Broken Bolts on GM Products

[Tim Martin]

I got a 85 Chevy P30 here with a 5.7L engine. It came in to replace the intake manifold gaskets cause they were leaking coolant externally. The problem is that several intake manifold fastening bolts are breaking off due to corrosion. The situation is that several years ago someone installed an Edelbrock Performance intake manifold on and now the gaskets are leaking. With the experience that you fellows have with differing metals on these modern engines, what seems to be the best way to keep these bi-metal engines form developing so much reaction with each other and allowing corrosion to build up? Is there some kind of whatever that is available that will neutralize the chemical reaction between these metals or is this just something us techs have to put up with so long as we choose to be in this business? I put this post in the GM section cause I I am working on a GM product.

[steven kiser]

speaking as a tech that has fough off many intakes on gm's i hear your pain. corrosion and gm go hand in hand. as a rule you still have enough of the bolt showing to get it out. usually you don't have to work real hard at it. drilling them out isn't a big deal. in the past when i replaced the gasket in one of these beauties i replaced the bolts with stainless or L10 bolts. i never reused the original ones. generally the trucks run hotter, harder, and longer than the cars and should be treated as such. another question pops up, why in the h#@@ is there a performance manifold on it? i know that the performance intakes are readily available and sometimes less expensive that an oem replacement but on a P30, come on............................................oh ya, hows the radiator? take a good look for cold spots in it. prepare the customer for the replacement cost. just a tip here, if it needs to be replaced and has a/c take the radiator and condensor out in the unit they're in and seperate on the bench. you may want to mention a/c lines may have to be replaced.

[Tim Martin]

The owner had a Edelbrock intake and carb, as well as stainless headers and 3" exhaust system put on this thing. It was his personal Tastykake baby. And does it ever run. But, this arrangement has been a can of worms from day one. Just one thing after another after another. Heat unreal from the engine compartment. We had to insulate the engine compartment cover to reduce heat inside the truck. But corroded bolts are a very common issue with this setup. Anywheres on this engine. I wonder if there isn't some kind of abnormal chemical reaction between the coolant and the metals that is causing all this. But I agree that corrosion and gm are common. Although last week I got a Ford Taurus that I had to cut the timing cover off of the engine because of corrosion in the long bolts going into the block. Not a nice situation to be in.

[Stewart Levy]

Heat the bolts and use the vice grips works for me.

[steven kiser]

just a tip here. i purchased the otc tool that can heat metal through a magnetic (i think) field. you just place the probe on the bolt and step on the pedal. i've used this on 1/4" bolts and up to 3/4" ones. it makes heating close quarter areas a snap and there is no chance of "collateral" damage. on another point here, when i'm drilling out broken studs i'll use left hand drill bits. i can't begin to say how many times the drill has bitten and the stud backs out.

[Tim Martin]

so, ya got one of those things. I seen them advertised already but kinda considered the cost somewhat unjustifiable, but maybe I should reconsider.

Thanks for the input steve. I wondered how those things might work in real life.

[ricmorin]

just a tip here. i purchased the otc tool that can heat metal through a magnetic (i think) field. you just place the probe on the bolt and step on the pedal. i've used this on 1/4" bolts and up to 3/4" ones. it makes heating close quarter areas a snap and there is no chance of "collateral" damage. on another point here, when i'm drilling out broken studs i'll use left hand drill bits. i can't begin to say how many times the drill has bitten and the stud backs out.

Steve,

We were just talking about that tool last week. Which one did you get? Where from? How much?