Mann.

Could hear it in the cabin today so I whipped out the phone and took a vid once I got to my parking garage.

Once at idle for a minute or two it quieted down...before I took the vid I gunned the throttle a couple times and it came back.

Well, it was the heater hose. I tore everything out, slapped some of that electrician's goo over the hole in the firewall, and it works. What an ENORMOUS pain in my a$$!

Thanks for the help

Actually, screw it, I found the mod where people bypass the coupler and simply use 5/8 heater hose

However, I'd still appreciate any insight on what''s in that green circle!

Well, let me partially answer my own question. Appears that I need:

http://www.fcpgroton.com/product-exec/product_id/1757/nm/1994_1997_Volvo_850_Turbo_Outlet_Heater_Hose_Engine_to_heater/category_id/80

http://www.fcpgroton.com/product-exec/product_id/1764/nm/1994_1997_Volvo_850_Turbo_Inlet_Heater ...

Also just noticed the little cracked hose and oily? residue around the greent circle. Whassat?!

Been losing coolant the last few days, getting progressively worse. Finally tracked it down to this hose:

http://i46.tinypic.com/rmjya1.jpg

The red mark indicates the hole...with throttle it's actually spraying coolant up onto the fireall/windshield with the hood up.

I tried to get underneath ...

Oil pressure light has NEVER come on.

I'd like to do one more change and throw in some Lucas snake oil and see what happens.

My 170kish 850 GLT wagon has a valvetrain tap at hot idle (sometimes) and cold start. I suspect the sump o-rings. It's been going off and on for maybe four months. I run Mobil 1 10-30 high mileage and Mann filters.

I just did the timing belt/water pump/etc. a few weeks ago and am a little fatigued ...

Thanks for the replies - I will give it "fresh" (as fresh as I can after a two day intensive roadtrip) eyes this afternoon.

Water pump is in fact new. Old one looked fine, probably could have left it alone.