This is the first winter for my son's 92 Camero RS, V6, w/100K miles. The heater blows somewhat warm air, but not "melt you out" hot air. To get it to it's current warm level, I replaced the thermostat with a 195. I also replaced the heater control valve, although I don't believe the old one was defective. I also backflusahed the heater core. The air blend door slams shut from cold to hot, so I don't think that is the problem. I though the heater circuit was air bound, so I bled the 3/4" reurn hose at the tube going back into the water pump (not the best place, but the easiest to access). I'm wondering if the flow circuit to the heater core could be restricted. Could some describe this pathe, because it looks like the heater gets its coolant suppy from a shared path with the coolant going to the throttle body. Since I don't have history on this car, I suppose anything is possible. I'm looking for some known problem areas that some of you might have found regarding coolant flow through the heater core. Also, any recommendations to de-aireate the heater core system, besides what I described?
Thanks, FJK

 

FJK,

I've had some difficulty getting air bled out of LT1s, and found that elevating the front of the vehicle can help. It might help dispel any entrapped air in your core. Realize that any fresh fill of water will have some dissolved air, and heat and time will deaerate the water, causing another "bubble". This air should work its way from the cooling system into the radiator through normal heat/cool cycles, so you'll have to monitor the overflow reservoir for the first few days to maintain the level.

It is also possible the core is plugged on the air side. Ten years of leaves, seeds, grass clippings, etc. can create a restriction. The "insulation blanket" of debris could prevent heat transfer to the air. One way to check this is to estimate the velocity of air delivered from the vents in the full heat position versus the blended position. There should be a minimal change in blower speed and air delivery if the heater core is clean.

As for the liquid side of the core, manually check the hose temperatures of both the supply and return hoses. There should be a small difference in temperature, but it might not even be noticable by hand. A flow restriction should be evident, however, in that the hose temperature difference will be much greater since more heat is leached from the stagnant coolant. It would be completely acceptable to eliminate the water valve if you suspect that, since earlier models have no such valve at all and constantly flow coolant through the core. Those cores tend to last longer, too.

If my recollection is correct, the return side of the core is directly to the left radiator tank. The supply is from the right cylinder bank. There may also be a return passage through the throttle body on the V-6, but I'm not sure of that.

 

Vader:
Good to hear from you again. To be quite honest, I thought I was done with these 3rd gens, but my older son bought a 92 Camero in addition to his 88GTA. Then he sells the 92 to his younger brother to finance a Vortec supercharger for the 88. Me, the old man, likes his Fords and is a reluctant player in the 3rd gen game. Nevertheless, I always enjoy conversing with you. Anyhoo, back to the tech stuff... the 92 V6 just seems like an engine that does not like to build alot of heat into the cooling system. I still have to check out more things. I'll give your air flow theory a try. Also, on the 88gta it looks like we have an oil leak at the oil pressure switch at the back of the block. The switch (sender) pressure checks ok... do those brass fittings have a reputation for cracking or leaking?? Any thoughts would be appreciated.

BTW, in looking at my original post, it looks like I don't know how to type, write, or spell. I hope this response is a little cleaner.

Regards, thanks, & Merry X-mas
FJK