Vintage Cars: Mercedes300D 1981 & 300TD 1983, needle nose pliers, climate control unit


Question
QUESTION: Ron:

Both cars have always had trouble with the fuel gauge.  Even when they are full of fuel the gauge will bounce around and never show full.  Usually they read between 1/2and 1/3 full. Any ideas?

ANSWER: Chuck
These cars have fuel senders that are prone to gunking up.  They can be removed and the float and wires cleaned. BE very careful not to distort the fine wires the float rides on.
You can easily access these senders just above the fuel tank.
When you take them out let the fuel run out the little holes.  On a bench you will have to pry the little prongs that holds on the stainless canister, once off you will see what I mean by gunking up.  Warning - this is a delicate procedure, but is most likely the cause of your issues
Good Luck
Happy Motoring
Ron

---------- FOLLOW-UP ----------

QUESTION: Ron:

I am having trouble with the climate control on the '81 300D.  The blower fan stops working?  I have traced the problem to the connectors on the climate control unit.  If you wiggle them you can sometimes get the fan to start again.  Any ideas how to improve the reliability?  I need my Air!

Answer
by wires I assume you mean the two main connectors one on each side of the unit?
If so , you can take those off and clean with electric cleaner and also tighten us the connections with a needle nose pliers.  It requires taking the connector apart , but usually this cure it. Make sure you keep the wires in the right orientation
The other common issue is a cracked solder joint, which can be fixed by locating and refilling
Just takes detective work