dddddyang

So I have an exhaust gasket leak. Trying to replace the gaskets but the bolts that bolts on the manifold to the engine block is badly corroded and stuck on it. I used enough strength that the whole car was moving but the bolt wasn't. Any ideas? Please help

Koda

Well, you are lucky you did not snap the bolt.


This will take time. You need to get a penetrating oil of your choice, apply it liberally, leave a soaked rag over it, and do this daily until it can be loosened. Some like PB blaster, others like Kroil, some like Sea foam. Others like 50/50 ATF and acetone.


Then there's a torch to heat it. Be careful as all that oil might catch on fire. It may take a week of soaking it to get it there.

Olds64

x2

I used some PB Blaster on a header bolt this morning. We'll see how it comes out. It wasn't too corroded, I just wanted to be sure it would come out since it's tucked away under the headers.

Ozzie

As indicated, you're lucky that you didn't break the bolt off. When that happens you can take off the head and send it to a machine shop for extraction. Try the soaking (over and over). If it works you will be lucky again. If that doesn't work try heating the head in the area of the bolt. If possible, chill the bolt at the same time. If it releases, again you will be lucky. If you should ever get to a point where you are reinstalling a bolt on an exhaust component always use anti-seize compound on the threads. If the first guy did it you probably wouldn't be currently having grief.

shiftbyear

A 50/50 mix of trans fluid and acetone has work the best for me. I'm sure heating would also help penetration. To help with removal next time, it would be wise to use an anti-seize product on threads and under bolt head contact area. Good luck

RocketDevo

The really bad ones you are going to need a acetylene torch and heat the metal around the bolt. I use non flammable penetrating fluid to cool the bolt and work it. It may take a few heating and cooling cycles.

Junkman

Not an Olds, but a '69 Cadillac that I own. Last fall, I decided to have a shop do the exhaust manifold gaskets, and after he tried the 3rd bolt, and it was the 3rd one to break off, he called, and asked me what to do. I told him to pull both heads, and I would take them to the machine shop to have them remove the broken bolts. The machine shop broke 12 more bolts just removing the exhaust manifolds. They told me that the bolts rust inside the holes of the exhaust manifold, and that is why they break off. I purchased all new head and exhaust manifold bolts, and they were all installed using anti seize. I hope that this is the last time that the car will ever need exhaust gaskets, but the next time, hopefully the bolts will come out without breaking.
As a side comment, when the Cadillac engine assembly plant shipped the engines to the assembly plants, the exhaust manifolds were already installed, and they were painted along with the engine block Cadillac blue. The engine must have really stunk until that paint burned away. I was told that Chevrolet did the same thing. I wonder how Olds handled engine / exhaust manifold painting.

Ozzie

I'm unsure if it's a good idea or not, but I've known of one fellow who got so frustrated that when he put it back together he used stainless steel bolts full of anti-seize compound.

rustyroger

When you reinstall the bolts, with the threads in the n heads tapped clean, maybe with helicoils if they were damaged, use a torque wrench and tighten them correctly.

More and more cars require a torque wrench for routine maintenance, on many European cars the oil filter housing will have the required torque stamped on them, important they aren't overtightened as they are plastic.
Many components need surprisingly little torque to tighten the fasteners correctly.
Of course, an old engine may well have never had manifold bolts touched before, and age and corrosion will be the cause of the issue. But don't overtighten them when you install them just so you don't give yourself a future problem.

Roger.

jfb

I went through a situation just like that within a year ago so here is a update on penetrants just remember time and thought process will help you. pb is not excellent anymore. sea foam deep creep takes 4 to 6 days and you need to budge a little everyday. kroil is sold by eastwood and looks to be the best and unchanged just read the directions temp etc and follow it. everything else has been changed to a greener product and is in a new learning phase. my olds is rebuilt but periodicaly I help others and constantly learn from new experiences and update my experience. I would not suggest seperating steel from aluminum until a decent metal temp is upon it. I have scene disasters from this and expensive to fix.

Firewalker

A few more wild and crazy ideas, for a possible stuck bolts or nut beyond whats been mentioned.

Acid. A mild solution of acid will eat rust faster than it will eat steel and can make it disappear fast.

Vibration. One of the secrets to impacts is it's vibrational shocks. Ever see someone take a stuck jar lid and whack it a few times with a knife?? So sticking a low low pressure impact on something, and let it whack away may loosen them up cracking any corrosion bonds with the vibrations. Lower pressure than what would be needed to actually back it out, or twist the bolt into.

Ozzie

Good suggestions; just be sure to go very light on the impact wrench impacts. Sometimes the bolts become brittle after an incalculable number of heat/cool cycles.