Gurgling noise

[alexbtango15]

I have a 1998 Pontiac Montana with 105,000 miles. lately I've noticed a slight "gurgling" noise. I checked under the hood and I saw the overflow reservoir was where the noise came from.

The temperature doesn't exceed 210 degrees ever, the van runs fine- no knocking, or rough operation. Just that noise kind of makes me uneasy.

Any ideas as to what could be wrong?

[tractorman]

That worries me. I see this all the time on diesel engines. A blown head gasket can cause it. I'm not familiar with a Montana- is the overflow tank pressurized? If that tank isn't pressurized, and you're seeing steady bubbles once it's good and warmed up... and they don't stop eventually... you have a blown head gasket.

Here's another check- if it's bubbling good and steady, have the wife hold the brake and step on the gas at the same time to load the engine pretty good. If it bubbles more, then you definitely have a problem.

Yeah, and make sure there's nothing in front of the van, including you.

[alexbtango15]

The overflow tank isnīt pressurized. It just has a little flap-like cover to close it off. Also, I donīt notice the noise every time. Maybe once out of every three times I drive it. When I do notice the noise, itīll stop about two or three minutes after the engine is turned off.

A buddy from work recomended that I purge the cooling system of air. He showed me a small screw that he says I should open while the engine is warming up, and it will let out any air trapped in the water lines. He said that when I start to see a solid stream of water coming out, I should close it off. And then pour more anti-freeze in the tank.

[tractorman]

Your buddy told you right.

If this gurgling thing doesn't happen every time, then it's probably not a head gasket. Are you saying that it keeps gurgling after you shut it off? That's just wierd... dont' know what to tell ya'.

[alexbtango15]

I haven't had a chance to check out the van, but today I'll be making some time. I want to try what you recomended, and what my friend from work told me. I'll let you know what comes of it.

[geldartb]

my grand am does this i noticed it one night while i was sitting in my car waiting for people to come back. car was not over 200, very rarely goes over due to the 180 t-stat. thought it might be a clogged heater core or something along that line.

[clevo]

My 1990 3.1 L has the gurgline sound, too. Couldn't bleed the air out of the system, even after multiple attempts.

In my case I think the head gasket is shot. I've removed the radiator cap from the engine when cold, and then started the car. Get a steady stream of bubbles.

One service guy told methe gurgling was due to the fact that a coolant line restrictor leading to the heater core had disinegrated, sending coolant at full blast into the core, thus causing the gurgle.

[SHOoff]

Try bleeding the air out. If you cant bleed it, it may be the head gasket. If it blows in the right spot, combustion gasses (<1000 degrees F) can leak into the coolant passages and boil the coolant.

At the same time, it could actually be overheating. Check your coolant level. See if it's low. These motors are good about blowing the LIM gaskets, whcih would cause it to overheat and lose coolant too.

[EspanolaGuitarista]

Check for a ......

bad heater core.