now warm up. Thanks a billion!

Now the dryer is icing up.