MajorMalfunction

I have a 2006 Equinox with 64,000 miles. It's been regularly maintained and has never overheated.

Recently it started making a faint gurgling noise in the dash on cold start, that goes away when the car warms up. It doesn't overheat, temp stays between 1/4 and 1/2, occasionally hitting 1/2 but no higher. It doesn't smoke, isn't losing coolant that I can see and isn't running rough, it runs fine. There are no visible leaks.

I was doing searches for the noise and came up with head gasket problems so I took it to my regular mechanic, who I implicitly trust. He pressure tested it and found nothing, it didn't leak. He also found the internet posts about head gasket problems but didn't want to charge me for a repair it might not need and told me to drive it until it came up with other symptoms.

I'm a worry wart and I need the car to get my kids to school in a different district. I'm also on a fixed income so if there is a problem I want to get the problem taken care of in its infancy before it gets more expensive. So I took it to the local dealership. They told me that a head gasket issue is really rare in this model and thought it was the radiator cap. They kept it two days, did a complete flush of the cooling system, put on a new cap and said it was holding pressure and the noise was gone and gave me my car back. That was yesterday. According to the receipt, there were no codes in the computer to indicate a problem and there's nothing on this in the GM databank.

Problem is when I started it this morning, it's making that same noise. I called the dealership and they said I could spend a lot of money chasing ghosts but until and unless it actually overheats there isn't anything they can really do about it. Now I'm sooo paranoid.

I ran it up to pick up my kids and it stayed in the usual temperature range. After I got my daughter, about five minutes, when I turned the key it kind of choked but started and the temp was just above 1/2 but immediately dropped to the normal range. I drove it all the way home in stop and start traffic and the temp stayed below 1/2.

I'm stumped but still worried beyond reason about it being a head gasket. I live in a really expensive area and that would probably cost me $3K. I can't afford a new car. I really want to know what this is so I can relax about it.

Anybody have any idea what this could be other than a head gasket? Or do I just do what both mechanics said and keep driving it and keep an eye on the coolant level and temp and don't worry unless it overheats or comes up with another symptom?

Thanks in advance.

tech2

the sound most likely is from air in the cooling system. As you start the car or rev up the engine the coolant moves through the system. Air is trapped in the system and makes noise as the coolant moves.


these systems must be vacuum filled to prevent trapped air...even then it may happen.


when the head gasket goes it will pressurize the cooling system and spill coolant out of the reservoir. you are not at this point. You state the level is not dropping so I suspect no leaks are present.


if you really want to try something; have the system vacuum filled and thermocycled to remove the trapped air.

MajorMalfunction

Thanks for answering so quick!

The dealership receipt said they vacuum bled the system, is that the same thing?

As I understand it, air in the cooling system is pretty undesirable. Can I drive the car indefinitely like this as long as it's not overheating or giving other signs of leaks?

Rednucleus

As long as you are not overheating and not leaking coolant, should be fine. Just be aware and watch your gauges and for leaks. Our 05 did this when the water pump was going out. Took another 3 months before a leak showed up.

MajorMalfunction

Awesome, thank you!

tech2

cavitation occurs from trapped air. It is not desirable in the long run. I have heard off but never seen the long terms effects of this. For a laugh, try this; remember, air will migrate to the highest point


with the system hot, park the vehicle nose up on a steep incline (so the reservoir is higher than the heater core...run the engine at 2000rpm and see if the air burps out as the highest spot is no longer the hoses in the heater core.


if it doesn't work, nothing lost

MajorMalfunction

I'm kind of leery about working on my car myself, but I'll see if a handy friend can help me with this, thanks for the suggestion.

Does the reservoir cap have to be off to do that and isn't it dangerous for me to remove the cap when the engine is hot if so?

silverado 1500 2001

air is in the system (perhaps only the heating unit, where the gurgle is). if you have a leak (into or out of) your INSIDE radiator (air passes over) it will get air. HOWEVER: that's often not the case...

hot water from engine block flows past valve through unit and back to pump on engine

nothing i looked for was wrong

on my car (i posted about it), solution was to install a prestone flush kit (found at any car store). with the hose entry higher than engine block one can insure (following procedures) by opening/closing fill cap that there is no air. while supposedly one can do this without: supposedly also leave gurgling

the above is too darn convenient. and while you do it you can check for leaky hoses (only the ones going into/out of firewall matter; if anythign leaks it may be the connectors), but fix anything with green gook on it)