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1997 C280 Fuel Level Sensor replacement

27K views 15 replies 9 participants last post by  jpman 
#1 ·
I have a 1997 C280 and need to replace one or both fuel sensors. Can anyone give me a year specific (1997) description of the replacement, where they are specifically located, do I have to remove the seat, etc..
I would really appreciate the help!
Thank You in advance.
 
#4 ·
Manual is Haynes no. 3511 - C class (4 cyl and diesel only)1993-Aug 2000

Relevant for all except the engine - I don't think they do a 6 cyl version

Says drain from the sender unit drain plug

Overfilling is a common cause of erratic fuel guages on other models also - a bit of underfilling sometimes fixes itself over a week or two - fuel gets into the carbon filter and needs to drain off

Hope you don't have to remove the senders
 
#5 ·
oberoi said:
Manual is Haynes no. 3511 - C class (4 cyl and diesel only)1993-Aug 2000

Relevant for all except the engine - I don't think they do a 6 cyl version

Says drain from the sender unit drain plug

Overfilling is a common cause of erratic fuel guages on other models also - a bit of underfilling sometimes fixes itself over a week or two - fuel gets into the carbon filter and needs to drain off

Hope you don't have to remove the senders
about three years ago, my fuel sensor didn't work as well, I just fill half of the tank every time and I believed after 2 - 3 weeks, it is working fine again. It is still working fine now !

I hope that works for your car too !!
 
#6 ·
How do you know its giving you the right reading? It may be working but faulty. They may be times when tank would be full and the gauge shows at empty and opp.. other times I think empty and it shows empty?!!!!

I dont know if that method is a permanent fix, I've tried it and didnt seem to work for me.
 
#7 ·
Fill to first click only and the guage should read full

Put your odometer on zero and see what you've done when it gets to 3/4--1/2 etc -- should begin to make some sense

also see if the guage progresses gradually down

The 'low fill' is only a fix for previous 'overfilling' related errors

Some have had some success using a tank of the highest premium you can get in your locale -- apparently can free up the works in the sensor - do a search in W202 and also R170 forums
 
#9 ·
C280 1997 fuel tank 2nd half can not be used

I have a C280 1997 the fuel tank fills up both sections ( apparently it has two parts) when the fuel gauge reaches half. the car would stop running. So it seems I am using half the fuel tank. any ideas? what is happening? What should I change? I dont want to change the whole tank, cant it be fixed?
 
#11 ·
I solved my problem with additives. I used Berryman B-12, a full can on a full tank. Then in used 16oz of Marvel Mystery Oil for the next several tanks. The problem cleared up as the sending units were slowly cleaned.

The sending units use floaters attached to arms. As the floats lower, the arm swings along a metal strip, making contact with a slight electrical charge and getting a resistance reading. Those electrical signals are summed and sent to your fuel gauge.

Over time varnish buildup will interrupt the contact and give a false reading. So instead of replacing the senders, just attack the varnish with the additives over time. Much cheaper.

If you do choose to change the senders, you must replace both, as the units have been updated for more accuracy. They also require a new wiring harness. There is also a special wrench that must be used to remove and reinstall the senders.
 
#13 ·
I got a perfect fix for you guys.
STAR BRITE
Enzyme Formula Fuel Tank Cleaner
Hi jpman,
thank you for your response. I purchased the product you advised and have another question. The bottle contains 8 oz of cleaner and it is written that 1 oz should be used per 16 gallons of fuel. Should I follow what is written on the label or just throw the full bottle of the cleaner (8 oz) in the full tank of petrol (60 litters)?
Thank you in advance for your reply.
Peter
 
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