Was just driving my 2007 XK and got a message that said engine temp high then a couple of seconds later Engine overheating. I turned on the heat and a couple of seconds later the message turned off. Immediately parked and turned the car off and checked the codes no codes but both fans are running hard and the car did feel kinda sluggish when I was trying to park. There is no leaks and no smells and the expansion tank looks ok

 

It sounds like a thermostat failure. Most owners replace the entire thermostat and housing since parts of it break internally causing by-pass of the t-stat and plastic to make it's way into the water pump. If pieces make there way into the pump you'll have to fish all of them out. The coolant termperature sensor is also part of that as a unit as well. It is not an extremely difficult job to undertake DIY but a bit of a PIA to get to.
Research t-stat threads herer and you'll find lots of info on it, some quite detailed. I replaced mine my 07's with an aftermarket unit that was $$ cheaper than from a dealer.

 

+1 on the thermostat. What is your mileage and what were the weather and driving conditions? Stop-and-go traffic and 90+ degrees? Of course, your expansion tank will be full when the engine is hot because the coolant is hot and expands and flows into that tank. After the car has cooled down, open the radiator cap and check the level and condition of the coolant. When was the last time you flushed and refilled the radiator with fresh coolant? If it's been more than 4 years, you're overdue.

 

This raises a question that I had looked for and not found in the maint. manual. At what water temp does either of these warnings come on. I would believe there is some range span between the 1st warning and the last warning. I would assume you shut down after the 1st warning and check the system.

 

It's been mentioned before on here, pretty high like 218 or so.

It's kind of a mixed blessing to have warmish air out the heater after 45 seconds of run time. You know the coolant flow is very restricted when the T stat is closed.

 

So far I have found maybe 3 different ratings on the opening and fully open of the thermostat. The range for start to open has been 190*F to fully open at 216*F so I would suspect that with the pressure cap and 50/50 AF the 1st over temp sensor would be like 225*F-230*F with the red zone being around 240*F. Just my guess . The southern/western guys must see normal temps of around 210*-215*F during their 100*F days so 216*F seems a little low.

 

Depending on traffic, not uncommon for me to see 210+ on 100* days...

 

I have my Torque App set to flash RED on the temp gauge on my touch screen at 220 F. It hasn't happened yet, although I DID set it to 190 once just to see it work. Can't miss it when it goes off! Also have the voltage gauge set to flash below 12.5VDC.
Hopefully I'll never see either happen, but it's set up just in case.

 

Hi everyone, I saw this post, and now I too am having an overheat issue. I drive my 2002 S-type 4.0 to and from work 2.6 miles. The temp pegged out after about 1.5 miles so I thought I'd pull into this mech shop nearby but then after about 2 minutes, it dropped back down to the middle and no issues the rest of the way. This has happened 3 times so far and the same thing, 2 minutes after pegging out, back down it goes and no problems. This just started happening since last week and happening daily. I'm thinking this too, may be a thermostat issue. The car has all of 38,000 miles on it. I live near Chicago and so far, the weather I've been driving in has been great, not too hot, and certainly not cold. I want to get this taken care of before the cold sets in.
Thanks for any help and direction.
Boston

 

I would move from Chicago to Boston.

 

Naw, I couldn't ever get that accent correct. It's worse than Chicago's !! Anyway, I'm changing it out tomorrow and i'll let you know how it turns out.
Thanks.
Ps. you didn't ask why the name Boston when I'm from Chicago.

 

I figured that you were from Boston. I don't understand why anyone would trade Boston pizza and lobster rolls for Chicago deep dish and drivebys thanks to Lawless Lori Lightfoot and Kim Foxx, the Sisters of Anarchy!