so I just installed a fresh rebuild into my S5 T2 and the coolant passage on the rear and waterpump housing have been welded shut. I really wanted this car to be 100% stock. All fresh so I could put another 100K on the the car. So at this point the finishing touches are the upper intake, TB, and intercooler.

This also means there is no coolant flowing over the BAC.

Can I just tighten the screw on the thermowax to have a normal idle at running temp or am I going to have to mod the throttle body?

or... should I find a new waterpump housing and rig a line off the main water hose on the drivers side? my money is spread super thin and I am trying to get this car back on the road as soon as possible. Otherwise I am going to leave it as it sits and presumably drive it with a high "cold" idle.

I don't like the idea of the TB mod. I've never had one work right except for my last S5, but that was Halteched. So if someone has a USDM S5 T2 TB that has been modded and works correctly on the stock ECU and wants to sell it cheap (or trade for something) that will work even better.

 

Drill a 3/8" hole where it should go.
Tap a 3/8" NPT thread.
Buy a 3/8" NPT to 3/8" barb fitting adapter.

Hookup like stock.

 

I don't have tap set and I don't want metal flakes getting stuck in the cooling system otherwise it's a good idea.

 

Don't worry about a few metal chips in the cooling system.

If you just disconnect the coolant lines, you will always have the 1500 RPM idle regardless of whether the car is warm or not.

If you eliminate the thermowax/cold start cam assembly, then the car will be a pain to drive until it warms up as the engine will want to stall at low RPMs.

 

shocking, a few metal chips in the coolant system is ok?
hmm

so what else can i stuff in there!? legos? drugs? lol!!!

but yea, if oyu dont want to drill n tap...
you could always get a few fittings and tap from the heater core line, i beleave a tee and some hoses is all you need.
aaron, if this present a problem let me know now. it was just an alternitive.

 

If you screw in the screw that sits atop the water thermowax's piston, all the way, the cam and roller seperate and that results in the equiv of no thermowax device. Plates close all the way at idle.

 

lol that cracked me up!

yeah I could just see something like a little scrap getting stuck in the jiggle pin, weep whole, or some how screwing something else up. cooling system is the weakest part of the damn engine.

 

then my day has been a succsess!

I thought our apex seals were the weakest

 

Best idea here if you really want the car to drive like stock.

I actually put my thermowax back on after the previous owner had removed it. It's annoying to drive the car with no cold idle. It takes longer to warm up and just runs like crap, especially with no BAC like my setup. I went through a whole ordeal of trying to set all those throttlebody screws correctly because I didn't have a 100% pristine TB.

And if you think the cooling system is the weakest part of an FC, you've obviously never owned or worked on an FD. My 88 GTU had a bigger, better, and more reliable radiator, oil cooler, and other cooling system components compared to any US spec FD.

 

yeah I've been looking at this thing for an hour and going over the fc3spro mod. It seems like if I screw down the thermowax screw and unscrew the screw by the water outlet nipple then cap the nipples on the theremowax I could get it to idle like it should without removing anything.

the the BREW was designed to fail. two oil injectors, little oil coolers, twin turbo precat. they knew just from under hood temps it wasn't going to last long.

 

Why dont you take the waterpump off and take it to a machine shop then?

On top of that, how big do you think the metal flakes will be, this is aluminum were talking about here. Just clean it off as youre working, maybe use compressed air.

Youll be draining the system anyway, might as well flush it with clean water again anyway.