Thermostat replacement how-to

Anyone know of a B5 thermostat replacement "how-to"--pref. w/ pics, of course--somewhere on the Net? Or if you, gentle reader, could add one (even w/o pics) to our "how to," I'd be much obliged. Thanks!

OlyDLG

Pretty easy, just 2 screws. BUT, only use a genuine OEM thermostat, get a new water neck, new o-ring, and some G12 coolant.

Part numbers:

044-121-113 thermostat
038-121-119-B seal ring
038-121-121-B adapter
G-012-A8F-M1 coolant

It is in the connection at the side of the block, behind and below the alternator, more-or-less out in the open on the BHW. The new thermostat twist-locks into the new adapter, with the o-ring squeezed between, for ease of assembly.

oilhammer said:

Pretty easy, just 2 screws. BUT, only use a genuine OEM thermostat, get a new water neck, new o-ring, and some G12 coolant.

Part numbers:

044-121-113 thermostat
038-121-119-B seal ring
038-121-121-B adapter
G-012-A8F-M1 coolant

It is in the connection at the side of the block, behind and below the alternator, more-or-less out in the open on the BHW. The new thermostat twist-locks into the new adapter, with the o-ring squeezed between, for ease of assembly.

Click to expand...

Thanks! BHW=?

The engine code for that car. Or "Bring Heavy Wallet" to some folks.

OK, thanks!

DG

OH - why replace the neck? Is it practically guaranteed (i.e., engineered) to break on removal?

Oh please Mr. Kotter, Mr. Kotter... can I answer??!!!!

You replace the neck because:

a) guaranteed that during removal you will break the little plastic fingers that hold the t-stat in place for reassembly... the t-stat is going to stay behind in the block, locked with the o-ring. You could use a string, etc to hold the new t-stat in place, however... see 2 and 3

b) they are plastic and *love* to warp... causing leaks that will drive you crazy since they are hidden by the big engine bracket at the front

c) they are dirt cheap

Three strikes... in my books... they're OUT!!

Also there is o-ring N 907 653 01 in the connection between the adapter and the radiator hose. It may survive being reused, but I prefer to replace since I'm there.

I may be able to put together a PDF by week's end if the parts arrive on Wednesday (weather permitting). I'll also have one for the coolant temp sensor replacement.

Neither of these are as easy as on the transverse mounted engines.

I'll also have a new method of refilling the cooling system. VW's latest procedure applies vacuum to the system and then lets that vacuum suck in the coolant. Yes, there's a special tool for this.

I have had one of those vacuum things for years, it is kinda hit-and-miss on its effectiveness, but I have never tried on the BHW. It is noisy too (uses shop air).

dgoldsmith said:

Anyone know of a B5 thermostat replacement "how-to"--pref. w/ pics, of course--somewhere on the Net? Or if you, gentle reader, could add one (even w/o pics) to our "how to," I'd be much obliged. Thanks!

OlyDLG

Click to expand...

Here are pics, feel free to look around my site for more handy FAQ and DIY
http://www.myturbodiesel.com/1000q/b5/thermostat-replacement-vw-passat.htm

Great site CCBB. Thanks for having it there for us.

chittychittybangbang said:

Here are pics, feel free to look around my site for more handy FAQ and DIY
http://www.myturbodiesel.com/1000q/b5/thermostat-replacement-vw-passat.htm

Click to expand...

Thanks! I'm in the end game, but having trouble getting the old flange off its hose--is there a "trick," or "just keep pulling"?

chittychittybangbang said:

Here are pics, feel free to look around my site for more handy FAQ and DIY
http://www.myturbodiesel.com/1000q/b5/thermostat-replacement-vw-passat.htm

Click to expand...

Also, with regard to the linked coolant refill instructions, please clarify (perhaps w/ pictures) the instructions "Remove the upper radiator hose and fill as much coolant mix as you can. (Paragraph) [Then] Put back and secure any hoses/drains that [one] loosened earlier."

Is there a trick to removing the upper radiator hose? I figured out that that little metal ridge-loop comes up, but it didn't make it any easier to pull the hose off the radiator intake; or am I even trying to get the correct hose off (this is where a picture would help, e.g.)? Then we're supposed to "fill as much [mix] as [we] can": fill what, the radiator hose? I have to assume so based on what comes next, but I don't like having to assume things when I'm working on a $30000 car. _Then_ we're supposed to "secure any hoses/drains [we] loosened earlier"--this is why I assume earlier that "fill" can't refer to the radiator, but maybe you accidentally mixed-up the order when writing this, I don't know. So please, help!!!

OlyDLG

If you have questions about content on another site, please post those questions there.

Personally, I don't recommend following that procedure.
I'd secure any drain before attempting any fill, for one.

Leave all hoses attached, fill it through the expansion bottle. Make sure you allow air to come out of the smaller hose attached to the bottle. Allow it to settle down. See http://forums.tdiclub.com/showpost.php?p=1808372&postcount=11 for how to bleed air out of the system.

MOGolf said:

If you have questions about content on another site, please post those questions there.

Click to expand...

But it's a follow-up to _this_ thread, plus I, ostensibly, have the attention of the "other site's" author here (though perhaps I don't, evidently).

MOGolf said:

Personally, I don't recommend following that procedure.
I'd secure any drain before attempting any fill, for one.

Click to expand...

That's what I thought.

MOGolf said:

Leave all hoses attached, fill it through the expansion bottle. Make sure you allow air to come out of the smaller hose attached to the bottle. Allow it to settle down. See http://forums.tdiclub.com/showpost.php?p=1808372&postcount=11 for how to bleed air out of the system.

Click to expand...

Thanks. Given the quality of that other site, does anyone else have a "how to" for thermostat replacement? (Or can at least tell me how to get the old flange off?)

Thanks again!

DG

Yes, I just wrote one. BHW_Engine_Thermostat_Replacement.pdf

It is listed in the How-To thread here now too.

Thanks!!!

dgoldsmith said:

...plus I, ostensibly, have the attention of the "other site's" author here (though perhaps I don't, evidently).

Click to expand...

Sorry, I have so many online conversations at the same time that it's not possible to keep track of them all. If you have any questions about something you see on my website the best way to get my attention is to send me a PM here or post a message on my site. Looks like MOGolf put something together that you found satisfactory so the important thing is that you got your answers.

MOGolf said:

Personally, I don't recommend following that procedure.
I'd secure any drain before attempting any fill, for one.

Click to expand...

Installation is the reverse of removal! Do you see any other errors? I gladly accept any constructive criticism to improve the articles on my site.

Finally done: despite its simple appearance, this one was a nightmare--I don't recommend it for the amateur, break down and pay a professional!

It finally dawned on me: my engine, esp. on that side, may be much harder to work on than the typical one due to the presence of a greasecar kit--lots of extra hoses and hardware, methinks.

dgoldsmith said:

It finally dawned on me: my engine, esp. on that side, may be much harder to work on than the typical one due to the presence of a greasecar kit--lots of extra hoses and hardware, methinks.

Click to expand...

You have a greasecar kit on a the Passat BHW? No wonder.....this is a first I believe.

Not according to the company's founder, Justin Carven (quoted from an email he sent me): "My wife and I drove a 2005 Passat for two years through our cold New England winters without issue, it sounds like you may have a problem with your thermostat if your engine coolant is not heating up."

Anyway, I bought the car that way...

I have not heard of anyone else (besides you) that is routinely posting here with a greasecar kit on a $30,000 car. Most folks put them on old Jetta's without PD injectors so when they ruin an injector, its not a $600 replacement.

Good luck.

As I said, I bought it that way (used--not for $30K): The Green Car Co. here in Bellevue, WA put it in at the request of a couple whose financing fell through, so then they had this car they weren't expecting to have in inventory at the same time that my '03 Jetta needed a new fuel injector pump (I think it was). I'm very happy w/ it, but I'll be more so if/when I can get the thing to run "at temp" so it can heat up the veggie oil to a usable temp.

aja8888 - "Kevin" has had his 2005 running on vege since 2004. http://getoffoil.blogspot.com/ I use the word "running" loosely, given that he has trashed one engine so far...

owr084 said:

aja8888 - "Kevin" has had his 2005 running on vege since 2004. http://getoffoil.blogspot.com/ I use the word "running" loosely, given that he has trashed one engine so far...

Click to expand...

Thanks, I had not seen that site by Kevin. With so few of the BHW's out there, and the expensive issue with the balance shaft upgrade facing all owners, I wouldn't expect to see one with a grease kit as those are usually put on older TDI's and non-TDI diesels that don't have PD injectors and are not that expensive of a car to start with. But, a new engine for the BHW is only about $8,000.00 or so.

Do these go bad very often?
Is this a replace only when needed or should it be done along with the waterpump during a timing belt R&R?

They SHOULD last 100k miles and be done with timing belt. That said, my last one failed about 20k miles after it was replaced.

glad I don't have to worry about collecting grease for my car. From what I've read, grease should be sure death for a pd tdi engine, even changing oil every thousand miles or so. also sounds like the grease carbon buildup on Kevin's gp's probably contributed to his engine's demise.