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Discussion Starter #1
Hello, everyone!

I have been getting ready to replace all the fuel injector seals on my 560SL and 420SEL. I purchased an ultrasonic cleaner and cleaned the 560SL injectors in it using SeaFoam as a solvent. It seemed to work very well, indeed.

I am ordering the injector "Insulators" (the "cups" the injectors fit into, with a nipple for the idle air line). I notice that AutohausAZ has two different brands, "MTC" and "Mercedes (OE)". The Mercedes part is about twice as expensive as the MTC. I am ordering the Mercedes bits, but I was just wondering if anyone knew what the difference (if any) was between these parts.

Also, on a completely different note, does anyone know if there is a difference between the heat dissipation of a standard-type radiator in extremely humid conditions? That is, does humid air carry away more or less heat from a radiator than dry air, all else being equal?

Thanks!

-Robert
 

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That's interesting. I don't see why you couln't clean out your injectors ultrasonically and just replace the rubber nozzle components, o-rings/seals.

Anyone else tried revitalizing their old injectors? I can't imagine there would be errosion issues in the metal...just clogging issues.
 

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Okay, I finished up the injector cleaning - OH MY GOD! This has worked out better than I hoped. Before cleaning, the injectors had asymmetric spray patterns, and there was a large difference from one injector to another.

I used a cheap ultrasonic cleaner from Harbor Freight and SeaFoam as the solvent. I ran the ultrasonic cleaner for 8 minutes (the longest the timer can be set), about four times, and on the dirtier injectors, let them soak for about a week, and ran them a couple more times.

After cleaning, the injectors are spraying completely symmetric patterns of MUCH finer mist.

I have installed the cleaned injectors in both my 420SEL and my 560SL, and the difference is amazing. The 420SEL, in particular, idles MUCH smoother and quieter, and seems to have better off-throttle response than it ever has. The 560SL still needs some work, so it is not as smooth as the 420SEL, but I'm sure it will be when I get done with it.

I recommend anyone who is looking to buy new injectors (at $35 each last I checked) to try cleaning them first - you may save quite a bit of money!

-Robert
 

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I got a cheap one at Harbor Freight (cheap place selling cheap chinese tools) for around USD $60. There's another model there that's all stainless for $179 - probably a better bet when using volatile solvents.

-Robert
 

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OCStrider said:
I got a cheap one at Harbor Freight (cheap place selling cheap chinese tools) for around USD $60. There's another model there that's all stainless for $179 - probably a better bet when using volatile solvents.

-Robert
yeah, I had to return my hand vacuum pump 4 times because it kept springing a leak internally.
 

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I wonder if any shops can still do injector cleaning? A friend of mine just had a set of electronic injectors tested for flow rate, spray pattern, etc. Seems they should be able to do any injector with the equipment.
 

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i know there are several... i know of one guy in sound hobe in florida.
but there are companies online as well
wish i could do that ,too. but then again, i got k-jet.
 

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RC does blueprinting. probably worth the money considering how spendy it is for a new set of injectors. not to mention i've seen brand new injectors spray worse than old ones. and the new ones were fresh out of the box!
 

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Thanks for the heads up! I plan on doing this myself. We tend to throw stuff away too quickly in this country when often there's a simple solution with a little bit of ingenuity. Great job!
 

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iam sorry in case this is a bit of a hyjack.
but what can you do if you got k-jet?

and to get back on track. someone told me that what makes a new injector superior is not just the spray pattern, but how the injector will close. how timely to be more exact
 

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Okay, I finished up the injector cleaning - OH MY GOD! This has worked out better than I hoped. Before cleaning, the injectors had asymmetric spray patterns, and there was a large difference from one injector to another.

I used a cheap ultrasonic cleaner from Harbor Freight and SeaFoam as the solvent. I ran the ultrasonic cleaner for 8 minutes (the longest the timer can be set), about four times, and on the dirtier injectors, let them soak for about a week, and ran them a couple more times.

After cleaning, the injectors are spraying completely symmetric patterns of MUCH finer mist.

I have installed the cleaned injectors in both my 420SEL and my 560SL, and the difference is amazing. The 420SEL, in particular, idles MUCH smoother and quieter, and seems to have better off-throttle response than it ever has. The 560SL still needs some work, so it is not as smooth as the 420SEL, but I'm sure it will be when I get done with it.

I recommend anyone who is looking to buy new injectors (at $35 each last I checked) to try cleaning them first - you may save quite a bit of money!

-Robert
Make sure to back-flush them, I got an amazing amount of crap out of mine.
 

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Many original injectors on our cars were made of steel. MB later replaced those with brass as the steel ones would rust if any moisture "water" was in your fuel tank. I have had great success with new brass injectors. Gen1's run about $19 each but Gen2's cost nearly $50 each. New ones have a wax on the openings to keep them sealed on the shelf which results in sub normal performance right out of the box. I usually run a strong fuel injector cleaner in the system when first installed as these were designed for 100% fuel, not the stuff we get in the USA with ethanol added. Ethanol can't remove the wax applied when manufactured.
 

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Many original injectors on our cars were made of steel. MB later replaced those with brass as the steel ones would rust if any moisture "water" was in your fuel tank. I have had great success with new brass injectors. Gen1's run about $19 each but Gen2's cost nearly $50 each. New ones have a wax on the openings to keep them sealed on the shelf which results in sub normal performance right out of the box. I usually run a strong fuel injector cleaner in the system when first installed as these were designed for 100% fuel, not the stuff we get in the USA with ethanol added. Ethanol can't remove the wax applied when manufactured.
Can said wax be removed (even partially) by first soaking new injectors, before cleaner in running engine?
 

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Good idea on cleaning, NAPA sells a gallon of carb cleaner for about $20 which is more economic than spray cans and soaking is much easier as well.
 
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