Gil Exhaust
 

I have a leak between my Gil Manifold and Gil Riser. I can see the leak externally coming through the gaskets. I want to know if I should replace the stainless steel risers or just the gaskets. I removed the risers and did a home leak test by filling the riser's outer jacket with water to see if it would leak on the inside of the riser. I could see no leaking but of it was not pressurized. Any advice? The risers are 10 years old in brackish water. Thanks

Re: Gil Exhaust
 

No water get circulated directly between the manifold and riser through the gasket on Gils. The water is transfered with a hose.
If it was just a bad gasket, you would only have exhaust gas gases leaking there. Chances are that you have a crack in the manifold in that area. Look for cracks between the dividers at the top of the manifold. The SS risers wil outlast the the aluminum manifolds by a long time. If the riser had a leak, I doubt it would leak all the way back down to where the riser meets the manifold.

Re: Gil Exhaust
 

This is a strange problem because the Manafolds are only 6 months old and they are Gil. The risers are 10 years old. I defenely see water dripping from the gasket bettween manifold and riser down the side of the manfold.

Re: Gil Exhaust
 

you didnt mention if they are one peice water jacketed risers all the way out the back if they are i just had same problem, one of the inside welds went bad and was leaking in. they repaired the weld but i was told i would have to get new risers eventually but in the mean time drain the manifolds after every use, just pull the hose off the bottom. also you can check whers the riser meets the manifold make sure its in good shape.

Re: Gil Exhaust
 

I would guess that the weld at the bolting flange or the next weld at the bend is leaking then. Also it may not leak till it gets hot and the metal expands.

BTW, I've got a set of Gil Risers that came off my 1996 525SC. The manifolds were bad, but the risers look fine. I would sell um cheap. I replaced them with CMI's about 3 years ago. Had about 300hrs on them.

Re: Gil Exhaust
 

I would bet that the water is from reversion. Probably from a bad gasket.

Re: Gil Exhaust
 

Nobody mentioned the possibility of head gasket leaking? That could be it also.
What do you think?

Re: Gil Exhaust
 

This weekend I was winterizing my 420's w/Gils and when I filled the riser via the hose the fluid leaked out the manifold hose assembly at the bottom in one of 4 risers. : :( Meee thinks this is not so good :( Thoughts

Re: Gil Exhaust
 

I found a little water in Cylinder #3. The plug was a little rusty and wet. Got the water out of there and sprayed WD40. Did a compression test and each cylinder has good compression. I would think it would be the head gasket but all cylinders have good compression. If water is not coming from risers or manafolds or head gasket where could it be coming from? I found a very small amount of water in the oil. Very small. I think I'm approching this problem in the vey early stages so its very hard to determine. Any suggestions would be helpful.
Thanks

Re: Gil Exhaust
 

Intake gasket leak would next on my list.

Re: Gil Exhaust
 

Being winterizing is in the near future I would send the risers & manifolds back to Gil to be pressure tested. Unless your able to psi test the manifolds yourself. I'd put my $$ on the exhaust.
Out of couriousity, what heads are you running ?

Re: Gil Exhaust
 

Look at the center devider in your Gil manifold. Take it off the boat. Make an adapter for a garden hose and put it on one of the hose barbs. Then cap the other one. That should give you enough presure o find your leak.

That is where mine was leaking and was able to be repaired.

Re: Gil Exhaust
 

Stan,
I have no idea what heads are on there. I think they are the ones that came standard with the 420 hp package. I know it has Dart intake and Crane roller rockers etc. I checked the risers and manifolds and couldn't find any leaks. Payton, I can't find a leak. I hooked up to a gardent hose on full blast.

The thing I don't understand is how could both gaskets left and right side have leakage from a crack in a head? Also both oil caps had milkshake oil in the caps. So what could cause these symptoms. The engines have 650 hrs.

Re: Gil Exhaust
 

I would suspect the risers or a cracked head. I have 2 pairs off of the '88 & not sure if there any good. I would pressure test the block. I use a regular radiator tester w/an adaptor to a hose & engine full of water with some dish washing soap in it.

Re: Gil Exhaust
 

I've had bad luck with Gil cast manifolds. I'd be very suspect of your Gils.

Re: Gil Exhaust
 

I'm very suspect of the Gils. I'm going to send them back to Gil to be tested before tearing into the heads. What are the chances it would be a craked head or cracked valve seat? Then again, I'll be pissed if gil sold me 2 new defective manafolds.

Re: Gil Exhaust
 

GRIFF
If Gil risers are stil available please email me.
[email protected]
THANKS! :D

Re: Gil Exhaust
 

I had simaler problem, thought the oil cooler was leaking but it was a bad head gasket (normal compression btw) and one a cracked gil. A piston finally detonated. Engine had only 2 hours on it. The water pressure in cly blew the gasket I would think.