Where Are the 2 Coolant Sensors on 07 Audi A4 2.0

Souder Johns1967

06-20-201412:31 PM #1

Established Member Two Rings

engine coolant sensor 2.0T

Hello guys, can anyone please help me to locate an engine coolant sensor on B8 2.0T? Pictures can help. Thanks a lot!!
06-20-201412:47 PM #2

Veteran Member Four Rings

2012 Audi A4 Premium +MT, Quattro, Xpel bra, SLine BBS CI-R 20x8.5 ET 32

Mods: APR HFC/DP, APR K04, Bilstein PSS10 Coilovers, Okada Coilpacks, AWE Boost Gauge, Eurocode SSK, OSIR CF Spoiler, APR Carbonio Intake, AWE Exhaust, OSIR CF valence, �SS Adjustable Stabilizer set, Alu Kreuz, RS4 grille, Fluidampr,Apikol differential, folding mirrors,Brembo GT BBK, Deval CF splitter,ECS skid plate, RS4 rear brakes, Snow performance Stage3
06-20-201401:37 PM #3

Established Member Two Rings

Originally Posted by kwbdc

Thank you for your answer, actually, I cant find it ON the engine :)
06-20-201409:39 PM #4

Veteran Member Four Rings

LOL that's funny. you should have said THE engine coolant sensor, not AN haha

this should help, it's from a B7 2.0T but i'd imagine its in the same location still

looks like this: http://c1552172.r72.cf0.rackcdn.com/102684_x600.jpg
06-21-201402:40 AM #5

Established Member Two Rings

Originally Posted by Liquid Smoke

Thank you a lot!!!! :)
06-21-201406:48 AM #6

Active Member Two Rings

It is located on the top left corner of the waterpump housing. Just under the intake manifold. If I remember correctly, there is just one bolt holding it on. Two wire plug. You may have to remove the manifold support bracket to get to it. Need small fingers too!
06-21-201411:36 AM #7

Senior Member Two Rings

Number 7...
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Look below the throttle body, back at the engine block.
06-21-201412:28 PM #8

Established Member Two Rings

Perfect! Thank you very much !
02-03-201507:21 PM #9

Veteran Member Four Rings

QUESTION? Was going to start a new thread but as I was ready to start typing, I found this thread! Thanks search engine:) Now on to my question. So After getting my injector issue fix by Audi, I noticed my Coolant Temp Needle was dipping down when at idle. So i took it back to Audi and they replaced the T-stat and Water Pump. The issue has gotten better. However, now on cold starts, I drive the car with heat on full blast and in stop and go traffic to my college in the morning and notice that when driving the Coolant temp needle will reach the halfway point.. BUT when i stop at a stoplight, I start to notice the needle dip down under the halfway point. If I turn the heat off, then there is no problem.. The temp will stay around 179-209 degrees via P3 Gauge when heat is off. When heat is on the car will dip down to around 165-170 at a stop light. So pretty much the issue is that when at idle, the needle will come down a little bit when the heat is on.

I have the ross tech cable and was wondering how to use it to log data from the car. Also, does this sound like it could be a bad coolant temp sensor? My cars under warranty but there saying that not to worry unless the needle goes over the middle line.

Any input!? T.I.A:)

-MRR GROUNDFORCE GF06 19X9.5 38MM 5X112 MACHINED SILVER -HANKOOK K110 VENTUS V12 245/35/19 -H&R Street Coilovers -Ecodes -OEM roof rack -Side blades -RS4 grille -Fog grille covers -13' shifter -HFC Eurocode -Stasis Exhaust -APR Stage II -10' B8 A4 AT
02-03-201507:55 PM #10

Veteran Member Three Rings

Are your electric fans both on?
02-03-201507:58 PM #11

Veteran Member Four Rings

Originally Posted by van462

Are your electric fans both on?

I do not notice the fans coming on in the morning, will verify tomorrow.

-MRR GROUNDFORCE GF06 19X9.5 38MM 5X112 MACHINED SILVER -HANKOOK K110 VENTUS V12 245/35/19 -H&R Street Coilovers -Ecodes -OEM roof rack -Side blades -RS4 grille -Fog grille covers -13' shifter -HFC Eurocode -Stasis Exhaust -APR Stage II -10' B8 A4 AT
02-04-201507:03 AM #12

Veteran Member Four Rings

In very cold weather, don't turn on your heat until the engine is warmed up..............
02-04-201511:56 AM #13

Veteran Member Four Rings

Originally Posted by S4'ed

In very cold weather, don't turn on your heat until the engine is warmed up..............

Yes, I understand that. but find it odd that on 55-60 degree days, and driving in stop and go traffic, the car will never reach operating temperature unless there are 4 consecutive green lights. When compared to my friends A4 B8, his engine reaches operating temp just fine in 20-40 degree temp. (with his heat on high). I have read up on the CTS and seems like some people experience slow warm ups with a faulty sensor. So that is why I'm curious.

Is it normal to see your coolant temp needle go from half way to a little over a fourth within seconds while at an idle? (May be a silly question but never noticed this owning my car the last 3 winters)

-MRR GROUNDFORCE GF06 19X9.5 38MM 5X112 MACHINED SILVER -HANKOOK K110 VENTUS V12 245/35/19 -H&R Street Coilovers -Ecodes -OEM roof rack -Side blades -RS4 grille -Fog grille covers -13' shifter -HFC Eurocode -Stasis Exhaust -APR Stage II -10' B8 A4 AT
02-04-201504:36 PM #14

Veteran Member Three Rings

We actually have 2(possible 3) coolant sensors. One on the waterpump assembly, that is the one the temp gauge is tied to. If it has a fault it should trigger a code. On the radiator is another sensor. It is responsible for controlling cooling fans. It will not generate a code, but as a safegaurd your fans will always run. I have read of a G17 coolant sensor in some tech documents but I haven't been able to verify it it applies to the A4 or not.

VMR 710's, APR software, Eurocode HFC
12-23-201504:03 PM #15

Veteran Member Four Rings

Where on the radiator is the coolant temp sensor? @van462
12-23-201505:53 PM #16

Veteran Member Three Rings

I was going off a VW tech document for the TSI motor and it calls for a sensor on the radiator. I know the G62 sensor is on the water pump and reads the coolant temp inside of the engine block. I pulled my radiator this summer and didn't see a sensor on it. I didn't look over the fan assembly to see if was a part of it. Every document about the ECU mentions a G83 sensor. I assume its somewhere on the cold water side of the radiator or on a hose from the cool side to check cooling performance. The documents state if that sensor fails no MIL illuminates and the fans will permanently run. This document was written more for the GTI than the A4 and states cooling system may vary.

I will try to look for it again this weekend. Tomorrow night I am putting the car into service position and attempting a timing chain and tensioner replacement. I'll have better access to look around then. I also want to see if there is a sensor on the back on the block below the fuel pump or not.

VMR 710's, APR software, Eurocode HFC
01-02-201601:25 PM #17

Veteran Member Three Rings

I can now verify the radiator doesn't have a sensor on it. I looked it over when I had the core out last night. I didn't check the back of the block where I believe the coolant flange is. I didn't have a mirror handy.

VMR 710's, APR software, Eurocode HFC
01-02-201602:30 PM #18

Veteran Member Four Rings

I think the "radiator coolant sensor" is actually located in one of the radiator hoses.
03-13-201812:52 PM #19

Active Member One Ring

Originally Posted by van462

I was going off a VW tech document for the TSI motor and it calls for a sensor on the radiator. I know the G62 sensor is on the water pump and reads the coolant temp inside of the engine block. I pulled my radiator this summer and didn't see a sensor on it. I didn't look over the fan assembly to see if was a part of it. Every document about the ECU mentions a G83 sensor. I assume its somewhere on the cold water side of the radiator or on a hose from the cool side to check cooling performance. The documents state if that sensor fails no MIL illuminates and the fans will permanently run. This document was written more for the GTI than the A4 and states cooling system may vary.

I will try to look for it again this weekend. Tomorrow night I am putting the car into service position and attempting a timing chain and tensioner replacement. I'll have better access to look around then. I also want to see if there is a sensor on the back on the block below the fuel pump or not.

@van462: I have a problem with my B8 A4 where my cooling fans are constantly running - when I unlock the cold car (before I even start it) 15-20 seconds later both cooling fans start up on the highest setting. Then they would stay on during my drive, and remain on until about 1-2 minutes after I shut off and lock the car which is when they finally turn off. Going by your comments in the quote above, it sounds like the document you are referring to explains my exact situation. However, after looking at online radiator part diagrams, I am not seeing a coolant temp sensor on the radiator. Does this document pertain only to the GTI? My temp gauge in the cluster seems to be working fine, so could my CTS at the water pump be faulty? Wouldn't that throw a code? Where exactly does the temp gauge in the cluster get its info from?