Hi,

Just got that 240D, I gotta a lot to learn! So...I have found that the car does have automatic locks....they are just very very slow. Doing some reading I have found that A LOT on this car is vacuum related...exactly what is?

The car has been sitting for atleast 2 years....would that explain the really slow/non existant door locks? What about the blower motor for the heat, is that related?! How do I open the gas door...luckily the car came with a full tank (2 years)...should I add diesel treatment? I am going to have to open it eventually, really haven't looked for the release...where is it?

Anything else I should know about these vacuums?!

Man, I am used to working on SAABs and a Fiat, but this BENZO is in a COMPLETELY different world!!!!

Thanks,
-Kurt



P.s. I am planning on installing a new radiator, fuel filters, oil filter/oil change, air filter...primer hand pump (leaks, anyone got the PN), do i need to do glow plugs...how do I adjust the valves?! Should I do the belts at the same time? Could use some tires...acch!!! Busy winter!

The door locks, trunk door lock, trunk lock, brakes, transmission shifting, engine shut off and god knows what else works on vacuum.

The engine has a vacuum pump as the diesel can't rely on crankcase vacuum (don't ask me why.. I don't really know). The vacuum from the pump is stored in a vacuum tank in the trunk under the rear deck (where the speakers, and first aid kit are).

That stored vacuum is used when the engine is shut off. That is to open all the locks.

Check for leaks to all the vacuum locking elements.

Now.. for the fuel door.. it's not gas door :p just joking

The locking element is behind the right rear plastic panel in the trunk. Remove that plastic cover slowly (don't break things) and located the element. There should be plastic vacuum lines running through it connected by rubber vacuum hoses. The element is probably busted or the lines are leaking anyway once you get there you can figure it out.

Either replace the element or replace the vacuum lines.

Good luck!

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2008 BMW 335i Coupe

Kurt:

The usual reason that the vac locks aren't working well on a benz as old as yours is that the little rubber connectors for the hard plastic lines have deteriorated to the point the vac leaks off.

In the engine compartment you will find three vac lines branching off the mail hose to the brake booster. The brown line is the supply for the vacuum powered fuel shutoff, the green lines are for the AC/heater system, and the yellow lines are for the door locks.

There are two vac reservoirs -- the one for the locks is under the left front fender or inside the font bumper, and the one for the AC is inside the rear bumper. The hoses "T" by the firewall and one hose goes to the tank, the other to the locks or AC. There is a check valve before the T.

The door locks operate off a mechanical switch in the driver's door, supplied by the yellow plastic line. When the door is locked, vac is ported to a set of yellow with red stripe lines to the other three doors, the trunk lock, and the filler door lock. Unlocking is performed by the yellow with green line going to the other side of the servos.

The best way to troubleshoot vac systems is to get a MitiVac hand pump ($30-40 at the local parts store). This handy little device will allow you to "make" vac on demand, and has a nice gauge on it, too. Also has the bits to do brake bleeding, etc.

You can unplug the vac lines and attach them to the MitiVac and see if the entire system holds vac and operates properly, you can test individual parts, and you can check engine supplied vac.

I'd get some vacuum hose of the correct size and replace all the deteriorated connectors first, the check to make sure you have good vac by hooking up the MitiVac with the engine running. You should be getting 18" vac or so. If not, you have a leaking main line or a bad vac pump (not impossible in a 22 year old car!).

If you have vac and still have door lock trouble, you are going to have to test the individual vac elements in the doors. When you get the system vac tight again (also look for cracked hard plastic lines), the locks, AC, and shutoff will work properly!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Hey,

YOu might check the y-connectors right above the oil filter housing in the engine compartment-that's the most likely place for one to be loose.

Vacuum elements and leaks are the #1 problem on these cars... especially the 300d's with automatic climate control.

Michael

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Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E