CR Timing belt / thermostat replacement.

[_Diesel_Dan]

Going to be doing the thermostat and Timing belt on my 2010 Jetta cjaa, manual trans. Any parts you guys suggest getting besides the obvious? Have read some threads about nightmares about doing the thermostat and different o rings and tubes I should purchase... however no part numbers are listed. Looking for input and possibly part numbers I should grab! Thanks

 

[backfast61]

Go to IDPARTS.... GREAT service and great parts. You can also look at some of the suggested parts that they recommend.
Hope this helps....

 

[billnlana]

Id parts.com Get the whole kit with the gates belt , tensioner, water pump. I have done it 3 times in 14 years. Never had a belt or water pump fail. Only did the thermostat once.

 

[_Diesel_Dan]

I already have their timing belt kit. That seems straight forward, looking for more info on the thermostat

 

[KidFromAkron]

Is it recommended to change the thermostat when doing the timing belt? I'm about to do this same job and already got my parts from through the links Dieselgeek has on his thread. I have the turbo back exhaust from Rawtek and stage 2 tune from Malone. My cruising temps stay at 160-170 and I wonder if its the exhaust or if I need a new thermostat?

 

[oilhammer]

Don't mess with the thermostat unless you have good reason to. The ECU monitors this, so if it gets bad enough you'll be alerted via a MIL requested DTC. It isn't a quick easy thing on the CJAA, and it really doesn't have much overlap with a timing belt anyway.

 

[Metal Man]

I'll say, I did one not long ago just because the customer wanted it. I'm not doing that again unless it's truly needed.

 

[oilhammer]

I take the front of the car off. It isn't too bad then. Still isn't the 5 minute job like on an ALH!

 

[Stromaluski]

The ECU monitors this, so if it gets bad enough you'll be alerted via a MIL requested DTC.

How bad does it have to be for the MIL to come on? I recently picked up a '10 Jetta TDI and it seems like the temp gauge only spends half of the time at operating temperature. It warms up just fine, but then will cool back down if I'm driving down a hill. I've even seen it get as far as half way back down to cold coming down a mountain. I would have thought the ECU would have cared more about maintaining operating temperature than that.

 

[oilhammer]

Monitor the ECU's data and see.

 

[Stromaluski]

Monitor the ECU's data and see.

I can monitor the data, but that just tells me the operating temp. My question was more of when does it trigger warning light? Is it an issue of how long it's below a certain temp vs how low the temp gets temporarily?

 

[oilhammer]

What I was getting at, was the gauge isn't necessarily lock step the same as the ECU's input. The ECU time stamps the coolant temp at start up, then monitors the rate at which it climbs. Honestly, though, the TDIs, even the CR engines, seem to be pretty lenient about that sort of thing. I have seen a few set a P0128 (coolant temp below operating range) but it may be one of those things that if the temp has passed the threshold after the initial check, then the ECU is satisfied for that drive cycle, and if it cools back down (which, going down a mountain it certainly would), the ECU does not care.

But since you asked, I looked it up:

For the CJAA engine, the test criteria is start up coolant temp is below 60 C, but above -10 C. If it is TOO cold, the ECU is told to ignore this, as the logic knows the engine may NEVER get up to temp as it ideally should. Then the time is 900 seconds. It shows it wants to see an increase of 3K at the CTS, I would take that to mean 3k Ohms value change.

So looking at the CTS resistance chart, let's say you started the car at -5 C, it should be around 7K Ohm, and at 15 C it is around 3K. This difference of 4K Ohm so long as it occurred in 900 seconds, then the ECU's coolant temp logic is satisfied for that drive cycle. The drive cycle will not "reset" until the coolant is back down below 60 C and the engine is turned off.

So, in the Queen's terms, if you started your engine up cold with the coolant around 20F, and after 15 minutes it was around 60F, the ECU is happy, and will not flag a P0128 DTC. I can tell you though that most any TDI can get through that test easily. And once that is done, you can cool that engine back down to a block of ice if you want, so long as the engine has not been shut off, the ECU thinks everything is normal.

So, you could certainly still have a weak or (by most accounts) a "bad" thermostat and still not have the P0128 DTC setting, as the test criteria is not hard to satisfy at all.

 

[Stromaluski]

What I was getting at, was the gauge isn't necessarily lock step the same as the ECU's input. The ECU time stamps the coolant temp at start up, then monitors the rate at which it climbs. Honestly, though, the TDIs, even the CR engines, seem to be pretty lenient about that sort of thing. I have seen a few set a P0128 (coolant temp below operating range) but it may be one of those things that if the temp has passed the threshold after the initial check, then the ECU is satisfied for that drive cycle, and if it cools back down (which, going down a mountain it certainly would), the ECU does not care.

But since you asked, I looked it up:

For the CJAA engine, the test criteria is start up coolant temp is below 60 C, but above -10 C. If it is TOO cold, the ECU is told to ignore this, as the logic knows the engine may NEVER get up to temp as it ideally should. Then the time is 900 seconds. It shows it wants to see an increase of 3K at the CTS, I would take that to mean 3k Ohms value change.

So looking at the CTS resistance chart, let's say you started the car at -5 C, it should be around 7K Ohm, and at 15 C it is around 3K. This difference of 4K Ohm so long as it occurred in 900 seconds, then the ECU's coolant temp logic is satisfied for that drive cycle. The drive cycle will not "reset" until the coolant is back down below 60 C and the engine is turned off.

So, in the Queen's terms, if you started your engine up cold with the coolant around 20F, and after 15 minutes it was around 60F, the ECU is happy, and will not flag a P0128 DTC. I can tell you though that most any TDI can get through that test easily. And once that is done, you can cool that engine back down to a block of ice if you want, so long as the engine has not been shut off, the ECU thinks everything is normal.

So, you could certainly still have a weak or (by most accounts) a "bad" thermostat and still not have the P0128 DTC setting, as the test criteria is not hard to satisfy at all.

That's exactly what I was looking for. Thanks for taking the time to look it up for me!

 

[B100]

Can anyone speak to what dealerships or independent shops are charging these days for a straight TB replacement on a 2009 JSW? Not thermostat, just the belts, pulleys, water pump. I think I was spoiled on how simple it was on my 2003 Golf.

 

[Nuje]

If you can do TB on a ALH, you can do one on a 2009 CBEA.
Same principles, but IP (HPFP) isn't nearly as finicky about precise positioning; locking of crank and camshaft (and tightening) are easier; easier to get the mount bracket in/out.