Exhaust Manifold

S

Stars

Member
Joined
Dec 22, 2009
RO Number
31885
Messages
10
I've been doing this for years. Just draining the blocks, manifolds, water pumps, mufflers and refilling the blocks with anti-freeze (yes, the proper stuff) through the thermostat. And, I've also put about a half gallon in each manifold.

I wonder if I really need to add antifreeze to the manifolds? Is half gallon even worth it?

What do you guys that do, that are do-it-yourselfors?
 
I like the easy way. Open up the sea strainers, turn on engine and pour a couple of gallons of AF into the strainer. A couple of minutes and it's done.
 
You're right about the outdrives. OP didn't say what kind of boat/engine set up he has.
Of course, if the boat has outdrives and is trailerable, I take a short hose connected to the ear muffs, put a funnel in the other end and pour AF into the funnel while the engine is running. If the engine is RWC, take out the t-stat first.
Still quick and easy.
 
I just drain the manifolds/risers by removing the hose from the bottom of each manifold and let gravity do the work. Thats all I do to them.
I drain the blocks, then I remove the hose from the thermostat housing and pour the pink down it until the pink comes out of the housing.
I've never had a problem doing it this way.
 
I was always under the impression that by just draining them you are exposing the insides to air and speeding up rust. When I had raw water cooled motors I always filled everything with antifreeze.
 
An RO (DoubleD I think) had a flush kit for sale a couple of days ago. It's the model I used on my Regal. Worked really well.
 
quote:
Originally posted by zane

I was always under the impression that by just draining them you are exposing the insides to air and speeding up rust. When I had raw water cooled motors I always filled everything with antifreeze.

Click to expand...


For those people that just drain the engine or don't winterize and instead put a heater in the engine room...
When you start the engine the first time in the spring after sitting 3-4-5 months, look at your exhaust when the engine first starts. When you see what comes out, you will never do your engine again like that again. The exhaust looks like mud when you don't use AF.
 
Back when I had a boat with a raw water cooled merc outdrive, I would put antifreeze in the manifold. It was a straight six, so it only had one manifold. There was a hose barb on the front of the manifold, where the raw water entered the manifold. I would open the drain on the riser, which was on the downhill side of the riser at the exhaust output side. I would attach a hose to the hose barb that was long enough to get my funnel higher than the top of the riser. I would then pour antifreeze until it started to come out of the riser drain. I liked to think that antifreeze helped to slow down the effects of rust, during the off season. I now have closed cooled inboards, that have engine coolant cooling the exhaust manifolds. I don't have to worry about it now.

FWIW
eric
 
Closed or not, I think it's still raw sea water in the riser/manifold.
Still not sure about adding pink stuff to them. I only get about a half gallon of water when I drain them (each). That's why I've always added about a 1/2 gallon of pink. That's harldy enough to fill them up. In fact, you can only fill them so high before they start to overflow into the mufflers.
 
quote:
Originally posted by Stars

Closed or not, I think it's still raw sea water in the riser/manifold.
Still not sure about adding pink stuff to them. I only get about a half gallon of water when I drain them (each). That's why I've always added about a 1/2 gallon of pink. That's harldy enough to fill them up. In fact, you can only fill them so high before they start to overflow into the mufflers.

Click to expand...


Risers/elbows are ALWAYS cooled by raw water. If the FWC system is a full system, the manifolds are cooled by the closed system anti-freeze, NOT raw water. Some engines have what is called a "half" system where the engine is a closed system but the manifolds are RWC.

I've never had a half system. All my boats have always had full systems and I never had to worry aboat the manifolds. As I said, just start the engine and pour a couple gallons of AF into the sea strainer and it's done. Can't be easier or quicker.
 
True enough on your technique cwms. However I already have done the blocks and used about 10 gallons and so I don't want to run the engines this time. I think that I will just put about a half gallon AF in each manifold - approx the amount of raw water that I drained.
 
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