Osirus9

iTrader: (10)

So I'm putting coolant into the system for the first time since I tore the engine down and just as I'm almost done I see some coolant leaking out over the top of the engine on the driver's side. I trace it back to the coolant bypass hose that connects the rear iron to the TB. This hose is conveniently located where nobody could ever possibly get to it so I pull off the whole UIM. but as I remove it I see that there is coolant INSIDE the elbow (s4 Turbo "elbow" that connects the TB to the TMIC)

how in the world did coolant manage to get INSIDE the TB?? the engine never RAN, so it had to have seeped in through somewhere else right? anybody got any ideas?

just don't say I need a new TB... cuz im out of teh monies

SureShot

That coolant circuit works the thermo-wax pull off for the fast idle cam and also stabilizes the temperature of the BAC.

Yes, you have to pull the UIM to get to it, but it only should need replacing once every 10 years.

How coolant got in the TB inlet is probably not directly related. Maybe the PO splashed some in the intake sometime in the past while the engine was running?
If the small coolant line leak sprayed in just the right direction, the intake could have sucked it in?

Osirus9

iTrader: (10)

there's no way the intake could have sucked anything in, the car hasn't been running in almost 2 months.

I already pulled off the UIM and took a look inside the TB, and sure enough, fresh coolant was in there.

the car is 20 years old... so ya think it's due for a new thermo-wax? I've only owned the car for 2 months, so maybe one of the previous owners replaced it, but I doubt it considering the state the rest of the car was in when I bought it. can I just remove this thing and run the coolant line straight from the block to the BAC?

Osirus9

iTrader: (10)

I'm going to reinstall the UIM and tighten the hose up real tight.

then pray...

Icemark

so this is a Turbo? If so, I'd look at a coolant seal failing in the Turbo

Osirus9

iTrader: (10)

here is my UIM assembley. I took off the thermowax and I am wondering what to do with the spare vacuum lines/spot where the thermowax used to be.

is my picture right???

SureShot

If you're deleting the thermo-wax then you can delete that whole 3/8" coolant circuit along with the aluminum attachment on the BAC.
I did it by scrounging up some steel pins that press fit in the nipples & capped them off.
Now your getting close to what we call the TB mod. You can remove the secondary double throttle & its linkages & vac lines. Plug the shaft holes & cap the vac nipples.
Here's what it looks like on an S5 NA.

Osirus9

iTrader: (10)

I see....

well for some reason my picture isn't displaying now, but it was before. anyways. I have an s4 turbo, so I think my tb looks quite a bit different from yours. I want to keep the secondary throttle plates (for now) and just remove the thermowax since its the thing leaking coolant.

anyways, what do I do with the 2 vacuum lines that used to hook up to the thermowax?

I was just gonna cap them both off. is that a good idea? I don't know exactly how the thermowax works, so I'm not sure how to properly delete it.

SureShot

You can cap them off.

While you're in there check the secondary double throttle to make sure it's opening.
As that dash pot & cam gets old it tends to stick closed.
You can just wire it open.