I've got a steel hood on my 87 base model and recently picked up an Al hood. The FSM mentions using different (electrically isolated?) mounts for the Al hood.

Is there anything to worry about if I stick with my steel hood hinges? (Hood latch as well.)

14 Body 14-13



Thanks in advance.

 

If you have what's necessary to swap the hinges, you might as well do it, just to be safe.

Also, my TII's aluminum hood's latch froze up on me, so I was forced to temporarily use a steel hoods latch (from my base N/A). It was a PITA and took some force to shut the Al. hood with the steel hood's latch. Instead of just 'dropping' the hood from 10" up, you have to raise it up and then slam it forcefully down.

 

Interesting stuff, anybody have a definite answer?

 

Does that really matter? I THINK NOT!

 

aluminum corrodes through electrolosis(spelling??)

anyways......we do a TONNE of warranty work for aluminum corrosion on Peterbilt Transport trucks here at the body shop.......what causes the corrosion on the aluminum is the transefer of electricity (no matter how minimal) through dissimilar metals....ie. steel hinges, aluminum hood......etc.

We ALWAYS put a layer of two face tape between the mirrors (Stainless) and the doors (aluminum) on the trucks...........the hood on your rex should be no different.


On this note as well, I can't even remember if they put it infrom the factory on our cars........but the didn't on Buick Rendevous.........I have done 5 hoods from Rendevous in the last two months.........

 

its called dissimilar metal corrosion. Its for Mazda really...not for you. Over time the corrosion could occur and Poof your hood is gone. LOL. If you ever seen rivets on sheet metal you you'll see DMC

 

It matters quite a bit, actually. For example, my Honda Insight is all aluminium. Anytime a steel bolt threads into aluminium it is a special "Dacryl" coated bolt to prevent corrosion. The service manual warns on almost EVERY page that only the proper bolts are to be used and under no circumstances are steel fasteners to be substituted.

Two dissimilar metals will corrode due to electrolysis in the presence of moisture. In this case, the aluminium will be reduced and thus rot away.

Compounds such as dielectric grease and anti-seize will prevent this, but over the long term they will eventually wear away and you'll get problems. Aircraft suppliers have some rather potent gooes that do a great job.

 

people have been swapping hoods for years and i have seen no one complain about pitting in the aluminum anywhere.

engineers usually put disclaimers to protect their own asses, it doesn't mean that it will happen or that it ever even was tested.

don't overread what i read though, electrolysis is common with a weak metal like aluminum but that doesn't mean that it will corrode, remember the faces are primered and treated.

 

Someone swapped a AL TII hood onto my 91 before i got it, i dont see any indication of this either

 

what should be takin into account though on this matter........

Most these TII hoods are approaching 20 years old (some of which have never been painted and see NO corrosion WHATSOEVER)

Buick Rendevous, Chevy Venture/Montana etc (aluminum hoods) are under 5 years old (mostly) and I see these vehicles on a regular basis for extreme corrosion because they were not properly prepared from the factory

NOW......our hoods must have been better prepped from the get go since they have lasted this long, however that doesn't mean completely disregard the fact that this type of corrosion exists since it is entirely likely that a swapped hood (onto an N/A) may show corrosion a few years down the road.....and thus b e one less good hood for use.

And besides...is it really that hard to put either dielectric grease of a gasket of some type on the hinges...and swap the latch? not really.

But to be fair you can swap it just as is and you MAY never see problems, its all a matter of what you want to risk.

cheers

 

if anyone is worried they can just run a ground strap from the hood to the chassis(many cars do as a precautionay measure anyways).

 

interesting. I'll keep this in mind if I ever do an aluminum swap...

 

I was doing a few different hoods on my car once way back and I had to swap a steel hood onto the latches that were made for my aluminum hood that the car came with and I permanently messed up my latches, bot for steel to aluminum I dont know--

 

I dont know, I have a GXL so my hood already aluminum

 

I have a '90 GXL, is my hood AL too?

 

take a magnet to it you fools