It cost me $150.00 and a 12 hour trip from CT back to NY to finally confirm this.

If the primary clogs slightly, the fuel pump will pull air around the clamps. The clamps won't leak fuel, however.

If you watch the second half of the video, air bubbles are happening 1 ft before the primary filter clamps. How can a restricted primary cause that?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Cannot cause that.

The bubbles would appear after the primary filter if it's the culprit.

ok that's better! I suspect a pinhole rusted fuel supply line. There may be more air intrusion points but the plan is to fix one leak at a time.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Air in fuel is fixed! There was a leak coming from the supply line. Steve (funola) ran a hard plastic line from the tank to the primary filter. The car is running amazingly smooth now. There was always a battle keeping her running at stop lights. The difference is so great, that it feels like a totally different car. She starts up on the first crank. I'm simply amazed.

Steve also adjusted the valves for me about a month ago. The valves were REALLY tight. I had the car about 2 years and never had them adjusted.

I was meaning to take more photos underneath the car but my car is wedged between two other cars making it hard to get under. Here's a picture from inside the engine compartment. There's a green arrow pointing at the new line and a red one pointing at the old.

I'm sure Steve can explain all this better than I.

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1984 300td euro turbo

Interesting redneck repair! Was on the verge of replacing the clear plastic lines but this interests me.

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1999 Mercedes E300TD daily driver sold at 238K miles 106K miles were mine, rust worm got it :-(
2006 Mercedes CDI new daily driver! 56,000 miles May 2016 now 85,625 Apr 2018 and Apr 2019 101,000 miles Apr 2020 109,875. March 2024 135,250

Did you put the Startron in? The fuel was pretty black when we were priming the line with the Mityvac and it sure looks like an Algae problem.

We did a few tests before replacing the fuel line since I hate replacing parts by trial and error.

1. Crimped off the supply line at the tank (rubber hose) then test it with Mityvac at the engine bay. It held vacuum but was leaking very slowly (almost imperceptible). It was hard to determine if it was actually a leak in the fuel line or in the Mityvac/connections. Although there were wet spots at the fuel line clamps under the car which indicate possible pinholes underneath. There were also oil leaks from the engine which made it onto the fuel lines so we couldn't be 100% sure.

2. Ran the engine out of a OJ bottle of diesel in the engine compartment and saw no more bubbles so it was almost certain we have a leak in the fuel supply line. Jaime had replaced the tank strainer not a few months ago so it can't be that.

Replaced the fuel line and problem fixed. With the help of Jaime, we did all of the above in 1.5 hrs.
Oh, and we did it without getting drenched or spill any fuel.

Good he didn't bring it to a shop. They'd probably want to replace the IP and charge him $3000

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Hey Steve. I have Valvtect BioGuard. Thought it was Stratron. Do you think this would work? I attached a photo. Car is running like a CHAMP!!!

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1984 300td euro turbo

Per product description, Valvtect should work. Unlike Startron, it may plug up your filters depending on the severity of the algae. Make sure you have spare filters and the tools to change them when they plug and engine stalls.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked