[Leadsled Coupe]

Here’s a picture after I removed my lower (no pics of the fresh thick RTV bead). I ran a gradual transition of bead thickness on the engine block to quite thin around the water ports. Where you have a little dab, right there I use perhaps 3x as much, thinning out quickly around the water ports.

The “gasket“ that my RTV makes is one piece and conforms perfectly if it has a dry thin skin layer and wet inside.

 

[strokeme]

The only end seals that you should use is either ultra black or grey. Its as fool proof as you can get.

 

[Cougar5.O]

I've had the opposite experience. I ONLY used those blue silicone seals for over 15 years. Over and over and over again, I reused them - they survived many intake removals and engine rebuilds. I still have them in my storage bins as they were like magic to me. I'd still be using them if they made them in the 9.5 deck width.

On my 427w, I used a nice tall bead of the best RTV. Everything looked fine and it squished out nicely. Then I noticed a tiny pool of oil in the front on the timing cover. Turns out there was a pin-hole in the RTV. I know I'm repeating the post above, but people have different experiences. You have to decide which "scold" post you read is the one you want to follow. I always used my common sense, but I'm just a dumb ol' ME.

 

[Leadsled Coupe]

Well there you go. Pick your poison OP. If it worked for Cougar you too can make it work. Just use MORE are your corners I’d suggest. Likely that’s where you leaked from IMHO.

I am jealous of your silicone bead laying stroke me. It looks like a beautiful aluminum TIG weld.

 

[strokeme]

Well there you go. Pick your poison OP. If it worked for Cougar you too can make it work. Just use MORE are your corners I’d suggest. Likely that’s where you leaked from IMHO.

I am jealous of your silicone bead laying stroke me. It looks like a beautiful aluminum TIG weld.

With silicone, this is usually what I encounter. Guys get wild with it and its a mess

 

[Leadsled Coupe]

I am glad I’ve not taken any pictures from that perspective. I am sure mine looks more along those lines that what a believe your beads would suggest yours looks like. Lol!

 

[Bestia]

I dry fitted everything before and I figured a bead on all 4 corners before the end seals went on followed by a little on top would be enough. Just the passenger side again and like I said, also seems like it’s wet on the back all along the head gasket. Car is at a mechanic right now who specializes in fox bodies to replace my header gaskets. As he’s replacing the passenger side, he’ll have a closer look. He said being the age of the car it could be the head gasket seeping oil back there. I’ll let you guys know.

 

[Mikes85&99]

The only end seals that you should use is either ultra black or grey. Its as fool proof as you can get.

From that picture it almost looks like you are using black rtv for the timing cover as well? Do you use just gaskets on the timing cover and water pump or are you using some sealant with gasket?

 

[strokeme]

From that picture it almost looks like you are using black rtv for the timing cover as well? Do you use just gaskets on the timing cover and water pump or are you using some sealant with gasket?

I use gakets on the cover and the pump. Also a VERY thin skim of ultra black. It goes on the block, then cover gasket then again on the gasket. VERY thin.

 

[Mikes85&99]

Thanks. Very thin, got it. Do they sell that stuff by the gallon. Too much is never enough when i get going with caulk, glue or any liquid really. There are probably still some of my Elmer's glue macaroni art projects out there drying from 45 years go.

 

[Bestia]

Thanks. Very thin, got it. Do they sell that stuff by the gallon. Too much is never enough when i get going with caulk, glue or any liquid really. There are probably still some of my Elmer's glue macaroni art projects out there drying from 45 years go.

When I did my timing cover gasket I did what Strokeme indicated but I used WP RTV 13 years ago and no issues.

 

[Bestia]

Just spoke with my mechanic and he’s leaning towards head gasket seeping. Doesn’t think I need to remove the lower again. Might be something I’ll tackle next year and simply enjoy the car while the season is short!

 

[Bestia]

Update: With the nice weather here, went out to the garage to change the oil and take the car for a drive and guess what I found in the oil? COOLANT! I'm so bummed right now. I guess I didn't replace the lower intake gasket correctly and I'm doing it again. I drove the car last summer ~400 miles after doing the lower and never noticed any coolant missing. I even drained a little oil after ~150 miles to see if any coolant would appear (let the car sit for a couple of days) and all that came out was clean oil. When I popped the hood today, the rad was completely full but I noticed the overflow down ~1/2" (I had marked a line to gauge). Just performed a pressure test and it dropped 1 PSI after 22 minutes. When I finished the lower a year ago, I pressure tested it and it had dropped 0.5 PSI after 1hr 40 min and I thought it was my Mitivac cap leaking (had to use a distributor o-ring to get the cap to seal). Guess the problem was there from the beginning.

Before I tear it down again and do it all over again, I'm wondering a few things:

1 - Did the silicon end seal "fingers" maybe get under the gasket and caused it to not seal properly? Maybe I should "snip" those fingers off?
2 - Did I let the Ultra Black dry too long before torquing the lower? (waited almost 1 hour)
3 - I used 4 studs to align the lower but it slipped out of my hands and dropped ~1" before bottoming out. It was on the studs so it landed straight and it sounded like the silicon end seals absorbed the shock.
4 - The lower gasket on the passenger side was misaligned a little (noticeable when looking at the right front coolant port). I was so nervous going through the steps that I didn't notice when I placed the gasket. I followed the Hayne's manual torque sequence. When I retorqued the lower again the next day, most of the bolts turned a little except for the one that helps hold the heater tube. Same behaviour after I torqued again after a couple of heat cycles. Below is a pick of the gaskets just before dropping the intake:

Anyway if there's anything that seams off with what I did above, please chime in with any words of wisdom. I don't want to repeat the same mistake(s) again! Thanks.

 

[96pushrod]

Those those end seals in the trash as many have recommended you to do. Maybe the gap between the lower and China rail is small, and the end seals are not allowing the intake to seat properly against the water port. Either way, throw that **** in the trash.

With a bead of rtv around the water ports, and good fit between the mating surface of the intake and cylinder heads, there really shouldn’t be much possibility of coolant leaks. Where the water ports are, I don’t really smooth out the rtv, I actually like a small bead so it’ll just squish out where it needs to.

If you used ultra black, an hour really shouldn’t have been too much time, but usually I torque mine before that. Usually I let my end seal bead tell me when it’s time to do the final torque sequence. When I can very lightly touch it and it doesn’t stick to my finger, I know it’s ready. As far as the exact Time, I couldn’t say, usually 15-20 mins I’d guess depending on ambient conditions.

 

[Leadsled Coupe]

Like 91 Notch I never use gaskets on ends. Always silicone and always after brake cleaning to make sure it has a good seal. I use more on those corners Like maybe 3x.

I don’t wait a time per day I wait until there’s a good thick skin but inside is mushy Still.

The drop you had could explain things too. Many maybes Here.

 

[Bestia]

Like 91 Notch I never use gaskets on ends. Always silicone and always after brake cleaning to make sure it has a good seal. I use more on those corners Like maybe 3x.

I don’t wait a time per day I wait until there’s a good thick skin but inside is mushy Still.

The drop you had could explain things too. Many maybes Here.

I'm not questioning the cleanliness of my work (it was spotless) before putting the gaskets so no maybe there. I'll go with just Ultra Black on the ends and like you both said, wait for it to not be sticky on the fingers anymore before setting the lower down (and not dropping it!). How thick of a bead do you lay down? Is it possible to have too much on the China walls? When I did my lower 16 years ago my buddy layed the beads for me so I don't recall.

 

[96pushrod]

I'm not questioning the cleanliness of my work (it was spotless) before putting the gaskets so no maybe there. I'll go with just Ultra Black on the ends and like you both said, wait for it to not be sticky on the fingers anymore before setting the lower down (and not dropping it!). How thick of a bead do you lay down? Is it possible to have too much on the China walls? When I did my lower 16 years ago my buddy layed the beads for me so I don't recall.

Lay the intake on dry, see how much of a gap is there and lay down that, plus 1/16-1/8in more for the height.

 

[Bestia]

Lay the intake on dry, see how much of a gap is there and lay down that, plus 1/16-1/8in more for the height.

Sound advice. I should be a lot quicker to do it since it’s still somewhat fresh in my mind.

 

[Leadsled Coupe]

Keep us posted!

 

[ndmp40]

Lay the intake on dry, see how much of a gap is there and lay down that, plus 1/16-1/8in more for the height.

This.

And I don’t wait to install and torque.

Throw those blue end pieces in the trash.