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Old 02-28-2003, 12:16 PM
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haasman haasman is offline
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Join Date: Jun 2001
Location: San Francisco, CA
Posts: 3,097

What the posting said was you do not have to remove it, that the fuel system cleaner got rid of all the accumulated varnish etc. and the unti returned to normal. The side benefit of course was a fuel system cleaning. Often it is recommended that you change your oil and filter soon after doing this since it tends to wash a lot of crud down into the engine and engine oil.

If you do have to remove the sending unit and needs to be taken apart, be aware that there are very fine (small) wires that the fuel sending unit float rides between that transfers the fuel level. Often these just get dirty and need to be cleaned.

The last unit I cleaned was out of a diesel, I pressume the gas ones are similiar. Whe you extract it from the fuel tank it will have fuel inside it so beware that it will need to drain for a few minutes. Once out you will need to take a tiny nut off the top (?) or bottom to be able to remove the outer tube from the inner section of the tube. The you will be able to see the float, the wires etc.

Not only the wires need to be cleaned but also the contacts at the bottom of the float AND the contacts at the lowest part of the travel that turn on the low fuel warning light.

Additionally, the fuel sending unit head is a very large nut size. Often either large channel locks or large crescent wrench will help start the turning and removal of the sending unit. It is always a good idea to replace the gasket that goes between the unit and the tank.

Hope this helps, keep us posted,

'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)
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