Vacuum Leak BIG

[stix518]

Okay guys, I know I have a very big vacuum leak but have been unsuccessful in finding it.

Details: 1986 560sl, 166k miles. Idles just a little rough although not enough to really even notice (I notice because I know the car) but the "economy" gauge is always pegged to the right. However, when I put the car in reverse and step on the gas, the needle moves to the left (like it is working normally only in reverse). Is there a vacuum line to the tranny that might be causing this? Or does anyone have any other suggestions? Thanks!!

Stix

[rocky raccoon]

The vac source most likely is located in a difficult place to see and service. It is at the rear of the engine between the intake manifold and the firewall a little to the passenger side. Follow the line from the four-way connector on the driver side, across the upper side of the firewall and you will see it.

The right angle soft connector is your likely culprit. It lives in a hot, oily environment and is usually the first to go. I used a piece of plastic tubing as a temporary fix until I was able to find the correct rubber connector. If you have big hands you may need help from someone smaller.

Let us know how you make out.

[stix518]

You guys on this forum are amazing as always! We finally got down in there and lo and behold, the elbow of which you speak, Rocky, had basically disintegrated but was not visible from the top side. We took a good elbow from the front of the engine (and replaced that with a short piece of silicone hose) and replaced the elbow behind engine and all is well with the world - the car runs smooth as silk, the "economy" gauge works as it should and I am absolutely loving life with my 560sl right now!!! (And what better time could that happen???) Humble motoring my SL bretheren and, as always, thank you for your words of wisdom!

Stix