[fastdustin]

So i recently got that dreaded check engine light so instead of driving over to advanced auto or bringing my car to the shop i bought the vag maxiscan off of amazon because i heard it was a good scanner but not a ross tech that for sure. It does have some vag functions though and overall I'm happy with it. So anyway i scanned my car and i got a code(don't remember the exact code #)for a coolant temp sensor inaccurate readings. Recently i replaced this part for Advanced Auto for like 10 bucks. Since then i have filled up like twice so thats about 700 miles ago. So first i opened the hood as i thought the sensor was loose and gave it a nudge and then reset the light. 25 miles later bam theres the light again. So did i just have bad luck with the sensor as its aftermarket. Should i go to the stealer-ship and get the OEM one or should i just replace it again with an aftermarket one.

 

[jfoj]

Coolant temp issues are very often mis managed for many reasons.

If you got a green top temp sensor from Advance you are probably in decent shape. The coolant sensors get blamed all the time as they are the easier item to change, but rarely the source of the problem.

Thermostats fail open or open too early and cause the engine to run cold VERY often. Some stats only last 2 years at a time. If you think you have the original stat, change it. A bit tricky, but I did not remove or disconnect my Alt on my car, just 1/4" ratchet, wobble extension and I was able to do it.

Also you need to read up on the plastic impeller water pump. These are problems.

You need to figure out if your temp code is too low or too high. Also see if you have any freeze frame data with your codes. Not sure your tool reads real time data, but my car with a bad stat only ran about 170-180F, with the newer 185F stat, the engine now runs around 200-205F.

Thermostat will likely run too cold, water pump likely too hot. There could also be some fan issues, would cause too hot as well.

Most thermostat codes are due to cold conditions caused by bad thermostats.

 

[fastdustin]

Ok i will report back with the code tommorow as im sure the dreaded light will come back on again. ughhh. Water pump should be good, stealership changed it in July/Aug.

 

[fastdustin]

So I went and changed the sensor again. The first time I did it I had no coolant loss but this time I forgot to de-pressurize the system so I had some leakage. I wrote the code down but I can't seem to find it but hopefully the code doesn't pop back up again. Recent discovery while I managed to drop that stupid black plastic U clip I reached down to find it and grabbed what I thought to be a leave. In reality it was a plastic bag with a cts o ring which is brand new and an oem dealer one as well. This is from the previous owners dealer in NJ. How they managed to not find it is besides me and the fact that its probably been lodged in there for quite some time without coming out. Also side note I recently had an oil change and they only put in 4 qts of oil. Isn't are capacity like 4.2 or something a little more than that.

 

[IndyTom]

Did you check your oil level? Is it within the marks?
With filter change it should take 4.5 quarts.

 

[fastdustin]

Ok here are the codes my reader pulled.
Code p0116 hopefully cts
Code 65535 no idea what that is but it's categorized as radio. My radio works so I dunno

 

[fastdustin]

As far as the oil I checked the dip stick and it was a little low so I think they shorted me. Glad I caught it early.

 

[IndyTom]

Ok here are the codes my reader pulled.
Code p0116 hopefully cts
Code 65535 no idea what that is but it's categorized as radio. My radio works so I dunno

Are you sure it's a radio code. According to Ross Tech it's a Control Module fault code which could be serious.

65535 - Ross-Tech Wiki

 

[jfoj]

Be prepared to replace the thermostat, trust me.

Hopefully the coolant sensor is your issue, but more often than not the thermostat is the problem.

You should not relay on trouble codes for indication of the running temp, you need a scan tool that reads real time data. I think the one you have may?

If the coolant sensor reads correct at ambient temp, it likely will read correct at operating temp.

But in any event, let us know what you find as it will likely help others here.

 

[fastdustin]

I will have someone check out that other fault code and as far as the thermostat I hope the cts fixes my prob. What should my temp be running at when warm and what is considered out of range. Off topic I had a friend that went to a public auction yesterday and a 2009 black beetle with 75,000 on it sold for $3500 plus 8% tax. Someone got lucky . If I was only there.

 

[jfoj]

My car typically runs in the 204-206F range when I have checked it. I just returned from testing a few things and it was 50F out and I was right around 204F.

I just replaced the stat about 1k miles ago, the older one was opening at about 160F.

I only once ever had a stat code, and cleared it and it never came back. Unfortunately at the time I had a cheaper scan tool that did not display real time data and since there is not temp gauge in these cars I could not tell where the temps were until I put my newer tool on the car and started to monitor the data.

Just because you do not get a code does not mean things are correct and in proper operating order!

 

[IndyTom]

I will have someone check out that other fault code and as far as the thermostat I hope the cts fixes my prob. What should my temp be running at when warm and what is considered out of range. Off topic I had a friend that went to a public auction yesterday and a 2009 black beetle with 75,000 on it sold for $3500 plus 8% tax. Someone got lucky . If I was only there.

WOW, High Mileage for an 09. I guess someone loved his Beetle and drove it a lot Still an excellent deal for only $3500 bucks. I Paid $3600 including tax for my 2000 Beetle. Still running strong at 160k miles

I would swap out the CTS. More often than not it is the Coolant sensor when the P0116 code comes up. Personally, I had never had a Thermostat fail in my 2 Audi TT's 1.8 and now my New Beetle 1.8, however I always changed them with the timing belt service at around 75k to 80k miles. If you do change the Termostat don't get a cheap aftermarket unit. I only use the True OEM VW type that the dealer sells. I had so many friends that used the aftermarket kind like the Whaler brand just to have them fail in a very short time. Since it is a little tricky to swap out the thermostat I wouldn't skimp on that particular part and get the real deal.

But for now I would just swap out the CTS and see what happens. When I bought my Beetle it still had the old Black CTS in it and I immediately swapped it for a new Green one.

Again, in this case I do prefer the Real Deal but a lot of people have been using the cheaper aftermarket sensors and most of them haven't had any issues.

Volkswagen New Beetle 1.8T > Search > Coolant Sensor > ES#264174 Coolant Temperature Sensor With O-Ring & Clip - 4 Pin - 078919501CKT

Volkswagen New Beetle 1.8T > Search > Coolant Sensor > ES#2535452 Coolant Temperature Sensor With O-Ring & Clip - 4 Pin - 059919501AKTU

Volkswagen New Beetle 1.8T > Search > Thermostat > ES#261231 87C Thermostat - 050121113C

If you do swap the Thermostat I also suggest a new Thermostat housing.

Volkswagen New Beetle 1.8T > Search > Thermostat > ES#259316 Thermostat Housing - 06A121121C

Good Luck and Keep us posted.

 

[IndyTom]

Quick question. Did you already replace the water pump and timing belt in your Beetle? If not you may want to put that on your to do list since the old Plastic Impellar Water Pump can really be a huge problem and could cause that code if the impellar blades are breaking up.

 

[fastdustin]

I couldn't believe the price of that beetle though, still a really good deal. No check engine light yet but it still hasn't passed the readiness test on my scanner yet. Praying that it was only the cts. As far as the timing belt and water pump I couldn't find any shop around me to do it so vw dealer got me on that one.

 

[IndyTom]

I couldn't believe the price of that beetle though, still a really good deal. No check engine light yet but it still hasn't passed the readiness test on my scanner yet. Praying that it was only the cts. As far as the timing belt and water pump I couldn't find any shop around me to do it so vw dealer got me on that one.

YIKES, I am sure that cost you a pretty penny. But at least you don't have to worry about it for a while

 

[fastdustin]

Code is back for inadequate readings from cts. I've noticed there seems to be another sensor that plugs into a coolant flange by the power steering res. could this be my problem. I'm also going to put some connection cleaner in where the cts plugs in. My scanner doesn't display live data, I'm just hoping its not the thermostat now. I took it to a shop and they suggested that my water pump might have failed or the fans may not be moving. I'm pretty sure my water pumps good and my fans both run I turned on the ac to check. Any suggestions.

 

[jfoj]

You really need to get a scan tool that at least displays freeze frame data and possibly live data. If you find a tool that displays freeze frame data, do not be surprised if you see a temp like 180-185. This still means your stat has failed.

Again, I expect your engine to be running too cool and you have failed open thermostat this happens far more than people really are aware of.

I do not believe there is a CEL/code for engine running too hot, just too cold.

If you had a fan or water pump problem you would likely have the red coolant light coming on and possibly a boil over issue. The water pump is a weak area, but deal with the low temp issue you likely have at this point. Also if you change the stat you can inspect/fell the back of the water pump impeller for damage or broken fins.

The thermostat and gasket is only like $20 as I recall and it really pretty easy to install if you have a 1/4" drive socket set and either a universal joint or wobble extension. 2 bolts and 1 hose clamp after draining the radiator which is a 1/4 turn and pull.

 

[IndyTom]

Code is back for inadequate readings from cts. I've noticed there seems to be another sensor that plugs into a coolant flange by the power steering res. could this be my problem. I'm also going to put some connection cleaner in where the cts plugs in. My scanner doesn't display live data, I'm just hoping its not the thermostat now. I took it to a shop and they suggested that my water pump might have failed or the fans may not be moving. I'm pretty sure my water pumps good and my fans both run I turned on the ac to check. Any suggestions.

So did you have the water pump replaced recently?
You did say that the dealership did your timing belt and water pump? How long ago was this?
If I misunderstood than it is quite possible that it is your water pump. Those old pumps plastic
Impeller break very easily after they get old.

 

[IndyTom]

Code is back for inadequate readings from cts. I've noticed there seems to be another sensor that plugs into a coolant flange by the power steering res. could this be my problem. I'm also going to put some connection cleaner in where the cts plugs in. My scanner doesn't display live data, I'm just hoping its not the thermostat now. I took it to a shop and they suggested that my water pump might have failed or the fans may not be moving. I'm pretty sure my water pumps good and my fans both run I turned on the ac to check. Any suggestions.

Oh, that sensor by the power steering pump is a 2 pin 112c Temp sensor which controls your fan speed once it reaches a certain temperature. It wouldn't have any bearing on your issue. If it wasn't working your fans would be on all the time.

 

[fastdustin]

So I'm having an issue with the cts code again and I just didn't want to deal with it myself so I took it to a shop where they said they monitored the real time data and said they left it running in the shop and the temperature was climbing normally so they don't think it's the thermostat but maybe a short in the cts wiring now. I've noticed that the check engine light will only come on when I'm going down a big hill. Elevation have anything to do with this at all??