Intake coolant leak

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Freezerman

Freezerman

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I have a 5.9 that leaks coolant from the corners. This engine hasn't run yet. It has new EngineQuest heads( not the NZ ones). I have tried 2 intakes and 4 sets of gaskets with the same result. If the heads had been resurfaced could that affect the sealing surface to the intake manifold? This is my 3rd 5.9 I have put together and never had any sealing problems.
 
When cutting the heads the intake should also be cut to fit. There is a fixture for this to get the angle correct. I believe this could be your problem. We see many customers buy used intakes that have already been fitted to a decked block or cut heads. For this reason some cannot be fitted to their engine. beware of buying used intakes. Know what you are buying.
 
Thanks for the reply. I have tried 2 different brand new intakes, the heads were bought new. I am wondering if there is a chance the "new" heads had been cut for surfacing when manufactured
 
Could block deck height be affecting this? I can't imagine shaving that much from the deck to cause a problem.
 
I would think block deck, head milling, intake could all cause problems. But this is an untouched bottom end 130k miles with only new cam bearings and cam, new, not reman heads and 2 different new intakes. I just don't get it. Like I said 3 other engines set up almost exactly the same with exception of one has actual original EQ heads and the others were Odessa new heads. Tried these enginequest ones, only thing different
 
Are you running magnum style heads that accept a Magnum bolt pattern intake? If you happen to be running LA heads and intake, that could be an issue, as the Magnum block deck is shorter than the LA.
 
Freezerman said:
I have a 5.9 that leaks coolant from the corners. This engine hasn't run yet. It has new EngineQuest heads( not the NZ ones). I have tried 2 intakes and 4 sets of gaskets with the same result. If the heads had been resurfaced could that affect the sealing surface to the intake manifold? This is my 3rd 5.9 I have put together and never had any sealing problems.
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I dont understand how the heads could be "recut" and be "new"
 
Yes deck height can be the culprit . 9.56 is stock, I have seen them cut to 8.90. Set the intake on without Gaskets, Take a look at the surface mating. The parts are in your possession. We can only guess at what is wrong. But the information given by all members should help resolve your issues
 
I am running magnum heads with dual bolt pattern intake. The heads "shouldn't " be cut because they are supposed to be new, but something is causing the misalignment. I was hoping I'm m8ssing something simple. At this point I am thinking I may need different heads.
 
Freezerman said:
I am running magnum heads with dual bolt pattern intake. The heads "shouldn't " be cut because they are supposed to be new, but something is causing the misalignment. I was hoping I'm m8ssing something simple. At this point I am thinking I may need different heads.
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U r missing something. Pics would sure help. Kim
 
These pictures are without gaskets. It leaks from lower corners where the block, intake and heads meet

20240915_091114.jpg


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I agree, when I take off the intake it appears the gasket along the lower edge doesn't get pinched as tight. That's why I am questioning the heads. I am using felpro .028 gaskets, would it help to use slightly thicker gaskets?
 
Freezerman said:
I agree, when I take off the intake it appears the gasket along the lower edge doesn't get pinched as tight. That's why I am questioning the heads. I am using felpro .028 gaskets, would it help to use slightly thicker gaskets?
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The intake needs to be milled or the intake side of the head. Try and measure the gap at the top and bottom with feeler gauges. Kim
 
It’s doubtful you have two different intakes that won’t seal.

Make damn sure the manifold isn’t sitting on the china walls.

I’m not sure why .028 gaskets. That’s pretty thin and usually has limited use. I used thin gaskets like that when I needed a thinker gasket and couldn’t get one. That’s basically a .030 gasket and I’d stick that with a .045 or .060 to get **** lined up.

When the manifold is sitting on the heads with NO gasket it shouldn’t be touching the china walls and the bolt holes in the manifold should NOT be lined up.

The holes in the intake should be lower than the bolt hole in the head.

If the holes line up perfectly with no gasket you need to machine the intake manifold face the thickness of the gasket plus .010.

If you can’t see the hole in the head because the hole in the manifold is too low then you need way thicker gaskets.

If you have to machine the intake make sure you have enough room between the intake and china walls so that when you machine the manifold it doesn’t end up on the china walls.
 
Thanks for the tips. Without the gaskets it is not touching the China wall. I went with the .028 because of Hughes engines recommendation and I used them on other magnums. The bolt hole theory doesn't really apply because with a magnum the bolts go straight down, so with or without gaskets they still line up
 
Freezerman said:
5.9 magnum with magnum heads, dual pattern intake
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Yeah I get that about the intake BUT that installed intake is using the LA bolt location. Are you using LA style intake gaskets? If so, the bolt holes are in some-what of a wrong position for Magnum bolt position.
20240915_091536.jpg
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If you look at the picture with the intake manifold, it is dual bolt pattern. The plugs are in the LA holes at a 45 degree, the holes that are open go straight down for magnum heads, and I am using magnum gaskets
 
Those are "plugs", got it. Set intake on, no gaskets, use feeler gage, that 1 picture looks like there's a gap at the top of the intake/head.
 
The intake is sitting with no gaskets right now, I have cleaned it up, I did use sealant. The 1st time I used only in the corners, 2nd time used some on the gaskets, 3rd time used more sealant, leaked terrible, 4th time used a smear on both sides of gasket around water passage and some in corners, leaked just a little.
 
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