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2008 Equinox 3.4L AWD
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Discussion Starter · #1 ·
2008 equinox 3.4L
Is overheating and I can hear bubbling when accelerating. Is this a guarantee of a headgasket issue or could the coolant just need bleeding. Previous owner has done lots other than the head gasket.
My real question is can I drive it 35min to get it home from seller? I can stop for it to cool down periodically. I'm worried that a hose might come off with the pressure in the coolant system.
I can then troubleshoot it better when I get it home.
Thanks for any help...
 

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We had a 1976 Chevy Nova. Everytime we started it up, we could hear gurgling in the heater core.
I was young so I didnt know what was up.
But- the car ran for years. Finally got rid of it in 2010 or so... still running.
Dad just made sure the coolant was topped up.
You may have a coolant leak in the water pump. Weep hole.

Do you know if these engines have a bleed screw at the highest point in cooling system?
Some engines are notorious for having air pockets... that are hard to get rid of--- and so the manuf. puts in these bleed screws.-
open them and air is expelled.
 

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Discussion Starter · #3 ·
Thanks for that... I've too have heard that they are a pain to bleed. I'll bleed it as best I can before driving and keep my fingers crossed!
 

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Discussion Starter · #4 ·
I just noticed there a silver metallic looking specs in the coolant. The wrong coolant has been put in also (should be cool max but super tech extended life was put in.)

Any idea what the metallic flakes are?
 

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2017 Equinox LT 2.4 FWD
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I just noticed there a silver metallic looking specs in the coolant. The wrong coolant has been put in also (should be cool max but super tech extended life was put in.)

Any idea what the metallic flakes are?
Just a wild guess but you mentioned PO and head gasket. Perhaps the PO tried using some sort of stop leak as a stop gap measure. Your burbling noise may be exhaust gases making their way into the coolant.
 

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Discussion Starter · #6 ·
The PO did use a stop leak! That hopefully explains that.

The coolant system is still holding pressure at least over 36 hours... Is this useful diagnostic information (ie is this less suggestive of a headgasket with an exhaust - coolant leak? I will pressure test the system properly when I get it home.
Thanks again!
 

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Stop leak could have partially plugged the heater core trapping air in it.
If it's holding pressure for that long I would replace the cap. It should loose pressure after cooling down so air can bleed out and coolant can be sucked back in replacing that air. That's how recovery systems work.
 
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Discussion Starter · #8 ·
I bled the cooling system however I think there still may be a small amount in there. The inside heater (center console) is warm but not hot. The side vents are not warming up. The coolant pipes through the firewall are both hot. The top of the radiator is cold when the car overheats. It drives fine for 5-10 minutes then rapidly overheats as though it happens when the thermostat opens up (or something else opening) even though both fans were on full speed well before the overheating. Coolant escaped through the coolant reservoir overflow pipe.
I don't think the coolant is flowing through the heater matrix properly... Do you agree?
Is there a sticky solenoid that can affect heater matrix function?
I assume if the radiator is cold then either the water pump isn't working or there is air in it.
Any advice would be greatly appreciated!
Thanks again everyone.
 

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Overheats in 5-10 min. then change the thermostat first.
 

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Discussion Starter · #11 ·
Update...
Changed the thermostat for a 180 deg one. Old one opened in boiling water but I don't have a thermometer to see what th actual opening temp was.
When I drained the coolant system there was no fluid in the radiator!
Flushed the old stuff out... It was very viscous. Looked like was more rad weld than coolant! Took the thermostat out whilst doing this.
Used a cleaner kept flushing. Then filled wi h dex cool after putting the thermostat in.
Test drive it went for 10 then overheated. Bled some more air... Now it runs without overheating however the temperature gauge is at 9 o'clock whils its warming up (or just under). Then when it's warm it rises to 10 o'clock then down to 9 o'clock. There is still some air in the system and I'm just going to drive it to operating temp and let it cool down and bleed some more.
Is the temperature gauge behaviour normal or should it stay pretty still at the 9 o'clock mark?
 

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With a 180 thermostat the gauge will read lower. Gauge is calibrated for the 195 'stat. Not positive but those years GM gauges usually run at 12 o'clock for normal temp. Others will chime in.
It should have the 195 in it as its designed for that. Possibly low engine temp. codes could be set also along with lower heater output.
Putting in a lower temp. 'stat will not be the cure for other issues in the cooling system like air or plugged radiator or fans not working properly.
 

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Discussion Starter · #13 ·
I understand that the lower temp thermostat won't solve the problem...
I've been bleeding the system at idle for over an hour with plenty of air coming out the bleed screw. I can still feel air in the top radiator hose when the car is running.
I'm not sure if this is cylinder gas or just trapped gas.
I need to borrow a coolant system pressure tester and I'll do a cylinder compression test as I think this will confirm whether the head gasket is involved or not.
 

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2008 Equinox LS AWD Summit white, 2007 Torrent GT FWD Jet Black, 05 Pursuit 2.2L Titanium Metallic
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Having the exact same issue with my moms 07 torrent. I spoke to a very reputable radiator shop that I deal with both for personal vehicles and my work fleet and they told me that chances are that the head gasket is gone.

Bleeding the cooling system on these is NOT fun. Point blank. I've heard even with a vacuum powered system, it is still a huge PITA. All I do is start the car up, heat on. Let it get to just below half on the gague, then hold the RPM'S just a bit below limiter for 30 seconds, let sit for another 30, repeat for ten minutes. Shut off, let cool down for 30 mins, start it up, let it idle for an hour. Seems extreme, but that's the best method I've found so far. I do undo the heater hoses, and fill the heater core up with coolant through the upper hose and then reattach it. Do NOT use the water pump bleeder, in my experience, it's useless and it's not the highest point in the system.

Her heater core went four years ago, went a winter with about 2/3 heat capacity but coolant smell in the interior and having to top off with less then half a quart weekly ever 60-80 miles or so. After doing the heater core, i had no heat at all, and the car was still consuming coolant. I replaced the heater core again, thinking I got a defective one, and low and behold I didn't tighten the HVAC box behind the dash all the way. Tightened it all back up, reassembled, after checking every fastener 10 times, no joke.

Start it up, sure enough no heat. But had a gurgling/surging noise coming from my reservoir. Now, we've owned the torrent since 2011 at 92k km's. We have done the vast majority of repairs in this vehicles life time, including coolant service. We only used dexcool 50/50 mix. No green, nothing but dexcool. And no sealers or additives. When we flushed it, we did it with prestone chemical flush and distilled water.

The shop I spoke to said that they don't always spit the coolant out of the exhaust via white smoke, and you don't always have tell tale signs, but most of the time, its the surging in the tank, wont be able to bleed the cooling system and constantly having to top it off, all of which we're currently experiencing, in addition to no heat in the cabin, but it's june so we could care less.

I am not looking forward to repairing it and doing the head gasket, but I've already done it on my 08 equinox twice, thanks to the rocker arms stripping out even when using a heli-coil. But it is easier than the older montanas, rendezvous and grand ams and what not. There is a lot more working room. Gasket kit is about 300 depending where you go and what you get. I spent about $400 CDN total, on fluid, oil, filter, plugs, gaskets, bolts and a few other little odds and ends ("while you're in there" kinda stuff). No timing chain/cam stuff to worry about aside from the rocker arms and pushrods, but as long as you put the pushrods back in the right place, and you torque everything to spec, there's really not a whole lot to it compared to other engines, at least IMHO.
 

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Discussion Starter · #15 ·
I did a combustion check and the colour went from blue to green so I think this tells me it's the headgasket.
It's done 170k miles with unknown service history (although I can tell it's been looked after). What else do I do when I'm in there?
Is it standard to grind the head flat regardless of the problem I find?
BTW.. I've done head gaskets on a few mercs (190E, 230SL and 320CE) in the past but not in a modern car and not on a V 6 engine.
Thanks again for all your help... I really appreciate everyone's contributions.
 

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Discussion Starter · #16 ·
In case anyone is interested the gasket was damaged on both cylinders 1 and 2. No warp. Both gone in the same place however 1 was much worse than the 2.
 
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