So I've read numerous threads where the thermostat may be going bad or be bad if the gauge is not reaching the proper temperature. Thing is, the threads I read, have a very obvious discrepancy between full temperature or not. In my situation, with the last few drives being on the cooler side outdoors (45-50 degrees) the temperature gauge only gets to about 4/10's of the way up, or has the needle at 1/2 way at points during a longer drive, and then dropping down just slightly to say 4/10 and staying there for the rest of the ride, or bouncing back up to 1/2. The situation is not quite as obvious as other threads where owners say their gauge doesn't go above 1/4 or 1/3.

So pretty much I'm Looking for some insight... I know this is a part that is known to go bad... just not sure if mine is ok...or at the replace ASAP stage. Any advice would be great. Also, curious if anyone knows the typical dealer labor cost to replace this. Tomorrow's going to be 60 so I'll be driving it again on some short trips, and will report if I notice anything more obvious.

 

If it fails 2 drive cycles in a row, you will get the CEL on. If your not seeing it in the middle on the gauge after a 15min drive then it's time for a change. Which you should do a coolant drain/fill along with the thermostat replacement. Most likely a few hours labor and parts. It's not good for the engine running excessive high fuel mixture so I would just get it changed soon.

 

Thanks for the quick response, and sorry if this sounds silly... but are you saying that if I'm not getting a CEL or if it's not doing it consecutively then things are "normal"? For example when I drove last on a 45 min drive to and from where I needed... going I had the temp gauge just slightly under 1/2 way... like 4/10's... but on the return drive it was mostly at 1/2 with moments where it would drop under for about 5 or so minutes before returning to dead center. Outside temps were around 45. No CEL.

I don't mind getting it changed if needed... but obviously don't want to spend money to do something that isn't necessarily needed either.

 

It doesn't sound normal as you describe and you have noticed its low reading. You can wait until it does turn on the light, that's the design of the system operation. I would definitely look into changing it soon. Cold engine and running rich isn't nice for your engine. Do a search and you'll find an alternate Ford or Jaguar part and install instructions.

 

+1

typically the temperature will go to the "normal" level when standing and idling / slow city driving and then drop when doing a low power overland cruise.
The usual damage is that the thermostat does not fully close (as it's rubber seal disintegrates), thus the engine gets more cold water from the radiator as it should.

 

yes you absolutely need a new thermostat

mine did exactly the same thing... when driving fast on a cool day it would stay around 3-4/10th's but when idling or longer drives on a hot day it would actually go up to 1/2

it would also take forever for the engine to warm up

never had a CEL

I used the aston dealer to install this motorcraft RT1163 https://amzn.to/33lrZ1K

some people have reported issues with it, but they had none

 

Thanks guys! Will probably reach out to Aston to try and schedule something in the near future! Appreciate all the insight

 

Your thermostat is starting to go. I just had the same symptoms on my 09 in the summer. I went with the Ford thermostat and it works perfectly fine and substantially cheaper. I am also hoping it will last longer. Only thing is the Ford part have an extra 1/2 coil in the spring so you will need tools to get the thermostat in.

 

Spoke to Aston Martin by me today and seems like everyone's in agreement. I'll be bringing them the Jaguar thermostat from redpants, which they said they'll have no issue installing. They said 2hrs labor. I know I could go cheaper with the ford option but didn't want to risk them turning around and saying it's not a 100% direct replacement.

 

Nothing wrong with that, your getting it fixed and you have been involved with the process of diagnosing an issue with your car. Happy days ahead.

 

I just replaced mine yesterday in my 09 V8V using the Jaguar part from Redpants and Rich's video. It was super easy and took me about 90 minutes, even though this was the first time I've worked on this car (only had it about a month). The new part works perfectly, and the needle now holds dead level even in 35-degree weather, so you'll have nothing to worry about.

 

I'd love to do this myself too, but currently don't have access to many of my tools, nor the room to get the car up with jacks at the moment. Everything above engine seems simple enough... but how important is removing the undertray. Does a significant amount of coolant drop out that towels alone won't do much good? Curious to hear another's perspective, especially since it was the first time working on the car, as it would be for me from the engine perspective (all I changed so far were some struts lol).

 

I didn't remove the undertray or jack up the car. Yes, you'll get about 3/4 of a gallon of fluid out.
Here's how I did it: I removed the PCV and AOS, moved the air lines and wiring harness out of the way. Then I carefully maneuvered a trash bag over the serpentine belt and pulleys so no coolant would get on it, and stuffed a large bath towel down into the area underneath the housing. I took an old washer fluid bottle and cut the bottom off, then stuffed it under the housing, as well. I removed the bottom bolt and the top forward bolt. I then loosened the top rearward bolt just enough to pop the housing loose so that fluid started leaking out into my makeshift catch cup. When the catch cup was nearly full I tightened the bolt, removed the cup, and poured the fluid into an old empty coolant bottle (do NOT use a milk jug or washer fluid bottle for the coolant; not all plastic is the same, and the coolant will degrade them and leak through). I had to do this a few times until there was no more coolant left to leak out the housing. Ended up with about 3/4 gallon. After that, I replaced the thermostat, reinstalled the housing, torqued the studs to the values in the service manual, put everything else back together and removed the towel and trash bag. Vóila... mess-free job.

 

100% doing this myself. Thanks so much for taking the time to write up everything!

 

My pleasure.

Make sure you watch Redpants' video on it before you start, have some oil dry (kitty litter) available just in case, and dispose of the fluids properly, including the coolant-soaked towel.

If you don't already have one, you'll need a 13mm crow's foot to torque the top rearward stud; there's no way to get a socket on that one. Everything else is just regular metric hand tools (socket wrench, open-end wrenches, torque wrench, etc.).

After replacing it, you'll need to top off the coolant. Be sure to use OAT coolant. I used Peak brand 50/50 pre-diluted pink silicate-free OAT formula from Advance (and I plan to have a full flush and refill done when I have it in for a clutch replacement in a couple weeks). After topping off, start the engine and let it run until it's warm, so that the thermostat opens and cycles fluid through the whole system. When it does it will give you a low-coolant warning, at which point you'll need to top off again.