New engine, water in exhaust manifolds

[utexasrick]

So I was in the process of setting the timing on my new 4.3 engine. I got it set but after about 5min of running it died. I started it again then shut it off after noticing a leak. The leak was coming from the gasket between the exhaust manifold and riser near a bolt hole.
I bought the exhaust manifolds and risers new on ebay, I was upgrading from one piece to the two piece style.
ebay link

I decided to remove the risers and see if I could reseat them but lo and behold when I took them off there was water inside the manifold! It seems as though water was seeping into the manifold from the gasket. I looked into the exhaust ports and the valves looked dry. I removed the spark plugs and also no water. I don't think there was enough water to cause any damage but it could have been very bad. I removed the other side and also same situation!
The bolts were torqued down to 20 ft-lbs as I found in the manual. Is this incorrect?
Has anyone had any trouble with these manifolds/risers? They are Sierra
The gaskets I used were the ones that came with the kit. They say cmp-4000 by interface
It seems as though since both manifolds were leaking either I didn't tighten them down enough or the gasket material is not good.
I will take the manifolds and risers to a machine shop and have them check the face and have them resurfaced if necessary, but from the looks of it both surfaces looked pretty flat against a straight edge.

 

[utexasrick]

Re: New engine, water in exhaust manifolds

Huh attachments don't seem to be working but I will post pics once I get it to work

 

[Pete104]

Re: New engine, water in exhaust manifolds

You get what you pay for!

Bond-o has been thru this & he wound up machining them, also.
Loose the the gaskets & use OEM!

 

[r.j.dawg]

Re: New engine, water in exhaust manifolds

I read the ad from your link and it states that those manifolds and risers are NOT a direct replacement for one piece exhaust manifolds. Did you cross reference the casting numbers the seller posted in the ad?

 

[utexasrick]

Re: New engine, water in exhaust manifolds

well it's missing the down tubes, but I got those from a junk yard, the conversion kit he sells has the same risers and manifolds

 

[tpenfield]

Re: New engine, water in exhaust manifolds

I am assuming you drained down the manifolds before you separated the riser/elbows? Those green paper gaskets as shown on the eBay pictures, do not work so good. I would also check the mating surfaces of the manifold & elbow to see if they are true.

 

[utexasrick]

Re: New engine, water in exhaust manifolds

Yes manifolds were drained,
Has anyone used sealant around the water passages on the riser to manifold gasket?
I think I will try using OEM gaskets first and see if it still leaks
I also should have stripped the face of any paint which was the first mistake

 

[Don S]

Re: New engine, water in exhaust manifolds

If the gasket surfaces between the manifolds and risers aren't flat, no gasket will seal.
How long was that water in the manifold?

 

[Bondo]

Re: New engine, water in exhaust manifolds

I also should have stripped the face of any paint which was the first mistake

Ayuh,.... Take 'em to a Machine Shop, 'n have 'em run those faces on their Beltsander, to Flatten 'em....

I'd do both the manifolds, 'n risers....

Then use the Oem, metallic graphite gaskets...

 

[utexasrick]

Re: New engine, water in exhaust manifolds

I had started the engine about 2 weeks ago when I was testing it out once everything was back together. I think water got in there since then which started to corrode the manifold.
I will be taking them tomorrow to a machine shop to have them checked out.
What kind of test can I do to check for internal damage? Compression test?

 

[Don S]

Re: New engine, water in exhaust manifolds

First, Ground the coil wire, remove the spark plugs so if any water is in the cylinder, it will not hydrolock the engine. Turn the engine over by just bumping the starter until you are sure the water is out of the cylinders. Then put a little oil in each cylinder (a couple of tablespoons full) then bump the starter a couple of rounds. Put the plugs in and crank the engine for a few seconds to distribute the oil.
Then get your manifolds fixed.

 

[utexasrick]

Re: New engine, water in exhaust manifolds

**Update**
So I got the manifolds and risers resurfaced at a machine shop, they told me they looked pretty good originally but just took off a small amount. I put a straight edge against all the surfaces and they looked good.
I also got new original metallic type gaskets.
I reassembled everything, torqued the risers to manifolds down to 25 ft lb incrementally. I started it up and it ran fine for about 3 min then I noticed again a small water leak at a corner and the engine started to stumble a little. I shut it off and took the risers off again. What do you know... water again in the manifold, just a little so I took a shop towel and stuck it in there to dry it off.
Is 25 ft lb the correct torque spec?
I'm thinking its not tightened down enough, when I removed the riser I saw some water residue on top of the gasket connecting the passage holes.

 

[achris]

Re: New engine, water in exhaust manifolds

Which 4.3l engine are you working on? From 1996 and on these engines have a fair amount of overlap on the cam, so if you idle them for long periods out of the water (ie, on flushers) they will suck water back in though the exhaust. Have a read of your owners handbook, in there it states you need to run at 1300 rpm on flushers.

And yes, 25 lb.ft.

Chris........

 

[utexasrick]

Re: New engine, water in exhaust manifolds

Well I thought I had found the problem but I was wrong...
So it turns out that I had the wrong size bolt for the exhaust risers to manifold, I was using a 6in where it should have been a 5 3/4, the 6" will barely bottom out. I couldn't find anyone around town that carries a 5 3/4 grade 8 so I ended up cutting the ones I had.
I thought this would be the answer to all my troubles but yet again after 1 min idle there is water in both exhaust manifolds.
Looking at the gaskets the top surface which mates to the riser has a clear outline of the ports, but when I look at the bottom side which mates up to the manifold there is only a slight outline. seems like the gasket isn't being compressed. I dont think the engine is sucking water in due to seeing a leak by one of the bolts which seems like a sealing problem. Engine was running around 1000-1100 rpm at idle and this was for about 1 min.
I'm stumped as to what the problem is. I even tried torquing the riser down to 35 to see if the gasket indentions would change and nothing. Manifolds have also been swapped with each other and I still get the same leak on the port side by one of the corners.
Both risers/elbows I have are identical, should there be a difference between port side and starboard side?

 

[Leedanger]

Re: New engine, water in exhaust manifolds

Well I thought I had found the problem but I was wrong...
So it turns out that I had the wrong size bolt for the exhaust risers to manifold, I was using a 6in where it should have been a 5 3/4, the 6" will barely bottom out. I couldn't find anyone around town that carries a 5 3/4 grade 8 so I ended up cutting the ones I had.
I thought this would be the answer to all my troubles but yet again after 1 min idle there is water in both exhaust manifolds.
Looking at the gaskets the top surface which mates to the riser has a clear outline of the ports, but when I look at the bottom side which mates up to the manifold there is only a slight outline. seems like the gasket isn't being compressed. I dont think the engine is sucking water in due to seeing a leak by one of the bolts which seems like a sealing problem. Engine was running around 1000-1100 rpm at idle and this was for about 1 min.
I'm stumped as to what the problem is. I even tried torquing the riser down to 35 to see if the gasket indentions would change and nothing. Manifolds have also been swapped with each other and I still get the same leak on the port side by one of the corners.
Both risers/elbows I have are identical, should there be a difference between port side and starboard side?

View attachment 146309View attachment 146310View attachment 146311

Are you doing this on the trailer with the muffs on or in the water? If you are in the drink have you considered your exhaust shutters being bad or none existant? Don't mean to throw a kink into your solutions chain but your engine might be sucking up lake water when you are shutting down if they are bad. I think with your model you should be able to easily see them with the manifold off....something to consider but most likely not your cure all.

 

[utexasrick]

Re: New engine, water in exhaust manifolds

Are you doing this on the trailer with the muffs on or in the water? If you are in the drink have you considered your exhaust shutters being bad or none existant? Don't mean to throw a kink into your solutions chain but your engine might be sucking up lake water when you are shutting down if they are bad. I think with your model you should be able to easily see them with the manifold off....something to consider but most likely not your cure all.

I'm starting it out of the water. Are the shutters supposed to be completely closed? i noticed mine don't close all the way but they still had some spring to them. But yeah i don't think this is the cause of my water leak but could be a problem later on

 

[pyrotek]

Re: New engine, water in exhaust manifolds

I'm not entirely sure of the details, but maybe check the type of gaskets. There are a few configurations with some blocking flow, other are open. Maybe someone more familiar could say whether this could happen if the wrong configuration was used.

 

[utexasrick]

Re: New engine, water in exhaust manifolds

I'm not entirely sure of the details, but maybe check the type of gaskets. There are a few configurations with some blocking flow, other are open. Maybe someone more familiar could say whether this could happen if the wrong configuration was used.

Yeah im using the gaskets that restrict the flow, i think those are the correct ones
One thing that i did notice was that the lower rubber boot for the exhaust elbow to to y pipe wasnt allowing the manifod to fully seat straight when I tightened down the clamps. These were the original boots used with the one piece. So I ended up cutting the top off of them and making them shorter. Now the top part only has one clamp . I tried going to a boat yard and picking some up but the ones they had were to small for my y pipe. Still had a leak after the cutting.
I think next I will try running the engine not connected to the y pipe and see if those boots are the problem. All these gaskets are getting expensive ...