So it begins...

You know what I hate? Troubleshooting vacuum systems. Of course, with a 700k mile Benz, everything in the vacuum system is shot. Started having an intermittent no-stop issue last week. Engine wouldn't turn off, and a couple times the emergency stop didn't work. Yesterday I replaced all the rubber in the engine bay (6 ft), and pulled/tested/cleaned the shut off valve. It works (so a waste of 2 hours).

I can suck on the hose in the engine bay and the one connected to the ignition switch and turn off the engine, signs point to the ignition switch (ugh $$$). I think eventually I need to replace a lot of the engine bay hard line and rubber (with the proper size on the rubber, big box auto store only has SAE sizes in hose, everything is either too big or too small. I've got electrical tape keeping everything airtight at the moment).

Ah, the joys of old cars. Just needed to vent some frustrations.

The good news is that it still runs like a top and today's oil change went smoothly (every Benz I've worked on has has a rounded off drain plug). $50 for 9 qts, big box red shirt auto parts store would not honor posted sale price on Rotella.

Also, need some advice on bleeding air from the cooling system, as there's no cap on the radiator. I had to pull off a heater hose to take the SOV out, lost some coolant. A bunch of air got trapped. Ran the car with the res cap off, topped it off. Still could tell there was air in the top rad hose. I loosened the clamp on the top rad hose until coolant started to come out. Feels more full, is this good enough or is there some better method?

Also also, poll: Should I bring this boat to the autocross and make a video for the lulz?

In reply to RoughandReady:

Please do!! It's always a great thing when someone shows up with something unexpected.

Are you getting good vacuum to the other side of the ignition switch? If I recall correctly you can replace just the vacuum part of the switch.

Fill both the radiator and engine through the upper coolant hose on the radiator, attach the hose and drive in a low gear to keep the RPMs up to burp it.

In reply to bgkast:

Not sure about the other side of the ignition switch. I've been trouble shooting without a vacuum gauge so far (putting my finger on the source and feeling for a suck). I'm going to get a gauge at HF tomorrow. I know, at this point, that when I put my finger over the nipple on the ignition switch, I don't feel anything when I turn the key off.

Do you know if the vacuum part of the switch is the same on a W123/300d?

Who knows what the actual size of MB vacuum hose? I've got (I think) 1/8" and I'm still getting leaks from where the hard line and rubber line meet.

Well, car turns off now. Ignition switch was not at fault, the switch wasn't getting vacuum. $15 HF vacuum gauge saved the day. I can get 50 cm from the line to the brake booster, pretty much everything down stream from that is only giving 20 cm. By the time you get to the 4 way that runs to the hose on the ignition switch, you get like 2 cm. I can get okay vacuum to the source on the 4 way, so I think there's a leak from either the clear/blue line or red/green line on either side of the brown hose that runs to the ignition switch. I don't know what either of those lines do though. I ended up running a line directly from a plugged t fitting on the brake booster line to the ignition switch. A temporary fix. I think I've got just a ton of small leaks from all the old Y and 4 way and T fittings and by the time the hoses get to the ignition there's nothing left sucking.

You can buy new tubing by the meter online. I would start with the rubber connectors though. The tubing can get brittle, but doesn't usually leak unless it's snapped in half. It's also color coded like a wiring harness, and replacing it will loose the color codes. The multi-leg rubber joints can look fine, but still leak.

http://vibrantperformance.com/catalog/index.php?cPath=1022_1073_1142_1189

http://www.samcosport.com/usa/rp_vacuum_tubing.asp

color coding done. when i setup itbs i wouldn't be able to get it sorted without color coding.

In reply to bgkast:

I've found it for line $12 a meter, not a great deal. I think all the hard line is really fine though

Captdownshift, the plastic hard line is color coded. All the rubber is just black. I'll have to get some pictures so y'all can see the rat's nest in all it's glory.

You can also simplify the system by pulling a bunch of emissions crap off.

Google up "VW vacuum hose". That's all metric, too, and you'll find lots of options, including silicone.

bgkast wrote: You can also simplify the system by pulling a bunch of emissions crap off.

That sounds like a plan. Cruise control can go while I'm in there. What do these have for emissions besides EGR?

Seal between the pan and the turbo return line E36 M3 itself. AWESOME.

Mostly EGR, but it has a bunch of valves on top of the valve cover that control it.

The turbo drain is a fun one. There is a piece that bolts to the bottom of the turbo and a piece between the upper hose and the pan that has an O ring on each end "sandwiched" between the upper hose and the pan. You can also try cleaning it real good and squishing some RTV over the leaky joint for a ghetto repair.

In reply to bgkast:

May go ghetto repair. I've heard a lot of rumbling about that line still leaking after replacing the seals. I imagine that the turbo has to come off? Or at least the compressor side/center section?

I don't see anything on my valve cover except my throttle linkage and a microswitch.

I think the turbo can stay on, but you have to work at a funny angle to get at the two bolts that hold the drain line to the bottom of it.

The earlier cars had a Rube Goldberg vacuum valve set-up on the valve cover. Consider yourself lucky.