No water draining from exhaust manifold

regal_bill

Cadet
Joined
Sep 30, 2011
Messages
27
Good Afternoon!
I have a 1990 Volvo 5.7 (DP-A). While winterizing, I got no water to drain from the SB exhaust manifold. I got some wire (and zip ties, and nails) and have spend 2-3 hours trying to dislodge gunk. I can get the wire in about 3-4 inches, then I can't get it any further. I keep pulling out bits of gunk - moist black sooty gritty stuff, a couple of grams at a time. I can get a mirror and see down into the drain about 3-4 inches, then I can't tell if if turns or is just blocked. I pulled the port plug, and it looks to me like there are two channels inside. On the SB side I only see one - and what could possibly be one that is completely blocked off by that same black gritty stuff.

I can't get a good shot in with the wire because of the exhaust (see below). Do I keep chipping away at the gunk and hope at some point it breaks free? Do I pull the exhaust so I can get a better shot in to try to clean it out (and if so, how is that done? I'm assuming it's NOT as easy as loosening the hose clamps and pulling...). Is there something I can pour into the manifold at the thermostat side to eat away from the inside?

I've never pulled this drain plug before - for 20 years I've been winterizing by feeding antifreeze in through the muffs. Yes, I know people cringe at that, but it's worked okay for me - although not pulling the plugs probably contributed to the gunk buildup. I gave up with the muff method because I can't get the engine to pull the AF in anymore.

I poured AF into the manifold until it came out the drive unit, but without draining it first, I have no idea what the mixture with the water that was inside is. I'm most likely still a freeze risk.

Any help, ideas, suggestions would be greatly appreciated!

Bill20211016_142925_resized.jpg
 

regal_bill

Cadet
Joined
Sep 30, 2011
Messages
27
I tried a little, but sort of half heartedly (I ran out of air and didn't have electricity nearby). I can try again (with electricity). Wouldn't the air just come out the exhaust though?
 

regal_bill

Cadet
Joined
Sep 30, 2011
Messages
27
"Chunks" is over selling it. I get bits, a couple of grams at a time. I tried the compressor again - just blowing out the exhaust.
 

regal_bill

Cadet
Joined
Sep 30, 2011
Messages
27
You're saying that blowing out the manifold from the t-stat - so only air is coming out the exhaust - is sufficient to expel all the liquid? Since the exhaust exits at the top of the manifold, it seems to me (NOT a mechanic!) that there would still be quite a bit of residual liquid in the lower reaches of the manifold.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,582
No, air into the bottom of the exhaust manifold water connection. Blow that out and then see if the water flows back out the same drain
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,304
If your manifold is that plugged, pull the manifold
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,582
I see. The logic being that the manifold will drain out either side?
I'm sorry, guess I'm missing something not shown or realized in the pic.

My assumption is the water comes into the Man from the bottom and exits out the elbow and out thru the prop. There is one hose coming from the thermostat housing into the bottom of the Exh Man, and only one. If yours is not this way then advise
 

regal_bill

Cadet
Joined
Sep 30, 2011
Messages
27
Apologies if I was unclear. The elbow in the pic - center bottom - is actually the fuel line going to the filter. Water enters the manifold on the right/fore side (through an elbow, but not really visible in the pic) - at a level just above the six mounting bolts. The drain is on the left/aft side at the same level. The purpose of the pic was to show how close the exhaust line is to the drain, and how I couldn't get a clear shot into the hole with a wire. My assumption is that water is forced up through the top of the manifold, and runs out with the exhaust through the hose clamps and exhaust line at far left.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,582
ok thanks.
Don't bother with the drain on the right since its hard to get to. Disconnect the hose on left going into the exhaust and drain it there
 

regal_bill

Cadet
Joined
Sep 30, 2011
Messages
27
"The hose on the left going into the exhaust" - you mean the big hose at the top of the manifold? That won't drain anything? The problem drain plug is on the left, not the right. I can disconnect the water input hose (at the right, from the t-stat) - I thought that's what you were recommending?
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,582
Pic below is closed cooling but connection is the same for raw water. To the right there is a hose connected which moves cool water in. There is a plug on the left.

Remove the hose, not the plug to drain the manifold

maxresdefault.jpg

This one also has a blue drain plug in the bottom center, don't think yours does
 

regal_bill

Cadet
Joined
Sep 30, 2011
Messages
27
Geez - hopefully you didn't pull that just for the pic!! Thanks for the discussion and the advice. As for the blockage at the drain - should I worry about that, or just leave it be and drain as you suggest going forward?
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,802
That does seen odd, I've been draining raw water cooled manifolds in salt water for many years and never ran into that. Unless the boat sucked up silt and it passed though the raw water side of the cooling system and clogged the manifold. Has this manifold been running hotter than the other? If so I'd probably pull the manifold and blast it out with a garden hose.
 

regal_bill

Cadet
Joined
Sep 30, 2011
Messages
27
That does seen odd, I've been draining raw water cooled manifolds in salt water for many years and never ran into that. Unless the boat sucked up silt and it passed though the raw water side of the cooling system and clogged the manifold. Has this manifold been running hotter than the other? If so I'd probably pull the manifold and blast it out with a garden hose.
Hard to say. I've had the boat for 20 years - fairly sure I've never sucked up silt like that. Can't speak to the boat's first 10 years, though (and, like I said, I've never pulled this plug before, so I can't say it wasn't like that when I bought it). I'll have to check the manifold temps in the spring - thanks for the idea.
 
Top