2010 V8 Overheating

[rhubarb9999]

Tonight we were driving my 2010 4.6 (83K miles) in stop and go traffic. It as running smoothly. Then I notice steam coming from under the hood. I look at the water temp gauge and it is at the bottom, reading cold. No check engine light.

Continue to try and get out of traffic .. finally break free .. check engine light comes on. Car is still running fine but I can smell coolant.

Get it to a gas station and park. Steam from under the hood and coolant dripping on the ground on the drivers side. Finally it cools down enough that I can open the hood. The reservoir 'dipstick' is laying on top of the engine. The reservoir lid is popped open and that is where the steam is coming from. When i first stopped, the fan was running at hyperspeed.

I was not able to pull the codes .. I will have it towed back to the house in the morning. Any ideas on the issue? I am curious why the water temp gauge did not move at all. I did not look at it when i first started the car .. so I am not sure if it had started to climb. After it cooled down I started it for a few seconds ... ran fine.

Thermostat? Water pump?

 

[Gunkk]

Yep, my guesses in order of probability:

1. thermostat failure.
2. water temp sender failure.
3. water pump failure.
4. low on coolant and pump cavitated.
5. Temp sender can false report if there's no water touching it... but that's not normal on a very hot engine... so possibly a combination of 1 and 2 or 2 and 3.

Let us know what you find out.

 

[rhubarb9999]

Update ..

Last night I left the car at a gas station about 10 miles from home. Went there this morning ..

Put about 8 liters of water in the radiator. It started right up. Started to drive home. Had the heat on full blast .. it got very hot so I assume the thermostat is letting water flow. Water temp gauge never moved .. so the sensor is most likely shot.

Got home and no signs of overheating. The fan was not even running when I turned off the car. So .. hopefully it was just low on coolant and being caught in stop and go traffic last night pushed it over the edge. I'll order a new temp sensor today and continue to monitor.

 

[EdP]

Update ..

Last night I left the car at a gas station about 10 miles from home. Went there this morning ..

Put about 8 liters of water in the radiator. It started right up. Started to drive home. Had the heat on full blast .. it got very hot so I assume the thermostat is letting water flow. Water temp gauge never moved .. so the sensor is most likely shot.

Got home and no signs of overheating. The fan was not even running when I turned off the car. So .. hopefully it was just low on coolant and being caught in stop and go traffic last night pushed it over the edge. I'll order a new temp sensor today and continue to monitor.

I'd also check why the coolant was low too. Yes, easy to neglect and not check but it had to be fairly low to overheat. Most of the 8 liters was probably blown off as steam.
Given the age of the car, hoses can be deteriorating.

 

[396chevy]

I would normally think the temp sensor would control the fan unit, unless there is an additional sensor for the fan itself. Which makes me question why the fan was on if the temp sensor was reading cold.

I find it interesting that the overflow tank was open and the dipstick was on top of the engine. The overflow portion of the cooling system isn’t normally pressured but I suppose the system would vent hot (boiling) coolant into the overflow and that could cause enough pressure to pop open the overflow and eject the dipstick.

I agree the majority of the coolant loss could have been from the overheating incident.

I agree a thermostat failure is the most likely cause, it may have been stuck and has since freed up which would explain why it only overheated the once.

I would suggest new thermostat and a coolant flush.

 

[rhubarb9999]

I got a new temp sensor .. where does it go? The service manual does not have instructions for replacing it. I found a few images on line, but I still cant find it in the engine. Does somethng have to be removed to get to it?

 

[Hero6]

Resurrecting this thread...My 2011 4.6 overheated the other day. About 2 weeks ago the A/C quit working, checked Freon, all good. Then a few days later the wife was sitting in a drive thru and called me saying the car smelled hot and the check engine light was on. Had her shut it off and park it. It overheated, but the coolant gauge quit working. I let it set for a few, started it up and noticed the cooling fan was not coming on. Did a little research and replaced the temperature sending unit. The gauge still did not work. Tapped on the fan control module under the fuse box, disconnected the battery for 30 minutes or so. Tried it again and the fan comes on and runs all the time, even when cold. I tested the fan relay, it shows good. I replaced the cooling fan control module under the fuse box, still the same. No A/C, fan runs all the time, coolant full, temp gauge does not work. I tried to clear the codes P0116 (Engine Coolant Temperature Circuit Rang/Performance) with my scanner, but they wont go away.

I left the battery disconnected overnight and will connect it and try it again this evening. I read somewhere on here, that I may need to have a shop clear all the codes, even the ones I cannot see with my handheld scanner and that may fix it. I was hoping to clear all codes with battery disconnected 24 hours, but that may not work, but will find out this evening. Just looking for any input or ideas?

Note: I have plenty of heat, so thermostat is probably not part of the issue

Edit: I found the thread I referenced above concerning the clearing of codes, and pasted below so if anyone runs into the same issue, it all in one place.

"I ended up taking the car to a trusted mechanic. The connected their scanner and found additional codes that my handheld scanner didn't. The important code being oil temperature sensor. At some point (cause still unknown) the oil temp read too high and caused the car to go into limp mode. This cause the a/c to blow hot air and the thermostat to stay open with the radiator fan on keeping the cooling as cold as possible. They simply reset the trouble codes and completed a drive cycle and had the car functioning as normal. It has been a week since and so far no issues."

 

[Hero6]

Leaving the battery disconnected for 24 hours did not clear the check engine light or codes. I am taking it to a mechanic today to attempt to clear the codes.

 

[Hero6]

Leaving the battery disconnected for 24 hours did not clear the check engine light or codes. I am taking it to a mechanic today to attempt to clear the codes.

In case anyone is interested, had a mechanic clear the codes using a snap-on solus scanner. I started the car and the temp gauge immediately started working again, the check engine light was off. I had to drive and shut it off several times around town and then the AC started working again. Fan performs as advertised as well. Appears limp mode was cleared and all good now.

 

[azgee13]

Resurrecting this thread...My 2011 4.6 overheated the other day. About 2 weeks ago the A/C quit working, checked Freon, all good. Then a few days later the wife was sitting in a drive thru and called me saying the car smelled hot and the check engine light was on. Had her shut it off and park it. It overheated, but the coolant gauge quit working. I let it set for a few, started it up and noticed the cooling fan was not coming on. Did a little research and replaced the temperature sending unit. The gauge still did not work. Tapped on the fan control module under the fuse box, disconnected the battery for 30 minutes or so. Tried it again and the fan comes on and runs all the time, even when cold. I tested the fan relay, it shows good. I replaced the cooling fan control module under the fuse box, still the same. No A/C, fan runs all the time, coolant full, temp gauge does not work. I tried to clear the codes P0116 (Engine Coolant Temperature Circuit Rang/Performance) with my scanner, but they wont go away.

I left the battery disconnected overnight and will connect it and try it again this evening. I read somewhere on here, that I may need to have a shop clear all the codes, even the ones I cannot see with my handheld scanner and that may fix it. I was hoping to clear all codes with battery disconnected 24 hours, but that may not work, but will find out this evening. Just looking for any input or ideas?

Note: I have plenty of heat, so thermostat is probably not part of the issue

Edit: I found the thread I referenced above concerning the clearing of codes, and pasted below so if anyone runs into the same issue, it all in one place.

"I ended up taking the car to a trusted mechanic. The connected their scanner and found additional codes that my handheld scanner didn't. The important code being oil temperature sensor. At some point (cause still unknown) the oil temp read too high and caused the car to go into limp mode. This cause the a/c to blow hot air and the thermostat to stay open with the radiator fan on keeping the cooling as cold as possible. They simply reset the trouble codes and completed a drive cycle and had the car functioning as normal. It has been a week since and so far no issues."

Have.

In case anyone is interested, had a mechanic clear the codes using a snap-on solus scanner. I started the car and the temp gauge immediately started working again, the check engine light was off. I had to drive and shut it off several times around town and then the AC started working again. Fan performs as advertised as well. Appears limp mode was cleared and all good now.

I have a 2012 4.6, living in AZ. The wife was driving home one day and called saying ac wasn't blowing cold at all. As she's pulling up I can smell freon and as she's parking, it starts coming out the overflow reservoir, temp gauge was at 3/4 BTW. Put my diagnostic on it, same code p0016 (also ECT Sensor) We take it to closest dealership with our warranty, they changed out the radiator cap and cleared the code. Drive it home (8 miles) and the car starts doing the same thing. Get it towed to our dealership they change out the ECT Sensor clear codes add freon and send us on the way.
Drive it away from the lot, same thing starts going on. Apparently shops don't do tests anymore to check their work. Anyways, they state it's a fan module, fix that, it melts from too much power. Ultimately after a month of tests, have a complete engine harness installed and fan controller. Battery dies the next day. Went to jump and was checking fuses etc to see if anything was blown. It appears quite a bit of fuses and relays aren't present per the fuse box guides on the lids.
1st question: Anyone have these diagrams/photos of their fuse compartments?
2nd question: Anyone had these issues before?

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[joegr]

Have.

I have a 2012 4.6, living in AZ. The wife was driving home one day and called saying ac wasn't blowing cold at all. As she's pulling up I can smell freon and as she's parking,...

No, you can't.
Freon is the brand name of R-12 refrigerant. Your 2012 likely uses R-134 (brand name Suva). Anyway, I've not heard of anyone being able to smell either when it leaks. Refrigerant is used in the air conditioning.
What you did smell was coolant. Coolant is half water and half anti-freeze. It is used to cool you engine.


From your owner's manual: