some help please,my temp gauge does not stay at 1/4 always at 1/2 and 3/4 on the gauge .it does this in stop and go traffic ,on the high way it seems to be okay a little above 1/4 .i just replaced the thermastat with oem 1 and still does the same.ther car runs fine and no smoke ,i have coolant in there and it does not boil over.1 pic i posted has a sensor it looks like it has a small crack but it is not leaking could this be the problem .and is there anyway i can tell if my fan is operating properly.oh bye the way in the pic it is not leaking from the cap ,i over filled and it dripped down, the cap is new .

Are the belly pan and relay cover plastics in place? Are you using the stock fan shroud?

Options:





Clogged Rad or Rad Fins

Worn Thermoclutch Fan

Non-OEM Thermostat (use ONLY dealership thermostats)

isnt there 3 different types of t-stats? Like winter, summer, and year roud, which ones do you use?Cause I bought a summer one, and all it didnt help my car.

If your gauge isn't hitting red and the overflow isn't boiling; you have no problem

No but if he uses a NON OEM thermostat he will have overheat problems regardless





It's been tested that auto part store replacement thermostats don't function the same as OEM thermostats



ALWAYS goto the dealer for your thermostat, I don't care who you are.



Try it and come back

Here's the deal:

A few years ago I had a bad fan clutch, so I did some exploratory surgery on it:

The fan clutch uses a silicon oil viscous fluid in two chambers inside.

A Bi-metal strip on the front bends outward as it warms and opens the valve from the reservoir side to the clutch side.

Centripetal force provides the pumping action to move the fluid.

When it sits for a few hours, it will spin the fan briefly on startup, then freewheel.

After 100,000 miles the bearing seals inside wear, and the bearing lube starts to weaken the clutch fluid's grip.

Both the S4 & S5 clutch freewheel when cold.

The s4 clutch increases it's bite gradually with temperature rise.

The s5 clutch is more on-off. (It just coasts until is gets warm)

Once they are warm, the fan speed goes up with engine speed to about 4000 RPM.

As the engine revs higher the fan stays at ~4K.



If your warmed up fan only revs up to < 2500 RPM, it's worn out.