Protect engine from water damage after cracked intake manifold

[Bill Songstad]

I had a bad crack in my intake manifold on my '97 4.3 GL. I pulled the valve covers and intake manifold and found a lot of water. I don't want things to rust while I'm waiting for parts. What steps should I take to prevent damage from the water while I wait for the new manifold and gaskets? Naturally pump out the existing oil. I've also sprayed everything I can see with fogging fluid, but I'd be interested in what experts have to say about it all.

Thanks in advance for any assistance.
-Bill

 

[tpenfield]

:welcome: to iBoats . . .

I don't consider myself an expert, nor have ever played one on TV, also have not stayed at a Holiday Inn Express . . .

It seems like you have done the right thing by using fogging oil . . . and then cover the exposed areas with some shop rags if you have not already. Maybe get a squirt or 2 of fogging oil into the cylinders as well.

 

[Scott Danforth]

if you had a crack in your intake manifold, it came from freezing. you also most likely will have a crack on both sides of the block, the heads as well as the exhaust manifolds.

unless you drained everything and forgot to drain the intake manifold thermostat cross-over. only in that case would you have only a crack in the intake.

use a spray can of WD 40 or PB blaster and hose everything down.

 

[Bill Songstad]

Thanks guys. This is actually the second time I've cracked the intake manifold. I removed all the plugs last winter, but I think maybe tilting the nose of the boat up left some water in the rear of the manifold. This year, I will tilt it down and use a wick to suck out all the water. I was both glad and irritated to find the crack. A lot less damage than a blown head gasket or a crack further down, but I learned my lesson before and I thought I did all the right things.

-Bill

 

[Lou C]

Ok, the later model 4.3s (Vortec) intakes have a drain plug in the front face of it. The only place where there is water is right under the thermostat housing, it is a water passage connecting both cyl heads. So depending on the angle of the engine in storage, it can crack if that plug is not removed. In fact OMC had a service bulletin on this very problem. The older pre-vortec models like mine are not prone to this.

 

[Lou C]

take a look at this pic....
see the drain plug is missing...take the plug out and let it drain...coat the threads with gasket sealer like Permatex Aviation...no more worries.....

 

[Bill Songstad]

Problem is, after I cracked the manifold the first time, I always loosen the alternator arm to access that plug and let it drain. But I noticed when I pulled the thermostat housing there was still quite a bit of water left after I pulled the drain plug; even after I lowered the trailer jack all the way. I stuffed a paper towel in the drain hole and used it to wick out the remaining water. I think that will have to be new lay-up procedure. To be honest, I am pretty surprised at the crack. With the space only half full of water, you would think it would find a better way to expand. Perhaps the first portion to freeze plugged a channel some how.

-Bill

 

[Lou C]

This is why I back fill my engine with good marine AF (not -50 or -60 but -100 which can still protect if a bit diluted). Not sure why the Vortec intake is prone to this yet the pre Vortec just drains naturally when you pull the block drains and pull the bottom end of the big hose that connects the thermostat housing and the circulation pump.
you are pulling the bottom end of that big hose right?
maybe get a small mini wet vac and suck out the water?

 

[Bill Songstad]

I pull the drain plug on each side of the block, the drain plug on the front of the intake manifold, both hoses at the fresh water pump, and the hoses from the thermostat housing to the heater (Yep. It has a heater which is really nice if you are skiing in the spring and fall.) I may just make a vacuum adapter and suck it out like you suggested. Way cheaper and easier than replacing the intake manifold every 3-4 years.