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Todd M
Todd M,
Category: Chevy
Satisfied Customers: 1259
Experience:  Technician at Montgomery Motors
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Overheating, i have done everything i know. i have been

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overheating
JA: Have you checked the coolant? Have you checked for a leak in the cooling system?
Customer: i have done everything i know. i have been working on my own cars for 40 years, i know a little. The pressure is good, no leaks, bled the air from the system, flushed the system, radiator and fans replaced 1 year ago.
JA: What is the model/year of your Chevy?
Customer: 2008 equinox 3.4
JA: Are you fixing your Equinox yourself? What have you tried so far?
Customer: yes
JA: Anything else you want the mechanic to know before I connect you?
Customer: no

Hello. My name is ***** ***** I will be assisting you today. I see that you have done a few things and are overheating still. There are a few things that should be suspected. The thermostat(#4) and the water pump should be suspected, but first, you need to inspect the fans and be sure that both are functioning as it should. If the fans are coming on as they should and you have not noticed any leaks, then the first thing that I would suspect is the thermostat. The water pump will usually start to leak through the weep hole when it begins to fail.

Customer: replied 1 month ago.
2008 Chev Equinox 3.4 - started overheating with AC on about 1 year ago. Intermittent, not all the time. In the last few days, started overheating when car came to stop lights; a/c off bells and whistles going off on dash board. I flushed the system, did not put the cool Dex anti-freeze in but used the generic for all vehicles. Bled air from system, heater is hot, ac cold, both fans run as they should, hi and low speeds. I noticed today while idle and ac on. the engine would bog down like it wanted to shut off and heard a bad sound from engine compartment. Could not tell where it was coming from. Almost sounded like one of the tension pulleys locked up, happened for only a second. Yesterday after test drive, the car did stall for the first time and was not overheating. I have not changed thermostat or water pump. Nether seams to be the problem. Preasure stays in the system over night and seems to be around 15psi.
Customer: replied 1 month ago.
If the thermostat was stuck closed, wouldn't the car overheat immediately? Within 5 minutes or so?

Is the vehicle running rough? Have you removed the belt, and inspected the pulleys to be sure that none are beginning to lock up?

Customer: replied 1 month ago.
I'm not working on the car at this point or I would take the phone call.

No problem. Yes, if the thermostat is stuck closed, the vehicle would quickly overheat. If the vehicle couldn't cycle the coolant properly, then this will occur.

How does the vehicle run otherwise?

Customer: replied 1 month ago.
The engine runs smooth. My next step was to check all the pulleys because as I stated, It sounded like one of them stopped for a moment.

That sounds like a plan. If the pulleys prove to be intact. then I would suggest that you inspect the water pump and the thermostat.

If you require more information on this issue and/or are not satisfied, let me know, please, and I will attempt to assist you further on this. I hope this information points you in the right direction. If you have any further questions or concerns on this issue, feel free to ask. If you are satisfied, and have found this information helpful, a positive rating would be greatly appreciated. Thank you.

Customer: replied 1 month ago.
I heard this sound 2 or 3 times today with the ac on. With the ac off, never heard it. So I'm thinking maybe the ac clutch is getting ready to go out. What are your thoughts on this?

That is a definite sign that the clutch is beginning to malfunction, which would explain the overheating.

Customer: replied 1 month ago.
Can the ac clutch lock up and stop turning?

I'm thinking that there is too much resistance in that pulley.

Yes. If the clutch locks up it will shortly pop the belt. Leaving the vehicle unable to be operated.

Customer: replied 1 month ago.
I will check pulleys and thermostat and get back with you on the results. Thanks for your input.

Sounds good. Keep me posted. If you need me, I'm here. Also, please, do not forget to rate the service as it is necessary in order for experts to receive credit for answers provided. Thanks again.

Just as a reminder, if you have found this information helpful, please do not forget to rate the service. Thanks again.

Customer: replied 1 month ago.
Checked the pulleys and thermostat, both are good. The car has a rough idle, like a vacuum leak. I'm not able to determine where or what the cause is. The 12v going to the EGR valve disappears when plugged in. I did a complete test on EGR and everything passed except when it's plugged in (the connector to the EGR) the 12v is gone. I checked the wire from EGR to the ECM connector and it's good. What is the cause? ECM bad? Car is still overheating when driving. The other day I was getting bubbles coming up from the reservoir, today, nothing. I am suspecting intake manifold gasket but have no way to test. I sprayed some carb cleaner around manifold but could not find a leak. Any suggestions on finding a leak? I do have a small amount of white smoke coming from exhaust, no water in oil. The car sometime wants to stop running when at idle, bogs down, RPM's constantly fluctuate between 700 and 900 @. I don't have a test kit to test for exhaust fumes in radiator but hoping not necessary. Your thoughts would be appreciated.
Customer: replied 1 month ago.
One other thing to note. This car belongs to my 70 year old Mother-in-law and I know she drove it awhile when it overheated, possibly causing more damage.
Customer: replied 1 month ago.
The radiator does hold it's pressure over-night.

I'm here. When the 12v go away, if it disappears completely, then the issue is likely to be the ECM. If you just loses voltage, then the issue could be a faulty wire. Also, to check for the over heating, you need to have the compression tested on the vehicle. The best way to find this type a leak, is to use a smoke machine to inject smoke into the system. This will give a tell tale sign. The idling issue is like due to a vacuum leak. The best way to find a vacuum leak is to also use a smoke machine.

Customer: replied 1 month ago.
I did a continuity test on the 12v wire earlier today and it showed it was good but I will put a jumper on it tomorrow between the connectors (EGR and ECM) just to verify the 12v is not being lost to a intermittent ground somewhere in the wire. Last year the pigtail for the EGR was replaced because of broken wires. I can do a compression test on the cylinders but do not have a smoke machine. May need to take this into the shop. I'm just about out of things to check.

I completely understand. Here, are the specs for compression of the vehicle. I am suspecting the compression and likely a vacuum leak. Both testings will be necessary in order to rule out the possibilities.

Customer: replied 1 month ago.
Thanks. Do you know if the EGR 12v from the ECM feeds anything else besides the EGR? I may have to cut it out of the circuit when I perform the jumper test tomorrow.

That wire is solely for the EGR. Here is the connector view and the connector

Customer: replied 1 month ago.
The spec sheet for compression you linked, is for Intake Manifold Runner Position Sensor

It is cylinder compression.

Customer: replied 1 month ago.
I'm not sure what you were sending me. You said specs for compression but the sheet does not have compression specs on it. I thought you may be referring to cylinder compression specs.

I'm sorry. Here, you are. I thought I had attached this information.

Customer: replied 1 month ago.
Didn't get much done today. The 12v supplying the EGR goes to .07v so I am assuming the ECM is bad. I accidentally dropped it on top of the battery a few days ago and is did short so I probably damaged it. I checked cylinders 2,4 and 6, all 3 are at @129lbs. I'll check the others tomorrow and do a smoke test. Thanks for the specs.

Keep me posted.

Customer: replied 1 month ago.
Well, time to change the head gasket. Air bubbles in reservoir tank. Heavy white steam from exhaust with smell of antifreeze. Still don't have 12v at EGR. I picked up a used ECM for $27 from pick-n-pull. I will have it flashed after the over-haul. I will send heads off to get checked and valves done.
I want to thank you for your input on this and will let you know the out come. If you have the torque specs on the heads and manifolds, it would be appreciated, also, any tips on the over-haul would be welcomed. Thanks
1. Tighten the M11 cylinder head bolts a first pass in sequence to 30 N.m (22 lb ft).
2. Tighten the M11 cylinder head bolts a second pass in sequence an additional 150 degrees using the J 45059.
Tighten the exhaust manifold nuts and bolts to 25 N.m (18 lb ft).

Also, please do not forget to rate the service, as it is necessary in order for experts to receive credit for answers provided. Thanks again.

Todd M and other Chevy Specialists are ready to help you
Customer: replied 22 days ago.
I finished rebuild on engine but now after having the battery discovered for several days, the car won't turn over. I'm at a total loss. Checked Internet without any luck. My code reader won't work either, just displays kw 200 which I believe means no communication with ecm.
Any suggestions?
Is the battery fully charged?
Customer: replied 22 days ago.
New battery. Security light on dash, not on but I did the let reprogram anyway. I even tried the other ecm.
Customer: replied 22 days ago.
This is a common problem when disconnecting ECM or battery according to post on the net. Do I need to have the ECM flashed or do you know something I can do myself to get this started? Remember, the car started before the head gasket change. The battery and ECM were disconnected for 4 days. So to me, it's obvious it has something to do with power loss to the ECM.
Customer: replied 22 days ago.
Todd, are we done with this issue?
I am working and not near my computer. As soon as I'm finished here, i will check for information on this issue
Customer: replied 22 days ago.
Okay...good to here. Thanks
Customer: replied 21 days ago.
I found a connector not pushed in all the way under the hood. Works great, no codes or lights. Test drove, over heating issued solved. Thanks for your help.

I am glad you have gotten the issue taken care of. You are very welcome. I am always happy to help.