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rubberband
12-07-2009, 11:44 AM
Hi, my 2000 1.8t (atw) has had recent coolant temp gage issues with the gage going up and down but never over the half way mark. I figured that if I changed out the coolant temp sensor (blue 4 pin d-shape connector) with the green top all of this would go away. I changed it out with the green one the other day but my gage still goes up and down and now my hi-speed fan is on when the ignition is on...w/out the ac or defroster on.

anyone run into anything like this before or could possibly have a reccomendation? with the blue sensor in there the fan never came on like this unless the ac was on. [up]

lifwanian
12-07-2009, 02:50 PM
Im having similar problems.... Check out your thermostat..

NJx
12-07-2009, 03:47 PM
does the temp sensor go down when ur driving then back up when ur idleing?

frameshift18
12-07-2009, 05:52 PM
Check out your thermostat..

x2

PoormansA4
12-07-2009, 05:55 PM
kinda stupid question but are you sure you changed you CTS and not the fan switch on the bottom radiator hose

Amorphic
12-07-2009, 06:06 PM
x2 on thermostat. i have the same issue and im going to be changing my CTS and thermo.

revolution337
12-07-2009, 06:21 PM
x4 on thermostat. i had the same problem, and i just replaced mine about a week ago. now it warms up in no time and stays right in the middle.

Armenian
12-08-2009, 12:31 PM
i have had this issue like few months back, even when i drive the car for couple of miles the temp gauge never seems to come to the middle and stay in the middle as it did before when the car was warm....
--- i think when it reaches to the middle and i idle it seems to go down
so what seems to be the conclusion ? what do you guys say needs to be adjusted or changed?

Thanks

ECS Tuning-Audi
12-08-2009, 01:24 PM
x5 or x6, I forget which were on, but thermostat.

We have plenty in stock, common issue (http://www.ecstuning.com/Audi-B5_A4-Quattro-1.8T/Search/Thermostat/?salesrep=CArmbruster&utm_source=audizine&utm_medium=forum&utm_content=CArmbruster&utm_campaign=postreply)
http://www.ecstuning.com/product_library/32120/300/Thermostat%20-%2087C.jpg (http://www.ecstuning.com/Audi-B5_A4-Quattro-1.8T/Search/Thermostat/?salesrep=CArmbruster&utm_source=audizine&utm_medium=forum&utm_content=CArmbruster&utm_campaign=postreply)

I will say this, you are going to do 50% of a timing belt job to change your thermostat, consider doing the TB if you are close to needing one!

frameshift18
12-08-2009, 02:18 PM
Just ordered a thermostat from ecs yesterday for this same problem [up]

ECS Tuning-Audi
12-08-2009, 02:23 PM
Just ordered a thermostat from ecs yesterday for this same problem [up]

Hey, thanks for the order!

walky_talky20
12-08-2009, 04:11 PM
I figured that if I changed out the coolant temp sensor (blue 4 pin d-shape connector) with the green top all of this would go away. I changed it out with the green one the other day[up]

...and now my hi-speed fan is on when the ignition is on...w/out the ac or defroster on.


Sounds to me like you mistakenly replaced the fan switch in the lower rad hose with a CTS. I know this because:

1 - "blue 4 pin d shape connector" describes a fan switch, not a CTS
2 - Putting a CTS in place of a fan switch will cause the fan to run constantly, ask me how I know.

The funny thing is that Audi used the same exact connector style for the fan switches and the coolant temp sensors on the newer B5's. Making this switch-a-roo possible.

Anyhow, still could be the CTS or the thermostat. I suggest you grab your blue temp sender out the trash and reinstall it. Then put your CTS where it should go, in the flange at the back of cylinder head. If the gauge is still funny, change the thermostat.

rubberband
12-09-2009, 10:46 AM
Sounds to me like you mistakenly replaced the fan switch in the lower rad hose with a CTS. I know this because:

1 - "blue 4 pin d shape connector" describes a fan switch, not a CTS
2 - Putting a CTS in place of a fan switch will cause the fan to run constantly, ask me how I know.

The funny thing is that Audi used the same exact connector style for the fan switches and the coolant temp sensors on the newer B5's. Making this switch-a-roo possible.

Anyhow, still could be the CTS or the thermostat. I suggest you grab your blue temp sender out the trash and reinstall it. Then put your CTS where it should go, in the flange at the back of cylinder head. If the gauge is still funny, change the thermostat.

hahahaha, yep. boy do i feel stoopid. Thank you guys for the replies. I am good to go now.

ECS Tuning-Audi
12-09-2009, 11:36 AM
hahahaha, yep. boy do i feel stoopid. Thank you guys for the replies. I am good to go now.

Ha ha, glad you got it sorted!

A4DRIVR
12-09-2009, 11:50 AM
I think I did the same thing...

Chris... can you PM me the part number and cost for the Fan Switch on an 01' 1.8T?

Thanks!

sgt_g
12-09-2009, 12:50 PM
I been woundering about mine. The thermostate is new like 4 months ago. When i drive the temp is dead in the middle but when i'm idling it goes just over half and sits there. allways the same point and never higher. As soon as i start to drive again it goes back down. any idea's.

ECS Tuning-Audi
12-09-2009, 01:34 PM
I think I did the same thing...

Chris... can you PM me the part number and cost for the Fan Switch on an 01' 1.8T?

Thanks!

I think you posted about that in the last few weeks? I thought I head this same story recently?!

As soon as I find it, you got PM.

VirginiaBeachA4
12-09-2009, 03:52 PM
alright folks, i have the problem of the needle never leave "C" on the gauge. it only goes up when i idle, barely. i have changed my cts and thermostat and the needle is still sitting on the C in the gauge. then what is it?

PoormansA4
12-09-2009, 04:04 PM
I been wondering about mine. The thermostat is new like 4 months ago. When i drive the temp is dead in the middle but when I'm idling it goes just over half and sits there. always the same point and never higher. As soon as i start to drive again it goes back down. any idea's.

how much over half? if you were to park and press the gas and hold it at like 1.5k or 2k does it go down? or only when driving? id imagine it would be your water pump going out or possibly you have a lot of bent fins on your radiator

dangerous_dave
12-09-2009, 04:10 PM
x5 or x6, I forget which were on, but thermostat.

We have plenty in stock, common issue (http://www.ecstuning.com/Audi-B5_A4-Quattro-1.8T/Search/Thermostat/?salesrep=CArmbruster&utm_source=audizine&utm_medium=forum&utm_content=CArmbruster&utm_campaign=postreply)
http://www.ecstuning.com/product_library/32120/300/Thermostat%20-%2087C.jpg (http://www.ecstuning.com/Audi-B5_A4-Quattro-1.8T/Search/Thermostat/?salesrep=CArmbruster&utm_source=audizine&utm_medium=forum&utm_content=CArmbruster&utm_campaign=postreply)

I will say this, you are going to do 50% of a timing belt job to change your thermostat, consider doing the TB if you are close to needing one!

Not on a 1.8t he's not. You don't touch the thermostat on his car to do a T belt. Older 1.8t's have an external water pump and the T stat is in that housing. Newer 1.8t's with an internal water pump have the thermostat on the side of the block. Either way, you dont need to touch the thermostat to do a T belt.

walky_talky20
12-09-2009, 04:44 PM
I think I did the same thing...

Chris... can you PM me the part number and cost for the Fan Switch on an 01' 1.8T?

Thanks!

This is the 4-pin blue fan switch you need:
http://www.ecstuning.com/product_library/22526/300/Auxiliary%20Fan%20Switch.jpg

http://www.ecstuning.com/Audi-B5_S4--2.7T/Engine/Cooling/Fan_Switch/ES262920/

It is listed for the A6 and S4, but for some reason every parts supplier I've tried doesn't list it for the A4, go figure. I had this same problem, caused by the previous owner, took me a while to figure it out.

sgt_g
12-11-2009, 05:35 AM
how much over half? if you were to park and press the gas and hold it at like 1.5k or 2k does it go down? or only when driving? id imagine it would be your water pump going out or possibly you have a lot of bent fins on your radiator

No it only goes down when i start driving. i did the t-belt like 4 months ago and did the water pump and t-stat at the same time. would it possibly be my sensor?

Edit: scratch that i double checked on my way to work this morning and it does go back down when i hold it at 2k RPMS. This makes no sense. as i said i replaced the water pump when i did the T-belt 4 months ago.

ECS Tuning-Audi
12-11-2009, 07:52 AM
Start with a CTS, it is as cheap and easy fix if it is the problem, or if it is not the problem.

Check to see if you have a green or blue one. I think you'll have a green one.
As you can see, they are pretty cheap (http://www.ecstuning.com/Audi-B5_A4-Quattro-1.8T/Search/Coolant_Temp_Sensor/?salesrep=CArmbruster&utm_source=audizine&utm_medium=forum&utm_content=CArmbruster&utm_campaign=postreply).

PoormansA4
12-11-2009, 10:47 PM
No it only goes down when i start driving. i did the t-belt like 4 months ago and did the water pump and t-stat at the same time. would it possibly be my sensor?

Edit: scratch that i double checked on my way to work this morning and it does go back down when i hold it at 2k RPMS. This makes no sense. as i said i replaced the water pump when i did the T-belt 4 months ago.

you could try your CTS sensor but it seems to be doing its job if it shows its cooling down during those things, id imagine it would be something effecting cooling efficiency, did you replace your water pump with one with a metal impeller? id would think it would have something to do with that since your temps change when the pump is driven harder.

sgt_g
12-11-2009, 10:59 PM
h,mm yea i got the kit from fcpgroten that has the metal impeller. Is there suppose to be coolant in the coolant tank when the motor is cold?

PoormansA4
12-11-2009, 11:18 PM
h,mm yea i got the kit from fcpgroten that has the metal impeller. Is there suppose to be coolant in the coolant tank when the motor is cold?

lol ya should be at least to the minimum line.

ECS Tuning-Audi
12-14-2009, 08:27 AM
h,mm yea i got the kit from fcpgroten that has the metal impeller. Is there suppose to be coolant in the coolant tank when the motor is cold?

Absolutely! There is a cold line and a hot line I believe? You should be full to the cold line when your car is cold. I fill mined in between the two marks to give way for expansion.