1972 350SL (4.5 litres). Fuel leaking from around the injector but not sure if it is the connection of the rubber tube or the two injectors gone bad. Do I need to replace all 8 if the injectors are leaking? Also, when it was running, it sometimes does not restart after running for a while (hot) - is this condition called vapour block and what part needs replacement or what to do to fix problem? What is the name of that part that seals the connection between the air filter housing and th combustion chamber?
Country: United StatesMake: Mercedes-BenzModel: 350SLYear: 1972Engine: 4.5 petrol
tighten connection (at max)
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To stop the injector leak you need to replace the short pieces of rubber hose. It attaches with clamps. I would replace all 8 of them, and be sure the hose is a high pressure hose designed for fuel injection pressures. Just a note about the fuel injectors. Many places will want to sell you a new/rebuilt injector when the rubber hose is leaking, but changing the hose is the best way to go, it cost a lot less, and I have don this on dozens of early Mercedes, it works great, just be sure to match the hose size, and get the exact replacement size hose.
As far a vapor lock, fuel injected vehicles can't vapor lock because the fuel line is pressurized. Vapor lick happens to vehicles with carburetors, that have a mechanical fuel pump mounted on the engine. What I would look at as far as the hot starting problem is to make sure the engine is tuned up properly. From there I would check the fuel pressure when it wont start, when it is hot. Many times a fuel pump that has problems, and is failing, wont work when it is hot, but if you let it cool, it will work like it should. If the pump is tested when the engine will run it will almost always test as good, that is why it needs to be tested when the engine is hot and wont start. When this type of fuel pump problem happens it acts a lot like vapor lock.
The piece that goes between the air filter and the engine is commonly referred to as a duct, there are other names for the part, so be ready for that if you are looking for one. To find one of these, or any other part I would check with a source I use. It is actually owned by Mercedes, and they are dedicated to restoring, and keeping older Mercedes vehicles running. It is called the Mercedes Benz Classic Center, I will post a link for them HERE. If you have any more questions, as always, I am here to help. Good luck with it, have a great day, and Thanks for using Just Answer.
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