Question about 1994 GMC Suburban

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Heater Core Local mechanic said there is an access door on some models that allow easy access when changing out a heater core which may save time/cost. Mine................ 1994 GMC Surburban 3/4 ton ww/454ci. Not getting heat inside the car. Engine temp, coolant levels etc seem ok. Any ideas? Thanks

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Is the coolant going in and out of the heater core hot? if so the heater core is not the problem, the problem is the outlet air temp control blend door is stuck and or the actuator for the door is inop.

Posted on Dec 17, 2008

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3 Answers

I bought a 99 tahoe four door 5.7 350. No heat. Previous owner bypassed heater core. Need to see how heater hoses attach.


Have you replaced the heater core? If not, most likely the reason the previous owner bypassed the heater core was because it leaked. I will be happy to send you photos of how the hoses attach but I will need your email address.

Dec 21, 2014 | 1999 Chevrolet Tahoe

1 Answer

My 1997 ford expedition is only blowing cold air, is there a fuse i could change or is it the heater core?


Sounds like the common blend door failure on the Expedition. The problem is either with the heater core not getting hot, or the blend door not diverting air through the core. This is a common problem that Fords have. It is caused by the blend door getting stuck. This door is located behind the glove box and it controls the flow of Heat and A/C. Its probably stuck or broken, allowing the cold air from outside to come in instead of the heat from the heater core.
The heater core is difficult to change on the Ford trucks. They have it buried in the plenum box and you have to remove the steering wheel, steering column, dash, evacuate the refrigerant system, drain the radiator, and remove the plenum box to get to the core.

Replacing the core is easy, getting to it is a day's work. The Expedition is particularly difficult to get to. It is almost above the transmission tunnel and well buried behind the dash. The Expedition uses the same plenum box as the F150, so any information on that system applies to the Expedition/Navigator.

You need to be sure that the heater core is really the problem before tackling this job. If you have a pool of coolant on the floor, you'll have to go after the core. If the problem is lack of heat, there are some things you need to eliminate before tearing into the truck. You need to make sure that coolant is flowing through the core. Check the temperature of the heater hoses going into the firewall when the engine is cool and see if they warm up together as the engine warms up. If both hoses get hot at about the same rate, this is a good indication that coolant is flowing through the core. You can also remove the hoses and flush the core with a water hose splice from Home Depot and a water hose. Water should flow unobstructed through the core.

If it appears that coolant is flowing and you don't have obvious leaks, the next step is to check the blend door. This door controls the air flow through the heater core and failure is common on Ford trucks. When the door breaks, it can block the flow of air through the core and kill heat and will also have an impact on AC. If the system seems to work intermittently, it's a good indication that the door is broken and rattling around randomly blocking or opening the passage to the core.

For diagnostic information on how to check the operation of the blend door and a cheap easy fix, check the heatertreater listing on Ebay or the web site at heatertreater.net. The dealer fix for the blend door is basically the same procedure for replacing the heater core, so it will be expensive. The HeaterTreater alternative will solve the problem at a fraction of the cost and work and is well within the capability of the average shade tree mechanic.

You can try to fix it yourself if you check THIS VIDEO: Ford Expedition Lincoln Navigator


Hope helps.

Dec 21, 2010 | 1997 Ford Expedition

1 Answer

After a new heater core was installed by a local mechanic who is non longer in business, my heater will only blow cold air. How does one access controls?


Hi,
I think the problem is the blend door cable is out of adjustment,The easiest way to access the cable is to drop down the glove box and remove the inner part of the glove box.You will be able to reach on top of the heater box and adjust the cable to allow heat to pass into cab.

Dec 11, 2010 | 1987 Ford F 150

1 Answer

How To Replace The Heater Core In A 1997 Ford Thunderbird LX


Heater Core Removal
  1. Partially drain the cooling system.
  1. Remove the tube gasket from the heater core tubes.
  1. Remove four heater core access cover retaining screws and remove the access cover from the A/C evaporator housing (19850).
  1. Remove A/C electronic blend door actuator.
  1. Slide heater core (18476) and seals from the A/C evaporator housing.
Installation
  1. Install the heater core in the A/C evaporator housing with the tube gasket on the outside of the case.
  1. Install A/C electronic blend door actuator as described.
  1. Position the heater core cover on the A/C evaporator housing. Install the four retaining screws.
  1. Refill the cooling system.


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    Item Part Number Description 1 18596 Heater Core Tube Gasket 2 18476 Heater Core 3 18B300 Heater Core Cover 4 390747-S2 Screw (4 Req'd) 5 18N267 Heater Core Cover Seal


    Hope this helps... Cobra

Jun 12, 2010 | 1997 Ford Thunderbird LX

1 Answer

2001 FORD EXPEDITION XLT 4.6L V8 BLOWING MILD WARM BUT NOT WARMING THOROUGHLY. HAVE FLUSHED COOLING SYSTEM THREE TIMES, AND CHANGED THERMOSTAT. HAVE ALSO REMOVED DASH AND REPLACED "BLEND DOOR" AND BLEND...


You hot air comes from the water circulated through the heater core. It is like a miniture radiator with water flowing thru it constantly. So by opening the "Blend Door" you are permitting so much of this hot air to pass thru.

Seems like for some reason your heater core is plugged up. Just like a radiator can be. So water may be passing through your heater core but not passing through fully. Your heater core gets hot from water passing throught it from the engine. Then your doors open up, in proportion to how much air is permitted to pass over the heater core.

Suggest to remove the heater core and replace it. Seems the blend doors are working properly but again, if you have a non working heater core then no air can pass over the "Hot Core" for you to recieve hot air.

If you are not mechanically inclined, then go to a local parts store and you can buy a car manual, such as Chilton's or Hane's Car manuals, for your year and make to show you how to replace it. Then you can also have it for any other problems that may arise.

Jan 24, 2010 | 2000 Ford Expedition

3 Answers

Remove and replace heater core 86 f150


This is not a terribly complicated job -- it's mostly bolts, hoses and clamps. It can be messy depending on how much coolant there is in it.

Access to it may be the biggest headache depending on whether it's under the hood or under the dashboard.

Doing this job for the first time will probably take about 4 hours.

Apr 28, 2009 | 1986 Ford F150 SuperCab

1 Answer

1997 Pathfinder only blows cold air


Sounds like one of 2 problems - Either - and best - sounds like an air mix door (or Heater control valve) is stuck in the closed (or cool) position - a fairly easy thing to repair, but sometimes a bit difficult to get to - some mix doors are near the evaporator box under the dash, and other heater control valves are under the hood (fairly easy to access), they it allow hot coolant to flow through the heater core, where air is blown by athe hot core to provide heat. The worst of the possibilities is that the heater core its-self is clogged and not allowing hot coolant to flow through, in which case, the dash (alot of the time) has to be removed to replace it. A good repair shop can actually save you a bit of money here, if they are familiar with P-finders and how they come apart, not to mention that an experienced tech doesn't have "left-over" fasteners. Bad squeaks and noises can come from an incorrectly re-installed dashboard, and often alot of time can be save as well - and we know time is money - godd luck and I hope this helps a bit at least!!! DD

Jan 21, 2009 | 1997 Nissan Pathfinder

2 Answers

2000 Vw passat,had no heat.


The heater in your car depends upon a flow of hot coolant going through the heater core in order to get hot air into the car. If the heater core is partially plugged, it will restrict the flow. If you have a head gasket that is putting exhaust into the cooling system, it will eventually get into the heater core. When this happens there is no coolant in the heater core to make the air warm. If the water pump vanes have corroded away the result will be very poor coolant circulation causing the heater to not blow hot air. If your car is equipped with a heater control valve that is not functioning properly, the coolant flow will be restricted. One or a combination of these factors is likely the culprit in your case.

To attempt to clean the core, you must flush the system multiple times. If it is still problematic, changing it is your only remaining option besides the water pump itself.

Jan 15, 2009 | 2000 Volkswagen Passat 4Motion

2 Answers

Replace heater core on 1992 buick roadmaster


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

Dec 16, 2008 | Buick Roadmaster Cars & Trucks

1 Answer

Dodge ram 2500 1999 heter core need to be reaplace


I have a 2000 1500, but from what I can see it is the same fix. You need to pull dash forward. 2 bolts behind kick panels one on either side. Screws along top windshield I believe there are 6. Detach steering shaft. (lay down on drivers side facing up. 2 bolts hold in place) This should allow entire dash to tilt towards seats. Heater core is passenger side. You will see 2 metal lines going through firewall. This is your heater core lines. Detach these from rubber hoses inside engine compartment.

Here's where you can follow the book, or do it the easy way... The book says you need to remove the ENTIRE dash and discharge A/C unit before removing.... I have a way better fix.

With a hacksaw cut the metal lines off the top of the heater core (its already junk so don't worry). Pull up on heater core to remove. Now the tricky part. With the hacksaw, cut through the plastic housing. Start far right and cut down until you meet the natural break in the 2 pieces of plastic. Now start another cut on the far left of the housing and again cut straight down. You are creating a door for the new heater core to install. ***Save this piece of plastic housing as you will need it***.

Install new heater core and then use JB Weld to fasten "door" back into place. This should save you about $300 and hours of time. Have fun...

Oct 18, 2008 | 1988 Dodge D-Series Pickups

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