Rusty/frozen manifold bolts: Soaking the bolts to be removed hasn't worked. I have had good luck removing rusty bolts by heating them and melting a candle around them, which will usually flow into the threads and allow a previously frozen bolt be removed. Heating, then quenching with ice water has worked before. This time, I've been unsuccessful with either.

I have a Ford integral-intake engine, that has several exhaust manifold bolts stuck. I have resisted breaking the bolts, so far, and have used a variety of lubes to soak the bolts. However, after two weeks of soaking, heating, and trying to remove the bolts, I've been able to remove only one bolt!

I'm beginning to wish I'd stayed with Chevy engines, as this is the first time I've experienced manifold bolts stuck this badly. Of the two Ford engines (200 inchers) I've attempted to work on, lately, both have the same danged problem!

Anyone have advice for removing these bolts, without breaking them off, re-drilling, and re-threading them?

I also need help with stop using profanity, which stems from frustration! It hasn't seemed to help any!

The method that usually never fails for me is to heat the rusted parts till their cherry red. Cherry red is usually hot enough to burn off the oxidation.

The two penetrants that I've used are Mr Gibbs oil;

http://getgibbs.com/testimonials.php

and Kroil by Kano Labs;

http://www.kanolabs.com/

I don't have a preference between the two, either one seems to work better than PB blaster or,,,,,,

Larry

Forwarding a prior e:mail on the subject (though heating to cherry red is the final method like Larry above suggests):

Machinist's Workshop V20 number 2, April/May 2007, page 35

Article: “Testing Penetrating oils”
This reports a test of penetrating oils where they measured
the force required to loosen rusty test devices. The
details reported here were validated by the original
article author. He also added some details on the methods.
You must buy the issue if you want to see how they did the
test. The back issue is available for purchase.
The table below extracts the results table The lower the
number of pounds the better. Interesting that a simple mix
of acetone and power steering fluid (PSF) works the best!


Penetrating oil - Average load -Price per fluid ounce
None ...............516 pounds -- 0
WD-40 ..............238 pounds --$0.25
PB Blaster..........214 pounds --$0.35
Liquid Wrench ......127 pounds --$0.21
Kano Kroil .........106 pounds --$0.75
PSF-Acetone mix ....53 pounds ---$0.10 (50/50 mix)

Note from original article author:
1) These are loads required to free the test piece after
8 hours of immersion in penetrating oil. This is
probably not representative of a quick squirt just
before a wrench is applied.
2) The original article incorrectly stated Automatic Transmission Fluid was used in the DIY.
mix. Power Steering Fluid was actually used.