Fuel Stabilizer

[Kevkeller]

I rarely drive my 280sl so I used Lucas fuel stabilizer to keep my fuel pump from seizing up.

The car has been off the road about 14 months while doing some work on it. The pump was frozen again so I took it apart. I was shocked to see that it was full of gray gunk. The impellor had a lot of corrosion and had been partially eaten away.

I have taken the pump apart many times prior and have never seen this before.

I am wondering if this had taken place because of the fuel stabilizer. Has anyone else had an issue with this?

[mdsalemi]

I'm assuming you are talking about the fuel feed pump at the rear of the car, near the fuel tank and not the fuel injection pump, right?

"Frozen again" means its been frozen before; did you ever install a rebuilt pump, or have yours rebuilt? Sounds like an issue with your pump at the end of its service life, meaning something has failed.  Check with Bob Youngman (baronyoungman) as he is our resident expert on pumps having rebuilt many.

There's always that possibility that the gray gunk is some jelled fuel mixed with metal particles from something wearing excessively. I think the impeller is hardened aluminum.

Its possible you've got some water in your fuel system and on a car that doesn't get used often this can be trouble. The fuel stabilizer (Lucas and others) are pure petroleum products not likely to cause harm.

[Kevkeller]

Michael,

Thanks for the reply. Yes it’s the electric pump.

What I meant by frozen again was that it would varnish up and become difficult to turn. Usually I could loosen up the end plate bolts and it would start turning again.  Sometimes I would take the impellor off and completely clean it and put it back in. Every time though there was no corrosion just varnish.

However this time after using the ethonal fuel conditioner the impellor has actually corroded and the pump section was full of grey gunk. Out of 20 years of ownership and taking it apart several times I’ve never seen that before. I’m not sure if it was caused by the conditioner or not but that is the only thing I did differently from previous times.

I also have never seen the pump inlet screen so full of rust and crap. I did look at the flower pot filter in the tank and it looked ok. Maybe a I got a bad load of gas in my car.

I replaced the pump with a good relatively new one. I think I’ll put a chunk of aluminum in the conditioner and see what happens.

[hauser]

Racing fuel will last longer without the usual problems you get from today's blend of gasoline.

[mdsalemi]

...Yes it’s the electric pump...the impellor has actually corroded and the pump section was full of grey gunk...I also have never seen the pump inlet screen so full of rust and crap. I did look at the flower pot filter in the tank and it looked ok. Maybe a I got a bad load of gas in my car.

Do you know if your fuel TANK is the original? Based on what you say, I bet the inside of your tank is now corroding, ever so slowly...and microscopic particles of rust are beginning to form, causing the inlet screen issue.

[BaronYoungman]

The use of ethanol brings negative effects regarding corrosion of metals.
In the automotive industry aluminum has been seen affected by a novel very aggressive corrosion phenomenon, alcoholate corrosion. It is odd but this occurs within a certain spectrum of water content with ethanol gasoline that has water (condensation) greater than .05% and less than .082%. So it could be in the past years your tank was at one end or another of this spectrum and for whatever reason this past year it fell in the "sweet" or I should say "sour" spot.  It also depends on temperature. So I know isn't much help now but this could explain the results you have seen.  I know in the past I have opened pumps that were obviously flooded at some point and had a combination of water and gas in them and the impeller was great and others that seemed empty until i got to the impeller and the teeth were just gone, not even just broken off but literally gone not to be found in the pump.
Bob

[Kevkeller]

Baron,
You hit the nail on the head. It was a grey gunk material that the aluminum had turned into. The impeller had obviously been eaten away. The vanes are seriously weakened and I’m sure will break if used again. Thank you for the post.

The tank is probably original but seemed pretty clean when looking into it from the sender unit hole. I’d like to buy a tank but am leery about it fitting. I think the preservative might have rusted the metal lines too. My filters were clogged like I’ve never seen before.

My FIP has 3 plungers frozen I just hope they are not damaged.

I won’t be using gas preservatives again. Maybe others should take not too.

Thanks for everyone’s input.

Kevin

[specracer]

I just went through my "short" pump after it sat for 6-7-8 (?) years (prior owner). Had the same gray junk. Was some visible corrosion on the impeller. Cleaned it all up with lacquer thinner to cut the varnish, and a new new seal kit. It worked on the bench, and has started the car. Sorting other issues before I can drive it again.

14 months of sitting I would drain the tank. 

[Kevkeller]

It was drained.

I guess the best word to describe what I saw was a sludge.