Vortec Intake Oil Leak

mrweelr

mrweelr

New member
I need some help guys. My RPM motor has Vortec heads and ported/polished modified stock intake and the passenger side FelPro gasket is leaking oil after less than 100 miles :-( I torqued all ARP fasteners to correct specs and in the right order and it's leaking along the passenger side gasket in two places. Oil eventually pools in the intake well near the front. The driver's side is bone dry and the motor runs fine. What bothers me is I have no clue why this thing is leaking and don't feel like pulling the intake until I have a good idea as to what the cause could be. Both valve covers vent directly to a Moroso catch can and I verified there is no restriction, so I don't think it's a crankcase pressure issue. There is a small gap/opening close to the area that's leaking that I've circled in the pic; is that normal with the Vortecs? I removed that little allen plug and resealed it, but I verified for certain that's not what's leaking. Mike suggested I try some "Right Stuff" sealant which I picked up at Autozone, but in theory I shouldn't need to use anything for this to seal properly other than new gaskets, right? Should I try thicker gaskets or something? Here are some pics. Let me know what you guys suggest.

Front.JPG

Front2.JPG

Front3.JPG

Front4.JPG

Gap.JPG

Rear.JPG
 
MRKING

MRKING

New Parts for Old Trucks
Re: Vortec Intake Oil Leak

could oil be coming through the threads in either the manifold bolts or the allen head plugs in the heads?
 
sy#2716

sy#2716

SyTy 4 Life
Re: Vortec Intake Oil Leak

Looks like the intake manifold is not welded to fill the gaps that is needed for the vortec heads.

I would contact Mike and see what he would do.
 
4C FED

4C FED

Absolutum Dominium
Re: Vortec Intake Oil Leak

You sure it's not the valve cover gasket leaking right there?
 
Don W.

Don W.

Stab it and steer it
Re: Vortec Intake Oil Leak

There are, what, 3 or 4? Allen screws for the vortec intake on each head that should be plugged. Did you seal each of them?

I've heard of difficulty in this area before so I used Loctite gasket seal 1 around all the openings in the gaskets on both sides. Like you, I have less than 200 miles on my motor. So far so good I think.:roll: If / when you remove the intake make sure that when the manifold sits on the heads that there is a gap between the rails on each end where it sits on the block. I might even have the spec somewhere. One last shot in the dark, check that the manifold is machined exactly 90* side to side.
 
mrweelr

mrweelr

New member
Re: Vortec Intake Oil Leak

Yeah, I put RTV on all of the bolt threads. The valve covers were leaking before, but I took them off a few weekends ago to adjust the rockers and fixed the leaks at the same time. Those were causing oil to run down the back of the engine, a completely different symptom. This is DEFINITELY the passenger side gasket. If I dry those areas off completely and drive it hard for a few minutes, oil starts seeping out of both areas again. I really hope it's not a machining or fitment issue, but I don't have a good feeling about it since I really took my time installing it properly the first time. How can I verify that the machined surfaces are correct on both sides? Don't they make some special paper for film for that? I forget what it's called.
 
TYTILIDIE

TYTILIDIE

METH HEAD
Re: Vortec Intake Oil Leak

mrweelr said:
Yeah, I put RTV on all of the bolt threads. The valve covers were leaking before, but I took them off a few weekends ago to adjust the rockers and fixed the leaks at the same time. Those were causing oil to run down the back of the engine, a completely different symptom. This is DEFINITELY the passenger side gasket. If I dry those areas off completely and drive it hard for a few minutes, oil starts seeping out of both areas again. I really hope it's not a machining or fitment issue, but I don't have a good feeling about it since I really took my time installing it properly the first time. How can I verify that the machined surfaces are correct on both sides? Don't they make some special paper for film for that? I forget what it's called.
Click to expand...

If you can get it to where it leaks a quart a week, you don't need to worry about changing your oil:rotf:j/k I would just pull the intake, investigate it and seal it back up with something better if there is anything. Just watching it puddle won't get you far.
 
Ty 1885

Ty 1885

New member
Re: Vortec Intake Oil Leak

What i would do, remove intake, clean heads and intake with brake cleaner, put high temp rtv around ALL the ports, put new gasket on the head, put more rtv on the gasket ( both sides ), dont forget front and back of the block, install the intake,
put rtv on the bolts, tourqe the bolt to 25 pounds, start from center out. Worked for me..
 
mrweelr

mrweelr

New member
Re: Vortec Intake Oil Leak

Ty 1885 said:
What i would do, remove intake, clean heads and intake with brake cleaner, put high temp rtv around ALL the ports, put new gasket on the head, put more rtv on the gasket ( both sides ), dont forget front and back of the block, install the intake,
put rtv on the bolts, tourqe the bolt to 25 pounds, start from center out. Worked for me..
Click to expand...

That sounds like a good idea. I also plan to use that Right Stuff RTV which is supposed to be the best. Assuming the intake surfaces aren't warped or anything, that should work. I will put a straightedge on all surfaces before putting it back together to make sure nothing is whacky. The last thing I really want to do is pull this MF intake back off, but it has to be fixed. Will post some pics after I get the intake off. Maybe it will be obvious when I get it apart.
 
WyoSyclone

WyoSyclone

Active member
Re: Vortec Intake Oil Leak

mrweelr said:
That sounds like a good idea. I also plan to use that Right Stuff RTV which is supposed to be the best. Assuming the intake surfaces aren't warped or anything, that should work. I will put a straightedge on all surfaces before putting it back together to make sure nothing is whacky. The last thing I really want to do is pull this MF intake back off, but it has to be fixed. Will post some pics after I get the intake off. Maybe it will be obvious when I get it apart.
Click to expand...

Just a thought, but whenever I use any type of sealant on an engine I let things set for at least 3 days to make sure it's dried and cured.... I've seen a lot of leaks caused by oiling and heating things up before things are dry... just my :2cents: :D
 
Don W.

Don W.

Stab it and steer it
Re: Vortec Intake Oil Leak

There is a torque sequence specified in the manual that I’ll try to explain. Counting from the front bolts are numbered:

Pas front 12 5 4 2 7 10

Drivers front 11 6 1 3 8 9

First sequence torque not specified but I went 25 #

Now it gets weird. Same sequence, final torque 35 ft lbs EXCEPT #9 which gets 41 ft lbs. No clue as to why but that's what it says.

Don't forget to bring the RTV you spread on the block up onto the gasket about 1/2 to 3/4 inches so you have a good seal at the junction between the block, head and gasket where they all come together in the corners.

HTH Jeremy. I hate leaks. You work so darn hard to do it right and you get some piss-ant leak. :rant:
 
mrweelr

mrweelr

New member
Re: Vortec Intake Oil Leak

BTW, the gaskets I used were FelPro 1203s. Do they make identical gaskets that are slightly thicker?
 
bezerk

bezerk

New member
Re: Vortec Intake Oil Leak

always use RTV on lower intakes converted to vortecs.!
been there done that
 
Big Mike

Big Mike

New member
Re: Vortec Intake Oil Leak

Make sure the sides of your intake are clearing the heads and intake sits flat before you put gaskets on. On this past rebuild i had to mill the sides so mine would sit flat and not sit up on the lip where the valve cover gasket sits, i also had to drill lower intake bolt holes oval so intake would pull down to seal on gasket.
 
Ty 1885

Ty 1885

New member
Re: Vortec Intake Oil Leak

You need to be carefull with thicker gaskets! They may raise the intake, then the bolt holes may not line up.
 
mrweelr

mrweelr

New member
Re: Vortec Intake Oil Leak

Big Mike said:
Make sure the sides of your intake are clearing the heads and intake sits flat before you put gaskets on. On this past rebuild i had to mill the sides so mine would sit flat and not sit up on the lip where the valve cover gasket sits, i also had to drill lower intake bolt holes oval so intake would pull down to seal on gasket.
Click to expand...

This is a great point. Mike suggested I check the bolt holes and notch if necessary. I did use plenty of RTV around the coolant ports and on the ARP studs when I assembled, but not the oil passages. Should I be using that Right Stuff on both sides of the FelPros around all ports, even though they have that rubber ring?
 
Ty 1885

Ty 1885

New member
Re: Vortec Intake Oil Leak

I never used (Right Stuff), however, i allways used RTV around ALL of the ports, NEVER had a problem in 25 years i been playing with cars.
 
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