Engine Noise
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 6 of 6
HT4100 4.1, 4.5, 4.9 Discussion, Engine Noise in Cadillac Engine Technical Discussion; My mother has a 1995 Sedan Deville. The last year it has been making noise under the hood that we ...
  1. #1
    moondok is offline Cadillac Owners Member
    Automobile(s): Cadillac
    Join Date
    Jun 2007
    Posts
    3

    Engine Noise

    My mother has a 1995 Sedan Deville. The last year it has been making noise under the hood that we just can't explain. We thought it was gas related and tried both medium and high test grade fuels and fuel/engine cleaners. We have tried mechanics who don't have a clue. At this point, I think it actually is something under the hood. I realize this is the hardest thing to figure out over the net, but I'm willing to give it a try if any of you will.

    The sound is only when we give it gas. It reminds me of a head sticking...like a tap-it. Don't know if that's how it's spelled. Does this sound familiar to anyone?

    Thanks to anyone who might have a clue.

    Thomas

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    HUF's Avatar
    HUF
    HUF is offline Cadillac Owners Connoisseur
    Automobile(s): 1995 FWB 100,*** miles CURRENT. 1991 Seville 175,000 SOLD
    Join Date
    Dec 2005
    Location
    MA
    Age
    55
    Posts
    1,987

    Re: Engine Noise

    Quote Originally Posted by moondok View Post
    My mother has a 1995 Sedan Deville. The last year it has been making noise under the hood that we just can't explain. We thought it was gas related and tried both medium and high test grade fuels and fuel/engine cleaners. We have tried mechanics who don't have a clue. At this point, I think it actually is something under the hood. I realize this is the hardest thing to figure out over the net, but I'm willing to give it a try if any of you will.

    The sound is only when we give it gas. It reminds me of a head sticking...like a tap-it. Don't know if that's how it's spelled. Does this sound familiar to anyone?

    Thanks to anyone who might have a clue.

    Thomas
    Probably spark knock because of EGR system fault or #1 main bearing knock. The both are harmless.

    1. Is the noise is more pronounced when engine is hot and at light throttle. Say, while driving around a block (10-20 MPH) with hot engine (180F plus) ? If so it is most likely plugged with carbon EGR tubes inside of throttle body, a bad EGR valve or/and a bad EGR solenoid, or vacuum leak caused with cracked vacuum tubes (most likely ones around the throttle body).

    2. To eliminate the bearing knock decrease the tension on the serpentine belt by turning the belt tensioner with a 1/2" wrench or a bar while engine is running (be careful). If the noise goes away it is the bearing knock. If you use a thicker oil say Rotella 15W-40 the noise will be reduced.

    3. Another possibility is lifters.

  4. #3
    moondok is offline Cadillac Owners Member
    Automobile(s): Cadillac
    Join Date
    Jun 2007
    Posts
    3

    Re: Engine Noise

    I've taken the car to the same mechanic twice with the information from HUF. He has blown the carbon out twice now, but the rattle keeps coming back. It definitely occurs at any speed but only while giving the car a little gas. Even depressing the peddle half way can get rid of the sound at higher speeds. If I really lay on it, the sound goes away no matter the starting speed. I almost want to say something is either sticking, or it's not getting enough gas, even though it accelerates fine.

  5. #4
    chazglenn3's Avatar
    chazglenn3 is offline Cadillac Owners Connoisseur
    Automobile(s): 2005 White Diamond STS N* 1SF RWD ACC/HUD
    Join Date
    Sep 2004
    Location
    Tacoma, WA
    Age
    51
    Posts
    1,927

    Re: Engine Noise

    Did the mechanic check the operation of the EGR valve or just clean the carbon from the tubes?

  6. #5
    moondok is offline Cadillac Owners Member
    Automobile(s): Cadillac
    Join Date
    Jun 2007
    Posts
    3

    Re: Engine Noise

    Quote Originally Posted by chazglenn3 View Post
    Did the mechanic check the operation of the EGR valve or just clean the carbon from the tubes?
    I know he examined the throttle body and of course blew the tubes out, but I'll have to check with him on the EGR valve.

  7. #6
    JK2402 is offline Cadillac Owners Member
    Automobile(s): 1991 Cadillac Fleetwood
    Join Date
    Nov 2005
    Posts
    24

    Re: Engine Noise

    What about an exhaust leak where the manifolds connect to the front pipe or the manifold itself? My Father had a 2000 Tundra V8 that had a cracked manifold and it ticked just like a bad lifter.

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