heater system
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Results 1 to 9 of 9
Cadillac DeVille 1985 to 2005 including:
1985-1992 Fleetwood, 1993 Sixty Special, All FWD Forum Discussion, heater system in Past Cadillac Vehicle Discussion; my 1992 fleetwood FWD blows cold on driver side defroster and not very hot on passenger side. told i need ...
  1. #1
    binelli is offline Cadillac Owners Member
    Join Date
    Oct 2004
    Posts
    2

    heater system

    my 1992 fleetwood FWD blows cold on driver side defroster and not very hot on passenger side. told i need modification from G. E. mod No. T-92-30-A also mod. No. T-92-14 . can someone tell me what these entail.

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    brougham is offline Cadillac Owners Master
    Automobile(s): 1991 Cadillac Brougham D'Elegance 5.7 Litre
    Join Date
    Jun 2003
    Location
    Canada
    Posts
    5,557

    Re: heater system

    Look at the other posts about heater problems that are in this part of the forum. Maybe some of them will help you.

  4. #3
    pman is offline Cadillac Owners Member
    Join Date
    Nov 2004
    Posts
    2

    Re: heater system

    I have a 94 sedan deville that i love to deaf ,but for some reason the heat only comes out of the defroster.an cold air comes out of the floor vents . my heater core gets hot like it should ,when i turn the cc to 85 it blows heat out of the dash vents for a second the goes to cool.a/c is very good in this car.

    any ideas on the problem
    Attached Images

  5. #4
    BeelzeBob's Avatar
    BeelzeBob is offline I'm a Cadillac Fanatic!
    Join Date
    Dec 2002
    Location
    Fort Lauderdale, Florida
    Age
    50
    Posts
    9,577

    Re: heater system

    Quote Originally Posted by binelli
    my 1992 fleetwood FWD blows cold on driver side defroster and not very hot on passenger side. told i need modification from G. E. mod No. T-92-30-A also mod. No. T-92-14 . can someone tell me what these entail.

    I would suspect a partially blocked heater core due to sediment and gelled coolant. Disconnect the heater hoses at the engine and start flushing the heater core with a strong garden hose alternating from both directions. Usually you can clear it out. A partially clogged heater core has been the cause of several posters having dissimilar air delivery temps on the side of the car.

    The other thing to check is the tee that feeds the heater coolant circuit. There is a tee about 1 foot from the thermostat that feeds the heater from the coolant bypass loop hose. That tee needs to be open on the thermostat side and the heater feed side. There must be an orifice on the third side of the tee that is toward the water pump end of the tee. The orifice is about 1/4 or 5/16 inch. If the tee was ever replaced with a generic plastic or metal tee without an orifice then the heater circuit will not feed and the overall heater performance will suffer and any clogging will be exacerbated. Check this too.

  6. #5
    BeelzeBob's Avatar
    BeelzeBob is offline I'm a Cadillac Fanatic!
    Join Date
    Dec 2002
    Location
    Fort Lauderdale, Florida
    Age
    50
    Posts
    9,577

    Re: heater system

    Quote Originally Posted by pman
    I have a 94 sedan deville that i love to deaf ,but for some reason the heat only comes out of the defroster.an cold air comes out of the floor vents . my heater core gets hot like it should ,when i turn the cc to 85 it blows heat out of the dash vents for a second the goes to cool.a/c is very good in this car.

    any ideas on the problem

    See the previous answer...I suspect it applies to you also. I would also check the vacuum feel line to the HVAC that comes from the vacuum accumulator thru the firewall. There should be a vacuum line from the engine thru a check valve to a container that accumulates the vacuum and then feeds thru a hose thru the firewall. If the vacuum line has a crack or leak or the accumulator is not holding vacuum then the air will come out the wrong vents as the vent control door is vacuumed controlled.

  7. #6
    N0DIH's Avatar
    N0DIH is offline Cadillac Owners Master
    Automobile(s): 94 Fleetwood Brougham
    Join Date
    Aug 2004
    Location
    Rockford, IL
    Age
    47
    Posts
    7,497

    Re: heater system

    A possible related symptom my 91 has had for years is if you are on heater, say 78-80 degrees the defroster will putting out cold air, still warm from down below. Put it on defrost and it gets warmer, but not HOT, even at 90. It doesn't do it immediately, just after about 10-15 minutes of driving (high vacuum driving, not a low vacuum where air diverts to the defroster like on a hill in a weak V6...My 91 3800 Bonneville would do that from time to time)

    And lately, it is getting worse. I will work on the heater core flushing this weekend. I don't think dad did the coolant very often

    Any thoughts on the std Prestone backflush kit? Should I refil with Dexcool or just std Walmart antifreeze? I typically flush yearly, but would go long if Dexcool would allow.

    Tom

  8. #7
    BeelzeBob's Avatar
    BeelzeBob is offline I'm a Cadillac Fanatic!
    Join Date
    Dec 2002
    Location
    Fort Lauderdale, Florida
    Age
    50
    Posts
    9,577

    Re: heater system

    Quote Originally Posted by N0DIH
    A possible related symptom my 91 has had for years is if you are on heater, say 78-80 degrees the defroster will putting out cold air, still warm from down below. Put it on defrost and it gets warmer, but not HOT, even at 90. It doesn't do it immediately, just after about 10-15 minutes of driving (high vacuum driving, not a low vacuum where air diverts to the defroster like on a hill in a weak V6...My 91 3800 Bonneville would do that from time to time)

    And lately, it is getting worse. I will work on the heater core flushing this weekend. I don't think dad did the coolant very often

    Any thoughts on the std Prestone backflush kit? Should I refil with Dexcool or just std Walmart antifreeze? I typically flush yearly, but would go long if Dexcool would allow.

    Tom
    you don't really need any sort of kit. Just disconnect the heater hose at the tee and at the pipe at the front of the engine and stick the garden hose to it. Flush from either end of the heater hoses to back flush the heater core thoroughly.

    If the coolant was not replaced frequently then the heater core could easily be clogged or partially restricted. Have some patience flushing it. It may take some time and several attempts as flushing from either direction to start to clear it out.

    DexCool is not the recommended coolant for your engine and really serves no advantage once the system has been filled and used with conventional green silicated coolant. The silicates plate out on the interior surfaces of the cooling system and negate the effect of the DexCool. I would recommend either Prestone or Texaco brands of conventional green coolant. Mix 50/50 with distilled water ($.99 per gallon at the food store - look in the bottled water section) and fill the system.

    I would simply drain and refill the engine and raditor with fresh coolant. No real need to flush or anthing drastic. Just drain and refill with fresh 50/50. Flushing the heater core is a different story as there is some sign of problem with clogging that mandates the flushing, the flushing can be contained to that section of the cooling loop and that section can be blown out to eliminate the plain water when you are done.

    Search in the archive useing the search feature and type in "coolant supplement"...read my posts on the subject. Use of the GM coolant supplement pellets is MANDATORY in the 4.1/4.5/4.9 engines. It is a sealer that prevents any coolant intrusion into the oil should a gasket weep or seep coolant internally. If you are at Walmart, cruise the auto section and find the BarsLeaks "golden seal" powder in the clear plastic vial. Use two of those when you are finished and are filling the system with fresh coolant. The BarsLeaks golden seal powder is the exact same material as the GM coolant supplement pellets. use it.

    As long as you are doing the cooling system maintenance it would be a good idea to change the thermostat. Stats have a finite life and after 13 years they do not owe you a dime. Pop a new GM stat in there so it doesn't stick and strand you.

  9. #8
    N0DIH's Avatar
    N0DIH is offline Cadillac Owners Master
    Automobile(s): 94 Fleetwood Brougham
    Join Date
    Aug 2004
    Location
    Rockford, IL
    Age
    47
    Posts
    7,497

    Re: heater system

    We did the stat a few years back, but while I am in there, might not be a bad idea, it is cheap enough. It holds 92-93C pretty well.

    I have the GM Pellets sitting in a sealed container ready for use....My dad's nieghbor worked for GM at the tech school, I have a few stacks of older books on the C3I and the CCC systems. They are a wealth of knowledge. You learn GM a lot that way. And he came up with lots of GM stuff when he cleaned out his garage.... Including a 91 FSM....

    Good point on the distilled water, I always preach it too, WELL WORTH IT!! Considering I have NEVER had to replace a heater core yet. And don't plan to. Keep it down on the acids, and it will take care of you for a long long time. Iused to have some of the test strips that checked coolant temp and acid level. Amazing, on my rebuilt 455 in my 80 Turbo Trans AM, it was high on acid levels within hours of startup. Flushed it and all was well....

    Tom

  10. #9
    N0DIH's Avatar
    N0DIH is offline Cadillac Owners Master
    Automobile(s): 94 Fleetwood Brougham
    Join Date
    Aug 2004
    Location
    Rockford, IL
    Age
    47
    Posts
    7,497

    Re: heater system

    Quote Originally Posted by binelli
    my 1992 fleetwood FWD blows cold on driver side defroster and not very hot on passenger side. told i need modification from G. E. mod No. T-92-30-A also mod. No. T-92-14 . can someone tell me what these entail.
    Anyone ever find out anything on these mods?

    My 91 does this also. Only hot on pass side and not very on the drivers side.

    Tom

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting