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Discussion Starter #1
Hello.

I mean the immediate protection, not advanced like the engine itself.

I change the fuel filter every 15k km (~10k miles). I used to change it every 20k km (~12.5k miles) under the impression that will specifically protect the injectors but then the engine started cutting and nothing fixed that other than replacing the injectors so I changed the plane to the 15k km. After ~100k km (~62k miles) the problem happened again and had to replace the injectors again.

This made me add another field in my maintenance schedule of 80k km for injectors replacement (which by chance happened to be the same for the spark plug cables).

Is this normal? Should I go back to the 20k km plan since the 15k km plan did not help? I don't know the real change interval for fuel filters. I improvised to find that 15-20k km interval.

For the sake if the discussion, I only find German made Bosch copper injectors for around $104 USD + labor for ~$27 USD (~$130 USD total).
 

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CIS fuel injectors should last at least 150k miles (240k km). HFM-SFI ones, even longer (not sure ours have been replaced on either car, both have over 250k miles (400k km)

on a CIS car, the fuel filter protects the fuel distributor and the fuel injectors. on a EIS system, it protects the injectors and fuel pressure regulator. a tiny spec of grit would be all it would take to mess up any of these things.
 

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Besides filtering out physical contaminants, the main purpose of the main fuel filter is to trap moisture and the like from entering the injection system.
 

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Discussion Starter #4
So I guess I'd better change the fuel filter even earlier. If 15k km didn't work, I guess 10k km? Sounds too early for me, but I guess there's nothing else I can do about it since the fuel filter is the only defense line.
 

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I believe that depends on the quality of the fuel. That sounds way too soon. I think the maintenance calls for replacement every 36K miles ~ 55K Km.

Also the dealer here in the US claims fueling with Chevron with Techron will make the injectors last practically forever. I think Shell has a similar additive. Mine was replaced for the first time at 180K miles / 270K Km.

So you could add a little bit of techron additive everytime you fuel up if fuel with techron is not available over there.

- Cheers!
 

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I believe that depends on the quality of the fuel. That sounds way too soon. I think the maintenance calls for replacement every 36K miles ~ 55K Km.

Also the dealer here in the US claims fueling with Chevron with Techron will make the injectors last practically forever. I think Shell has a similar additive. Mine was replaced for the first time at 180K miles / 270K Km.

So you could add a little bit of techron additive everytime you fuel up if fuel with techron is not available over there.

- Cheers!
Most of the major petrol stations (Shell, Texaco, ARCO, Chevron, etc) have their fuel additive which cleans injectors.

I use Techron twice a year. I buy it on coupon at Costco (it ends being ~$2 a bottle) and split the pack with two co workers.

One of the ways you can prevent dirty fuel is to use stations that have "fast" pumps. When they pump slowly that is generally indicative of a clogged filter. A clogged filter is less likely to catch all the contaminants.
 

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I did the petrol fuel filter 2 years ago it was 30 years old like all the parts on the car. The speedo clock reads 98.000 from new . I had a problem with dirty hot starts ,[still the same] . This made no change,, so i know the fillter was good that was removed Just changed 6 fuel njectors after 30 years of problem free motoring along with all the ht side that too was 30 years old and never been changed in its life .So i did not have any problems to start with so these parts could have lasted longer i dont know .But as the cash was burning a hole in my pocket, - as my old dad would say ,i picked up everything i needed to replace them . Just to show the how long the Mercedes parts lasted , then .
 

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Discussion Starter #8
All fuel stations here get the stuff from one single distributor, I'm afraid. Additives are not found after market. I only managed to find some Liqui Moly octane boost. Yet I do choose the stations carefully. I only have two new stations in mind and both are on highways with tons of customers so the stuff are cleaner than other places and never stays underground for long.

I did everything I can think of to prevent or reduce the injection problem but no use. Guess I'll just stay the way I am after adding the new item to the maintenance schedule.
 

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I didn't mention busy petrol stations that have high turnover. Please, don't misinterpret what i said. How fast do the pumps pump your petrol. That is indicative of how often the filters are changed at the petrol station.

A slow petrol station selling 10000 liters a day (just as an example) could change their pumps once a month. A very busy petrol station selling 100000 liters a day could change their filters once a month. All things being equal (the tanker has just dumped a fresh load of petrol, etc) which has the dirtier filter?

I don't expect a station with old equipment to pump as fast as one with new equipment.
 

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Discussion Starter #10
You misjudge me. I didn't want to misinterpret anything in the first place. Sorry, I didn't mean to sound rude.

But anyway, the pumps are so fast there that I keep telling them to slow it down (two clicks out of, I think, three) to prevent pumping residue from the reservoir as much as possible (solid stuff come out more under more current). And to take a breath since I turn off the engine and sometimes do something light while filling. Yet it still fills up before I know it. And to add to my point, I believe residue increases the longer the fuel stays in the reservoir. Now that I think of it, seems like that also reduce force-pushing residue from the filters too.

I'm confused if the above matters much, tho, because I change the filter too early. 15k km is sooner than any other W124 (and similar) owners do and they don't face my subject problem.
 

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You worry to much over this .Just drive and enjoy your wheels . I use RED X in my tank every fill up - thats once a year in my case ,, and thats only to visit the mot station ..along with 6 car shows throughout the year at our local club ..lol
 

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Discussion Starter #12
Good advice. Today I noticed the last fuel fill finished too soon (bad MPG) and I said "what the heck, just relax and drive away."
 
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