380SL Thermostat & Cold Start/Stallling Problems?

[ezrider]

I'm trying to fix cold start (starts but dies when gas pedal is pressed for first 1-2 minutes) and stalling problems after warmed up.

Went to replace thermostat and found installed thermostat was gutted (wide open). Could the thermostat have anything to do with cold start and stalling problems?

Also, can anyone tell me where to find the monovalve for the heater?

Thank you.

[maheath]

A wide open thermostat will only cause the engine to take longer in warming up. It should not affect starting, stalling, etc.

The monovalve, if it's in the same location as my 560SL, is in the engine compartment, on the firewall, near the passenger side hood hinge. This picture is from a 126, but the monovalve for your car looks pretty much the same.

[ezrider]

Thanks Mike! I ordered a repair kit for the monovalve.

[ezrider]

I just took off the distributor cap, the cap looks fair but the rotor is burned really bad on the end of the top side. It's charred black and a good bit of the material, close to an inch, is actually burned away. Could the rotor be the cause of my problems? I am going to replace the cap and rotor in any event.

Thank you.

[maheath]

Yes, the rotor is probably the cause of your problem. Whenever I have starting problems, I always start with the ignition system first. Check the distributor cap, rotor, plug wires, and spark plugs. They're easy to check, easy to replace, and not terribly expensive.

If you're replacing the rotor, go ahead and replace the cap. If one is damaged, the other is very likely to be damaged as well.

The next step to solving starting problems is to get a fuel pressure gauge and check the fuel injection.

[ezrider]

The fuel pump has been making a high pitched whine for a long time so I am replacing it and the fuel filter too.

[maheath]

Before you order them, check out the condition of the hoses back there. When I first went to replace my fuel filter, I found out that most of my fuel hoses were dried out and cracking. I replaced all but one of them, and that was only because I forgot to order it.