HG and Block Test results
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
Page 1 of 2 1 2 LastLast
Results 1 to 15 of 19
Cadillac Seville / Cadillac Eldorado Forum Discussion, HG and Block Test results in Past Cadillac Vehicle Discussion; I have 99 Seville STS w/118,000 miles. Car has been losing coolant to the point of flagging the low coolant ...
  1. #1
    diggler1971 is offline Cadillac Owners Member
    Automobile(s): 99 STS Pearl White
    Join Date
    Feb 2010
    Posts
    8

    HG and Block Test results

    I have 99 Seville STS w/118,000 miles. Car has been losing coolant to the point of flagging the low coolant message, but never overheats, has no white smoke and runs perfect. Recently had to have the cat. converter replaced, due to clog. Muffler shop guy said it looked like coolant or oil had been getting thru to converter. It looked like whitish balls, a little smaller than b.b.s. At this point, I'm thinkin HG, so I did a block test on it today and I'm a little confused about the results. I tried to post a link to pics of test results, but I don't have enough posts for that. The test fluid started llight blue and after 5 minutes of aspirating the tester, with engine warm and running, the fluid changed to a lighter blue (almost clear). I understand that a failed HG should make the fluid turn yellow. Do my results indicate a "slightly" bad HG?
    Are there any other tests that I can run to determine if I have a HG failure for sure?

    Is there any other failure that will allow coolant into exhaust?

    Thanks, Dig

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    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
    74,752

    Re: HG and Block Test results

    A HG is the only thing that will put coolant into the exhaust. If you did the test right after adding coolant you could get a false negative. There is another leak down test that is more involved to test the HG's. It's located in the Tech Tips section.

    If it does not overheat it might not be a HG unless it is in the very early stages. You might want to try a cooling system pressure test. Rent the tester and pump up the cooling system to 16 psi and let it set. If it is an external leak, it will eventually show itself. Sometime a slow leak will evaporate before it drips, like a leak in the front of the side tank. You can't see it because the condenser is in front of the radiator and the coolant would evaporate as it drips down unless it was a real bad leak. Dried Dex-Cool leaves a whitish chalky telltale residue.

  4. #3
    Skiller.'s Avatar
    Skiller. is offline Cadillac Owners Connoisseur
    Automobile(s): NONE
    Join Date
    Sep 2009
    Location
    Buffalo, NY
    Age
    25
    Posts
    2,027

    Re: HG and Block Test results

    Coolant in the exhaust means that it's getting in the combustion chamber through a failed HG. How quickly is it using coolant?

  5. #4
    diggler1971 is offline Cadillac Owners Member
    Automobile(s): 99 STS Pearl White
    Join Date
    Feb 2010
    Posts
    8
    Thread Starter

    Re: HG and Block Test results

    I haven't driven it much since suspecting HG failure, but it was using about two quarts of coolant every couple hundred miles. This is approximate.

  6. #5
    iametarq's Avatar
    iametarq is offline Cadillac Owners Connoisseur
    Automobile(s): None
    Join Date
    Dec 2004
    Location
    Petoskey, MI
    Age
    33
    Posts
    3,289

    Re: HG and Block Test results

    Must be a week for testing HG's. Here's a video I took of a 98 Deville that's in the family. I will be taking over ownership of this in a few months, and its going to be my "new" winter sled. I'll be storing my convertible again for the whole winter.

    Anyway here's the video:


  7. #6
    diggler1971 is offline Cadillac Owners Member
    Automobile(s): 99 STS Pearl White
    Join Date
    Feb 2010
    Posts
    8
    Thread Starter

    Re: HG and Block Test results

    Is it typical for the color change to happen as fast as in the video?
    As I said, mine never did change to green or yellow, it did however turn to a lighter shade of blue. My tester was not run off a vacuum line, it came with a bulb like what's on a blood pressure tester, and when I was pumping it, it was pulling alot of bubbles thru the tester. It took 3 to 5 minutes of constant aspiration to achieve the color change that did occur, and did not change any more, even though I continued to pump it for 7 minutes.
    I got a coolant pressure tester from AZ last night and I'm gonna go put that on there this morning. I assume I just put the this tester on with the engine cold and not running, pump it up to about 16 pounds and let it sit and see if it holds pressure, and if not, see if I see any leaks. If this tester does not hold pressure, couldn't that be because it is escaping thru a bad head gasket thoough? I'm gonna try it to see if I detect any leaks that are evaporating (burning up in hat parts) when the egine is hot.

  8. #7
    diggler1971 is offline Cadillac Owners Member
    Automobile(s): 99 STS Pearl White
    Join Date
    Feb 2010
    Posts
    8
    Thread Starter

    Re: HG and Block Test results

    Hit a road block. The tester does not have a threaded adapter to go on the surge tank threads. It's designed for the old style spring loaded rad caps. I've called around and haven't been able to find an adapter yet, so now I'm calling to try to find another place with a press tester that already has the correct adapter. AARRGGHH

  9. #8
    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
    74,752

    Re: HG and Block Test results

    Those testers should come with adapters to fit all the different types of caps.

    It will not detect a bad HG unless it is pretty bad and by then it should be pretty evident. Remember you are only pumping it up to 16 psi. That is rarely enough pressure to force coolant through an early stage HG leak. Pressures on the other side of the gasket are coming from the combustion chamber and are MUCH higher.

  10. #9
    Submariner409's Avatar
    Submariner409 is offline If it won't run, stick on fender vents
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    75
    Posts
    45,927

    Re: HG and Block Test results

    You may have a long wait while doing a block/cooling system pressure test: they are usually inconclusive for the Northstar failed head gasket diagnosis.

    Post #6 - If there's any more than trace concentration of exhaust byproduct in the air over the coolant the liquid will turn past green to yellow pretty quickly. From the Lisle #75500 tester kit: "........continue bubbling the fluid for 2 minutes unless the fluid turns yellow sooner........".

    Bubbling for 7 minutes may give a false reading.

  11. #10
    diggler1971 is offline Cadillac Owners Member
    Automobile(s): 99 STS Pearl White
    Join Date
    Feb 2010
    Posts
    8
    Thread Starter

    Re: HG and Block Test results

    Well I'm glad to hear that this test may not tell me much, because I've called around and nobody has an adapter or a tester with the correct adapter. I think I'm gonna run the block test again. I don't think I had added coolant recently when I did the first test, but the car had not been run much in the last couple weeks. I drove it about 70 miles yesterday (with no problems and if the level in the surge tank dropped any, from yesterday morning to this morning, it's not a noticable drop) so I'll try it again and see if I get the same results.

  12. #11
    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
    74,752

    Re: HG and Block Test results

    Follow the instructions closely.

  13. #12
    Submariner409's Avatar
    Submariner409 is offline If it won't run, stick on fender vents
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    75
    Posts
    45,927

    Re: HG and Block Test results

    Drive it for more than today - a week or so would be better.

    Check your coolant level cold, and try to resist the urge to fill above halfway up in the reservoir.

  14. #13
    diggler1971 is offline Cadillac Owners Member
    Automobile(s): 99 STS Pearl White
    Join Date
    Feb 2010
    Posts
    8
    Thread Starter

    Re: HG and Block Test results

    Here are some pics of the block test just now. First, one of test fluid b4 test:


    And after exactly 2 minutes of aspiration:


    And finally after 5 minutes of aspiration (just to see diff.):



    I want to do the leak down test ranger mentioned, but I don't have the materials on hand to do it. So I'm gonna get what I need for that test tommorow. I was avoiding driving the car for fear that I would clog my new converter, however, I think I was overthinking that a bit. I go back to work tomm. and I'm gonna start driving the Seville, which will be around 300 miles in the next 4 or 5 days. I'm also gonna make up a gauge stick for the coolant in the surge tank and check the level each morning, for an accurate measure of just how much coolant I'm losing. Thank you for the comments so far, and what do you guys think about the color change in todays test?

  15. #14
    diggler1971 is offline Cadillac Owners Member
    Automobile(s): 99 STS Pearl White
    Join Date
    Feb 2010
    Posts
    8
    Thread Starter

  16. #15
    Submariner409's Avatar
    Submariner409 is offline If it won't run, stick on fender vents
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    75
    Posts
    45,927

    Re: HG and Block Test results

    You're OK: That test is GOOD: no gas in the airspace.

    IF you want to go paranoid, do it again in 10 days or so. Then lock the tester in a cabinet and throw away the key. Drive the car.

    .............and don't fill that coolant reservoir more than halfway, cold !!! If your reservoir is half black, half translucent, there's a fill note and arrow molded into the tank top and side. The FULL COLD mark is right about the black/clear tank seam.

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