Hi guys been a long time, so i am now getting used to my "S" , sorted engine issues and running well. But i still have the fan running at high speed after short runs(short meaning 6or 7 miles or so) And i also have an issue when braking, the front bearings have been replaced, and the disc's and pads are all new, yet after a while when everything is all warmed up , i have noticed this awful rumbling/grinding noise which you can feel under foot on the brake pedal in a pulsating way, it happens when the fan runs at high speed. It seems to me something is getting too warm causing this to happen , can anybody on here point me in the right direction as to what this could be, it has been in the garage many times , it has passed it's MOT with flying colors, and the garage say they can not find anything wrong.......Please help!!

 

A few thoughts:

What was the recent engine work you mentioned? Just trying to get a feel if it was relevant to the current situation.

As far as I know, two things put the radiator fan into high mode.

One is an elevated engine temperature. On the early V6, this comes from the Cylinder Head Temperature sensor. The early V6 models don't have anything to directly measure coolant temperature, just the metal in the cylinder heat. What does your temperature gauge show when the fan kicks into high mode? It should not be above center.

The second thing is excessive pressure on the high side of the AC system. If the pressure climbs over a certain limit, the fan is commanded to run at max speed to cool the refrigerant and lower the pressure.

For some quick troubleshooting, how about switching off the AC? Press the AC button once on the control panel and the light should go off. Then try your typical drive and see if the fan kicks into high again. If not, then you know the command is coming from the AC system. In that case, the problem could be an actual overpressure situation, or a bad sensor.

Any chance the noise/grinding is coming from the radiator fan? See my experience here:


https://www.jaguarforums.com/forum/s...-gauge-159542/


In my situation, the fan motor stopped altogether, but I'd imagine it's possible for a motor to make a lot of noise on its deathbed.

 

If the radiator fan continues to run after the engine has been shut off, more than likely the thermostat is sticking and must be replaced.

 

Hi senior member, thank you for your reply. The work done was only changing 2 coil packs and a new thermostat, the grinding rubbing noise i can feel on the brake peddle when i apply the brakes, after running around for a few miles, stopping starting while doing shopping ect, the fan runs high even if i have the AC on or off. And the temperature gauge comes up to temp after 5 minutes and never moves above the center .

 

Hi thanks for your reply, the thermostat is new. coolant is topped up as normal, the temperature gauge comes up to temp after 5 minutes from the off, and never moves from center . And even if the AC is on or off the fan will run high after the said milage.

 

The temperature gauge is rather meaningless on the X200.

Did the radiator fan exhibit the same behaviour prior to the thermostat being replaced? Did the shop doing the work replace it with the correct thermostat?

 

Crackpot Theory Du Jour(tm):

How can the fan and brake pedal pulsation be connected? What if there’s some erroneous signal (still to be determined) commanding the fan to run at high speed? With the fan screaming away, if the charging system and/or battery is marginal, the overall system voltage will drop. This low voltage (or other unspecified electrical fault) induces a funk in the brake system’s anti-lock feature. The pulsation you feel at the pedal is the anti-lock kicking in. Is there a way to temporarily disable the anti-lock for troubleshooting?

How old is your battery? One function of the battery is to dampen pulses from the alternator, acting like a giant capacitor. As a battery ages, the capacitance capability decreases. Could be part of the equation, just thinking out loud.

 

The ABS was my thoughts as well.
If the discs and pads have been replaced already with new ones, then the pulsing through the brake pedal could be the abs trying to work itself abnormally.
You could try disconnecting the abs sensors at the wheels one at a time, or fronts first and then rears, and see what happens.
It'll throw a code for sure and a light on the dash for an abs fault because it won't read anything, but easily reset.
And it's not unknown to have a slightly warped disc from new.
I used to be an approved brake centre and have had warped discs from new before.
The sliders on the calipers could also cause the same if you have a sticky one.
As for the fan running high all the time, has the cooling system been bled properly? Have you forward and backward flushed the system to make sure there are no blockages in the radiator or heater matrix?
Change the temp switch in the head just for the hell of it, they're cheap and it could be a quick fix. If the fan still runs fast all the time, at least it's one thing that can be ruled out of the equation.

 

This thread may be of interest, specifically the link in post #5 explaining the deliberately misleading temperature gauge:

https://www.jaguarforums.com/forum/s...rature-186873/

Also note my experience with new parts being bad from stock, both the thermostat and the CHT sensor. There is absolutely no guarantee your new thermostat is accurate.

Re: NBCat's question, it's very important to know if the change in fan operation was a new symptom after the thermostat was replaced. Also, on a related note, why was the thermostat replaced in the first place?

 

To temporarily disable the system for troubleshooting, how about pulling a fuse instead? That would be a lot easier to do. Anybody have any thoughts on that?


Good idea, but one little hitch. This is an early V6 that uses a Cylinder Head Temperature sensor. From recent memory, this chunk of brass set me back about $80 or so. That's a little on the spendy side to replace on a whim, at least for me, especially when the first one was bad from stock and I had to get another.

I think a really good step here would be to hook up a scanner and see what the temperature reading is when the fan is commanded to high speed.

 

Thanks fro your reply,i understand what you are saying, how can the 2 be connected, but the 2 seem to happen at the same time, the car runs well , but after a while (say an hour or so running around) the fan starts to run high and then this is when the brake problem starts, the battery was replaced last year, the braking system has all been dismantled and inspected, and no faults have been found....it is becoming a nightmare.

 

Hi thanks for the reply ,
The thermostat was replaced to try to eliminate the aforementioned problem, like all things it is now becoming an elimination issue (a case of go through the list), it just seems strange that a the fan starts run high the braking problem starts....why are they connected ..? if they are, it seems to me that something is getting hot and effecting the brakes and running the fan on high..... i am at a lose.

 

Thanks fro your reply,i understand what you are saying, how can the 2 be connected, but the 2 seem to happen at the same time, the car runs well , but after a while (say an hour or so running around) the fan starts to run high and then this is when the brake problem starts, the battery was replaced last year, the braking system has all been dismantled and inspected, and no faults have been found....it is becoming a nightmare.

 

At least use OBD to look at some data. ECT especially but anything else you can grasp.

E.g. on a cold car you'd expect ECT and IAT to be about equal and when started IAT will rise a bit but ECT a lot.

ECT should max out in the range in the workshop manual (it'll be hot but not horrifically so).

Over 6-7 miles it's not going to get very hot or at least shouldn't especially at this time of year.

For the fans to run as they do probably ECT will not be as expected. Then you get to figure why / how to fix it but you need data first...

 

Hi , thanks for your imput, i have hooked up a scanner, and the radiator temp is at 105c when the fan is running high.? not sure if this is good or bad, and the only other thing the scanner shows is a code for D solenoid which i know about.

 

So watch it as it warms.

You'd for sure expect the fans on high if that's the true temp but is it? You're going to have to put in more time to figure it out.

 

On the scanner the coolant temp runs at 105c when the fan is running high.

 

See post #16 again.

 

If the correct thermostat was installed in the correct direction, the thermostat is faulty. The fan is running because the coolant temperature is at 105°C.

For the 3.0 litre engine, the thermostat begins to open at 88°C - 92°C and is fully open at 102°C.

 

Interesting thread. Something to keep in mind is we still don't know if the actual temperature is higher than normal, or just the indication.

Given the chance to spend your time and money, I'd suggest springing for a new thermostat. Remove the old one and test the two side by side with a thermometer in a pot of water on the stove. You may very well find the old one not opening properly. See the thread I linked in post #9 where I ran into a similar situation. The existing one had failed, and a replacement wasn't much better. It wasn't until I purchased a second replacement and tested all three side by side that I could see the problem.

But that wasn't the full extend of it, as I also had an indication problem. If the old and new thermostats open at the correct temperature, then next is to try a new CHT sensor. The part number is XR813484. Look at that same thread to see how I compared the sensors with an ohmmeter, side by side in a pot of hot water.

So I'd say you've got to do some homework to determine if you've got an actual overheat, an indication problem, or a combination of the two like I had.

Now none of that still explains the pulsing brake pedal when the fan kicks into high speed. Maybe give the wiring harness a good visual inspection for external damage. For all we know, if two wires are rubbing, the command to run the fan at high speed could also be inadvertently feeding into the ABS system. The fan controller is on the back side of the radiator shroud, down low on the US driver's side. Follow the harness from there over to the ABS pump module on the other side of the engine compartment. Maybe you'll get lucky and find something obvious.