The 280C i just bought had been sitting for years and has a fuel gauge that does not work properly and a engine that runs hot. I have a feeling my thermostat and fuel gauge sensor might be 'stuck'. Any ideas how to fix these? (I plan on removing the radiator and having it cleaned and flushed also)

This is a W114 chassis and M110 motor, FYI

Thanks!
Nathan

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Nathan
'74 280C - gone to a new home for the finishing it deserves.
'64 356SC
'74 914 2.0

On my 280C, the fuel gauge turned out to be a corroded connector in the trunk under the trunk mat.

The thermostat is an easy job. 3 10mm bolts to remove the housing. It uses an O-ring instead of a gasket for a seal. You can get them here from Phil or any auto parts store or the dealer. It should most of the time be at the 175 mark altho it can run as high as the unnumbered mark which is 212F without problems. The aux fan should come on right around 212F.

Michael

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Usta haves '69 250/8, '76 280C, 1971 250C 114.023, 1976 450SEL 116.033
Current have, 1983 300SD 126.120

I'll check the fuel connector.

Mine was pegged at the top of the temp gauge, so I know something was/is funky.

Thanks,

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Nathan
'74 280C - gone to a new home for the finishing it deserves.
'64 356SC
'74 914 2.0

Do NOT run the engine that hot! You can easily warp the heads if you do.

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Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

also can be the ground to the instrument panel.

very common problem. typically makes all the electric guages jumpy.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Make sure your engine is running hot. An old gauge will often move to "operating range" and then peg out.

Pull and replace the thermostat. Check for corrosion and obstruction of the coolant passages. It is almost a given if the M110 sat for a long period of time the coolant separated and the glyceren (SIC) has congealed into a mass. You'll usually find it in the thermo housing and in the lower heater hose-radiator hose housing.

You'll probably find the housing has corroded where the lower radiator hose connects. Go buy a tap set. You'll need it.

The fuel sending unit probably needs cleaning. I guarantee the screen inside the tank does. Do a search for the problems on this web site.

Search before you ask. These guys are wonderfull and have posted a wealth of information. I'm relatively knowledgable (despite my spelling) and I have found solutions to problems here which have stumped me.

dont feel too bad if you cant find what you want with a search.

i usually have a heckofa time myself.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.