Are aluminum heads (Edelbrocks in this case) prone to eventual leagage? I developed a coolant leak around the rearmost outer head bolt on the passenger side. I was fortunately able to reach it with a wrench and actually get about a quarter turn on it! Leak stopped.

Now, the driver's side is leaking. Also at the rear, but not around a bolt (as far as I can tell). Again, I was able to get a wrench on one bolt and turn it a little.

Thus far (knock on wood), I have found no traces of coolant in the oil or on the plugs. The engine's got nearly 40K miles on it, now.

It looks like I need to pull the exhaust manifolds and rocker covers and re-torque everything. Y'all know what a major PITA this is! But is this common for aluminum heads? They move alot more, so do their head bolts normally require re-torquing? Is there a torque spec other than the shop manual I should go by?

 

Did you use any sealer on the head bolts?

 

Yes, silicone.

BTW, the mileage on the engine is only 25K miles.

 

Silicone? Hmmmm. That may be most of the problem right there. You should have used a non hardending sealer, or more preferably what the factory uses... teflon paste.

Shouldnt need to retorque them if you used any of the more common and popular gaskets.

 

I might also add that cranking down one of the head bolts more than the rest like that is a VERY bad idea.... It can do things like warp or crack heads and blow head gaskets. If you have to tighten any of the bolts you should retorque all of them the same amount.

I have to back up madmax on this one too... A hardening silicone on the head bolts is a definate no-no..... Always use what the bolt manufacturer recommends - which is usually liquid teflon (or another type of non-hardening sealer, as madmax points out) on the threads and a moly lube on the washers or heads of the bolts where they contact the head casting.

Something to think about,
Matt

 

I used anti-sieze under the heads (of the bolts) and silicone on the threads. Do y'all recommend removing and reinstalling the head bolts (one at a time) using Teflon this time, instead of silicone? Since a couple were "loose", it just follows that others are, too, so at least re-torquing seems to be in order, here.

Again, what about torque specs?

 

Sort of a silly question... when you torqued them, did you follow the proper sequence? (starting from the center and working your way out evenly...there's a pic of it in the Chilton's book or any other automotive book.)

 

Well, if you're going through all the trouble to retorque them, why not go the whole 9 yards and pull the heads, run a tap through the threads to clean out the silicone, and put it all back together correctly?

You really do need to clean the silicone out of the threads anyway, so you might as well...

 

Yup, just like Ed says, you will need to clean the silicone out of the bolt holes if you are going to reseal the threads of each bolt..... All threads need to be absolutely clean any time you are torqueing anything down or the torque will not be accurate. Plus the silicone may have adverse effects on the teflon sealer's abilities to seal.....

Anti-sieze is a good lubricant, but the idea behind the moly lube is that it is able to handle the extreme pressures exerted on the surface of the head of the bolt (and/or washer) and the block and keep the torque readings true.... I have doubts about the anti-sieze having this kind of property...

It is really up to you on what you want to do. The proper thing to do is to remove the heads, clean the holes, and remount the heads properly. But I really have to tell ya that I doubt I would do that myself until the problem got unbearable.... You *might* be able to get away with just retorqueing all of the heads bolts in the proper sequence and to the proper settings. If this were my baby or a car that I push hard a lot or had a lot of money into, I wouldn't screw around and I would just do it the right way while nothing else appears to have been worse for what happened. Be sure to check the surfaces for warpage if you do remove the heads.

Good Luck,
Matt

 

It is my baby, no doubt, but because of the AIR tubes bolted to the back of the heads and the impossibility of reaching those bolts without removing the engine, I think I'll stop at retorquing, for now. If after that, the leak isn't stopped and I start getting water into the oil or combustion chamber, I will pull the engine and start over.

 

I'm no engine builder, but have built three. I used silicone on the bolt threads in all three cases. I had no leakage problems out of the first two, but they had iron heads! That's why I'm thinking that the aluminum has something to do with the problem. You know it moves alot more. I just suspect that it works the bolts and the gaskets a bit more resulting in more "loosening" than with iron heads. Maybe I used the wrong gaskets and bolt torque. I'll get my torque wrench calibrated before retorquing the bolts, just in case.

 

I know the ones you're talking about, i struggled with these two bolts just a few days ago. They're a challenge, but nowhere near impossible with the engine installed. Either a swivelhead 3/8 ratchet with a long handle, or a really long 9/16 box end wrench should get you at them just fine. If you're removing the heads then the upper + lower intake, distributor, remote coil, egr solenoid, and whatever else will already have been removed giving you some room to breath. Take the lines off of the heater core, and you should be able to get them both just fine...

Think of it this way, if coolant has already made its way over the top of the gasket it's sealing properties are definately compromised. If you can afford to be without the vehicle for as much time as you'd need to fix it right, than its worth it.

 

I just had my heads rebuilt last week and left the engine in the car. Getting to the ground wires on the back of the head and the bolt to hold on the air tube are not a problem at all (didn't even scrape my nuckles on that one... the fan blade however was a different story .) Good luck.

 

I dunno, guys. I've tried a couple of times (I left one of the ground wires off when re-installing the engine) and can't even get a wrench on them! Do you try from above or below?

I want you to be right, but I'm not a believer, yet...

I agree. Pulling the heads is the best thing to do, but if I have to pull the engine to do it, the problem's gotta get seriously bad.

 

Well like somebody already said I think, when you have the heads off you also have off the intake manifold/carb (or tpi setup if thats what ya got) and the distributor isn't in the way. With all this stuff out it's easy to just lean over the engine and get the bolts from above.

 

Thanks to everyone for your input.

 

Well, I spent this last weekend on "Project Retorque". What a PITA! That was arguably the toughest mechanikin' job I've ever tackled! I'll be sore for two days.

There are brackets on top of brackets that have to be removed just to get the manifolds off. The AIR hoses and pipes, coolant lines, harnesses, sheesh! I even had to remove the AC compressor and power steering pump (why does it need four bolts for anchorage?). How ridiculous!

The worst part is access to the manifold bolts. One had better have an excellent collection of ratchets, sockets, box ends, offset boxes, etc. to get at all of the bolts. And my favorite bolt, the one on the back of the passenger side head, was inaccessable! I might have been able to get to it if I removed the coolant pipe to the heater core, but that was more than I wanted to tackle.

The only way to get that rocker cover off is to either remove the AIR pipe to the cat, or bend it up dramatically. Since getting to the bolt is impossible, I bent it up. Later, I decided to sacrifice that pipe in order to get to "my" bolt. I just cut it off down toward the bottom, bent it over to the side as much as I could, and then could get my offset box end on it from below. I couldn't get that SOB off fast enough! I replaced the pipe with a section of hose upon reassembly.

Torquing the head bolts was easy, but forget about torquing the manifold bolts! About half are accessable with a torque wrench. The remainder are guesswork. And the dipstick tube - what a fiasco! I had to bend it to get it out because it wouldn't clear the accumulator, then couldn't get it back in with the manifold installed! After over an hour of trying to persuade it in myself, I had to call a friend over for help. With him pushing down from above and me coercing from below, we finally got it in.

All of the head bolts were "loose". My torque wrench was definitely off (nearly 20 ft-lbs). I used another friends brand new Craftsman wrench for the job and bumped them all up to 65 ft-lbs. I'll clean everything up real good tonight and see how it holds up.

My friend and I decided that if this doesn't work and the heads must come off, it will definitely be easier overall to pull the engine! This episode really tested my love for this car. A new Mustang GT is looking pretty good right now. I'll post a followup in a couple of weeks to let y'all know how this worked out.

 

A word of warning for your later (maybe) work...

At this point you have a foreign substance (dried silicone) in your oil/cooling system. It will slowly find it's way into your oil pickup, pushrods, lifters etc... It will be far worse if you ream out the holes with a tap because you will force some of the material out the other side as you thread the tap into the block.

There's a reason they say that you should use silicone sparingly... it will escape and clog things. A clogged oil pickup = seized engine.

I don't want to make you paranoid here but you should be watching your oil system far more closely now. First thing I would do is get it flushed.

 

Follow up:

The leak stopped - for awhile. Then it came back and got worse. I developed an oil leak, too. What a mess!

I decided to pull the heads. The hardest part of that job is removing the dipstick! Really! It only comes out about half way then hits the A/C accumulator. You have to bend it to get it all the way out. But it won't go back in with the new shape. So, you have to "unbend" it as you install it. This is ridiculous.

Having mangled mine, I bought a new dipstick tube from the dealer. I rebent mine to match (as close as possible). Then, I cut the part that sticks into the block down to about half its length. Worked like a charm! Now, I can get it just past the accumulator before I have to hit the hole. It pretty much slides right in, now. I used my old one as a guinea pig to see if this works. I can't see why this isn't OK to do. If there are no problems (and I don' t foresee any) I will modify the new one and install it.

I cleaned the combustion chambers, piston tops, and tops of cylinder bores. It all looked nearly new when done. I also cleaned all threaded holes with a tap and solvent (blew dry). I used ARP thread sealer on all head and intake bolts.

The bead of silicone at the back of the intake did not stick to the manifold. This was the source of my oil leak. In the Fel-Pro set, the front and rear cork gaskets are adhesive backed. This is a great improvement over the old, loose type. I chose to use them this time instead of silicone. I think they will work nicely.

I haven't totally finished reassembly. I have all of the accessories to reinstall along with the plenum, runners, etc. I should have it running by the weekend. I expect to have a perfectly leak free engine, now.

I'd like to hear some comments on the dipstick tube thing...

 

sleeper made a very good point... it would be wise to flush the oil system

 

Yep, that dipstick is a pain in the ***. Let us know how those cork things work.. I've got about six of them pasted onto my garage door so I remember NOT to use them. I don't trust cork in my engine for some reason, and I've got no reason for that except that it's cork. Silicone should work fine provided that you have cleaned everything off well and gave it a good thick bead. If you use it next time, make sure you don't let it sit too long before placing the manifold on top, and again, make sure it's clean. Good luck with having no leaks. Once they're gone, life is pretty sweet ...besides other things..

 

The head bolts go into the water jackets. Any silicone that gets pushed through while cleaning will not get into the oiling system. The cooling system is far more tolerant of debris (and tiny silicone chips are quite harmless). Intake bolts go through or into the heads. I cleaned those out with the heads off the car, so no debris got into the engine at all, there.

I don't know how to "flush" the oiling system. After completing assembly, I did change the oil and filter. I plan to run it for just a couple hundred miles and change the oil and filter again. That's all the "flushing" I know to do. I would like to be able to rinse out the oil pan, but can't think of an effective way to do that without removing it.

Debris in the cooling system tends to settle out into the bottom of the block and radiator. That's hard to get out. The radiator can be removed and rinsed out, of course. But I'm SOL on getting anything out of the bottom of the block. I did remove the block drain plugs, but they aren't low enough to drain out everything .

The real trash was generated while scraping head gasket residue off the block. As careful as I was, a few chunks did fall into the large water holes. I kept my shop vac handy and kept most from falling into the engine. Ideally, one should have the vac in one hand and the scraper in the other. That's quite difficult, though. Sometimes you need two hands just to scrape. A helper would be great, here.