GM

GM Repair Problems? Ask GM Repair Expert Now.

Ask an Expert,
Get an Answer ASAP!

GM

How do you change the heater core on a 1999 GMC Sierra

Customer Question
How do you change the heater core on a 1999 GMC Sierra
Submitted: 6 years ago.Category: GM
Ask Your Own GM Question
Answered in 3 hours by:
5/9/2011
GM Mechanic: jazzmaster, ASE Certified Tech replied 6 years ago
jazzmaster
jazzmaster, ASE Certified Tech
Category: GM
Satisfied Customers: 2,951
Experience: ase certified--32 yrs experience
Verified

hi ,here is the procedure, ...guy...

REMOVAL PROCEDURE

  1. Drain the coolant. Refer to Draining and Filling Cooling System .
  2. Remove the instrument panel storage compartment.
  3. Disconnect the electrical connectors, as necessary.
  4. Remove the center floor air distribution duct.
  5. Remove the hinge pillar trim panels.
  6. Remove the blower motor cover.
  7. Remove the blower motor.
  8. Remove the steering column.
  9. Roll back the instrument panel. Refer to IP Carrier Replacement in Instrument Panel, Gauges and Console.
  10. Remove the coolant recovery reservoir.
  11. Remove the heater hoses.

While holding the heater case to the cowl, remove the screw on the interior side of the cowl, near the evaporator pipe, if equipped

  • On the engine side of the cowl, remove the 4 screws that hold the heater case to the cowl.
  • On the engine side of the cowl, remove the 2 nuts that hold the heater case to the cowl.
  • Remove the heater case. Ask an assistant for help, if necessary.
  • Remove the 7 screws that hold the heater cover to the heater case.
  • Remove the heater cover.
  • Remove the heater core from the retainer
  • THIS IS FOR THE INSTRUMENT PANEL (BELOW) DO THIS FIRST
  •  

  • Remove the knee bolster.
  • Remove the knee bolster reinforcement.
  • Remove the knee deflector bracket.
  • Remove the tubular tie bar from under the steering column.
  • Remove the steering column.
  • Remove the IP storage compartment door
  •  

    Remove the 2 bolts from the PSIR bracket

     

  • Remove the left and the right lower instrument panel pivot bolts.
  •  

  • Remove the center support screw.
  • Pivot the instrument panel
  • Ask Your Own GM Question
    GM Mechanic: jazzmaster, ASE Certified Tech replied 6 years ago
    did this help you ...guy..
    Ask Your Own GM Question
    Ask jazzmaster Your Own Question
    jazzmaster
    jazzmaster
    jazzmaster, ASE Certified Tech
    Category: GM
    Satisfied Customers: 2,951
    2,951 Satisfied Customers
    Experience: ase certified--32 yrs experience

    jazzmaster is online now

    A new question is answered every 9 seconds

    How JustAnswer works:

    • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
    • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
    • 100% Satisfaction GuaranteeRate the answer you receive.

    JustAnswer in the News:

    Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
    JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
    Web sites like justanswer.com/legal
    ...leave nothing to chance.
    Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
    Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
    I will tell you that...the things you have to go through to be an Expert are quite rigorous.

    What Customers are Saying:

    I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money.

    Todd LRochester NY

    Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

    Mary C.Freshfield, Liverpool, UK

    This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

    AlexLos Angeles, CA

    Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

    GPHesperia, CA

    I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

    JustinKernersville, NC

    Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

    EstherWoodstock, NY

    Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

    RobinElkton, Maryland

    < Previous | Next >

    Meet the Experts:

    GM Tech (Cam)

    GM Tech (Cam)

    GMC Mechanic

    5,792 satisfied customers

    GM Grand Master Technician 2007. 14 years experience.

    Gary

    Gary

    GMC Technician

    1,523 satisfied customers

    15 years gm master tech/15 years ASE master tech

    car tech

    car tech

    ASE Certified Technician

    449 satisfied customers

    25 year master tech and shop owner

    Chris (aka- Moose)

    Chris (aka- Moose)

    GMC Technician

    203 satisfied customers

    16 years of experience

    Paul M ASE Master

    Paul M ASE Master

    ASE Master Tech

    187 satisfied customers

    ASE Master Tech 20+ Years

    Anthony

    Anthony

    GMC Technician

    489 satisfied customers

    GM Certified

    Amedee

    Amedee

    GMC Technician

    451 satisfied customers

    ASE certified tech with advanced level specialist. Wisconsin certified emissions state inspector

    < Previous | Next >

    Related GM Questions
    What fuse and location that operates the automatic switches
    what fuse and location that operates the automatic switches for the windows and door locks… read more
    Amedee
    Amedee
    GMC Technician
    Vocational, Technical or Trade Scho
    451 satisfied customers
    I changed out the front actuator, still no 4wd an it will go
    I changed out the front actuator, still no 4wd an it will go in 4 lo so that means the transfer case is workn right ?… read more
    Pete
    Pete
    Independent Auto Technician
    Vocational, Technical or Trade Scho
    138 satisfied customers
    I have a 2010 chevy traverse and the tailights weren't
    Hello sir I have a 2010 chevy traverse and the tailights weren't working so I was checking fuses and decided to look at the relay under hood and found the the tail lamp relay was bad replaced it and m… read more
    Chris (aka- Moose)
    Chris (aka- Moose)
    GMC Technician
    Vocational, Technical or Trade School
    203 satisfied customers
    1996 ext cab - 4cyl - 5 speed - orig. owner - mileage
    1996 ext cab - 4cyl - 5 speed - orig. owner - mileage 1,000,163. -BRAKES (!)(P) light just came on this weekend; after starting and releasing the brake to go -Have practically rebuilt this vehicle. On… read more
    Mcgruder73
    Mcgruder73
    Auto Technician
    Associate Degree
    0 satisfied customers
    Exhaust fluid system see owners manual now. 39,000 klm 2016
    39,000 klm 2016 Sierra. Stopped and filled DEF but still have same message. … read more
    Chris (aka- Moose)
    Chris (aka- Moose)
    GMC Technician
    Vocational, Technical or Trade School
    203 satisfied customers
    I have a 1998 C1500 with automatic, 2 wheel drive. My son
    I have a 1998 C1500 with automatic,***** My son borrowed the truck and said he broke the shift lever when he put it in park. … read more
    Eric
    Eric
    Retired
    N/A
    14,436 satisfied customers
    SALUDOS. 2013. CODE U0101-00. I put the keys to another car
    I put the keys to another car misplaced and I have a problem with the trasmission … read more
    Chris (aka- Moose)
    Chris (aka- Moose)
    GMC Technician
    Vocational, Technical or Trade School
    203 satisfied customers
    2014 GMC the temperature gage down to 160 and when engine is
    2014 GMC the temperature gage down to 160 and when engine is turned off the fan keeps running for awhile? … read more
    GM Bob
    GM Bob
    Automobile Technician
    High School or GED
    989 satisfied customers
    My 2011 SLT2 Acadia driver seat will not go forward or back.
    my 2011 SLT2 Acadia driver seat will not go forward or back. Up and down is fine. My wife is short and cannot drive it as is. HELP. … read more
    BOBBYSS
    BOBBYSS
    TECHNICIAN/ADVISOR
    Associate Degree
    8,343 satisfied customers
    I've replaced my autoride suspension on my 07 Tahoe with
    I've replaced my autoride suspension on my 07 Tahoe with conventional shocks and 5" lift. Id the recommended resistors (4) 1 at each shock and the service suspension light stays on … read more
    kwiggins29059
    kwiggins29059
    Associate Degree
    219 satisfied customers
    I put 2 gallons of diesel by mistake. From a gas can. 2007
    I put 2 gallons of diesel by mistake JA: How old is the engine? And when was it last serviced? Customer: From a gas can JA: What is the model/year of your GM? Customer: 2007 envoy JA: Are you fixing y… read more
    Gary
    Gary
    GMC Technician
    Vocational, Technical or Trade Scho
    1,523 satisfied customers
    ABS and Brake Light on. Both. With ABS codes B2610, U1000,
    With ABS codes B2610, U1000, U1096, U1161 2005 Chevy Tahoe 5.3L … read more
    Pete
    Pete
    Independent Auto Technician
    Vocational, Technical or Trade Scho
    138 satisfied customers
    I just got a 2003 H2 at an auction and wont shift gears
    I just got a 2003 H2 at an auction and wont shift gears after 40mph and service 4wd light is on, vehicle has 129k miles, what should I check for? … read more
    Chris (aka- Moose)
    Chris (aka- Moose)
    GMC Technician
    Vocational, Technical or Trade School
    203 satisfied customers
    Low beams will not come on. 2007 GMC Envoy. Checked lamps,
    yes - checked lamps, fuses. Both OK. High beams will only come on in manual, not with flicker. … read more
    Pete
    Pete
    Independent Auto Technician
    Vocational, Technical or Trade Scho
    138 satisfied customers
    Where is the day time running light module? Well my low beam
    Well my low beam and running lights aren't working and there's no power at the fuse. It's an 04 envoy … read more
    Mechanic01
    Mechanic01
    1,164 satisfied customers
    Will the 20” rims of my previous owned 2011 Yukon Denali fit
    Will the 20” rims of my previous owned 2011 Yukon Denali fit my 2015 Sierra Denali 1500 series… read more
    Expert
    Expert
    13 satisfied customers
    I have a 2007 Hummer H2 w a swing out spare tire mount. I
    I have a 2007 Hummer H2 w a swing out spare tire mount. I would like to remove it. 1) is the removal of the swing arm simply an un-bolt or will I have to buy replacement parts. 2) I want to replace th… read more
    Pete
    Pete
    Independent Auto Technician
    Vocational, Technical or Trade Scho
    138 satisfied customers
    97 1500 5.7 Installed new fuel pump, Have 55psi at the rail,
    97 1500 5.7 Installed new fuel pump, Have 55psi at the rail, only runs on either. What could have happened?… read more
    Edward Clayton
    Edward Clayton
    Associate Degree
    1,033 satisfied customers
    Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

    Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

    Show MoreShow Less

    Ask Your Question

    x