My hubby wants to remove the manifolds which he suspects are the originals but is worried that the bolts will be frozen. What is the best way to unfasten 40yr old exhaust manifold bolts from the cylinder heads.

 

I hear that heating them and melt a candle on them...the wax lines the threads.....A muffler shop guy told me of this trick!!

 

what i did with mine was to give them a shot of kroil everyday for a few days and then tried them... the lower 4 are very easy as they can be lubed from above (just under the spark plugs) the center one that is up by itself may take a little longer but the lube will wick up in there, just takes a little longer.

 

Thanks for your responses. We have never heard of this product.
So did you use the aerosol or the oil in the can?

 

I like the aerosol better for two reasons:

1. It sprays farther (good for hitting things that are hard to get a can near)

2. It keeps longer. There are volatile compounds in the oil that will evaporate out over time, rendering it less effective.

- Eric

 

i used the aeresol. you should be able to get kroil at about any parts store... i don't care for the smell but it works great!

 

Use a quality SIX point socket - if it fits loose, try a smaller (even metric one). Sometimes as the heads rust and shed, they do get smaller..

 

Everything the ^^guys said should work. If you do end up busting a bolt (and there's a good chance it will happen) you can always drill them out and heli coil them or retap them.

Heat works well to release frozen bolts. Don't put the heat on the bolt, put it on the manifold around the bolt. That will help expand the metal a bit to allow the bolt to release easier. Remind him to wear leather gloves because that metal will be hot.

 

As this thread seems to be developing, I will mention now that this exact suject was well covered in this thread, rather than have all of us blowhards re-pontificate .

- Eric

 

x2 on the 6pt socket! if you use a wrench make sure that it is 6pt also & only use the box end until the bolt turns freely. like i stated earlier the lower 4 bolts are all in "through" holes and the top center is the only blind hole, that is the one that will give you trouble. if you do use heat it needs to be applied to the cylinder head, not the bolt or the manifold and it needs to be a strong enough source that it will heat the iron quick so you can start turning the bolt before it heats up. heat on the bolt will only cause it to soften or expand and heat on the manifold will cause it to expand and put more load on the threads.

i would also recommend taking the heat riser shrouding off the passenger side manifold too, it improves acess to some of the bolts
.

 

Good catch Eric. Dang! what are we going to pontificate about now that you've ruined our fun??

 

Pontificate is a big word for this place.


I've never had any problems getting exhaust manifold bolts loose, rounding off the heads you do have to be careful of.
If you can run and heat up the engine good first beforehand it helps.

 

Yes, but according to my wife, I have a big mouth to match!

- Eric

 

So is Cardboardbox and elephantitus and Maxillofacial mandibular surgery....Hmmmm Maybe he leared it on the "Pontiac" forums . FWIW I hate working on e manifolds just after the car has been run. So easy to get burned. Helps a lot if the inner liners are out of the way though.

You'd be wanting to advertise that here?

 

I'll be attempting this soon too but keep putting it off for fear of rounding heads also. I'll try all these tips.

 

Hi,
Thanks for all the responses and the link to the other thread. I did a quick search for manifold removal and didn't see what I wanted...I guess I should have just searched for rusty bolts ..LOL The Kroil oil tip was new on this thread so I think he will try that too.
You guys are great!

 

Let us know how it turns out. Maybe it will encourage me to get with it

 

Just curious, are you planning to reinstall the OEM manifolds or go to a dual exhaust system?

 

I have done this many times and you are most likely to succeed if you use a torch(an acetylene torch not one of those hand held MAP torches). You need to heat the head not the manifold around the bolt till it glows then immediately start removing the bolt, (make certain you have already bent the locks on the bolt retainers beforehand) they generally come right out, if they start to get tight you aren't moving fast enough and it's time to heat it back up. Using this method works about 99% of the time. I never use any penetrating oil because it just causes fires. Also have some wet rags available in case you start any grease on fire.

 

I wish I had a lady to do all the research and get the answers for me while I was working on the car. I hate doing the research and figuring out what to use and how to use it. I just wanna turn the wrench. Lucky man you got there Ro.... make sure he knows it, we guys need to be reminded of it once in awhile.... I'm sure the whole rusty bolt thing will turn out well.... all things come apart - one way or the other... Haha

 

One thing that almost never gets mentioned is to use anti-sieze when putting things back together. Will make the job much easier if it ever needs to be taken apart again. I use it on most bolts.