Using stainless bolts for the thermostat cover?

[Ashyukun]

With the shipment of parts in from MidWest yesterday (though, somewhat unsurprisingly, I need to make another already :wrenchin: ) I can now replace the thermostat that I think has been a bit flakey (and definitely looks like it's been in there for a while).

The original bolts don't look bad and I could easily clean them up- but I generally replace most original hardware with stainless when I can, and they're fairly standard bolts. Given the original ones are also steel bolts I wouldn't expect that going to stainless would cause any issues, but since I've not really replaced much of anything going into the engine yet I figured it wouldn't hurt to ask...

[Farrar]

Aren't the thermostat housing and water pump cast aluminum? I wouldn't want to mix stainless with that.

Farrar

[Nicholas R]

There is no problem with that. Just remember that the stainless is stronger than the aluminum so if you over torque them, it's the stainless that will win. (not that this is much different than using steel bolts)

I always replace with stainless bolts. They hold up WAY better than plated or black oxide, plus they look great! Just remember to use anti-seize and you'll never have an issue.

[Farrar]

Just remember to use anti-seize

Good thinking. At those locations, there's no chance the anti-seize will get into the coolant. Nice!

Farrar

[Ashyukun]

Aren't the thermostat housing and water pump cast aluminum? I wouldn't want to mix stainless with that.

Galvanic corrosion was my primary concern in this, given I believe stainless is a lot more cathodic than standard steel...

[jmettee]

Anyone whose taken apart an original water pump to transfer the backing plate know the worst form of moisture, heat, & galvanic corrosion. The PRV factory used black oxide steel blots & copper washers in the cast aluminum water pump. The result is a crusty, rusty mess. That said, I believe the original bolts had a poor black oxide coating which did not do much to keep them from corroding/rusting.

I use Stainless all over the engine wherever I can. Whether regular or stainless steel, I ALWAYS use anti-seize on the threads. This will help prevent galvanic corrosion & also rusting since it helps to maintain a film barrier in the threads between the metals.

Use stainless wherever you can...the galvanic corrosion difference is not much different between steel & stainless steel. If you are concerned about galvanic corrosion, use zinc-plated steel bolts with anti-seize for the lowest corrosion potential.

[jmettee]

Good thinking. At those locations, there's no chance the anti-seize will get into the coolant. Nice!

Farrar

I sense sarcasm, pretty thick too! If you're not sloppily applying anti-seize, there's no way it will make it into the cooling system...there are gaskets, o-rings, & other barriers between the bolt threads & the cooling cavities.

Are you implying differently or am I misinterpreting your sarcasm with an actual 'atta-boy'?

[Farrar]

Are you implying differently or am I misinterpreting your sarcasm with an actual 'atta-boy'?

No, that was a definite "atta boy" with no sarcasm involved at all.

I guess I could have been more explicit by adding a "DOH! I was wrong. Good idea." But I had not had my coffee yet today.

Farrar

[jmettee]

No, that was a definite "atta boy" with no sarcasm involved at all.

I guess I could have been more explicit by adding a "DOH! I was wrong. Good idea." But I had not had my coffee yet today.

Farrar

LOL! My faux pax! I think the "Nice!" at the end made me think it was heavy sarcasm :)

[Farrar]

LOL! My faux pax! I think the "Nice!" at the end made me think it was heavy sarcasm :)

I think you have to hear in your head the way I say "nice." It's a downward turn. Very serious stuff.

Farrar