Coolant puddles under Passat

[jw4free]

So I ordered up the Oil Filter housing, gasket, thermostat assembly, and coolant.
I will be taking the intercooler off and replacing the defective unit when the parts show up and weather permits.

Where is a good place to get the lower intercooler elbow? Mine has a cut (not through) and is soft from heat and coolant exposure?
Thanks.

 

[oilhammer]

Your local dealer.

Not sure how you are going about the job, but it is much easier with the front of the car off. Given the placement of the A/C lines to the condenser, you can leave those attached, and with a suitable way to support it, you can "swing" the lock carrier assembly out of the way, as I did on this V6 B5:

A tip for slipping the pipe loose from the thermostat housing:

Unbolt it from the front of the block, then get a long extension and swivel with the XZN bit and loosen (but do not remove) that bolt holding the pipe to the flywheel end of the block, back underneath the vacuum pump area. This makes that pipe move enough to make the thermostat R&R much, much easier, and you won't have to mess with the belt or alternator or any of that. Make sure you replace that double-lip o-ring on that pipe, too. The thermostat assembly already comes with a seal on it (the one to the block). Lube that double-lip guy with clean coolant, and use a little mirror to make certain it has slipped completely into the housing on the blind side, because if not careful it can roll out, and as soon as you go to fill the cooling system you'll have a pink puddle (ask me how I know).

 

[jw4free]

Amazing.
thanks so much for the images.

 

[jw4free]

Well, I put the car up on jackstands to investigate/ confirm the coolant leakage.
The left side of the block is bone dry. The fluid on the intercooler coupling was oil from a lazy oil filter change. The right side of the engine (above the right axle) is drooling oil. Like it’s been doing for about 75k miles.
The puddle of coolant is actually next to the right tire. It appears to be leaking from behind the timing belt cover.
Are there any bolts that thread into the water jacket over there, or do I need to psych myself up for another timing belt and water pump change?

 

[oilhammer]

That sounds like the water pump has started leaking.

 

[eugene89us]

I think the only things that can leak on that side are the expansion tank and antifreeze lines running from it. But their leak will be blatantly obvious. If the coolant leaks from behind the cover, I am afraid the water pump is the likely scenario. When doing TB change at 110k miles, there were coolant streaks all over the place. The pump would leak barely and belt would create air movements that spread pink dry stuff all over the place. When I removed the water pump, there were dried coolant spots all over including on the outside of gasket. When was the timing belt changed last time? In order to remove lower TB cover, you would have to remove the harmonic balancer pulley, which will require you to change the 4 bolts that hold it in place, since they are stretch bolts. You can wiggle the top cover off without removing the bottom one in case you think you could see it. But frankly, I would go ahead and remove the wheel well cover, remove the accessory belt, remove the harmonic balancer, and the bottom cover. You will be able to tell, without any doubt in your mind, whether that is your culprit.

I think sooner or later I may be in the same predicament as you, because when I changed my TB and removed old pump, there was a lot of dried up coolant. I used scotch brite pad to clean mating surfaces, but thinking back, I don't think I went aggressive enough. There were still parts of the mating surface that did not feel perfectly smooth. I achieved a good seal, but I may not have it for long. But you don't want to get too aggressive and mar the aluminum surface. OH, you're in the trade, do you have suggestions for cleaning off the dried up coolant in the water pump opening? I didn't know of something fine enough to avoid gouging metal, yet strong enough to get rid of hard dry deposits. Scotch brite did not do a complete job I am afraid.

 

[jw4free]

How about a leaking egr cooler? Passenger firewall side. I have a few pictures I can upload.

 

[eugene89us]

How about a leaking egr cooler? Passenger firewall side. I have a few pictures I can upload.

Great - another point of failure. If you have a chance, please share some pictures for us to see. Thanks.

 

[Dalon]

Your local dealer.

Not sure how you are going about the job, but it is much easier with the front of the car off. Given the placement of the A/C lines to the condenser, you can leave those attached, and with a suitable way to support it, you can "swing" the lock carrier assembly out of the way, as I did on this V6 B5:

A tip for slipping the pipe loose from the thermostat housing:

Unbolt it from the front of the block, then get a long extension and swivel with the XZN bit and loosen (but do not remove) that bolt holding the pipe to the flywheel end of the block, back underneath the vacuum pump area. This makes that pipe move enough to make the thermostat R&R much, much easier, and you won't have to mess with the belt or alternator or any of that. Make sure you replace that double-lip o-ring on that pipe, too. The thermostat assembly already comes with a seal on it (the one to the block). Lube that double-lip guy with clean coolant, and use a little mirror to make certain it has slipped completely into the housing on the blind side, because if not careful it can roll out, and as soon as you go to fill the cooling system you'll have a pink puddle (ask me how I know).

Not to hijack the thread but do you think there is enough space to make the plastic intercooler pipe out of constant diameter stainless? It seemed like there would be but I haven’t had a good look

 

[jw4free]

EEF106BF-7D2F-4FBE-8FA4-DCC6ABF0322E.jpeg

• jw4free
• Feb 13, 2023

Coolant leak along timing belt cover.

54F42DBC-C61E-4D21-BD7F-3D03E70ED660.png

• jw4free
• Feb 13, 2023

Coolant leak _2

 

[jw4free]

In the dirty image and then the cleaned up screenshot of video, hopefully you can see the line of coolant following the mating line between the block and front crank seal housing. (I’m guessing at the part name). It comes from just above ( behind the rear timing cover. I’m guessing the seal of the water pump.

 

[jw4free]

Speculation: During the -10f weather here shrinkage between the iron block and aluminum pump and rubber o-ring allowed a decent amount of coolant to leak out over a few days. Since the temps have warmed, it’s barely a teaspoon of fluid over two nights.

I put the car back together and intend to drive it until the leak rate becomes higher that a monthly coolant topup of the reservoir. Radiator coolant, it’s a consumable now.