Fast68 has a good outline of the steps. I'd guess the hard part is getting the hoses off under the hood. It requires a long reach on a special side tool to get to the clamps on the hoses over the tubes sticking through from the heater.

Someone who had done it sounded like it'* a matter of sealing the core so air doesn't bypass when you reinstall it. Have some caulk like sealer. Note that cover has two screws holding it and has clip slots holding it on the back end.

Having spent some quality time troubleshooting a programmer on my 98, I've laid on the seat and floor long enough to know it'* not pretty, but when the globebox is off, it'* easier to get to than it seems.

I'd recommend doing it on a warm day so the caulk on the cover and the heater core are softer for removal.

fast68, I'm on my way to your house for visual guidance.

Reading your post in a new topic about overheating, I wonder if you have a leak under the hood and you're taking fumes in through the air intake. Is your water pump working? Has it ever been replaced? Might be worth taking the belt loose and spinning the pump by hand to see if it feels like the impeller is there and pushing coolant.

What about the bypass tube that comes out of the intake manifold; they were plastic originally. The replacements are metal.

Did you check in the radiator to be sure it'* full when you were overheating?

I'll try to check the water pump tomorrow, in 7 degree weather. I don't know how old the pump is neither. The bypass tube goes into the intake manifold and comes from the water pump?

When you checked the coolant level, did you check in the radiator or the reservoir tank? Your radiator could be low due to a leak somewhere but the overflow tank at normal level. That might explain overheating.

the reservoir and the radiator is empty. It doesn't over heat when I first start the car up and let it idle, but when I start driving the temp goes up. I think I found the bypass hose which is where the water pump right? It was greasy looking in that area. I haven't moved the alt to look in that spot yet, I couldn't find my long socket wrench.

Isn't the passengers carpet suppose to be wet when the heater core goes out? I haven't experienced this. I'm gonna try to do what I can tomorrow. I have someone who would buy it from me for $600 right now and it'* getting temping since I found a 93' SSEI for $900 in probably better condition than mine.

Low coolant causes no heat and overheating. Please read this thread (especially page two): http://www.bonnevilleclub.com/forum/...ic.php?t=91570

wouldn't the heater core cause the engine to overheat too, since it maybe leaking and the coolant system wouldn't stay pressurized?

EDIT: I did see a small coolant leak from the water pump about 6 months ago, but Kind of ignored it since the car was running fine. Let me get out here in this cold weather?

I confirmed it'* the heater core I saw some coolant hanging from the casing of the heater core. Ok I started tearing down the glove box and bottom panel now I'm stuck. the vent (2 square holes) thats behind the glove box is in the way. Is there a way to remove it? I took the bottom panel off, the glove box, and the glove box door. My main concern is getting to the top of the heater core casing.

Overheating in your case is caused by low coolant, not a loss of pressure.

Did you notice this leak when the car was running or when it was off and cool? If it is leaking a little bit when cool, it will probably be leaking a lot more when hot and under pressure.