1998 Deville overheating
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
Northstar Engines and System Technical Discussion Discussion, 1998 Deville overheating in Cadillac Engine Technical Discussion; Greetings, As recently as a few days ago I had my coolant reservoir tank completely replaced. There was a bad ...
  1. #1
    Jason Henry is offline Cadillac Owners Member
    Automobile(s): Cadillac
    Join Date
    Dec 2007
    Posts
    3

    1998 Deville overheating

    Greetings,

    As recently as a few days ago I had my coolant reservoir tank
    completely replaced. There was a bad leak which caused the car 's temp to rise to 260. Today I drove the car about 20 miles on the freeway with the new
    tank installed and the temperature rose to 228, but did not go above
    that reading. On my way back home, I drove the freeway in the other
    direction for 20 miles and toward the end of my journey the temp crept past
    231.

    I parked the car to enter the grocery store. I returned 20 minutes
    later, drove home (which is about 5 miles) and the car's temp rose to 237.

    I have heard that the car's temp isn't supposed to rise above 228, then
    I heard that a normal temp is 240.

    I am in need of assistance as I have had this temperature issue since
    March. Also, I have had numerous mechanics run a diagnostics on my
    vehicle and no-one is able to pinpoint a cause of the temp rise. Thanks"

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    misfit6794 is offline Cadillac Owners Connoisseur
    Automobile(s): 1996 Deville (sold), 2000 Mustang GT
    Join Date
    Jan 2007
    Location
    Jersey
    Age
    30
    Posts
    1,300

    Re: 1998 Cadillac Deville overheating

    There's a couple things that could cause it. Do a search on the forum for "purge line" as it could be clogged. You could have dislodged some crud in the system replacing the tank. Also make sure your cooling fans are kicking in. BEFORE you start throwing any more money or parts at it, have the coolant tested for exhaust gases, you can buy the kit urself at pepboys or napa, etc, very cheap. You could have a failing headgasket, and if thats the case its between a 2500-3500 dollar repair, and there is nothing you can pour in the engine to fix it cheaply. Some of the syptoms of a failing hg is having coolant in your tailpipes (stick your finger in there, if it comes out slimey, thats coolant), bubbling or overflowing out of the coolant resevior, white smoke out the exhaust (thats burning coolant, not to be confused with water vapor burning off). There is a TON of info on this site about headgaskets, do a little bit of searching. Hope its not that, but it probably is. After my headgaskets were done my car never went over 197, when they were failing between 225-235 and the 255-265

  4. #3
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
    74,767

    Re: 1998 Cadillac Deville overheating

    Normal running temperature is 205-215. In addition to the purge line, have the cap checked to be sure it is holding pressure. Check the water pump belt tensioner.

  5. #4
    Jason Henry is offline Cadillac Owners Member
    Automobile(s): Cadillac
    Join Date
    Dec 2007
    Posts
    3
    Thread Starter

    Re: 1998 Cadillac Deville overheating

    Thanks for the help. I am a novice when it comes to cars, so bare with me. When I take the car back to the auto mechanic, should I ask for a test on the purge line?

    -JH

  6. #5
    chubbyranger is offline Cadillac Owners Connoisseur
    Automobile(s): 99 Seville STS, 08 STS4 N* 1SG F55
    Join Date
    Apr 2007
    Location
    The Ocean State
    Age
    51
    Posts
    3,516

    Re: 1998 Cadillac Deville overheating

    Quote Originally Posted by Jason Henry View Post
    Thanks for the help. I am a novice when it comes to cars, so bare with me. When I take the car back to the auto mechanic, should I ask for a test on the purge line?

    -JH
    Yes - have the purge line checked.

  7. #6
    misfit6794 is offline Cadillac Owners Connoisseur
    Automobile(s): 1996 Deville (sold), 2000 Mustang GT
    Join Date
    Jan 2007
    Location
    Jersey
    Age
    30
    Posts
    1,300

    Re: 1998 Cadillac Deville overheating

    Have the mechanic check the purge line and cap, but if he wants to start replacing high dollar items, make sure he tests the coolant for exhaust gases before doing so. All too many times forum members replace just about every part of the cooling system only to find out it was the hg's.

  8. #7
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
    74,767

    Re: 1998 Cadillac Deville overheating

    Quote Originally Posted by Jason Henry View Post
    Thanks for the help. I am a novice when it comes to cars, so bare with me. When I take the car back to the auto mechanic, should I ask for a test on the purge line?

    -JH
    No need to take it to a mechanic. See the 3/8" line attached to the surge tank near the top? That is the purge line. Loosen the clamp and slide it back on the line so you can pull the hose off. Then start the engine (cold so as not to burn yourself). Pull the line and if it spits coolant. If so, quickly plug it back on. Shut the engine off and replace the clamp. If it does not spit coolant (flow increases with higher RPM), then there is a clog. THEN take it to your mechanic if you are not comfortable clearing it.

  9. #8
    sahtt57 is offline Cadillac Owners Member
    Automobile(s): Cadillac
    Join Date
    Dec 2007
    Posts
    4

    Re: 1998 Cadillac Deville overheating

    Quote Originally Posted by Jason Henry View Post
    Greetings,

    As recently as a few days ago I had my coolant reservoir tank
    completely replaced. There was a bad leak which caused the car 's temp to rise to 260. Today I drove the car about 20 miles on the freeway with the new
    tank installed and the temperature rose to 228, but did not go above
    that reading. On my way back home, I drove the freeway in the other
    direction for 20 miles and toward the end of my journey the temp crept past
    231.

    I parked the car to enter the grocery store. I returned 20 minutes
    later, drove home (which is about 5 miles) and the car's temp rose to 237.

    I have heard that the car's temp isn't supposed to rise above 228, then
    I heard that a normal temp is 240.

    I am in need of assistance as I have had this temperature issue since
    March. Also, I have had numerous mechanics run a diagnostics on my
    vehicle and no-one is able to pinpoint a cause of the temp rise. Thanks"
    Before anything else, you need to have your compression checked. If your headgasket is blown everything you will do will be in vain and will never resolve your heating issues as they slowly get worse over time. Right now you may be able to replace the head gasket and be ok, if you continue to drive on it and it's indeed partially destroyed then particles will enter your combustion chambers and cause excess wear. After you figure out if your compression is ok and consistent, [assuming you check the purge line first because it's very easy] you can pressure check your coolant for leaks etc. and figure this out more accurately. Try here for cadillac over heating solutions.

  10. #9
    Zorb750 is offline Cadillac Owners Connoisseur
    Automobile(s): 1997 Eldorado, 2003 Audi RS6
    Join Date
    Apr 2005
    Location
    Oakland County, MI
    Age
    31
    Posts
    1,320

    Re: 1998 Cadillac Deville overheating

    Not compression test, leakdown test. Force air in and watch for bubbles. Compression test is less accurate (And less dramatic if it "fails").

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