Anti seize for exhaust manifold does not work

Joined
Jun 14, 2011
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Denmark, Europe
Hi,

On my Toyota Corolla exhaust manifold there is a heat shield mounted by means of four M6 screws. Thats approx 1/4" screws.

When I need to access the oil filter this heat shield needs to be removed which happens approx 1x pr year.

I ALWAYS struggled to undo these 4 screws and I always feared that they would break.

I tried copper, aluminium and nickel anti seize to no avail. Now 1 of the screws broke off and basically I need to pull the entire manifold to drill it out again.

Is there a product that will function in this environment? I think it's crazy that even 3M Nickel Anti seize gets completely stuck after just 1 year and maybe 10000 miles.

Copper and Aluminium for sure don't work either.

Will titanium screws work?

Lucas
 
Nickel is about as good as you're going to get. If that failed you then the fasteners are undersize or of improper material.

It sounds crazy but I've used milk of magnesia in extreme temperature applications and it's worked as well as nickel. Give it a shot. If it doesn't work and you get heart burn then you're one step ahead of the game.
 
Nickel is about as good as you're going to get. If that failed you then the fasteners are undersize or of improper material.

It sounds crazy but I've used milk of magnesia in extreme temperature applications and it's worked as well as nickel. Give it a shot. If it doesn't work and you get heart burn then you're one step ahead of the game.
Air Force T.O.'s spec'd milk of magnesia for certain turbine engine section assembly bolts as an anti seize...first time I read that I laughed; then one night in the engine backshop I saw a disassembly going on with several different engines, some had it and some didn't. The treated engines came apart easily, so I always kept some around in the garage...just in case I ran out of the traditional retail stuff.
 
a senior tech at work uses this and swears by it.

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Dumb question: can you buy a bottoming tap for this, and new bolts?

I'm wondering if you can, each time you have to do this job, remove the bolts and toss. Run the tap through the threads, making sure they are clean. Install new bolts with anti-seize.

I would think you can wire-wheel the existing bolts clean each time, but if they are getting heat-cycled they might weaken a bit, and if it's not that expensive to replace, maybe easier to do so.

Alternatively: instead of using bolts, could you change to a stud arrangement? Not sure if that buys anything or not.
 
Turbos are often held in place by brass screws to prevent the corrosion that always occurs with steel on steel there. Titanium screws aren't so good in steel because of galvanic corrosion (Mercedes Titanium alloy blocks and BMW Titanium alloy transmission cases require aluminum screws). Stainless, brass, or aluminum would be better choices. Brass or aluminum I'd change every time you pull the heat shield.
A ceramic based anti-seize might be a good choice if the standard types don't work.
Good luck!
 
Air Force T.O.'s spec'd milk of magnesia for certain turbine engine section assembly bolts as an anti seize...first time I read that I laughed; then one night in the engine backshop I saw a disassembly going on with several different engines, some had it and some didn't. The treated engines came apart easily, so I always kept some around in the garage...just in case I ran out of the traditional retail stuff.
As a former AF engine shop guy, worked well on old school engines.
 
I'm going to ask the obvious question, is there a way you haven't thought of to access the filter without removing the heat shield? Do you have big monkey hands or something? Maybe a filter cup socket?
 
Pictures needed. Sorry, haven't had to struggle that much with a Toyota filter removal.

Maybe consider 2 services a year and see if the parts come apart easier?

Good and tight is definitely too tight.

Consider an aftermarket header/downpipe or a remote oil filter kit.
 
Turbos are often held in place by brass screws to prevent the corrosion that always occurs with steel on steel there. Titanium screws aren't so good in steel because of galvanic corrosion (Mercedes Titanium alloy blocks and BMW Titanium alloy transmission cases require aluminum screws). Stainless, brass, or aluminum would be better choices. Brass or aluminum I'd change every time you pull the heat shield.
A ceramic based anti-seize might be a good choice if the standard types don't work.
Good luck!
Speaking of BMW, they use brass for the air injection valve. Comes off like butter even after 20 years.
 
If I have access to a car lift I can do the oil job from underneath without removing the heat shield. But as a home "street" mechanic I have to do it from above where a removal is required.
 
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^ I'd say sneak to an office park some weekend and throw the car up on ramps, get it done before someone spots you.
 
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