removal of exhaust manifold

[LSprad]

I'm attempting to replace the exhaust manifold gasket. My question is? should I get the exhaust manifold hot and then untighten the bolts or try doing them cold? I will be applying blaster prior to doing both cold and hot methods.

[divace73]

don't know why you would do it when hot?? A lot more chance of serious injury.
I have always done mine when cold, while you are there ensure all the studs are tight and all the way in.

[jctucker]

The benefit to getting the manifold hot is the expansion of all the parts and possibly loosening the corrosion.

My advice, the night before totally soak the nuts in some kind of rust penatrator. Then, it probably won't matter whether it's hot or not.

[narfire]

When you say exhaust manifold nuts.. ones that attatch to the head right-If the nuts don't come off, the stud will back out when undoing the nut.(usually) Then you can deal with it in a vice use heat ect.
The nuts/studs holding the down pipe can shear off sometimes, I don't know how one can get penitrating fluid in there.

[LSprad]

heating of the manifold sounds more like a safe method to loosen the rust with the help of the penatrating oil. Thank you all for your input. Wish me luck. I hope not to use all the curse words known to man in the process.

[baltobernie]

Wish me luck. I hope not to use all the curse words known to man in the process.

Luck being wished If you're working on the manifold/head connection, pay attention to the different stud lengths, and don't interchange them. The long ones protrude into the oil galley, and must have sealant applied to them when re-installing

[SouthSwedeSpider]

What type of sealant is recommended for the studs? I will be swapping my head (on my car... ) this spring, but since my new head don't have any studs I will have to transfer all of them from the existing head. Any advice on how to best do this, and how to get them tight? I just don't wanna join the curse club.

[jctucker]

Yeah, the studs will probably come out when you pull the nuts off. One can always hope though. =D

I'd buy new studs. They're pretty cheap. Take the new stud and hand thread it into the head. Then, take 2 nuts that will thread onto the stud. Spin one on after the other. Now, tighten them together (I usually do this right near the edge of the stud, not at where the threads turn into shoulder). You'll need to 13mm wrenches (or what ever size they are) probably, or a socket and a wrench. Get them nice and snug. Now you can run the stud in the rest of the way using the outside of the 2 nuts! Get it goodntight. When you've got it locked in, hold the inside nut with a wrench (don't let the stud move!) and loosen the outside nut. Lastly the inside nut should come off pretty easy.

Sorry, that reads rather complicated. It's not though! Also, I don't ever use any kind of Loctite because, later, I'd rather the stud pull out as opposed to it breaking in half during removal. If you get it properly tight you won't need anything. This is how I've been doing it with VWs, Audis and old American iron the last 20 years. Hope it helps!

[baltobernie]

I use Permatex 101BR copper-based sealant on the exhaust manifold - cylinder head studs. I also use it on the exhaust manifold - downpipe studs or bolts. I had occasion to temporarily remove the downpipe recently, and the fasteners came apart cleanly with just the right amount of effort, after two years of use. Actually, I use this stuff everywhere, high-temp applications or not. I like the orange color that's easy to confirm adequate coverage.

If you're overhauling an engine and will be removing/installing lots of studs, consider a special socket that fits your ratchet and grasps the stud without damaging the threads.

[jctucker]

Oh crap. I was re-reading Bernie's earlier post and didn't realize that some of the exhaust stufs go into the oil galley. My bad, I was offering advice based upon general exhaust stud work. Very sorry.

The orange sealant Bernie writes about is fantastic stuff.

[dantye]

I just learned by experience that you can drain the coolant to the level needed for removal of the heater pipe that goes from the water pump to the heater (necessary for removal of exhaust manifold) if you just place a two gallon bucket under the front passenger side of the oil pan and disconnect the flange that fastens the pipe to the water pump. It will run down a small area, drain into the bucket just fine, and doesn't make any more mess than you can wipe off the block and oil pan with a paper towel. Simpler that draining out more coolant than necessary.

First remove radiator cap and loosen the center bolt on the Manifold which holds the coolant tube bracket. Then, with bucket in place, just remove the heater pipe-to-water pump flange nuts and tap a putty knife gently between the flange and the water pump, then pry open with screwdriver, force it rearward until the center bracket clears the manifold stud so it will drop down. Make sure it has drained completely before removing hoses at the other end of the pipe.

So far, after soaking the exhaust manifold and down pipe nuts with blaster repeatedly for several days, no studs are coming out or breaking! I hope to post photos of the revealed areas and the cleaned and painted coolant pipe, manifold and down pipe later.

[dantye]

Slow work in the Winter. One broken stud so far - one that goes into the downpipe flange. NO studs in head broken OR pulled out. I will run a die on them and leave well enough alone unless there appears to be a leak around one.

Progress photos: (4) https://picasaweb.google.com/dantye/FIA ... 4777159970

(BTW: They are opening a plant to build Deusenberg replicas in Baldwin. WI, about 25 miles away - may see if they will hire a part-time septuagenarian.)