WTF VW?

I suppose anyone with VWs in the last 15 years knows the water pumps are a trouble spot. Well, I got the coolant-flow ECS lights/code this week (78k miles) which is pretty much a dead-ringer for water pump or thermostat, which is a complex assembly that's run by an electric motor with multiple connected valves (the water pump itself is belt-driven). Anyhow, the car went from fine to "insufficient coolant flow" for no reason - odd since no sign of weeping/leaking from the assembly, no coolant loss.

So pulled it off, and the theromostat assembly, as mentioned, is ridiculous in its complexity to do something that should be pretty simple. DIdn't see anything obvious - good movement on the water pump, no sign of leaks, wtf. Well, time to take it apart. At one end is an electric motor that opens various cooland valves, so basically a secondary theormostat I guess. Figured the motor must have died or something, but instead I found this:

See that little gold gear I'm pointing to? It's not supposed to be there, it's supposed to be on the motor, to turn the worm gear, which then turns the larger gear, and then opens and closes two valves inside the assembly.

like so:

Anyhow, it somehow slid off (not pinned on there, wtf....) and of course nothing happens and the valves were partially stuck closed and restricting coolant flow enough to put the engine in limp mode

What a dumb berkeleying design. I assume it must be something to help warm-up emissions by 0.0001% or something, but whatever.

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Side note: I picked up an aftermarket one that eliminates all that and just uses a regular thermostat inside. It has a little circuit board to trick the car into thinking the motor/gears are still there, and seems to work fine. Car temps are normal, car runs great now, no codes....

comparison

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Side note 2: The other thing that started not working last winter (on the coldest day) was the heater valve....car wouldn't have any heat for like 15 minutes after warming up, and sometimes longer, so that made for some cold morning commutes. As it turns out, the heater valve on these is ALSO electric, and also in a highly inconvenient place to get to it - I finally just replaced it since it's easier to do with the intake manifold and stuff off.  I'm sure this is common with new cars with electronic controls, but seriously, at least put it someplace easy to change out when it fails....

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Side note 3: 78k miles and man my valves has a metric ton of carbon on them. So we did a good cleaning, while the IM was off (took 3 hours without walnut blasting in my garage...)

The coolant flow in the engine sometimes only goes through the cylinder head, one of those valves blocks off flow to the engine block.  Or something like that.

It's better than the setup Ford uses on the 1.6 Ecoboost.  There are three *external* coolant shutoff valves sprinkled all around the engine bay, hoses running everywhere, and the valves love to burn up electrically.  They run the coolant only through the exhaust valves side of the head, then through the whole head, then through the engine.  When it works.

Subaru has a setup similar to the VW one on the FB25s.  It fails too...

I'm convinced Rube Goldberg is a national hero in Germany.

Credit where it's due, though - the Passat's maze of coolant lines with a high temperature and low temperature circuit never seems to trap air bubbles even if you replace something with no obvious way for air bubbles to escape.

Man, that's goofy.

Man. WTF indeed.

We went car shopping this past Saturday and my wife asked my thoughts on VW. This post perfectly illustrates my response...

I'm not sure any of the modern cars are different, or any better in that respect...

SMH

Are these engineering teams filled with a bunch of guys going "I know, I know, what if we added this to do that" without anyone willing to ask "why not just keep it simple?" Basically a bunch of Rune Goldbergs.

I'd really like to understand the thinking. If you're going to complexify it, at least put a pin or something to hold that gear on!

There is more than one reason I got rid of my MK6 GTI. I loved the car but there is some weirdness in them. 

Chasing MPG efficiencies has mean a radical transition in the complexity of the Thermal Management.  Nearly everything is now going to complete TMM Thermal Management Module units which are typically self contained and relatively unrepairable.  The plan is for them to have the motor to optimum temp almost immediately and prevent it from varying by more than a few degrees.  

These guys are a pioneer of this but there are many others now as it was first launched ~10yrs back.  Schaefler.

How very German. 

Ford is proud that some of their engines can go from dead cold to full operational temperature in under 60 seconds.

Fast warmup is a huge priority.

Don't complain in the winter when your heat takes longer to heat. There are upsides and downsides to tech. I like my buns toasty fast and if its one thermostat module or two in a cars life, and it didn't even need to be towed, I think thats a win. 

In reply to Paul_VR6 (Forum Supporter) :

I live in the South and am insulated like a walrus. I could not care less about warm-up as long as the AC is ice cold. 

I guess adding a pin to keep that gear in place would negatively impact the engine warming up.

It looked like there is some sort of stop on the PCB to keep the gear from sliding off the shaft. 

Are you sure the gear didn't come off during disassembly? 

84FSP said:

Chasing MPG efficiencies has mean a radical transition in the complexity of the Thermal Management.  Nearly everything is now going to complete TMM Thermal Management Module units which are typically self contained and relatively unrepairable.  The plan is for them to have the motor to optimum temp almost immediately and prevent it from varying by more than a few degrees.  

These guys are a pioneer of this but there are many others now as it was first launched ~10yrs back.  Schaefler.

 

Came here to say this. It's all about that thermal efficiency to hit those EPA or EU marks. That looks like a very complex system and appears you did the smart thing in going with a more simple setup. What car is it irish?

Paul_VR6 (Forum Supporter) said:

Don't complain in the winter when your heat takes longer to heat. There are upsides and downsides to tech. I like my buns toasty fast and if its one thermostat module or two in a cars life, and it didn't even need to be towed, I think thats a win. 

I have three 1980s cars, I'm used to waiting for warm up.

And yes, it does take longer to get to operating temp now (even in May), but I live in Viriginia, not Alaska, so I'll survive lol.

The GTI has heated seats at least.

DirtyBird222 said:

84FSP said:

Chasing MPG efficiencies has mean a radical transition in the complexity of the Thermal Management.  Nearly everything is now going to complete TMM Thermal Management Module units which are typically self contained and relatively unrepairable.  The plan is for them to have the motor to optimum temp almost immediately and prevent it from varying by more than a few degrees.  

These guys are a pioneer of this but there are many others now as it was first launched ~10yrs back.  Schaefler.

 

Came here to say this. It's all about that thermal efficiency to hit those EPA or EU marks. That looks like a very complex system and appears you did the smart thing in going with a more simple setup. What car is it irish?

2018 GTI, but the part number applies to pretty much every single VW and Audi with this engine (turbo and non)

I wonder how Toyota or Honda handles this? Anyone know? Would be an interesting comparison 

In reply to amg_rx7 (Forum Supporter) :

Yeah, I'd love to see how Honda, Toyota, Mazda engineered this.

I had no idea they were so elaborate internally.  I just had mine replaced.  To my great shame, I paid a friend at a local shop to do it.  It's still under warranty but I don't want the lowest kid on the totem pole at the dealer trying to beat book time with the million plastic bits under the hood of my car.  

Huge shout out to FCPEuro.  I had the pump in my garage for months.  At some point, I left the box it in a stupid spot and my wife hit it with her car.  I didn't realize she broke off a fitting until I started taking the car apart (was going to do it myself initially).  Anyway, FCP has a very generous return policy and they gave me the value of the pump on my account despite it being 100% my fault.

GM uses a similar Coolant Control Valve with electric motors and an octopus of coolant hoses on the new 3- and 4-cylinder gas motors and the 3.0L I6 diesel. They die with amazing regularity, like, often before 5-difit mileage on the 1.3T.

amg_rx7 (Forum Supporter) said:

I wonder how Toyota or Honda handles this? Anyone know? Would be an interesting comparison 

They don't use iron blocks that require fancy coolant rerouting to get up to temperature?