Oil leak from intake manifold

[ship rider]

Has anyone ever known an oil leak to occur from a cracked lower intake manifold? The engine (3.4 push rod) has just been rebuilt within 500 miles. Initially thought it was the valve cover gasket closest to the firewall, but I just replaced both of them with rubber ones again yesterday and the leak came back in the same place. It pools in the crevices of the intake until it fills up and then leaks down the front side of the engine and drips on the exhaust.

Thanks

[bszopi]

Since you mentioned valve cover closest to the firewall, I'm assuming FWD? If so, then its a 3400 (for clarification).

Guess I'm having a hard time figuring out where it is pooling... The crevices of the intake is confusing. Just wondering if you didn't use RTV in all the places needed, such as the area where the head and intake manifold meet (the triangle bump outs of the valve cover gaskets).

[bszopi]

Oh yeah, and welcome to the site.

[ship rider]

Since you mentioned valve cover closest to the firewall, I'm assuming FWD? If so, then its a 3400 (for clarification).

Guess I'm having a hard time figuring out where it is pooling... The crevices of the intake is confusing. Just wondering if you didn't use RTV in all the places needed, such as the area where the head and intake manifold meet (the triangle bump outs of the valve cover gaskets).

Yes, I would be confused as well. What I mean, oil is pooling on top of the LIM in the low areas between the manifold bolts. Do the bolt holes open up into the oil valley in the block and would oil seep up past the threads in those bolts and pool?

[Rhedalert]

Did someone forget to apply sealant between the lifter valley area of the block and lower intake manifold?

[bszopi]

That's what I initially wondered, but it sounds like the oil is pooling down between the injectors. Possibly just a bad install of the valve cover gaskets? They can be a pain sometimes...

[WrathOfSocrus]

I'm pretty sure you are supposed to loctite the 4 long LIM bolts and put RTV under the head of each bolt. If the bolts are loose I would imagine oil could get pushed up through there.

[Skeith]

not sure if the installation of the LIM gasket is different on a 3400, but when I did my 3.1MPFI LIM I used no loctite on the bolts, and I'm certain they weren't installed with loctite before because they didn't take much effort to remove at all.

Plus as far as I could tell from the gasket, (don't remember exactly as I didn't pay much more attention to anything other than making sure everything went back in its proper spots) the bolts pass through holes in the gasket, so assuming the gasket was seated properly, it should seal oil from escaping the bolt holes. I have had no problem with leaks after installing mine as such, RTV was only applied to the block lip in the valley.

I do have a leak from my valve covers though as I tried to use RTV for those seals because I forgot to buy new valve cover seals, but mine is leaking from the bottom side of the valve cover onto the rear exhaust.

Run your finger along the edges of the valve cover where it meets the head, if that is your leak you will feel it. The valve covers are higher than the intake so if that Is where the leak is coming from oil should be present on the top seam.

weird that you say its pooling, because I don't get THAT much oil from my valve covers and I know I botched the seal.

[TGP37]

Sure it is not power steering fluid dripping from the pump lines?

[ship rider]

I am pretty sure the leak is coming from the bolts of the LIM. The one I can see has oil above the washer when you shine light on it. The motor was rebuilt by a local machine shop and they installed the LIM for me. I have a custom made intake coming and will seal with silicon when I break it down again. I am pretty sure it is not the valve cover gaskets. I just replaced them again and was very careful to make sure they sealed. Thanks for all the replies.

[TGP37]

I am pretty sure the leak is coming from the bolts of the LIM. The one I can see has oil above the washer when you shine light on it. The motor was rebuilt by a local machine shop and they installed the LIM for me. I have a custom made intake coming and will seal with silicon when I break it down again. I am pretty sure it is not the valve cover gaskets. I just replaced them again and was very careful to make sure they sealed. Thanks for all the replies.

It seems like you know what your talking about. I know GM states the LIM must be torqued down in a two step method. The 4 long bolts first, then the 4 side angled bolts. I read the LIM would leak if not done right. I, personally, had not had a LIM leak....yet. But I guess it happens, like any other leak.

Two of the side bolts are difficult to tighten with the socket wrench since they are recessed. I can see a technician failing to properly torque them.

I haven't used thread lock for the LIM, no leaks for me. I hope you don't have a crack, that would suck.