View Full Version : Is It A Head Gasket???

12-12-05, 05:49 PM
My 98 seville keeps loseing coolent. I took it to a reliable local shop and they said it looked like it was leaking from the waterpump.So i had them change it. Two weeks later the low coolant light comes.I took it back and they pressure tested the car. They said it was on the pressure tester all day and it never lost any pressure so they could not find any thing.I talked to the mechanic he told me that he thougth it was an air pocket.He told me he did not think it was a head gasket becouse of the pressure tester would have lost pressure and the car dosen"t run hott and dosen"t smoke. A week and half later I get the coolant message a again and had to top if off. Please help :banghead:

12-12-05, 06:03 PM
See the Technical section regarding "ways to test for a headgasket failure."

Also, I would recommend that the supplement tabs be added to a radiator hose (part number listed on the sticker on the radiator by the hood latch). If you have a tiny leak due to casting porosity (not uncommon in aluminum engines), the Barsleak Golden Powder or the Supplement tabs would take care of it. I would do this inexpensive procedure before everything else.

Not losing pressure, is a good sign.

12-12-05, 06:10 PM
I have used both the barsleak right when I noticed a problem and the GM coolant tabs after I took the car back the 2cd time

12-12-05, 06:42 PM
Just so you know, the GM coolant suppliment tabs are Barsleak. They are just sold as GM coolant suppliment. It's possible that the resevior cap wasn't tightened all the way. I had that happened once, and a bunch of coolant evaporated out, and I had the Check Coolant Level come on.

12-12-05, 07:07 PM
Also check the vapor vent line (or have the shop check it).

12-12-05, 07:19 PM
I have used both the barsleak right when I noticed a problem and the GM coolant tabs after I took the car back the 2cd time
I suppose you put it in a radiator hose instead of the pressure tank?

12-12-05, 08:14 PM
I did put it in the hose and I also replaced sure tank cap think it was that before I was told it was the waterpump

12-12-05, 11:30 PM
Surge tanks are know to crack and loose coolant. Dried Dex-Cool will leave a whitish residue as a telltale sign. My '97 Deville developed a small leak that I never saw at the base of the nipple where the purge line connected to it. One day I got the check coolant level message. Since I never saw any leaks I thought the worst. Topped it off and went on my way. Next day it was low again and I saw a little moisture at at he nipple. I pulled the hose and shortened it by 1/2" thinking the hose was just deformed over the years. When I restarted it I again saw a little moisture. Once again removed the hose and saw no crack. Only when I put some pressure on the hose with my hand, did the crack make itself apparent. It was a hairline crack that was undetecable unless the engine was running. Even then, it was only the slightest of seepage. Others have had cracks on the underside. Inspect it carefully and look for the telltale residue.

Not to be a naysayer but, a cooling system pressure check will not always detect a bad head gasket. The breach could be new and minor enough that it will hold 15 psi in the cooling system but will fail under the much higher cylinder pressures. A cylinder leak down test is the only positive way to rule it out.