So, I have learned from past experiences that when I find two disconnected things that look like they should be connected, always double check the manual. In this case, I can't find this listed in the service manual. What is the hose connection that's just behind the oil filter? Should I plug in this loose hose that's coming out of my firewall between the heater and the battery box?

Mystery fitting:


Mystery hose:

The first "hole" is a coolant block drain. There's a hex part to put a wrench on and it loosens from a brass fitting in the block. You aren't the first to be baffled by that fitting. It's all brass and cleans up nicely.
I think the hose is/was part of an A/C installation. -- Dave

Thanks! Still getting this one sorted out. I think this engine has an appointment with some nylon brushes and a bucket of degreaser.

Fran;

Dave has it right on the block drain, of course...and don't take this wrong, but why would you ask about a hose on a forum, before having a look yourself where the other end of it goes?

Cheers

Hello Fran,

As previously stated, the do hickey on the side of the block is a drain for the coolant. That appears to be the later version used on the OHC Volvo engines and requires a 13mm wrench/socket to open/close. Don't over tighten since that piece is hollow and the sealing end can become distorted which can cause a leak.

Originally, all of the fuel injected B20 engines didn't come with a coolant drain, Volvo installed a plug even though all of the previous versions including carbureted B20s came with a drain. Curiously, all of the later engines, IE B21, B23 and B230, came with a block drain.

Whenever I am rebuilding a fuel injected B20, I always remove the plug and install a drain.

That "loose" hose is 1 of 2 drain hoses connected to the the air intake port drain pipes for the heater box. The other hose is located on the other side of the heater box.

FYI, it's a good idea to remove the air intake grille and inner plastic bucket to check if the drain holes are plugged which is a common problem. If the drains are plugged, water can accumulate inside the air intake and then into the car at either of the 2 fresh air vents.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com