Blown fuse. Can they fail from age?
 

OK, I know what makes fuses pop, but can they also fail from age? I'm talking about the ceramic ones with the exposed wire. I had my car parked in the garage for about a week without driving it. No problems at all. Turned the key, started right up, and died within 5 sec. No start. Checked the fusees and the fuel pump fuse was blown. Replaced it and it started right up. I let it idle for several minutes and it didn't blow. The metal strip on the one i removed crumbled when i touched it.
I'm a little hesitant to drive it in case it pops the fuse again and leaves me stranded.
What do you think?

Similar experience here. Seems the metal ribbon just gives up. I’ve replaced with indentical rated fuse without issue.

Happens.

Also they can fail just sitting in their sockets, so you don,t see the obvious unless taking the fuse out. years of vibrations rub the heads of the wire within the socket's seat and breakes open an contact fails.

Just to add, it did blow, not just broken metal. The bottom part of the fuse was black from it blowing. I'm wondering if the metal had over time gotten weak enough from corrosion or whatever that it couldn't hold the current.

Its possible - might as well inspect and replace all the other ones.

edit

I will change to this...

https://www.classicretrofit.com/collections/blade-fuse-panels/products/911-front-fuse-panel-1974-1989

I found that over time the brass "terminals" that hold the fuses will corrode. If they are not shiny looking there is some corrosion. This will cause a slight electrical resistance resulting in heat and degradation of the fuse material.

You can verify this by using a digital voltmeter checking for voltage between the fuse and its connections.

Most old Porsche's fuse panels can benefit from a thorough cleaning and new fuses.

Metal corrodes. Esp the Aluminum. It turns to oxide, which cannot carry current. Leaving less and less metal to carry current.

Don’t use cheap fuses with aluminum. Use the ones with the brass strap like it originally came with (copper is okay but not as good). Spritz all fuses with WD40 and spin them once a year is what I do, no issues for 45 years....

Changing to an ATO fuse box format is the best solution, but the most work what with the myriad of system wires to transfer EXACTLY.

Use a regular pencil eraser, nothing too abrasive in the fuse contacts. Electrical contact cleaner is suggested, not lube oil (attracts stuff). DOW 111, a silicone grease, while potentially messy if over used, will protect the contacts from corrosion.

That is what I did and it was easy. Not a single fuse issue since!

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The fuse element can melt without excessive current if one or both contact points are slightly resistive from corrosion or loose spring pressure. (Which is highly likely with that crappy fuse design). Heat is generated at the resistances due to I2R which can melt the fuse. Soldered joints can fail in the same way. Folks will blame the soldered joint when the real culprit was the terminal connection right next to the soldered joint. Usually from not being tight enough or from slight corrosion. If your new fuse blows again, then perhaps you do have a problem with the load rather than the fuse. Fred

Thanks everyone. I feel better about driving it now. The fuse hasn't blown again, but I only let it idle in the garage for about 10 min. I guess it's time to remove, clean and replace any fuses that are suspect. I take it I can replace the ceramic fuses with the glass tube type fuses with no issue?

Has anyone here changed over to this? Curious if there are other issues that come from it being "different" to some extent, although I can't imagine what that would be.

ditto!

Using Buss GBC fuses are a plug & play option. they are glass fuses with pointy ends. & you can return fuse panel to stock
My car sat for over 10 years in unheated storage and I had no electrical problems when I got it running again

My fuses were also looking a little rough so I just replaced all of the fuses with new ones. Cleaned all the contacts with IPA and hit them with Deoxit. Also did the same with all of the grounds and replaced the transmission to body strap as well.

I used the "refuze" brand. The owner was helpful and the actual panel is year specific. It was easy once I wrapped my head around the project and got organized.
Here is before during and after (top right of image 3). https://uploads.tapatalk-cdn.com/201...b1c2d8be21.jpghttps://uploads.tapatalk-cdn.com/201...3a2ca752bd.jpghttps://uploads.tapatalk-cdn.com/201...3bc099fb1c.jpg

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I’ve never see glass versions of the pointy end fuses our cars use. Please share if you have a source.

If you want to ensure that it was just the fuse and not another problem, you can check the amperage draw on that circuit with everything on and see if it’s appropriate for the properly rated wring and fuse. I think the rule of thumb is that it should be less than 80% of the amperage that the wire is rated for.

I used this system:
https://www.cddautogear.com/shop
bought at Rennsport, got a nice discount, wouldn’t hesitate to pay full retail. Took a few hours to swap over, the fact that I never think about the fuse panel is nice. I had several problems with the old fuses corroding. During the swap, I ended fixing the POs wiring nightmares, eliminating the questionable fuse situation made the troubleshooting easier.
Do it!