I bought a 99 seville in Jan. with 108,000 miles. I drove to Kansas City, MO from Wisconsin two days after I bought it (moved). The car drove fine. The first weekend I drove downtown the car overheated. I found some threads online that say it is the head gasket. I brought the car to a cadillac dealership and they said "yes it is the head gasket". I brought the car to another place and they ran a test (mixed some liquid with the coolant and did not see a color change) and found not to be a head gasket. This mechanic stated there is nothing wrong with the head gasket and replaced the fan sensore and sent me on my way. One week later I drove downtown and the temp has from the middle about an 1/8 inch (about 3/4 of the gauge). After it raised it went back down after about a minute. When I pull off from a stop light I can hear air bubbles. I need help and hoping this is an easy fix before I drive it back to WI to the dealership to get fixed.

Any help PLEASE!!!!

There is an air purge line that begins at a hollow bolt above the water pump cover and flows through the throttle body and terminates at the top of the coolant reservoir. Be 100% certain that line is flowing a slow steady trickle of coolant by removing the rubber hose from the top of the reservoir with the engine at idle (cold engine!!).

If there is no coolant flow, locate and remove the blockage.

Once the air is purged from the system, you can expect the coolant level in the reservoir to drop a little so keep an eye on the level. Once again, with a cold engine.

I took your advice Jim and checked for blockage. The coolant was flowing good and fast. The noise (water bubbles) is coming from the console. Any other options or thoughts?????????

Has to be in the heater core....they can be a PITA to purge of all air bubbles. Try a few judicious high rpm moderate accelerations in gear position 2. Let the engine run up to the 1 - 2 shift with moderate throttle and then ease it up to over 5000 rpm and let it coast back down. Watch the temp gauge (it probably won't move) and do it again. Let the car cool, and maintain the coolant level at about halfway up the tank, cool.

It will make the bubbling sound even when in park and i raise the RPM's, I can start to hear it at about 2000 RPM's. Do you think the heater core needs to be replaced or is there a way to bleed the system (if brought into a mechanic). I need to try and figure out if it is worth driving back to WI (still under warranty) from Kansas City, MO or pay to get fixed here.

If you still have warranty I would take it back imo.

yeah, change the water pump, check the purge line, change the t stat and do all of what everyone is telling you to do. After you get done wasting all that time and money................it'll be the head gaskets. I'm rarely wrong on this. ;)

Thats is what I am guessing it is after everything I have read. Is there a reason when I had the dye test done it showed nothing?

Maybe they did the test wrong. You can't do it after you add fresh coolant or it will give a false negative. From what you are saying I doubt you'll make it to Wisc. Your symptoms do not sound promising I hate to say.

That's what I am afraid of. Towing is not in the warranty. I am trying to eliminate everything so I am 100% confident in spending the money to get the car back to WI.

Read the warranty closely and talk to them first. Some warranties have loopholes. I'd hate to see you go through the trouble and expense to get it back up here only to have them say oops, sorry.

I read it upside down and backwords. Have been dealing with them since the end of Jan. The only way they will fix it is if I bring it up there or they will send me a check for $2500 to get it fixed here but the cheapest I have found is $3500 after taxs.

You're very lucky to have a warranty that covers HG's. Most people are left to pay the $3500 to get them fixed. Oh btw, make sure that warranty includes timeserting. Most don't, and if the car isn't timeserted it will fail again.

Yeah, even if you have to foot the Timeserts out of your own pocket, DO IT.

Is there something I can do to make sure they fix the hg? I don't want to bring it all the way up there and have them do the same die with coolant test and tell me it's not the hg.

Test it again or have a cylinder pressure test done to confirm it. It should not be hard to diagnose to be sure before hauling it back up north.

If it is the hg, would it overheat all the time? I tried to get it to overheat last night by driving around for about an hour (fast, stop and go, everything) and I only got the temp to raise about and 1/8 inch and then it went back down after about a minute but the gurgling water sound seems to be getting louder/worse.

Usually in the early stages of a HG failure it will overheat under a load, a hill climb or WOT.

I have not had the car overheat under a load yet. Everytime has been in stop and go traffic or at stop lights. I drove from Kansas City tothe middle of Iowa about a month ago and I did not have any problems. The temp was chilly on the way there but 50's on the way back. I also drive the car to work and back and anywhere I need to go without it overheating (unless I get in stop and go traffic). Whats is the gurgling noise that I hear? Can the be part of the problem?

What is your definition of "overheating" ? Where on the picture is your idea of "overheating" ?

It will raise up to about 5/8 to 6/8. What is that girgling noise and how much $$ at a mechanic to fix?

The gurgling noise is air in the heater core.

What is 5/8 to 6/8? Where on that dial in temps listed?

210 - 225 degrees is what it raised to then goes back down. When it raises it takes about 4 seconds to get that high, then after a minute or so (depends everytime) it goes back down. It completley overheated once where I had to pull over. I hooked it up to a computer and did not get anything back.

Should I be worried about the gurgling?
Thanks for all the help!

The gurgling COULD be an indication of a problem if the purge line is clear.

If you don't have the A/C on or heater in Defrost mode the fans don't come on until the temperature gets to 225, and then only one starts. Two fans run in fast mode at 238 degrees. Did the car overheat (steam out of the surge tank) or did the DIC tell you to idle engine or stop the engine?

I popped the hood and there was steam and also coolant boiled out of the cap. I let it cool and made it to a gas station and added more coolant. I then made it all the way home (about 15 minutes) without the temp gauge raising. I have had the fan sensor replaced and now it raises to about the 225 mark if I am driving downtown otherwise it is fine.

Just drive it and keep an eye on it. IF it is the HG, it will let you know in due time.

What is the coolant level in the surge tank, cold. Empty, 1/2 full, or at the top ??? No questions this time: answers only.

It is full, just to the top of where the divider is. There is room left for expansion.

:hmm:

I'm running out of ideas, I sure would hate for the HG to go in 6 months after my warranty is done.

Well, if that is what you are worried about have the coolant tested again and/or a cylinder leak down test done.

I had another die test done and the color did change but it took about 30 minutes. The mechanic told me the reason it took so long is because it is a small leak. Does this sound like an accurate assumption? I am just trying to make sure the guy isn't trying to buffalo me :)

Unfortunately, you have a blown head gasket. I have repaired over 20 of these and all have the same symptoms as yours. I repair these for 1500 + parts, so if they only pay 2500, I could get you repaired for less than that, with a warranty. I'm in Ky, which might pose some issues, but you can email me if you have additional questions about your car. Mikelawson@ctky.com.

Mike