Dumb Question: Coolant Leak Problem
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FTE Legend
Joined: Jul 2010
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From: Northeast, OK
Dumb Question: Coolant Leak Problem
Today was to be the day, the one when I fire the rebuilt (sorta) 351W in my '82. I ticked all the things off my list, including adding coolant. But, before I started it I found a coolant leak from the driver's back corner of the intake manifold where it meets the head - a steady drip down onto the bell housing.
I'm 99.9% sure I know what the problem is. This intake is aluminum. Original Ford 2 Bbl. When I pulled the manifold it was obvious that some PO had run w/o antifreeze since the manifold was missing quite a bit of material on the opposite back corner. I had that corner welded up and ground back, but the driver's corner didn't look bad at all, so I left it alone. Looks like I was wrong.
However, I'm hoping that you will tell me that I'm wrong and that this is not only common but there's an easy fix. HELP!
I'm 99.9% sure I know what the problem is. This intake is aluminum. Original Ford 2 Bbl. When I pulled the manifold it was obvious that some PO had run w/o antifreeze since the manifold was missing quite a bit of material on the opposite back corner. I had that corner welded up and ground back, but the driver's corner didn't look bad at all, so I left it alone. Looks like I was wrong.
However, I'm hoping that you will tell me that I'm wrong and that this is not only common but there's an easy fix. HELP!
Elder User
Joined: Jun 2009
Posts: 907
Likes: 6
From: nw pa.
hey fix that leak before you fire it up
i knew a guy that blew a 3000.00 rebuilt engine cause of the same thing
coolant leaked in to the cylinder and it hydrolocked...
i would crank it over a few times with the plugs out to get the oil moving
and to make sure theres no coolant in there now.
i knew a guy that blew a 3000.00 rebuilt engine cause of the same thing
coolant leaked in to the cylinder and it hydrolocked...
i would crank it over a few times with the plugs out to get the oil moving
and to make sure theres no coolant in there now.
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FTE Legend
Joined: Jul 2010
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From: Northeast, OK
By saying "not enough RTV" are you trying to tell me I was supposed to use some? I just followed Felpro's instructions, which say none is needed. However, having reread Monroe's book on rebuilding your SBF I see he recommends using RTV around the water passages. BUMMER! 
Ok, I'll redo the intake - after Turkey day. Hopefully all the leak is out rather than in. But, to make sure I'll check the oil to ensure no coolant is in the pan and pull the plugs and crank it to make sure none is in the cylinders.
Thanks
Ok, I'll redo the intake - after Turkey day. Hopefully all the leak is out rather than in. But, to make sure I'll check the oil to ensure no coolant is in the pan and pull the plugs and crank it to make sure none is in the cylinders.
Thanks
Posting Guru
Joined: Apr 2009
Posts: 1,089
Likes: 1
From: Illernois
Ahhhh, then i more than imagine that that is your problem.
Infact, it sounds like if you went by the instructions that you ended up using the rubber front and back seal peices? Its getting to be real common for people to simply throw those right away when replacing a intake.
For the gaskets, on the sides ones i puta a light coat of rtv just to help insure its seal and to help it stick when setting the intake. As for the end seals I suggest you throw the rubber ones away and use a bead of RTV instead. As for how much too use i would make it slightly larger than the height of the rubber seal, than put an extra dot into each corner.
Infact, it sounds like if you went by the instructions that you ended up using the rubber front and back seal peices? Its getting to be real common for people to simply throw those right away when replacing a intake.
For the gaskets, on the sides ones i puta a light coat of rtv just to help insure its seal and to help it stick when setting the intake. As for the end seals I suggest you throw the rubber ones away and use a bead of RTV instead. As for how much too use i would make it slightly larger than the height of the rubber seal, than put an extra dot into each corner.
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FTE Legend
Joined: Jul 2010
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From: Northeast, OK
Yep, that's the prob. Pulled the manifold today and I'm not surprised it leaked. What I'm surprised about is that I installed it that way! Significant pits around the coolant ports - especially the driver's side rear.
Did a lot of dressing of it w/a file and a straightedge, but am considering taking it to the guy that welded up the other side, although he's not available 'til Monday. Still have 1/16" pits and am not sure RTV will seal it. Thoughts?
And, btw, I did use RTV in place of the end seals. Made pretty good gaskets about 1/8" thick with some excess. Will do that again.
Did a lot of dressing of it w/a file and a straightedge, but am considering taking it to the guy that welded up the other side, although he's not available 'til Monday. Still have 1/16" pits and am not sure RTV will seal it. Thoughts?
And, btw, I did use RTV in place of the end seals. Made pretty good gaskets about 1/8" thick with some excess. Will do that again.
Moderator
Joined: Nov 2007
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From: Denver Metro Area, CO
I don't use RTV (silicone rubber) for hardly anything (although I *do* use the black variant
for intake manifold ends instead of gaskets), I prefer Permatex High Tack or Form-a-Gasket,
Just my personal preference.
for intake manifold ends instead of gaskets), I prefer Permatex High Tack or Form-a-Gasket,
Just my personal preference.
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FTE Legend
Joined: Jul 2010
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From: Northeast, OK
It runs! I used blue RTV for the end seals and red around the water passages. No leaks, neither water or oil. And, with the new Comp Cams cam & lifter set, as well as machined heads and 11 new valves, it runs very well - when it runs properly.
Unfortunately, I think I have a carb problem - although it was rebuilt just prior to all this. The symptom is that the engine runs well for a while and then just loses power. I found myself running on the floor trying to maintain 50 MPH and the carb was moaning. It had done it a few minutes earlier and I got on it and the engine started running correctly. But, this time it didn't change until I'd pulled over and checked several things over.
Anyway, I'll pull the carb - yet again - tomorrow and see if there's something in the bowl. That's the way it acts as there's plenty of fuel coming out of the pump. Another possibility is the filter.
But, thanks to all for the input!
Unfortunately, I think I have a carb problem - although it was rebuilt just prior to all this. The symptom is that the engine runs well for a while and then just loses power. I found myself running on the floor trying to maintain 50 MPH and the carb was moaning. It had done it a few minutes earlier and I got on it and the engine started running correctly. But, this time it didn't change until I'd pulled over and checked several things over.
Anyway, I'll pull the carb - yet again - tomorrow and see if there's something in the bowl. That's the way it acts as there's plenty of fuel coming out of the pump. Another possibility is the filter.
But, thanks to all for the input!
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