How do you access the heater core on a 1998 buick reviera?

Heater core could be bad/clogged, the rust over time and the little gaps could he clogged.. just because the hoses are warm doesn't mean the core isn't clogged.. did u check the temp setting Gage..

That is where your Heater core is located. Its like a little radiater that your vents blow thru to get hot air for heating your interior. If thats leaking, its not gunna stop. Take this car in right away before you run your coolent dry and trash your car.

If it is necessary to remove the heater assembly, the cooling system must be drained before removing the heater core.
When a heater core leaks, a new heater core is installed or the old one repaired.
Heater Housing

• The heater housing is usually under the dash and must be removed to gain access to the heater core.
• Procedures for replacing the heater core vary with the year, make, and model of car. It threfore necessary to consult the manufacturer's repair manuals for the proper procedure for replacement.

The heater housing is disassembled to get to the heater core. Heater Core

• Remove the access panels(s) or the split heater/air conditioning case to gain acess to the heater core.
• Remove the heater coolant hoses.
• Remove the cable and/or vacuum control lines (if equipped).
• Remove the heater core securing brackets and/or clamps.
• Lift the core from the case. Do not use force. Take care not to damage the fins of the heater core when removing.
• To reinstall the heater core, reverse the removal steps.

When the heater core leaks and must be repaired or replaced, it is a very difficult and time-consuming job primarily because of the core's location deep within the firewall of the car. For this reason always leak test a replacement heater core before installation.

Inspect/Replace If it is necessary to remove the heater assembly, the cooling system must be drained before removing the heater core.
When a heater core leaks, a new heater core is installed or the old one repaired.
Heater Housing

• The heater housing is usually under the dash and must be removed to gain access to the heater core.
• Procedures for replacing the heater core vary with the year, make, and model of car. It threfore necessary to consult the manufacturer's repair manuals for the proper procedure for replacement.

The heater housing is disassembled to get to the heater core. Heater Core

• Remove the access panels(s) or the split heater/air conditioning case to gain acess to the heater core.
• Remove the heater coolant hoses.
• Remove the cable and/or vacuum control lines (if equipped).
• Remove the heater core securing brackets and/or clamps.
• Lift the core from the case. Do not use force. Take care not to damage the fins of the heater core when removing.
• To reinstall the heater core, reverse the removal steps.

When the heater core leaks and must be repaired or replaced, it is a very difficult and time-consuming job primarily because of the core's location deep within the firewall of the car. For this reason always leak test a replacement heater core before installation.

loop the heater hoses that go into the heater core,the big one(feed)hose re route to the thermostat housing.by pass return,you don't need if your by passing the heater core.











TIM......

Sounds like the heater radiator core under the dash has sprung a leak. Temporary fix to keep the cooling system operating is to bypass the heater by disconnecting the hoses where they go through the firewall and linking them together.
It's usually a big job to remove the under dash ducting to access the heater core, remove it, get it repaired and then replace all the bits.

I beleive that you may have low coolant because as your vehicle warms up the coolant volume increases which would give you just enough coolant to circulate to the heater core. When you are stopped your water pump also isn't circulating as fast and sending that little bit of coolant to your heater core, I imagine that if you top up your radiator or resevoir with coolant your problem should disappear. Keep an eye on it to see if it goes down again as this might just be air coming out of the system or it might indicate a leak either external (drip) or internal (whitish smoke in warm weather). Hope this helps.

LOCATION: You will find it inside the car , under the dash . Excuse me, in the CENTER of the car right above the Transmission tunnel.
PROCEDURE FOR REPLACEMENT:

Take the ashtray assembly out and remove the Glove Box and you will see a Black Plastic Box containing the Heater core. You may have to take apart the Lower dash on the Passenger Side. You will need a piece of pipe about 2" to 3"long that will fit inside the diameter of the two heater hoses at the firewall and two hose clamps.

1. disconnect the two hoses at the firewall;
2. slip a clamp on each hose;
3. slip the piece of pipe into both hose ends to connect the two hoses together;
4. install and tighten clamps on each end of hoses over pipe. (You might want to put a little grease on the pipe for easier removal when you are ready to install new core.)
5. Start engine and check for leaks at the connections.

It appears I was incorrect about removing the dash assembly, here are the instructions from a Buick owners club.

Under the passenger dash is an access panel that will allow you to remove the heater core, it really isn't that hard, there are lots of little dash screws and panel screws to remove before you get where you need to be but at least it is roomy. The AC evaporator is located by the heater core. I will give you a tip. I changed mine last year and the heater core that I ordered for my 92 Roadmaster was not correct, when I took my old one out and matched it in a book at the local part store, the heater core for my vehicle was listed as a 96 Caprice???? The car has been in my family since it was purchased new and the heater core had never been changed!!!! Explain that one!Oh yeah, one more tip, if your heater core is leaking, this access panel lowers towards you, if there is nasty sweet smelling water in there it will pour all over you, be careful! Caprice parts are the same as a Roadmaster,so if you ever need anything just look up caprices

I had this problem twice and it probably is the heater core. There is a temporary fix if you can't get it changed out right away. You can get it tied off but you won't have any heat, it will stop leaking though. Does your heater work? If your heater blows cold and only blows warm when your car warms up then starts blowing cool air again that's a surefire sign.