Thermostat Bad Again?
#21
07-28-2014, 01:59 PM
Just read the whole thread. I think this is what you’re seeing in a nutshell:
So to me:
So it seems to me you have far more reason to question the new CTS than the stat. Go the the dealer and get the right OEM CTS for your VIN#. It will cost you $10 more than Rock Auto, but you will be able to take it out of the equation. Again, if your heat is good, your stat is not stuck open.
- Heater is good.
- Gauge reads too low right after a CTS swap.
So to me:
- Stat is probably doing its job if the heat is good.
- The only reason to suspect a bad stat is if you absolutely trust the gauge.
- If the gauge went bad after a new CTS, why do you know it’s not the CTS providing bad data to the gauge? As MetalMan says, the CTS is what sends the temp reading to the inst. cluster.
So it seems to me you have far more reason to question the new CTS than the stat. Go the the dealer and get the right OEM CTS for your VIN#. It will cost you $10 more than Rock Auto, but you will be able to take it out of the equation. Again, if your heat is good, your stat is not stuck open.
I would take the CTS out and clean it and the connections but I don't want coolant all over the place again. Unless someone can tell me how to remove it without having coolant spray out. It was a decent amount that came out last time.
#22
07-28-2014, 02:27 PM
There's not much to clean. The sensor side is pretty smooth, the plug side doesn't get corroded. And you said this started the day you swapped for a new one, and I'll bet that wasn't corroded. Just get a new one. This one has cause problems from day one.
Just open the cap to release the pressure. Or better yet, let it cool off. That stuff is hot. When there's not pressure in the system you really don't lose much...at least on the V6.
#23
07-28-2014, 02:37 PM
As I mentioned before you can diagnose this with VAG-COM / VCDS. You would drive the car to operating temperature, check engine coolant temperature through the Engine Module, and see if that reading matches the engine coolant temperature data as accessed through the Instruments Module. If it doesn't, then the CTS or wire harness is bad. If the data matches, then that means something is up with your cluster.
#24
07-28-2014, 04:14 PM
Here is your answer:
If the output from the CTS which goes to the cluster is bad, but the output which goes to the ECU is good, then you wouldn't get a CEL because the ECU has no idea what reading the CTS is giving to the cluster.
As I mentioned before you can diagnose this with VAG-COM / VCDS. You would drive the car to operating temperature, check engine coolant temperature through the Engine Module, and see if that reading matches the engine coolant temperature data as accessed through the Instruments Module. If it doesn't, then the CTS or wire harness is bad. If the data matches, then that means something is up with your cluster.
If the output from the CTS which goes to the cluster is bad, but the output which goes to the ECU is good, then you wouldn't get a CEL because the ECU has no idea what reading the CTS is giving to the cluster.
As I mentioned before you can diagnose this with VAG-COM / VCDS. You would drive the car to operating temperature, check engine coolant temperature through the Engine Module, and see if that reading matches the engine coolant temperature data as accessed through the Instruments Module. If it doesn't, then the CTS or wire harness is bad. If the data matches, then that means something is up with your cluster.
I guess I will start by ordering a new CTS.
#25
07-28-2014, 04:31 PM
Agree with MetalMan. Would just add that although your CTS threw a check engine light before, they are notorious for going bad without throwing a code at all. Because of what MetalMan said, and "just because"....
#26
07-28-2014, 04:38 PM
This is the CTS I used by the way. If you guys don't think this is a good one to use please please link me to something else so I can get this right. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=221451049930#vi-ilComp
#27
07-28-2014, 05:39 PM
Wish I knew this before I spent the time and money to change my thermostat. Oh well.
This is the CTS I used by the way. If you guys don't think this is a good one to use please please link me to something else so I can get this right. New Green Coolant Temperature Sensor Water Temp Switch for Audi VW 059919501A | eBay
This is the CTS I used by the way. If you guys don't think this is a good one to use please please link me to something else so I can get this right. New Green Coolant Temperature Sensor Water Temp Switch for Audi VW 059919501A | eBay
The Genuine Audi part (what you would get from a dealer) is what most of us recommend when it comes to the CTS. Here is a good example:
http://genuineaudiparts.com/parts/in...&siteid=214407
Same part number, and this one is a Genuine Audi part. It's more expensive, yes, but there are some things you don't want to have to buy twice.
Last edited by MetalMan; 07-28-2014 at 05:41 PM.
#28
07-28-2014, 06:09 PM
In this prior post, it sounds like you called this eBay sensor "OEM". This sensor is "aftermarket OE" at best IMO and the product description lists "Direct Replacement for OEM". OEM would mean it's made by the same manufacturer as the Genuine Audi part, just not labelled as being Genuine.
The Genuine Audi part (what you would get from a dealer) is what most of us recommend when it comes to the CTS. Here is a good example:
Audi Parts - genuinevwaudiparts.com
Same part number, and this one is a Genuine Audi part. It's more expensive, yes, but there are some things you don't want to have to buy twice.
The Genuine Audi part (what you would get from a dealer) is what most of us recommend when it comes to the CTS. Here is a good example:
Audi Parts - genuinevwaudiparts.com
Same part number, and this one is a Genuine Audi part. It's more expensive, yes, but there are some things you don't want to have to buy twice.
#29
07-28-2014, 06:14 PM
This has the same part # as what you had linked me to, yes? New Audi VW Green Coolant Temperature Sensor Water Temp Switch 059919501A | eBay
#30
07-28-2014, 06:41 PM
I used the same part number from your first post with the eBay link, so I didn't mess with part numbers (just copied/pasted).
Just want to make sure we're on the same page: part number has no bearing on manufacturer/quality of part, it is only used to indicate interchangeability.
So if a part has an Audi part number, that just indicates it was made to fit/function as a replacement for the original Audi part.
Just want to make sure we're on the same page: part number has no bearing on manufacturer/quality of part, it is only used to indicate interchangeability.
So if a part has an Audi part number, that just indicates it was made to fit/function as a replacement for the original Audi part.
Last edited by MetalMan; 07-28-2014 at 06:44 PM.