Exhaust manifold bolt removal??

[Dangeranger95]

I've got a 1995 ranger with a 4.0. I've got the engine out of the truck right now and I need to take the exhaust manifolds off. The bolts seem really tight so I sprayed them down with PB Blaster. Tried them again a day later and they still feel like they may twist off. I know these bolts go through the manifolds and screw into the heads. My question is, what part do I heat up with a torch, the bolt head, the manifold, or the head where the bolt goes in it?? Any other tips or tricks?? And if I do break them off, how about then?? Any help would be appreciated, thanks.

 

[RollinWOT]

The last time I did something like this I just sprayed down the bolts with PB Blaster every couple of hours for 2 days and just let it soak in and they just came right out. I would just keep Blasting it. I really don't like using torches but it's up to you.

 

[DriverSideImpact]

Ditto. I'd keep spraying. The varying temp changes will help the metal to expand and contract naturally and the blaster will seep in.

Maybe use a torch a little bit around the bolt head, on the manifold, etc (heat will penetrate down through the bolt, and cast iron and aluminum have different expansion rates). Then spray PB blaster all over. The heat might make things expand a little bit, enough for more blaster to penetrate the threads. Tap the bolts with a hammer after you spray them down. Just go slow.

Do the bolts move at all? Try putting a consistant pressure on the bolts in both directions (tightening and loosening) and spray some blaster on there. I don't recommend hitting the wrench or ratchet with a hammer...that puts extra hard stress on everything.

Also, what are you using to try and get the bolts off?? The wrong tool can make all the difference.

If they break off then it's machine shop time.