1993 525i Touring Impulse Build

Good news!

I pulled the drain plug, and no coolant came out. It sat for 2 weeks, so if anything was going to separate, it would have done so by now. Also pulled the oil filter out (BMWs use canister filters where you can easily see the filter element) and the pleats are still straight, so no evidence of water in the oil there either. They swell and get wavy in the presence of coolant. There is a lot of dirt in the filter already though - it looks like the fresh synthetic oil is really softening all the deposits in the engine.

Final check was a 15 mile drive to emulsify any coolant in the oil to make it obvious, and then pulled the valve cover. No visible emulsification, and everything looks really good inside. I also cleaned out the CCV passages, which are incredibly simple and basically impossible to clog on this car. Cleaning the radiator cap seemed to fix the low cooling system pressure; the seals are looking a little square, so it will be replaced soon.

Valve cover. Normally emulsification shows up where the timing chain slings oil against it.

The head. I also checked under the baffle over the intake cam, and it also looks good.

The CCV passages. Crankcase gasses leave the valve cover at the top left of the pic. Nothing to really get clogged here, so it must have just been the hose getting clogged. It's pretty small ID.

Going to put another ~50 miles on it and do an oil change to get some of the crap out of the engine. I can't believe how much the sludge is just melting away. I will also reconnect the CCV when I do the oil change.

The good side: looks like everything is in working order for this to be a more comfortable daily.

The bad side: no immediate reason to do an S52 swap for awhile.

Proof that I've actually driven it:

More small stuff done. Nothing too exciting, but I need to collect my thoughts somewhere.

• Rear cigarette lighter installed, with backlight. Alarm system LED and mic also installed
• New rear hatch shocks installed. Eventually, I'll need to do the glass shocks as well.
• Removed all the trim in the hatch. It has been taken apart before, and done very poorly. Much of the trim is broken, so I'm keeping an eye out for replacement. If anyone has a line on parts, let me know...
• Removed hatch switches, as both were intermittent. Discovered that contact resistance is very high, preventing the switch from triggering the latch solenoid relay. Installed the better switch in the main door latch harness so I can at least get it open**.
• Checked the rifle plugs in the oil filter housing for leaks, and they are dry. I'm becoming more and more convinced that the dipstick oring is somehow what is actually leaking. I will check this tonight
• Hunting down check control faults. Brake lining error was eliminated by making pigtails for the pad wear sensors. I still have a low oil level warning (right on the low line. Waiting to fill up until after I check the dipstick), brake light out warning (3rd brake light bulbs; I have them, just need to solder them in), and suspension leveling warning.

I thought I had fixed the leveling warning, but there is a dearth of information about this system online. Only M5s, 540i M Sports, and Tourings got the system in the US, and the M5 guys don't tend to lower the rear of the car much more than stock. The check control module looks for a ground (from what I've been told) from the 'camber switch' in the rear suspension. If it goes open or goes high, the system knows the height is wrong. Cars not equipped with SLS (aka LAD) simply ground this pin; the check control (CCM) is the same for all E34s. I have verified ground at this pin, but still get the error, so my next step is to run pigtails to the switch to understand what signals it sends as I slowly jack the car up. I get the impression that the system changed for 1993+ cars, further limiting available information since the M5 was only sold here until 1993.

**hatch problems are usually in the harness. My harness appears okay, but the switches are bad. More and more of these are failing now it seems, and the switches are $70 each from BMW. Ridiculous. The hatch switches are standard submicroswitches, pin mounted through the body. Pin spacing is 0.375", which is fairly standard, but the wiring is side exit from the body of the switch. A clip goes over the rear of the switch body, where most switches' wiring comes out. Stock switch is SPST-NO, made by Saia-Burgess, and is a V4SH-GO switch.

Alternative switches. All are IP67 rated. Many variations of each will work; I've only listed the important part of the part number. Every major switch manufacturer has a datasheet out there listing all available options.

• Saia-Burgess V4NS. If you can find it, I think the V4NSYCUL would be the best.
• Honeywell ZW50 series. ZW50F92EW1 would be ideal.
• Omron D2SW-3L3M, which is what I bought. Not ideal wiring, but availability for these switches is a huge challenge without buying a bunch of them. This is the only one readily available in the US. I picked a few up from Digikey.

Thanks for the great info. I'm reading since my next new car may be a "backdate" to a 5 or 3 series touring. How much $ are you in it for to date?

In reply to Nomad:

No problem; glad it's useful to someone!

Cost so far:

• $1500 purchase price
• $350 for a cracked cylinder head with very fresh cams, lifters, trays, and new valves, an uncracked head with decent valves and double wound springs, and a front seat out of an E32
• $125 for a full set of carpets, the rear cigarette lighter piece, both front door seals and felts, rear seat map lights, and a few small trim pieces
• $503 for all new coolant hoses, thermostat, belts, misc. rubber parts, head bolts, top end gasket set, air filter, VANOS high pressure oil line, all new intake hoses, hood shocks, and hood emblem, and a few small interior parts and clips
• $221 for new accelerator pedal bushings, rear hatch shocks, a few more interior parts, a bottom end gasket set, and all new timing chain rails

So I'm in it $2699 so far, and have maybe $100-$200 worth of cams, valves, and other head parts that I can resell. I didn't need to do everything that I did, but the result is a car that has all new engine seals except for the rear main, an essentially new head including valves and valve guide seals, all new hoses (radiator and water pump were recently replaced by the PO), and once I change the oil and hook the CCV up again, no major issues to speak of. If I only did what needed to be done, I'd be right around $2100.

I'd say in general, parts prices are marginally more than for my E30, but are still very reasonable. Almost everything, even most wagon-specific parts, are still available from BMW if you're willing to pay for them.

E34 and E46 wagons are actually surprisingly similar in size, if that's what you're considering. I've not owned an E46, but I've driven and worked on both fairly extensively. Here's my take: E34 has the edge in reliability and simplicity to work on. E46 probably rusts less, and has better steering in my opinion. Both are rare as a manual, but the E46 was offered that way from the factory, and also with AWD. E46 automatic is miles better than the E34 automatic. Performance is actually fairly comparable if both are manuals. E34 auto is quite a bit slower than an E46 auto unless it's a 530iT, then they feel similar. E46s were only available here as a 323iT (one year only) and 325iT and 325xiT; no 330 wagons were made that I'm aware of.

The E34 is an almost unbelievably easy vehicle to swap to a manual, and many people install an S52 at the same time as it is a direct fit except for one temp sensor and requiring a different ECM chip.

Interior materials are generally better in the E34, except for headliner and door panel adhesives that tend to fall apart. 1995 E34s had better interior glue, apparently. E46 interiors don't 'feel' as nice from a material quality standpoint, but do seem to hold up generally better. Both are similarly priced on the used market, for nice examples.

I don't know as much about the E39s, but they seem to have a generally good reputation as well, aside from having more electrical gremlins than the E34.

No 330 tourings here, as I would've bought one had that been the case...

Thanks! I need to convince my wife an old car is better than a new car. She wanted to look at the E90 touring but I want to go older. Manual swap is very much on the radar. I need to decide on 5 or 3 though, just not sure. Kids are getting bigger though!

In reply to Nomad:

Neither one is really a 'big' car. I'm 6'4" and the front is comfy, but the rear is pretty tight in the E34. I fit, but it wouldn't be great for a long trip. E46 is roughly the same. Most of the difference in size between the two is I think the E34 is like 10" longer. Most of that is cargo space.

More good news on the car! Fingers grossed that I fixed the last oil leak - when I replaced the dipstick tube, I think I managed to fold the o-ring over the bump in the tube that retains it. Seems like the o-ring was a little oversized. Fortunately, I had a slightly smaller one lying around that appears to have worked perfectly. I'll know in a few more days if that is definitely fixed.

When I did the oring, I also added some oil and the low oil warning has gone away (surprise!). Sensor is a little overly sensitive, since the level was actually still slightly over the fill line on the dipstick, but whatever. I'm just glad it works.

SLS warning is gone - it took a few more key cycles, but I haven't seen it in the last three trips. It's not an OBD code so I don't know why there would be a key cycle clearing limit, but who knows. Maybe it had a bad connection that fixed itself when I checked for ground at the CCM.

The door locks are acting up regularly. Locking gets one beep, but no locking. Hit the button again, three beeps and no unlocking. hit it again and you get locking, followed by immediate unlocking. Another hit and you get 3 beeps, but it's already unlocked. On the third lock attempt, everything locks and stays locked. I haven't figured out exactly what is going on, but I do know that the passenger door lock doesn't work, nor does the passenger door lock cylinder seem to have any connection with the rest of the car. I'll have to pull the door apart and see what is going on. I bet the central locking system is getting confused because it can't see that all the locks are synced. Yes, there is a lock sync procedure, but it is done from the passenger door lock, which doesn't work. Of course.

Next steps are an oil change, reinstall the crank vent, install the new (used) passenger brake light (original has a big hole in it), replace the bulbs in the third brake light, and take the passenger door apart to fix the lock. Most of that will probably happen tonight, so that I can pull the suspension off of the KTM and send it out to make it even taller.

See how I said in the last post I get all this stuff done last night? That didn't happen. The central locking system on these cars is seriously somewhat insane. The passenger front door has 3 microswitches and a motor, and the driver's door has 4 microswitches, a motor, and a heater. The trunk also has 4 microswitches, all of this in addition to a switch in the door striker so the car knows if everything is shut. 6-7 hours of troubleshooting later, I know why it wasn't working, learned some things, and probably created some new problems.

The issue was the X481 wire splice, which is under the rear carpet. It supplies power to all the microswitches in the passenger door, and two of the microswitches in the hatch. What led me to this is that I only had 0.9v at the +12v pins that all tie to this circuit. Pulling the fuse (#33) dropped this down to 0v. I assumed either a partial short or bad connection, starting with the hatch as the likely suspect. Turns out the hatch harness has been (mostly) replaced. No dice; it's fine. Then I pulled the passenger door connector in the door frame and pinned out the whole door harness (power mirror over there also isn't working). Everything is fine there, too.

Crap. So somewhere, between the fuse box in the back seat, the front door, and the rear hatch, there is a problem. Of course, all the wiring is under the carpet that I just reinstalled. Pulled all the wiring out of the underseat area, and no dice. Check a few suspect connections, and they're all fine. Put it all back together (breaking plastic in the process, since I didn't see how everything clipped together until it was too late...) and pulled up the rear carpet. Finally found the splice I was looking for from the wiring diagram, and pull the cap off the splice. The whole splice and a bunch of wire breaks off with it. ding ding ding, found it!

This car had a heater core failure 6+ years ago, and ever since, this splice has been submerged in coolant. That caused a bunch of corrosion on the copper wires, eventually resulting in disintegration. Crazy.

Oh, and the passenger door lock actuator motor is jammed. I unstuck it once, but during my troubleshooting it acted up again.

In the process of all the troubleshooting, I think I fried something, too. I can't get the hatch or rear glass poppers to work anymore. No voltage at either one, and the fuse is fine. I'll be thrilled to have everything working again.

90's BMW wiring issues, HAHA. Never heard that one before.

Progress! And pictures!

Here's what trying to put electrons back in wires looks like on an E34.

There's a splice under the rear electronics box, which checked out.

Ah, the culprit! This is the splice under the rear carpet that I mentioned before. I hadn't trimmed the wires back yet; this is what it looked like when I pulled the cap off.

The non-working hatch ended up being a connector that I had unplugged and forgotten to plug back in, of course.

The 3rd brake light was about half burned out.

All new bulbs soldered in:

Much better.

New hatch switch is on the bottom. These actually worked out great, though I had to bend the actuator arm up slightly to get the engagement point I wanted. Now it just takes a light touch to open the hatch.

The original passenger door card had been destroyed with a crappy attempt at repairing the failed adhesive, but the 'new' 1995 door card was torn at the top and was missing all of the plastic door panel clip holders. Two door panels thus became one. Permatex makes some badass stuff called Heavy Duty Headliner and Trim glue, or something like that. Got it at Autozone. Kind of expensive but holy crap does this stuff stick.

Interior all back together, with everything working! Even got the mirrors working. As of right now, all of the electronic stuff works as it should. Note the droopy headliner...

And since I didn't really put up any pictures of the outside. I know a few of the pics above aren't working, and can't seem to figure out why. I'll work on it later I guess.

Please, Please, PLEASE, tell me this isn't you:

Because that SURE looks like your manual swapped Caprice wagon in the background.

Part out on the List of Craigs....

Dang it!