Plugged Valve Cover Drain Hole caused Cylinder Head Temp sensor to report overheating

[vanwerk]

Hi everyone, it's my first post here! Just had a weird snafu earlier this week and thought I'd share with you all. I have a 2015 TC XLT LWB, for reference.

 

I was leaving the grocery store the other day when my little driver's LCD reported, "High Engine Temperature, Stop Safely". The temperature meter in the dashboard was pegged on "H", and it felt like the car was shaking when I was stopped. Seemed really weird to me as I had driven about 360+ miles the weekend before with no issues, and even drove *to* the grocery store without any issues.

 

Anyway, I decided I didn't want to risk overheating the engine. I parked the van and popped the hood. After ferocious googling on my phone, I checked the coolant: full. Nothing leaking out of the bottom of the car. In fact, nothing looked out of the ordinary under the hood, although admittedly I'm a total car noob. I felt heat from the engine, but without an infrared thermometer, I had no way of knowing how hot it was. I decided to hedge my bets by getting a tow to my local Ford dealer. My logic was that if anyone should know how to deal with this, it would be them, despite holding a bias that I might end up paying more.

 

Well, they got back to me shortly despite a potential 2.5 week wait time due to COVID, and the problem was resolved. The "Valve Cover Drain Hole" basically got clogged with dirt and debris, causing water to spill over into the cylinder head temperature (CHT) sensor connector, presumably shorting the connectors and causing it to think it was maxed out in temperature, throwing codes as a result. It ended up costing about $250 to clean some junk out. Granted, in this scenario, it really made the most sense to just have someone look at it and fix it.

 

This experience really made me want to learn more about how to diagnose my own car problems. Hopefully I don't have this weird issue again, but if I do, I sure would like to be equipped to handle it on my own. My questions:

 

1. What/where is the valve cover drain hole?

2. Where is the CHT sensor? Where is its connector?

3. How would you have diagnosed this problem? I don't have an OBDII scanner, mind you, but I think the codes pasted below were very telling. Reading online about CHT sensors, how they work, and with reasonable electronic troubleshooting skills, I feel like I could have figured this out given enough time.

4. Is it worth investing in the service manual? I feel like this would clarify a lot of my questions re: part locations.

5. Any other recommendations for avoiding this issue in the future? Like I said, I don't even know where this drain hole is, or how it got clogged with dirt/debris.

 

For fun, here are the notes I got from the shop, including codes. I added my own comments/questions in parentheses:

P0217 - Engine Overheat Condition
P1285 - Cylinder head over temp sensed
P1299 - Cylinder Head Temperature Sensor Detected Engine Overheating Condition

Cooling system full
Set up test system for CHT (cylinder head temperature) sensor.
    - Reads 250 when cold.
    - Reads HOT when CHT sensor connector is jumped (shorted?)
    - Reads COLD when CHT sensor is disconnected (open circuit?)
Checked resistance of CHT sensor - read normal for cold engine temp.
Cleared CHT sensor connector of water.
Cleared Valve Cover Drain Hole of dirt/debris.
Cleared water with compressed air.

 

Edited September 21, 2020 by vanwerk

[G B L]

On 9/21/2020 at 12:43 AM, vanwerk said:

. Is it worth investing in the service manual? I feel like this would clarify a lot of my questions re: part locations.

Yes and get a 100.00 Scan tool, it will pay for it self the next Time.

[Fifty150]

On 9/20/2020 at 9:43 PM, vanwerk said:

Is it worth investing in the service manual?

 

On 9/20/2020 at 9:43 PM, vanwerk said:

Any other recommendations

 

Buy some tools. You're not fixing the car with just a scan tool and smart phone.

 

 

[vanwerk]

On 9/26/2020 at 2:51 AM, Fifty150 said:

 

 

Buy some tools. You're not fixing the car with just a scan tool and smart phone.

 

 

 

Of course. Care to be more specific? I have a socket set, various hand tools, multimeter, etc etc. But it seems like if I were to encounter this problem again, even if I had the right tools, I'd be in the dark without a code reader and service manual.

[Willygee]

Good post VanWerk..i'm curious where the drain hole is. I have a 2016 TC w/38k...engine dry,clean..looks new.