Cold Weather 1.8t Questions? comments? discussions?

**Vreihenmotor6** · 01-09-2009 12:24 PM

okay, so this is my second winter with the A4 and my first with it running full boost, and with most stuff fixed

I had some questions about coolant temps and plug choices

I currently run NGK BKR7E plugs gapped to .28 and change them every other oil change, I know this is one heat range colder than stock, my question is what is the stock heat range, and should I think of running that stock heat range in the winter time?

right now my idle is a bit rough, I'm not sure if its the age of the plugs, or the heat range cause its now colder out

speaking of heat, my car is running coolant temps of about 166 (measured via scan tool) , which is down from 188 that it normally sees in warmer weather. I know we have a mechanical fan that isn't gonna help with that any (electric fan conversion is on the to do list) I'm pretty sure the thermostat is good as the car has plenty of heat and warms up great, the temp gauge only goes up about a bit past 1/3 lately

I do run a 90% grill block all year round (save for cutouts for the intake and horns) for aerodynamics and I've never seen a measurable increase in intake air temps or coolant temps, and in this case I can't imagine it would hurt any

my mileage isn't much changed and the boost is right about where it should be so the cur is running pretty decent

are other people noticing lower coolant temps this time of year too, or is it just me, and should I go get another set of BKR7Es, or go for the normal heat range for this time of year?

**pac1085** · 01-09-2009 01:00 PM

Your coolant temp should hover around 190, it should never drop once it heats up. If it does you have one of the following: bad coolant temp sensor, bad or wrong temp thermostat or air in the cooling system.

**Vreihenmotor6** · 01-09-2009 01:17 PM

I won't rule out air in the system, but how would a coolant temp sensor affect coolant temp?

the main fan is clutch driven, and the aux fan isn't running excessively that I know of, how can the ecu affect coolant temp if it thinks its the wrong temp?

the thermostat is mechanical and it does heat up decently quick so I figure it can't be that

**pac1085** · 01-09-2009 01:26 PM

Well, your coolant temps may be fine, but you said you're reading them thru the scan tool, which goes off of your coolant temp sensor, which is a common failure on our cars.

In other words - it may be at the proper temp, but since the temp sensor is broken, it's giving you false readings.

Your symptoms are exactly that of a bad coolant temp sensor...

bad coolant temp sensor gives you false readings on the gauge and thru the scan tool, along with providing bad readings to your ECU which messes up your fuel mixture and can cause the rough idle, etc that you're talking about.

**Vreihenmotor6** · 01-09-2009 01:29 PM

now thats a pretty smart answer, okay, I'll have to put that on the to do list, thanks a bunch, I wonder how accurate an infrared reading of the coolant bubble would be to gauge the inaccuracy of the coolant temp gauge

**pac1085** · 01-09-2009 01:45 PM

Just replace it, it's a $20 part at most, easy to replace, and is a common failure on both the 1.8t and the 2.8 v6.

I recommend spending a few bucks more and buying an VW/Audi branded OEM one over something like Meyle or another aftermarket brand too.