These questions pertain to a 1989 420 SEL, 223, 000 KM.

1. Could someone tell me the part name, part number, and what is the purpose of the device shown in the photo, that has the 2 vacuum lines going to it, and is red in colour? It's located in the foward half on the right side, on top of the engine.

2. Next, when the engine is hot, there is no vacuum at the EGR valve. Is this proper operating procedure?

3. I disconnected the vacuum hose to the egr valve, when the engine was hot and there was no change in the way the engine was running. Using a Mityvac, I also applied 20 in. hg. vacuum to to egr valve and there was no change in the way the engine was running. Is this proper operating procedure?

4. Next, that little red vacuum valve shown in the pic, was connected to the EGR valve. The red valve had no vacuum to either side. Is this correct? I would have thought one side of it should have had a vacuum. I couldn't trace the other line very far, it disappeared under the air intake.

5. There was another vacuum valve, similar to the red one, but a little forward and closer to the drivers side. What is this valve called? It had 2 hoses, and neither one had a vacuum, when the engine was hot. Is this proper operating procedure?

6. Finally, the electric change-over valve, located forward of the passenger side front fender, had 20 in. hg. on one hose and zero on the other. Is this correct for a warm engine?

Any and all insight into these conditions is sincerely appreciated.

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1989 420 SEL

Those are thermo-vacuum valves, different colors open or close at different temps. The line that disappears below the intake manifold attaches to the throttle body. The fittings on the my throttle body were crumbling. Mike Tangas gives a good explaination of how to change them with long needle nosed pliers in his "560 sel accomplishments" thread. I haven't a clue how the system works though.

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Earl McLain
'02 C230 Kompressor
'89 560 SEL "Frau BlueCar" (retired April 2004)

Greenacres2:

Were you able to replace the rubber fittings under the intake manifold connected to the throttle body, without taking the manifold off? It looks like a big job to take-off the manifold.

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1989 420 SEL

Cigar,
My manifold was off when i did mine, but i had a head off too--so the manifold had to come off. Once i got a look at where the fittings were, i could understand how Mike Tangas did it with long angle nosed pliers. And patience. He doesn't mention whether he attached the vac lines to the fitting before putting them back on, but that may be wise. Check his 560 thread.

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Earl McLain
'02 C230 Kompressor
'89 560 SEL "Frau BlueCar" (retired April 2004)

is anybody having trouble reaching the 560 sel accompishments thread or is it just me, everytime i search it doesn't come up. thanks

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