Note: map sensor has a liquid on it like water or oil , now it’s changed and I will give update later

brake booster has little of oil and water after changing the old master cylinder .

 

Hello @Owner bentley ,
First off, please update your profile to include your location, as vehicles differ from market to market, also as to your climate.

I just saw your question to Shavic, and it made me think, as I now see that I misread your comment above, you replaced the electric water pump, not the serpentine belt driven pump, so, have you confirmed that the electric pumps are functioning properly ?

As to the thermostat, being that you have a 2004, you have the thermostat housing with the electric heating element, have you checked the wiring and plug for this heating element ?

And again, being a 2004, you should have a 100°C, not a 106°C, not that it is a huge difference, but depending on your climate and the market the vehicle was built for, it may be an issue, the spare (used) electronic thermostat I have is a 100°C, just to note, the late 2007 and up (2008) got rid of the electric heating element fitted to the thermostat, it's the same housing, but the wiring port is plugged off, AND, the thermostat is now a 87°C unit, someone said that they had replaced the entire engine in a 2006 with a 2008 engine, but had to put a resistor in the original thermostat plug to end the fault from the missing heating element, but I have never seen it confirmed to be a non issue afterwards.

As to your comment of fuel lines at the rack area, there are none, unless you mean that you used rubber fuel hose in place of the plastic vacuum lines, if show, I hope that you used a good rigid wall hose, that will not collapse while vacuum is sucking on it, therefore closing it off...

Please update as to the oil and or water, if your master cylinder failed as mine did, then you would end up with brake fluid in the brake booster itself, and then sucked out of the booster into the vacuum circuit lines.

Johnny

 

thanks for your interest,

the water pump is working fine , I have changed the electric pumps , one at the front bumper left and the other is near the serpentine belt also electric but didn’t change the mechanic ones , the thermostat is 106 with the plug new , my climate is between 15/25c ,


and about the vacuum lines , yes dear the fuel lines fixed in place for the old vacuum lines and there is leak sound rear of the manifold up area , master cylinder now is fine , vacuum pump work when only pressing brake pedal , the booster are charging air when rpm is little high but when pressing again and again it returns hard

 

@Owner bentley ,
What part number thermostat did you install in the engine ?

The 2004 GT does not use the "106°C" thermostat, that is 223°F, the correct part number is 07D 121 111 AQ, and it is a 100°C /212°F thermostat, the 106 even with the electric heating element to open the thermostat faster before reaching that temperature, that 106 thermostat is too hot, the factory 100°C with it's electric heating element opens and operates at between 87 - 90°C / 188.6 - 194°F, your 106°C is likely running up and over the 90°C / 200°F mark on the temperature gauge, which begs the question, when you say that it is overheating, is it spitting out coolant, or is the gauge just riding high ?

There are only two thermostats available for the Bentley, the AQ at 100°C with the electric heating element, and the AR at 87°C without the electric heating element, the AQ is for the vehicle equipped with the electric heating element as factory fitted, normally 2003 to 2006.5 or 2007, the AR is for 2007 up.


Johnny

.

 

yes mr . Johnny

I it’s correct

im using Audi thermostat 106c

and also I have 87c

but the question is ..

can I replace the thermostat alone without the housing

because the 87c once it’s came without a sensor

.

 

the car temp is 90 but the coolant is cold and engine is hot also while driving the temp and the reader is going high and fans works at full speed when I stop for a moments it’s returns normal

 

Hello @Owner bentley ,
I don't know who told you, or I am not sure why you would think that you could use an Audi 106°C thermostat in your Bentley GT engine, you can not, just as you can not remove and put the 87°C thermostat in the 106°C housing, or even you 100°C original housing without some issues, or having to trick the heating element circuit by use of a resistor, if even possible, I heard something to that affect, but never any follow-up, or confirmation, EDIT=( ) (I just checked with Jason, a well known top Technician on this issue minutes ago to confirm my thoughts on this resistor claim from another, Jason has never done the resistor on the heating element wiring, as the ECU'S, the thermostat, and maps must all be matching to operate properly) you really need the 100°C thermostat with the electric heating element as original, as these thermostats are MAP thermostats, they follow a pre programmed map for certain engine loads, vehicle speeds, and temperatures, so I am confused as to why you would purchase the 106°C, or even the 87°C that doesn't even have the heating element, it is NOT a "sensor", it is a heating element that heats the wax inside the thermostat to open and close at predetermined times according to the maps..

If you install the 87°C thermostat onto the electric heating element and housing, and install it on the engine that requires the 100°C thermostat, you will most likely if not definitely end up with cooling system errors, as the 87°C thermostat will open too soon, as the heating element will come on thinking it is heating up a 100°C thermostat, when in fact you have an 87°C thermostat in there, therefore not allowing the engine to reach operating temperature, kind of like having a partially or fully stuck open thermostat, the ECU'S see that the engine hasn't reached operating temperature and therfore thinks there is a problem, and in turn, turns the radiator fans on full blast jet speed mode, I have this at the moment on my Audi A8L W12, it's fine in the spring and summer, but come cool fall nights and winter, the engine fails to get up to operating temperature at first startup, unless I let it idle in the driveway until operating temperature is reached, driving around town at low speeds, it is somewhat ok, driving at highway speeds it starts to cool, and has lack of heat, also the fans will the kick in because the engine coolant temperature has fallen below mapped temperature, and the coolant temperature gauge falls below C, as we C and H for cold and hot in the NA Audi's, where the Audi needle sits dead at the 12 O'clock position, which is 194°F / 90°C, where as the Bentley temperature gauge is say 40°F to 260°F, and it sits at 194- 195°F / 90°C, in the audi with this cooling fault, I have to clear the fault codes to get the fans to stop running in jet mode, otherwise, the engine would never heat up, in the winter that is.

Johnny

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mmmmm… that’s great discussion

so now I should buy a 3rd thermostat , 100c 🥲

No way to bring 100c alone to fix it at this 106c ?

I think that the old one was 105c Bentley gt not 100c so 105 and 106 are the same ,

what do you think Johny????

 

What about programming the fans and thermostat heat element to opens Early?

 

@Owner bentley ,
Sorry that you need to purchase a "3rd" thermostat, to be honest, you should have purchased the correct equipment to begin with, BUT, since you claim that you think the "old one was 105c Bentley GT, not 100c", I take it that you are saying that this was the original thermostat in your vehicle and it has the "105°" information stamped into the thermostat housing as all do, so, PLEASE post a picture of said old part.

I have had and still possess some some Bentley engines, I have a complete 2004, two complete 2005's, with one 05 completely parted out, the other, close to it, a complete 2007 partially parted out, a complete 2008 completely parted out, a complete 2014 sold whole, and the complete 2011 SS in my 05 GT, I use the word "complete" because I purchased all these engine complete, with all accessories included, including the original thermostats, the 2004 and 2005's all have/had 100°C electric heating element MAP thermostats, the 2007 up to the 2014 all had 87°C non electric heating element thermostats.

So that is seven engines, and not one had a 105°C thermostat, nor is there any listing for a 105°C thermostat for a Bentley, so please show us your original thermostat.

I have attached just a few of my thousands of pictures of my working on Bentley engines during and after my GT rebuild, I post them so that you may understand that I am not just pulling information out of the air, or guessing, my information is based on hands on work, and knowledge gained, I wouldn't waste our time with inaccurate information.

So, that is not to say, is it possible that someone stuck a 105°C in your Bentley, just as you just put a "106°C" in it, sure, BUT, that is why I asked you for some history on the vehicle, not the GCC info you responded with, some actual history as to the issues with the vehicle, like, how long have you had it, when did the issues arise, what led to the electric water pump and thermostat chang, same as to the transmission, why did you change the fluid and filter, was there a prior issue to the change ?

As far as your next question of changing the fans and electric heating element speeds and time of operation, that is a question for a tuner that would tune both ECU'S for that operation.

Just a thought.
Being that you have a 106°C housing, and the 87°C housing, along with your original most likely 100°C housing, is there a reason why you haven't swapped the 87°C thermostat itself on to the 106°C thermostat housing, does the 87°C thermostat itself have the hole in the center for the electric heating element to slide into, is the 106°C thermostat new, or a used part, have you verified that the electric heating element is in working order on this 106 and your original thermostat plug with an ohm tester, the thermostats do slide off of the thermostat housing, compress and turn, and slide straight up off of the element.

I can't recall at this very moment if the 87°C thermostat itself has the hole for the element, I can check later today, as I believe I have one sitting on the shelf up at the garage, if it does have the hole, then it would slide on and you would have a heated 87°C thermostat, will it cause issues as I described earlier, only you can tell us if you try is...

Johnny

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dear I give you wrong info , the old thermostat is 100c and the housing has written in it 105c

this is the info that I want to tell

and the reason for replacing the. Water pumps that I saw them is not working,

and about the gear oil I just randomly changed it

so now if I return the 87 that fans will work full power non stoping ,

so what I need now is programming the heat element and fan degree ,

mr Johnny the car history was every thing is bad

engine , fuel pumps , air shocks , radiator ac compressor, fuel injectors, booster, master, batteries, and more .

you are good searcher I hope that we together help each other and all w12 owners .

soory if I miss reply any question,

iam here at diagnostics about this issues .

 

Note: the car now drive and not shutting off while driving and brake is getting good when rpm is high

but still the rpm drops down when I try to slow down at road humps

the brake pedal move little back to me when I give more rpm while moving at my home garage .

but still now the gear at not shifting and the screen in the cluster shows all PRND at yellow color and I drives only 20-30 kph speed I think it’s stuck in 2nd or 1st ,

once I scan the car by vcds is garage he said that steering angle sensor shows faulty .

fans not working the coolant temp is 90 and when I shut off the engine it’s work for 5min.

 

That's exactly the symptom I had and discussed in post #13 above and in more detail in the link provided there. Check that the magnets are seated properly (flat!). Mine came with the round one inserted sideways. Also remember that when installing it, the side with the magnets should be facing UP.

 

Hello @Owner bentley ,
Sorry, but if I may ask you to restate what you said, for clarification.

I believe that are saying that the original (Old) thermostat and it's housing are the 100°C, and has "100°" stamped into the thermostat housing, and that one of the new thermostats is a 105°C, and the other new one is the 87°C, both with their tempetures stamped to match, NOT that you have a 100° stamped 105°.

Here is my suggestion if you want to test, I know it is a lot of work, but since you do not have a good 100°, and the 105° gets to hot at low speeds and idle as designed, and the 87° housing has no heating element, then swap the 87° thermostat onto the 105° housing and heating element.

The 87° has a stud shaft to mount into it's housing to take the place of the heating element, you can remove the 105° from it's housing and heating element, then remove the 87° from it's housing, then pull the stud shaft out of the 87° thermostat, then slide said 87° thermostat onto the heating element of the 105° housing, compress and turn the wings/blades into their mounting position.

This way, you will have the electric heating element plugged into the harness, so, no missing heater to cause issues and faults, which may cause fan performance issues.

Johnny
.

 

@Owner bentley ,
As Bruce stated, you have to check the magnets, in both the replacement piece, and your original, they may have become dislodged and are in the wrong position, as the PRND all lit up points to that.

Johnny J J