PDA

View Full Version : Coolant temp gauge not working.



generik777
08-18-2007, 08:37 PM
I don't how long it has been like this but I just noticed it tonight. I just got home from a friends house about an hour drive away, and I just happened to glance at the coolant temp gauge and noticed that it was all the way to cold. What do I need to fix this and where can I get it. Thanx for the help.

Here is what it looks like with the ignition off
http://i2.photobucket.com/albums/y43/jramirez777/070818_220903.jpg

And here is what it looks like with the ignition on after an hour drive at hwy speeds, It barely goes up
http://i2.photobucket.com/albums/y43/jramirez777/070818_220928.jpg

Audi91a4
08-18-2007, 09:06 PM
IIRC, you need a new thermostat.

generik777
08-18-2007, 09:09 PM
Is that a pretty easy DIY?

mike-2ptzero
08-18-2007, 09:09 PM
If your oil temps also looked very low then you need a new thermostat.

Audi91a4
08-18-2007, 09:10 PM
Im not to sure about the install but the good thing is they arnt that much for a new one

generik777
08-18-2007, 09:17 PM
If your oil temps also looked very low then you need a new thermostat.

Yeah, It was noticeably lower than normal, probably about 1/8 of the way up. What would it be on a scale of 1-10 to replace this myself? Also this is the part (http://www.autopartswarehouse.com/products/products.php?year=1998&make_text=audi&model_text=a4_quattro&category=cooling_system&subcategory=thermostat) I would need, Correct?

kobefans
08-18-2007, 10:40 PM
i have the same thing happen to me, as well as the gauge on the lower left.. i thing the oil temp guage.. how can i fix it ?

and how much would it cost?

akielb
08-18-2007, 10:50 PM
jack up the front - its located towards the front of the engine on the drivers side. just behind the water pump. there is a tube/housing(back in the lower right of the picture) that is connected to where the green circles are - drain the coolant from the radiator, take off the black housing the thermostat is located in there make sure you remember how it was orientated when you removed the old one
http://www.audiworld.com/tech/pics/eng35-wp4.jpg
this pic is from below the engine of course

generik777
08-19-2007, 07:33 PM
So I'm gonna order the one at the top of this page (LINK) (http://www.autopartswarehouse.com/products/products.php?year=1998&make_text=audi&model_text=a4_quattro&category=cooling_system&subcategory=thermostat) Anyone know of a DIY write-up anywhere For installing this on a 2.8? Also, It will be ok to drive the car with a bad thermostat until I get this installed right. Thanx again.

Mike@PureMS
08-19-2007, 08:51 PM
There's a chance it's simply your coolant temp sensor. This is the sensor that sends the temp to the instrument cluster.

It's located on the back of the head, up against the firewall.

Check our website for replacements.

GR-RALLYE
08-19-2007, 08:57 PM
There's a chance it's simply your coolant temp sensor. This is the sensor that sends the temp to the instrument cluster.

It's located on the back of the head, up against the firewall.

Check our website for replacements.

Yep thats most likely what it is. only takes about 5 minutes to do. I highly doubt its the thermostat.. even if your thermostat was stuck open the coolant gauge would be higher than that

pinky
08-19-2007, 10:34 PM
to determine my temp sensor was bad, i used the a/c (could also use the vag com) to look at what reading the ecu is seeing from the sensor.

there are 4 pins, two for the gauge, two for the ecu (essentially two 2-pin gauges in one unit)

my gauge red zero, the engine saw regular temps... so i replaced the sensor and everything was fine.

matt_mcmhn
08-20-2007, 04:13 AM
I noticed someone mention that if it's the thermostat, the oil temps will be low as well, but what exactly should the oil temp be? I mean like a cruising kind of temperature, like what the engine temp gauge would normally read after it was warmed up.

mike-2ptzero
08-20-2007, 07:56 AM
I noticed someone mention that if it's the thermostat, the oil temps will be low as well, but what exactly should the oil temp be? I mean like a cruising kind of temperature, like what the engine temp gauge would normally read after it was warmed up.

It will cause the oil temp gauge to only move while the car is sitting still but stay at the lowest reading while the car is moving.

generik777
08-20-2007, 01:55 PM
It will cause the oil temp gauge to only move while the car is sitting still but stay at the lowest reading while the car is moving.

I guess I'll try the temp sensor first then. Cause my oil temp gauge doesn't do that. If that don't work then I'll move on to the thermostat. I also noticed today on the way home from work that the coolant temp gauge was not all the way down anymore, It got to the point were it was almost 1/2 the way up and then started slowly dropping back down. It went down to about 1/8 of the way up and then I was home so I just shut her off. Would those symptoms also suggest temp sensor rather than thermostat?

tomustang
08-20-2007, 07:33 PM
temp sensor... it can be had for like $20, easy fix, think it needs no tools, it's black, most common problem

pinky
08-20-2007, 09:28 PM
http://www.audiworld.com/tech/int6.shtml
thats how you use the a/c to check the ecu reading

and i think my temp sensor was blue.. if you have the black one, you should replace it with the green one (http://forums.vwvortex.com/zerothread?id=3322530)

SouRce4
08-20-2007, 09:49 PM
its prob the sensor not the thermo. The sensor is blue and can be purchased online for $22

matt_mcmhn
08-21-2007, 04:58 AM
I had the same problem, changed the sensor, and it didn't do anything. I guess that would mean my thermostat is bad, but my oil temp gauge is reading normally

generik777
08-21-2007, 02:10 PM
I ordered the sensor from purems.com. Only 13 bucks. Ordered a fuel filter while I was at it. Let ya know how it works out when it gets here.

sjthomas
08-21-2007, 02:39 PM
I had temp issues similar to this - never got quite up to temperature, always just a little shy of 12 o'clock on the gauge. if i sat in traffic it would drop a little cooler. oil temps only moved the needle if i drove for an extended period of time (more than 20 miles). I replaced the coolant temp sensor first - did nothing (I have a 1.8T-AWM- so it was the green sensor originally and replaced with another green one). Replaced the thermostat next and that solved it. Coolant temp sits in the middle, and oil temps are at 190-200 deg F within 10 minutes or so. Good luck with your situation, i found the thermostat an easier repair than the coolant sensor. I'll be interested to see how the behavior varies with the 2.8

generik777
08-25-2007, 04:59 PM
Got the part today, Put it in, Problem fixed! Man was it a tight fit. My hand is just throbbing right now from squeezing in and out of that tight space. But overall it wasn't to bad of a project. The hardest part was getting the clip back in after installing the new sensor, I was getting so pissed but finally got it. Thanx everyone for all the help, much appreciated. Now my next project is to replace my fuel filter, I ordered one along with my sensor since purems.com has a $15 minimum spending limit, I planned on getting one soon anyway so it didn't bother to much. Probably attempt to do that sometime in the coming week. Anyways thanx again for the help.

BTW here is the write-up I used to do the replacement in case anyone should need it. LINKY (http://www.audiworld.com/tech/eng54.shtml)