Running Temperatuire -- what's the verdict?

[alg]

I have just changed the thermostat...........2 divisions below 90oC on run (70oC) 90oC in traffic before and the same after

[Keeper of The Kitten]

Coolant exit temp will still fluctuate as a result of variation in the inlet temp - you have to consider the cooling to be a certain amount of temperature drop, not an absolute cooling temperature - but no way will that cause a drop in exit temp to 50°C

More likely to be a sensor problem and definitely not wind chill on the sensor. I can't believe the thinking people of this forum are suggesting that.

__MDC__

[CP951]

My cooling fan stopped working last week and the car was overheating. The fault was with the multifunction sensor. Thinking back my temp readings were similarly running very low on the run and goes to 1-2 markings above 90 in traffic. The temp readings have been more stable around 1 marking below 90 on the run and 1 marking above 90 in traffic. But then the weather has warmed up slightly since i've changed the switch so i have to wait and see. The chip within the switch must have been malfunctioning and going out of calibration. I've heard that this sensor does fail after as little as 2 years. Also wouldnt it be more common for the thermostat to get stuck closed rather than open when it fails?

[mcandmar]

I only got this problem AFTER fitting a new MFTS. Original was a four pin, new one was a three pin so i just put it down to the new sensors being a little different. Changed the thermostat twice since then and the temps allways read the same, only 90 when sitting still.

[CP951]

I only got this problem AFTER fitting a new MFTS. Original was a four pin, new one was a three pin so i just put it down to the new sensors being a little different. Changed the thermostat twice since then and the temps allways read the same, only 90 when sitting still.

Thats really unlucky. Maybe the sensor is so poorly designed even your new one is faulty?

[Sweeper]

I have than modern VW VR6 low temp thermostat , in the summer it worked great , but on this winter it constantly sit at 50-60C , whatever you do =]. And car run like ****. =]

[Keeper of The Kitten]

Thermostats can definitely stick open, but I don't know if stuck closed is more common.

Closed is the normal position of course but maybe it is "forced open" when heated and "springs" to the closed position - hence bimetal spring failure causes it to stay open?

__MDC__

[martinjs]

Mine used to sit at 70deg in traffic and drop slightly when cruising (with new thermostat fitted) , i thought this was a bit cool, anyway i changed water manifolds (modded one for fitment of AAN inlet manifold) i didnt swap MTFS sensors over. Since then it always sits at 90 deg. I put it down to a faulty MTFS.

[coupegt]

regarding change of the MFTS...

i just bought a new one, as i supsect the old of being faulty, but how do you change it.

Been messing a little, but cant even get room enough to get the electrical connector off, simply not enough room for my big hands.

Do you take more things apart for changing the MFTS, or is just me?

[Jas11n]

Thermostats can definitely stick open,
__MDC__

Oh yes

[CP951]

My plastic connector to the sensor was broken into bits, so I had to mark the wiring position first prior to pulling the plug off. Room is tight and I had to reposition the power steering hydraulic hoses out of the way out of their bracket (easier to use a flat blade screwdriver to lever them out, you'll never get them out by pulling onto the hoses). I had previously removed the plastic shielding to the right of the radiator, so I had a little more room. Use the open end os a 29mm (30mm might just do as well) spanner and slowly remove the sensor. You won't have enough room to use a deep 29mm socket even if you have one that deep. The torque setting should be 25Nm. I did that by guessing as I don't have a crowfoot that size. I also rewired the short part of the wiring loom as the connectors are all corroded and useless. I wouldn't bother refiitting the rubber boot onto the sensor. Its pretty useless and youll never tell whether theres a leak or not.

[Bowlerwell]

I usually warm up to 90 Degrees. Is that a problem?

[S2central.net]

90 is good

[Paulgo]

Be interesting to get to the bottom of this!

Both my old 80's would sit happliy at 90 when warmed up. The cq20v when I first got it was also like this until I bypassed the aux rad! Since then it only gets to the 90 mark in traffic, before the fan cuts in. Normal driving its on the mark below and on long runs and in the cold weather can drop below this even. Car poss is a little slow to warm up, and is about 5 mins for the heater to really have some heat, tho I can feel something a lot sooner than this.

I do remember the 2.3e was always like this despite its previous owner (Jas11n) changing various sensors to no avail (keep me right on this Jas! )

I just live with it and it doesnt seem to cause too many problems - tho petrol could well be better and I'd prefer the car to behave as it should if there's a fix that works (other than replacing the aux rad as I should )! Just always wondered what causes it - its usually just put down to some common quirk

cheers

Paul

[AAH!]

Changed my thermostat at the garage meet with the following results.

Before: approx 65º (3.75 notches below 90º) at speed - 90º in town
After: approx 78º (1.75 notches below 90º) at speed - 90º in town

Temperatures based on 6 notches between 50º and 90º @ 6.66º per notch.

So an improvement.