I bought a 1986 300SDL recently. The first time I went to fill up was a bit of a shock. Here is what I found:






I clean off the cap. It looks fine. The filler neck (i guess that's what it's called) I left alone. I didn't want to get rust particles into the fuel tank.

Any thoughts as to what I should do about this. Leave it alone?

Thanks.

Better focus on the camera would be good...

did the car sit for a long time before you bought it? Somehow extreme condensate or water got to the tank. Check your filters for the diesel fungus and for signs of rust.

Hopefully the tank will be fine, but if water is in there, you can bet rust will be as well.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Sorry about that second pic. That was the best of many attempts.

I know the vehicle sat for a while and wasn't driven much. The filters looked fine. I'll put some biocide stuff in the tank just to be sure.

How would I go about inspecting the fuel tank for rust?

It has to be drained, and you can peer in it (with a pen light) with the sender removed.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

try Naval Jelly to remove the rust.

run your tank when you are bored one weekend and inspect the tank strainer to make assumptions about internal rust.

then let me know, cuz I have the same issue

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I would replace the whole tank with a good used one and back flush the system very well. Rust is definitely something you don't want near your injection pump.

I'm seeing rust particles in my pre-filter. Maybe it's a coincidence, but my fuel thermostat started leaking a couple days ago. I want to take your advice and replace everything.

Where can I find a good used tank? Any online sources to look at?

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1981 300TD
1986 300SDL

eBay, craigslist, local junkyards and the forum's parts classified section: http://www.peachparts.com/shopforum/mercedes-benz-used-parts-sale-wanted/

You can also add something to your signature like "Fuel tank wanted, please PM me if you have one to sell." That will advertise it to more of the regulars that don't venture into the parts forum.

Wow a lot of condensation sat in their!

Pour out the spin on filter, bet its full of water.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

I already replaced both of the filters a couple weeks ago. I wasn't noticing anything in the old pre-filter, but the new one already have tiny little black flecks sitting on the bottom. Not a promising sign.

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1981 300TD
1986 300SDL

Thanks. I'll start looking around.

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1981 300TD
1986 300SDL

One question. Would a tank from a gasser work in my diesel?

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1981 300TD
1986 300SDL

Did this car ever meet Katrina???

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/mercedes-benz-cars-sale/296386-fs-1-owner-83-mb-300d-turbo-rebuild-parts.html

Do you mean was it in a Hurricane? No. It spent most of it's life in Kentucky.

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1981 300TD
1986 300SDL

Good luck finding a good used tank in a salvage-yard.
One thing I've noticed on my several trips to the Virginia Beach Pick-N-Pull, is that they puncture all the tanks, probably for environmental or safety reasons.
Would expect other yards today to have similar policies.

The fuel-cap on my '84 300TD is in similar rusty condition. So far no ill symptoms in several months of driving. Did snag a nice (looks like stainless) replacement fuel cap off an '82 300CD last week at the Pick-N-Pull.Also an OE metal oil-cap. I hate those black-plastic replacements, like the one that's on my engine now.
I'll transfer the new gasket from my plastic cap to the metal one.

Happy Motoring, Mark

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DrDKW