2010 Jetta Thermostat Change - What a Pain

[mctdi]

What a pain to change the thermostat on my 2010 Jetta. So far 8 hr. and just have the new thermostat bolted in. Yet to get everything else back on the engine. So far, I have only broke the middle mount of the oil dipstick tube.

The thermostat is within a housing that bolts to the block. Three hoses connect to it, and one plastic tube.

Bentley does not cover this thermostat. Nor was I able to find anything here. So I will soon add some pics.

Throttle pate and EGR valve removed so to have room to get at hose clamps and room for pulling the thermostat out once past the alternator. Alternator needs to be moved to the front of the car so thermostat housing can be pulled toward the passenger side to pull it off the plastic tube and spin it, so that it can come out along the dipstick tube.

 

[jetlagmech]

I haven't looked at the thermostat yet. I'll have to go take a look, I feel your pain, good luck on finishing up. take your time get it all nice and clean, would hate to get it all back together and find a seep because of some dirt on a mating surface.

Don....don't use your normal "have fun" sign-off on this one.

 

[jetlagmech]

just changed my oil and fuel filter today and looked....couldn't even see it so buried in there. Hopefully mine lasts until timing belt, just turned 70,000 miles. Sounds like something to change while everything is apart for timing belt. Very inexpensive part that becomes a very expensive job for time and labor. Even if I do it myself, my time is worth something too.

Can you tell since your that deep into it, would it be a fairly quick easy job with timing belt stuff apart??

 

[Henrick]

Out of curiousity, what mileage had the OPs car at the moment of replacement?
What symptoms did you experience which lead to thermostat replacement?

 

[mctdi]

I will try to get some pics posted tomorrow. Close to six hours today.

Replaced at 140,000 miles. Slow warm up and unsteady temp. And at about +15'F a bit low temp.

 

[DZL_Damon]

how slow was your warm up? Using the heater? what was the outside temps?

 

[mctdi]

Sorry notes to follow:

 

[mctdi]

how slow was your warm up? Using the heater? what was the outside temps?

20 miles / temp control 72'F with fan on low / outside 30'F

 

[Henrick]

My car never warms up in city driving. At temperatures of about 30 F I can get the oil temperature (there's oil/coolant heat exchanger, right?) to no more than 75 *C even after an hour of driving. The upper radiator hose isn't even warm so I doubt the t-stat is the problem in my case.

But from pics it looks a real PITA to change. I had troubles changing mine on my previous PD and I thought it was difficult... Now it looks like this one is even more complicated!

 

[740GLE]

I will try to get some pics posted tomorrow. Close to six hours today.

Replaced at 140,000 miles. Slow warm up and unsteady temp. And at about +15'F a bit low temp.

Is this the first winter with the car? have you noticed this getting worse?

At highway speeds of 65 mph, outside temps in the teens, with temp adjustment knob at max temp and fan settings at 1, increaseing the fan setting to 2 will result in the engine coolant gauge dropping, it's been that way since day one.

Maybe my Tstat has been bad since day one but I haven't noticed it change.

These cars are way too good at what they do, and not that great at heaters.

Granted I'm sure replacing the unit couldn't hurt, I'd just hope you get the outcome you want.

 

[DieselDubs83]

Definitely agree that this is a PITA job!!!!!!!!! How can you go from a thermostat replace time of several minutes to one of several hours.....just finished one. You will look like this by the time you are done!!!!!

 

[xmac81]

Hey fellow TDI owners...

I know this thread is old, but I just went through the removal of the thermostat assembly on my 2010 TDI Sportswagon and wanted to document the steps I went through. The notes and pictures in this thread assisted greatly, especially the picture showing the cocking of the thermostat assembly to remove it. I did this while changing my timing belt/water pump at 122k. Installation is the reverse of removal.

0. Remove the engine cover.
1. Disconnect the battery.
2. Drain the anti-freeze.
3. Removed the short intake feed hose from the throttle body to the lower connection.
4. Remove the three Throttle body bolts and upper dipstick tube mount bolt. You will need a new O-Ring when you re-mount the throttle body. Clean the Throttle body throat while you have it out.
5. Remove the large radiator hose from the bottom of the thermostat assembly and secure out of the way. This gives you clearance to remove the lower dipstick tube mounting screw.
6. Rotate back and forth and pull up to remove the dipstick tube from the engine hole. (Good opportunity to replace the tube's O-Ring at the engine end to prevent seepage)
7. Remove the remaining two hoses from the thermostat assembly. This leaves the one plastic tube still connected to the back of the thermostat assembly.
NOTE: replace all the spring hose clamps with quality hex head screw versions!
8. Remove the upper alternator bolt and loosen the lower one to rotate the top of the alternator toward the radiator side. This gives you the room needed to slide the thermostat assembly off of the horizontal plastic tube.
9. Remove the two thermostat assembly to engine mounting bolts.
NOTE: So far, I see no need to remove the screw securing the plastic anti-freeze tube that is behind the oil filter.
10. Reaching down with both hands, rock the thermostat assembly up and down to loosen it from the block, being careful to stop once it releases from the block.
11. Once loose from the engine, rotate the thermostat assembly on the plastic tube while sliding and cocking the mounting end towards the opening created by rotating the alternator forward. Please take your time with this step as you don't want to damage or crack the plastic tube. Once the thermostat assembly is loose, remove it from the top.
12. Clean the O-Ring sealing area on the block with fine sandpaper.
13. Lubricate the new O-Ring on the new thermostat assembly with fresh antifreeze along with the new seal on the plastic tube. Install the new thermostat assembly being careful not to roll either O-Rings out of their grooves.

The balance of the installation should be the reverse of removal...

Some of the hardest parts of the procedure were:
1. Coolant host spring clamp removal. I borrowed a friends clamp removal tool that has a cable between the handle and the action end. That's why I recommend replacing these clamps with a good quality screw type.
2. Breaking the seal on the hoses. I used a hand tool made for loosing hoses which has a odd angled "ice pick" end to get in between the hose and the seal. Once you get one section loose, twisting the hose will usually finished up the removal.
3. Once the upper alternator bolt was removed and the lower one was loosened, it still didn't want to rotate. My pry bar had to assist to rotate it.
4. Getting the thermostat out of the block. I had to use a long pry bar from the top of the engine between the upper thermostat assembly and the block to "encourage" it to separate from the block.

It wasn't easy, but up to this point, not impossible either. Budget at least a day or so. This is one job that you don't want to rush through!

Once the new O-Rings for the dipstick tube and plastic horizontal tube arrive, I'll re-assemble. I'll update this thread once done...

Hope this helps!

 

[meerschm]

Just an observation.

Nothing wrong with the spring clamps. (except being kind of hard to get off)

Yesterday I happened to catch an episode of Motor Week, which featured a segment on coolant with an explicit caution against use of the worm drive clamps. problem was stated that under the worm part of the clamp is a pressure concentration which can cause the plastic fittings under the hose to crack and leak.

 

[xmac81]

Point well taken...
I'll still replace them with worm clamps, but be careful not over tighten them. They are too much of a PITA to re-use in that tight confined space!

...also, this is the PERFECT time to replace the serpentine belt tensioner! If we don't expect the timing belt tensioner to last longer than 120k miles, why would we expect the serpentine belt tensioner to?

I want to do this job once and enjoy driving the car till 240k miles...

 

[bloc]

They are too much of a PITA to re-use in that tight confined space!

Not if you have a pair of these:

Remote spring clamp pliers. Worth EVERY PENNY of the ~$35 they cost. I don't know if you've worked with the intercooler pipes on a Mk4, but down by the intercooler.. the spring clamps take a special kind of person to not fantasize about nuking the whole world. This tool makes those a 5-second job.

I also have a pair of these for when radial access is better than tangential:

 

[Andy_2009_JSW]

Nice write-ups and pics guys.

So I had my 2009 in for a radiator leak (it was in the core, had to be replaced) and had my 120K service done as well while it was at the dealership anyway. I asked them what it would be to change out this t-stat as a proactive measure since they were already well into the engine so to speak. My jaw dropped when they told me $600+ even after some minor discount, and that it required taking off the intake manifold...!!! Told them hell no on doing that. Don't know if the intake manifold removal was/is perhaps the "official" method to get to it or not, but thought I'd pass along that tidbit.

 

[chittychittybangbang]

It's a major PITA. http://www.myturbodiesel.com/wiki/thermostat-removal-and-replacement-cjaa-tdi-engine/ Here are my notes and pics on it, very time consuming and a dumb design.

 

[mctdi]

Nice write-ups and pics guys.

So I had my 2009 in for a radiator leak (it was in the core, had to be replaced) and had my 120K service done as well while it was at the dealership anyway. I asked them what it would be to change out this t-stat as a proactive measure since they were already well into the engine so to speak. My jaw dropped when they told me $600+ even after some minor discount, and that it required taking off the intake manifold...!!! Told them hell no on doing that. Don't know if the intake manifold removal was/is perhaps the "official" method to get to it or not, but thought I'd pass along that tidbit.

I did not remove the intake manifold, but the two parts just before it. To have room to work. The dealer I go to for big jobs, told me it would be about 4 hours.

 

[meerschm]

if the accessory belt tensioner lets go, it will not cost you as much as if the timing belt one does. also not so touchy.

 

[xmac81]

if the accessory belt tensioner lets go, it will not cost you as much as if the timing belt one does. also not so touchy.

The one bolt that holds in the tensioner is on the backside, right below where the thermostat is. So to me, it's a no brainer. I have a new serpentine belt that was included in my timing belt kit, and everything is removed, so I'll just take care of it. Just a $70 insurance policy (tenisioner cost) to keep the family from being stranded and incurring a towing bill. I think I did see a thread where one user said his serpentine belt kinda shredded away and the strands walked into the timing belt area which caused problems...

 

[xmac81]

Well, the thermostat job is done now...

Couple of additional notes:
1. I found that using the coolant and pre-wetting the O-Rings on both the plastic tube and new thermostat wasn't helping with the installation. I ended up using a very thin coat of silicone grease that is used for installing O-Rings on plumbing fixtures. This helped with the installation immensely!
2. While I had the throttle body off, I used some old toothbrushes and throttle body cleaner to clean the throttle body throat and what I could get to of the still installed EGR throat. There was a light buildup.
3. After assembly and coolant was added, there was a small drip leak. I traced it down to one of the large radiator hose that attached to the bottom of the thermostat. Since I replaced all the spring clamps with screw type and positioned them to be accessible once assembled, I just used a long reach 1/4 drive extension to tighten it a little more. The leak stopped afterwards. Due to a previous reply in this thread, I was careful not to over tighten the clamps so that the plastic housing would not fail due to the pressure.

 

[Matthewhovis]

How did you drain the anti-freeze? I am having trouble locating any coolant tubes to un-clamp on my 2010 2.0 TDI. Thanks ~Matthew Hovis

 

[mctdi]

How did you drain the anti-freeze? I am having trouble locating any coolant tubes to un-clamp on my 2010 2.0 TDI. Thanks ~Matthew Hovis

Some have disconnected the hose from the overflow tank at the tank, and pulled is through to under the car to drain most of the coolant. One can also use an evacuator down this hose.

 

[Henrick]

Best way to drain coolant is from under the car - disconnect one hose of electric coolant pump which is in front of oil pan.

Question: does anyone have the above thermostat laying around? Is it possible to disassemble the plastic part and replace only the thermostat element, which is inside?

This entire part is overpriced..

 

[mishkaya]

Best way to drain coolant is from under the car - disconnect one hose of electric coolant pump which is in front of oil pan.

Question: does anyone have the above thermostat laying around? Is it possible to disassemble the plastic part and replace only the thermostat element, which is inside?


This entire part is overpriced..

No, you cannot. I still have my old one somewhere, and I do not think it can be taken apart without damaging the housing. I thought it would have been nice to just replace the thermostat portion for when needed in one my other vehicles.

 

[Henrick]

I have done some more research on this.
It seems that there has been a part number switch somewhere in 2011-08.

As for my 1.6 TDI engine (which uses 92 *C t-stat - it looks the same as in pics), the part number was 03L-121-111-R which later has been superceeded by 03L-121-111-S.

I did some google on the images for the first part number, and I can see that the flange at the bottom has got three screws:

To me it seems that under those screws the conventional t-stat hides. I wonder the measurements of it; VW earlier used t-stat elements rated for 92 *C in older diesels.

I think that if there would be a possibility to repalce just the element, this project would be less labour consuming and less PITA overall assuming the entire flange won't need to be removed from the car and there is decent access from the bottom....

... something what I might want to check upon my upcomming oil change

 

[runonbeer]

There is a small bolt behind the oil filter housing that secures the composite coolant pipe to the front of the block. Take this bolt out and you'll have a much easier time getting the thermostat assembly out/in.

Stick with spring clamps, just get the proper remote access cable operated tool. I like the ones at Sears.

 

[ThomasCo]

8. Remove the upper alternator bolt and loosen the lower one to rotate the top of the alternator toward the radiator side. This gives you the room needed to slide the thermostat assembly off of the horizontal plastic tube.

Question to xmac81 or anyone who can answer. Do I need to remove the belt from the alternator pulley before I can rotate it??

 

[k3ys3r_soz3]

Question to xmac81 or anyone who can answer. Do I need to remove the belt from the alternator pulley before I can rotate it??

I just did this job this weekend ( I have the same car as you btw) and removing the belt helps but I wish I didn't touch the alternator at all - it was a royal pita to push it back to its original spot. I ended up having to use a deadblow hammer to coax it back to its original position because there is nowhere really to place a prybar to get it back up so I could get the top bolt back in. I have 3 torque wrenches and none of them would fit even with the alternator pushed fully forward to torque the thermostat lower bolt so that was a complete waste of time for me. I was able to get the thermostat out without moving the alternator at all and I was able to get to the bolt behind the oil filter without having to remove the oil cooler. Just takes some very specific small tools that I happened to have. After spending the whole weekend on this frustrating job the o-ring on the hard pipe decided to leak and dump all the coolant on my test drive . Not sure if you can just buy a replacement o-ring for the hard pipe but thanks to that lil bastard I'm out an entire bottle of coolant and back to square one.

 

[ThomasCo]

I just did this job this weekend ( I have the same car as you btw) and removing the belt helps but I wish I didn't touch the alternator at all - it was a royal pita to push it back to its original spot. I ended up having to use a deadblow hammer to coax it back to its original position because there is nowhere really to place a prybar to get it back up so I could get the top bolt back in. I have 3 torque wrenches and none of them would fit even with the alternator pushed fully forward to torque the thermostat lower bolt so that was a complete waste of time for me. I was able to get the thermostat out without moving the alternator at all and I was able to get to the bolt behind the oil filter without having to remove the oil cooler. Just takes some very specific small tools that I happened to have. After spending the whole weekend on this frustrating job the o-ring on the hard pipe decided to leak and dump all the coolant on my test drive . Not sure if you can just buy a replacement o-ring for the hard pipe but thanks to that lil bastard I'm out an entire bottle of coolant and back to square one.

Dude you are heaven-sent! First off, the o-ring part number you're looking for is 06B121687. Second, what kind of socket/tool did you use to get that 12-point screw behind the oil filter? It looks like an 8 mm but the specs on VW parts say it's an M7. I was going to try a T45 bit which is 7.8 mm but haven't checked the clearance yet (i.e., does the bit and my ratched fit behind the oil filter housing).