Oil behind lower intake

[GRGT1994]

I see a pool of oil behind the lower intake manifold (on the top of the block back there just in front of firewall). Does this mean my rtv bead is blown? I was thinking that may be it, but the other day, I noticd that my pcv valve was popped out. So I am keeping an eye on it to see if the pool comes back.

Any thoughts?

 

[final5-0]

Yes, It does sound like one or the other.

For your sake, I hope it is only the pcv.

Grady

 

[CManT1914]

I see a pool of oil behind the lower intake manifold (on the top of the block back there just in front of firewall). Does this mean my rtv bead is blown? I was thinking that may be it, but the other day, I noticd that my pcv valve was popped out. So I am keeping an eye on it to see if the pool comes back.

Any thoughts?

If you PCV popped out, then it's probably just oil coming from there. If it comes back with the PCV in, then it looks like your RTV is squeezed out. That's a vacuum leak right there. Trust me, I know.

EDIT: RATS!!!! Grady beat me to it, and he's like 90!!

 

[GRGT1994]

Yes, It does sound like one or the other.

For your sake, I hope it is only the pcv.

Grady

Thanks.

Hey, even if its the rtv, that's just some disassembly, new gaskets and more RTV, right. Not a big deal. Or am I missing something?

 

[RacEoHolic330]

the disassembly is a pretty large PITA if you ask me

 

[CManT1914]

Thanks.

Hey, even if its the rtv, that's just some disassembly, new gaskets and more RTV, right. Not a big deal. Or am I missing something?

Nope, just another hour devoted to working on the stang when you could be doing other things. Not to mention I've taken my intake off about 6 or 7 times the last few months. It gets old after a while.

the disassembly is a pretty large PITA if you ask me

Maybe if you're blown, I can have my intake (upper and lower) off and back on in an hour tops.

 

[GRGT1994]

Maybe if you're blown, I can have my intake (upper and lower) off and back on in an hour tops.

That's what I was thinking. I have had my upper off too many times to count, and that is no sweat (even with pulling the strut brace). But I havent had to pop the lower off yet (thankfully).

Is it a guarantee that I will need new lower intake gaskets? Any suggestions since you have done the lower so much lately (no wonder you are getting tired of wrenching the stang)?

 

[CManT1914]

That's what I was thinking. I have had my upper off too many times to count, and that is no sweat (even with pulling the strut brace). But I havent had to pop the lower off yet (thankfully).

Is it a guarantee that I will need new lower intake gaskets? Any suggestions since you have done the lower so much lately (no wonder you are getting tired of wrenching the stang)?

You will definitely need new gaskets. Not just lowers, but your lower to upper plenum as well. Those lower gaskets after being heated up from driving will most likely tear when you rip them off. Even if they don't, replace them anyway. I've found that leaving the entire upper intake along with throttle body and intake pipe together works well. I just unhook the maf and lay it aside and lift the rest of it completely off. The injectors stay in, just move the rails outta the way. Just throw on some new gaskets, and a 1/2" bead of RTV. But you gotta let it kind of get tacky before setting the lower on so it doesn't get mushed everywhere and ooze down the inside and outside of the block.

Yea, I really got tired of working on it. Thankfully other than my fried alternator cable it's been running great since my whole h/c/i mess a few months back.

EDIT: Oh yea, you'll want to drain the coolant just enough to where none is in the lower plenum, no reason to drain the whole system. Just pop off the upper radiator hose, and unscrew the petcock until you can't see any coolant in the t-stat housing. Then drain for another 10 or 15 seconds, that should get the majority of it out. Also, the heater hoses can stay in place, just bend the rubber hoses outta the way, and don't drop any nuts/bolts down in the dizzy hole when you pull it, lol.

 

[GRGT1994]

Another couple of questions on this issue.

If an RTV failure at the lower manifold creates a vacuum leak, then couldn't I check the seal with that spray can method? (spray *something* around different parts of the engine and listen for revs to step up to local a vacuum leak) And if so, what is the stuff that you are supposed to use for this?

It seems like there would be positive pressure under the lower intake (PCV valve vents blowby into the intake - not the other way). So maybe the spray method does not work here. Any thoughts?

And if it turns out that I need to pull the lower intake and reseal it, could I deal with this after the snow flies? Or is it better to do the RTV in warmer weather? I'm not really losing oil that fast, so I'm thinking of waiting till winter. Is that a bad idea?

Many thanks.

 

[CManT1914]

It does blow air out of the crankcase, not the other way as you mentioned. So I don't think that spray method will work. FWIW, another mustang guy told me that it would create a vacuum leak, but didn't explain why. I didn't think about it much, since I was planning on fixing it anyway. You could always hook up a vacuum gauge to see where you're at. If you do decide to hold off on replacing those seals, I would keep a CLOSE eye on them. Check them every day, morning and night, to make sure they don't get blown completely out. In all honesty, it doesn't take long to fix, might as well just do it next time you get a little free time. Weather doesn't matter, but if it's cold, wait a little longer so it will tack up like I mentioned in a previous post. Good luck bro!

 

[Methodical]

If the seal is bad I'd say just fix it. Don't put off tomorrow what you can do today. Just get it over with. Like Nike says - Just Do It. Just One Man's Opinion. Peace

 

[final5-0]

If your rtv rope type end gasket blew out, it might or might not cause a v leak. It would depend on if any of the ports were loosing seal to the common area under the lower intake.

Grady