Ambient temp and fan oddities

[drbr0b0tnik]

I read through quite a few threads but didn’t quite find anything similar.

A couple of days ago my wife was waiting to pick up our kids from school, and texted me that the AC suddenly started to feel more like room air (cool but not cold). We’ve been in a heat advisory for over a month, but we haven’t had any issues with the AC before this.

She snapped a picture of the climate controls and sent it to me and everything was in order, no accidental “wrong buttons” pushed. She eventually put up our sun shade because she was staring at the sun and said soon after it was normal and felt cool again.

When I got home that evening I went to do a once over and the first thing I noticed when I started the car was instead of the usual “roar” of the fan, it sounded weaker, with almost a low tone to it. I also noticed that it was still reading the ambient air temp in the interior as 109*, even though it was down to 98*, which I know is fairly normal, but it usually corrects pretty quick. Even when driving it it only dropped to 105*.

Got home and popped the hood, I noticed the coolant reservoir was almost empty, so I noted to add some coolant in the AM. The ambient air temp sensor looked in good order. I hit it with a little compressed air, no corrosion or anything. Went out and hour later and I noticed that the front of the car was hotter than before. I could barely touch the hood latch. No weird smells or anything.

Yesterday morning I added coolant as it was still way low, and changed the oil since it was due. No visible leaks of coolant, and no issues with the AC since. I’ll probably just take it in for the odd fan noise.

Just looking for any advice on what else to maybe look at. Thanks

 

[mr_dave]

I'm assuming the lack of "roar" you're referring to is the engine/radiator fan? If so, that would point to a faulty fan clutch, which might also explain the missing coolant.

If the fan isn't working properly in hot weather, the AC condenser won't be getting proper airflow and will not have good cooling - especially at low speeds. It could also lead to overheating, which could cause the coolant to overflow.

It would also cause the external temp sensor to read hot since the heat from the radiator is not being adequately removed.

 

[99WhiteC5Coupe]

I read through quite a few threads but didn’t quite find anything similar.

A couple of days ago my wife was waiting to pick up our kids from school, and texted me that the AC suddenly started to feel more like room air (cool but not cold). We’ve been in a heat advisory for over a month, but we haven’t had any issues with the AC before this.

She snapped a picture of the climate controls and sent it to me and everything was in order, no accidental “wrong buttons” pushed. She eventually put up our sun shade because she was staring at the sun and said soon after it was normal and felt cool again.

When I got home that evening I went to do a once over and the first thing I noticed when I started the car was instead of the usual “roar” of the fan, it sounded weaker, with almost a low tone to it. I also noticed that it was still reading the ambient air temp in the interior as 109*, even though it was down to 98*, which I know is fairly normal, but it usually corrects pretty quick. Even when driving it it only dropped to 105*.

Got home and popped the hood, I noticed the coolant reservoir was almost empty, so I noted to add some coolant in the AM. The ambient air temp sensor looked in good order. I hit it with a little compressed air, no corrosion or anything. Went out and hour later and I noticed that the front of the car was hotter than before. I could barely touch the hood latch. No weird smells or anything.

Yesterday morning I added coolant as it was still way low, and changed the oil since it was due. No visible leaks of coolant, and no issues with the AC since. I’ll probably just take it in for the odd fan noise.

Just looking for any advice on what else to maybe look at. Thanks

The ambient air temperature display will not always display the current ambient air temperature immediately upon engine startup. Read your vehicle owner’s manual, which will explain how the ambient air temperature display has various operating characteristics.

You have an engine coolant leak. Keep you coolant level full until you determine what is leaking. I’d bet the water pump is leaking, and one or more coolant hoses (such as to or from the degas bottle - also known as the coolant reservoir).

The water pump on my 2015 would only leak slowly when the engine was running and the vehicle was being driven. It took multiple visits to my Ford dealer to diagnose it. They insisted there were no leaks due to a quick pressure test. The coolant level would drop about 2 inches per week in the jug. From posts on this forum, it seems as though the pump begins to leak about 70, 000 miles.

The low engine coolant can cause the vehicle to run hotter, and to “trick” the car’s computer on the temperature - which operates the speed of the two radiator cooling fans.

 

[JasonH]

Sounds like you could have two issues going on, which may or may not be related. If you get an OBD Bluetooth adapter, you can monitor the coolant temps while driving using the torque app. My water pump was done at 146,000, but it probably began failing long before that. Also check the blower fan resistor, as they melt the connector and you get funny operation when it starts going.

 

[drbr0b0tnik]

Thanks for the replies all. Some stuff for me to further investigate. A few things about the truck since I left it out in the OP:
2015 Limited 2wd, 108,*** miles. Daily driver, short distances. LOTS of ideling.

I’ll check on it tonight when I get home, and I’ll be driving it over the next few days so keep a close eye on it. I’m still planning to take it in to get the fans/cooling and AC checked out. Depending on what it is I may just to the repairs by myself. Water pump or radiator fan look pretty easy.

 

[JasonH]

You can put dye in the coolant to help spot leaks. My waterpump also made a rattling noise when it began to fail. It sounded as though it was coming from the cylinder head. Changing the pump isn't difficult but it's messy (coolant spillage) and you have to disassemble a lot of charge air plumbing, so plan on five to seven hours.

 

[drbr0b0tnik]

Update: I’m going to be at the helm of the Expy for the next 4 days. This morning I snapped a reference pic of my cold coolant level, then drove the kids to school. I noted that at best, the ambient temp was reading 7* higher than the actual temp, and at worst got to a 10* difference. I understand some variance, but this is not only unacceptable, it’s never happened in 3 years of ownership.

When I got home, I popped the hood to take a reference pic of operating temp coolant level. Vehicle operated normally, engine temps normal, AC normal.

Fan still sounding unhealthy. I climbed up to try and get a good look while it was spinning and noticed the passenger side fan of the assembly wasn’t spinning. At this point I’m leaning heavily toward replacing it. With both the condenser and ambient air temp sensor being on that side, compounded with odd fan noise, I’m guessing it may be my issue. For $200, I’ll take the shot.

 

[99WhiteC5Coupe]

Update: I’m going to be at the helm of the Expy for the next 4 days. This morning I snapped a reference pic of my cold coolant level, then drove the kids to school. I noted that at best, the ambient temp was reading 7* higher than the actual temp, and at worst got to a 10* difference. I understand some variance, but this is not only unacceptable, it’s never happened in 3 years of ownership.

When I got home, I popped the hood to take a reference pic of operating temp coolant level. Vehicle operated normally, engine temps normal, AC normal.

Fan still sounding unhealthy. I climbed up to try and get a good look while it was spinning and noticed the passenger side fan of the assembly wasn’t spinning. At this point I’m leaning heavily toward replacing it. With both the condenser and ambient air temp sensor being on that side, compounded with odd fan noise, I’m guessing it may be my issue. For $200, I’ll take the shot.

I have a 2015 Expeditor Limited 4x4, purchased new, with the factory HD towing / cooling package.

I live in the Midwest, and ambient temperature can reach the mid 90’s in the summer.

Since new, at times in the hot summer, often when stopped or in stop and go traffic, the auxiliary radiator cooling fan will turn on to a much higher speed. The noise is tremendous, and sounds like there is a problem (no mention in the owner’s manual of the noise).

I’ve had people tell me something is wrong while I’m gassing the vehicle, with the engine still running in the summer (a/c on with passengers).

The dealer checked the vehicle when new during the first year of summer, and said it was due to the HD cooling fan operation - which can speed up or slow down depending on the engine and ambient temperature.

If your radiator fans are not roaring at idle during hot weather, you must have a defective fan(s).


PS - Unrelated, but you are aware of the safety recall for the front HVAC blower fan? Ford has recently notified their dealers the part is now available.

 

[drbr0b0tnik]

I have a 2015 Expeditor Limited 4x4, purchased new, with the factory HD towing / cooling package.

I live in the Midwest, and ambient temperature can reach the mid 90’s in the summer.

Since new, at times in the hot summer, often when stopped or in stop and go traffic, the auxiliary radiator cooling fan will turn on to a much higher speed. The noise is tremendous, and sounds like there is a problem (no mention in the owner’s manual of the noise).

I’ve had people tell me something is wrong while I’m gassing the vehicle, with the engine still running in the summer (a/c on with passengers).

The dealer checked the vehicle when new during the first year of summer, and said it was due to the HD cooling fan operation - which can speed up or slow down depending on the engine and ambient temperature.

If your radiator fans are not roaring at idle during hot weather, you must have a defective fan(s).


PS - Unrelated, but you are aware of the safety recall for the front HVAC blower fan? Ford has recently notified their dealers the part is now available.

I also have the HD towing package. The fans have always had the roar to them since I purchased used in 2020 with 70k miles. A quick search at the time seem to indicate that it was normal. So now that its making a audibly different sound and not as loud, I've been suspicious since this started. I live in Tucson, and its usually hot anyways in the summer (honestly like 9 months out of the year). But this heat advisory has been nuts. We've had at least 37 days straight of 100*+ temps. Highest has been 111* I think. I also had noted above that I idle a lot in the Expy, which means more fan time with my AC on. I'll be ordering an OEM fan assembly from Rockauto today and hopefully get in put in over the next week or so.

As for the recall, yeah I got the letter. Given these issues I've had over the last few days, I'll take it in for that as well as having the cooling system and AC system looked over.