Spark plugs, fuel filter maintenance interval

[Kyiv]

I've been wondering about maintenance intervals for things such as spark plugs and fuel filter. For plugs and fuel filter MB specs, IIRC, 30k mi change interval. But. Is this interval based on fuel quality of early 90s? With modern Top Tier gas are these intervals still valid?

 

[gsxr]

IME both intervals are conservative, assuming normal conditions. The plugs may last closer to 50k before having significant wear on the center electrode. But while they are still so cheap (or, if you hoarded while cheap), it doesn't cost much to change at 30k. And, it wouldn't hurt to pull all that stuff out every 30k just to eyeball for oil leaks and whatnot.

The fuel filter also could go 50-60k, which is when I generally consider changing. The filter replacement is more of a PITA and since it's oversize, and there's already a tank strainer to catch coarse debris, I'm not sure why it would need to be done at 30k. @Klink?

 

[Kyiv]

The fuel filter also could go 50-60k

Why do you think our car's fuel filter has to be changed at 30-60k mi, when most/all new cars don't specify fuel filter change at all? Is it something inherent to our car's old-school design?

The plugs may last closer to 50k before having significant wear on the center electrode.

In comparison to 100k plugs on new cars, is that because of the material used in center electrode or something else?

 

[szvook]

If the plugs are gapped to 1mm, the interval to change them would shorten as well.

 

[gerryvz]

Just change the shit at 30K miles. It’s cheap insurance. You can peobably go 50K for plugs with no issue, but for air and fuel filters, I’d go 30K.

 

[Kyiv]

Just change the shit at 30K miles. It’s cheap insurance.

It's understood. I was just curious. Thanks

 

[gsxr]

Why do you think our car's fuel filter has to be changed at 30-60k mi, when most/all new cars don't specify fuel filter change at all? Is it something inherent to our car's old-school design?

I don't know. Perhaps fuel quality was more questionable in the 1980's worldwide - remember, MB designed these to survive anywhere, not just in USA concrete jungles.

In comparison to 100k plugs on new cars, is that because of the material used in center electrode or something else?

100k in newer cars is due to the fine-wire exotic electrodes (platinum, iridium, yttrium) which last much longer than plain copper. However for reasons I don't fully understand, the M119 ignition systems don't like these plugs. And, the exotic plugs are only available in resistor flavors.

If the plugs are gapped to 1mm, the interval to change them would shorten as well.

Good point, if you are starting with 1.0mm and plan to run to ~50k, they might require re-gapping at 30k. And if you gotta pull them anyway, just replace them at 30k.


It's the fuel filter that I personally don't want to mess with unless I have to. It's a PITA, potential fire hazard, and IMO the worst that would happen is a power loss if the filter became plugged. Again, this assumes you use quality fuel and have no concerns about what has been in the tank.