Removing the Fan, Fan Clutch, Water Pump Pulley on an E23 with an M30 engine

I need to replace the water pump on my 1984 BMW 733i E23.  I drained and removed the radiator (one screw on the driver side, one screw on the passenger side) and then I undid the four 10mm bolt-and-nut combinations that attach the fan to the fan clutch.  To my surprise, the fan didn’t come off. It was loose but something was still holding it in.  A 13mm bolt in the center of the pulley shaft was the culprit.

When I tried to loosen that bolt, I was unable to keep the pulley in position, to prevent it from slipping. I stuck a screwdriver vertically behind the fasteners that attach the pulley to the water pump, to try to keep the pulley from slipping.  I failed, but in the process I broke some of the aluminum teeth off the fan clutch.  Dangit.

Fortunately, I also have a 1983 BMW 733i E23.  I tried plan B, on that car. I bought a long 10mm bolts and stuck it into one of the holes for the 10mm bolt that connect the fan to the fan clutch.  This provided enough leverage so that I could retry my vertical-screwdriver trick again, but this time the screwdriver was pushing against the long 10mm bolt instead of the fragile aluminum teeth. Better. 🙂

Next, I need to undo the four size 5 metric Allen bolts that attach the water pump pulley to the water pump. In preparation, I loosened the alternator-and-water-pump belt by loosening the 13mm nut at the back of the top of the alternator.

The Allen bolts were so tight that the pulley slipped again. The end of the shaft is slotted so I stuck a long steel plate into the slot so as to immobilize the shaft. Even so, I couldn’t budge the Allen bolts. So, I tapped them with a hammer and now they are soaking in penetrating oil. I expect that will make them viable to remove.

BMW E23 7-Series Thermostat Housing Removal and Re-Installation

The typical reasons to replace this part are because:

  • There is a damage bleed screw atop this part, or
  • You’re replacing the thermostat.

It’s a good idea to replace the thermostat when you have this part removed anyway. In the past, I’ve lost an engine due to a bad thermostat (combined with a broken temperature gauge) so now I’m a lot more wary.

As part of the work, I use a new gasket (square, with bolt holes, made of a cardboard-like substance) and a new seal (round, black, made of a rubber-like substance).

The housing is attached with four 10mm bolts, two long and two short. Nothing very difficult there. A 1/4″ drive socket works well.

Much more tricky is the attachment of the lower radiator hose. Space is VERY tight. You are right up against the fan and radiator. I ended up using a 6mm socket on a 1/4″ drive because I couldn’t get either a nut driver or screwdriver to turn. And, I still ended up with a leak in that area.

The biggest danger is having the hose clamp interfere with (and destroy) the fan, I tried to make sure to check it for interference.

BMW 733i E23 Fuel Rail Information

My 1984 BMW 733i has been sitting, parked, for several years and it’s safe to say the fuel system is suspect. I drained the fuel tank, and cleaned out the crud at the bottom of the fuel tank as well as I reasonably could without removing the tank.

I swapped out the fuel sending unit and in-tank fuel pump with more-likely-to-be-reliable units. The replacement in-tank fuel pump ended up being dead too. These pumps are hard to find in good working condition. Without them the car will run but it’s vulnerable to vapor lock, typically on hot days.

I replaced the main (in-line) fuel pump and fuel filter.

I also removed and tested the fuel injectors, which involves removing and replacing the fuel rail.

My first step was to remove the 13mm bolts and nuts that attach the two struts (one in front, one in back) that connect the valve cover to the intake manifold, and make it impossible to remove the fuel rail while they are in place. The back strut has two sensor wire plugs attached. The front strut has a diagnostic plug attached. It’s not necessary to remove either of these. I just moved them out of the way.

My next step used a pick tool. This is sort of a smallish screwdriver with a not-quite-straight pointy tip like an awl. I used that to loosen the metal retaining rings that lock the plastic electrical connectors into each of the fuel injectors. The plastic was brittle and I found it impossibly hard to slip the little wire clip off each connector without breaking something. With the little wire clips off each connector, each connector and its attached wire could each be slid off its injector.

The next step involved using a flat-headed screwdriver to loosen the clamps around the fuel lines that attach to the fuel rail, then using a Vice-Grip to move the fuel line back and forth, and then using some combination of these tools to get the fuel lines slid off the fuel rail. There are three lines: the inlet line at the back, the return line that is attached to the fuel pressure regulator that’s at the front of the fuel rail, and then another line somewhere near the back and towards the bottom. I’m guessing that this is the line to the cold-start injector.

Next, I pulled the vacuum hose off the fuel pressure regulator.

The next step involved removing the four 10mm bolts that attach the fuel rail to the intake manifold. This freed up a slew of intimidating-looking brown ground-wire ring connectors.

At that point, I could remove the fuel rail and move it so that it is clear of the throttle body, and able to slide out the front. To loosen the injectors from their respective holes in the cylinder head, I tried to rock the rail back and forth. I tried to pull up on one side of the fuel rail and then the other. I tried to pry it up with a steel bar. Some combination of this worked.

The wiring harness tends to get in the way, but moving it aside isn’t a problem. Then, you can remove the fuel rail, and at the end of the exercise, you have a fuel rail with six fuel injectors in your hand.

If you have my sort of track record, you’ll notice that some of the O-rings that seal the injector to the head came with the fuel injectors and at least one didn’t. At the time, I worried about this a lot, and I raided a 1987 535i fuel rail that I had handy, only to find out the injectors are different. I then raided my 1983 733i and found the injectors to be the same, so out of twelve injectors I chose the sex best-looking ones for the fuel rail to be re-installed. I focused on which ones didn’t have O-ring damage. Later, I learned that NAPA sells replacement O-rings at very reasonable prices. I plan to buy some.

I tested each injector by putting 12V over it and listening for a “click” and seeing it spew liquid when I pressurized the fuel rail.

I have an informal test-bench set-up that uses rubbing alcohol instead of gasoline. The alcohol evaporates quickly so I don’t have to worry about it leaving a residue on the parts, and it’s not as much of a fire hazard as gasoline is.

I removed the old O-ring(s) that stayed behind in the little holes in the cylinder head. I next lubricated the O-rings on the to-be-re-installed injectors using a thin layer of white grease.

I then moved the newly-tested fuel rail back into position, and pushed it down firmly so that the each injector seated into its little cylinder-head hole.

Door Lock Issues

If your car’s door lock is failing, it might be helpful to know that the door locks are essentially identical on the E23 and E24 models from 1977 through 1986. The lock cylinder fits into the door with a complex structure that involves a tunnel at the end of the lock cylinder. Into that tunnel, we fit a tiny ball bearing, and a spring, and another ball bearing. Then, we turn the cylnder slightly, to keep these three items from falling out. We fit a spring with two tabs around the cylinder, and finally we slide in a plate that keeps it from falling out of the door.

Looking at Actual Parts, Carefully

I recall my surprise at analyzing some 3-series E30 glove boxes, and discovering that the glove boxes for cars with the later-than-Motronic-1.0 computer had a shallow notch at the inner front corner, so that the thicker fuel injection cable (three rows of pins vs. the earlier two) doesn’t chafe. It’s a very logical engineering change, and not surprising. The glove box with the notch even has a different part number.

What made this surprising is that the official BMW parts list mentions only one variation. So, by analyzing the parts, physically, carefully, in person, I found out more than if I’d just read about things online.

For a while, I tried to figure out what made some cars have the earlier-style glove box vs. not. The change seemed to center around 1987 but I couldn’t put my finger on it until I realized that cars with the older version of Motronic computer had the older version of glove box, and 1987 was the year when things changed a lot as such — but the 1987 325i cars had the newer-version computer whereas the 1987 eta-engined cars still had the older-version computer.


This experience really inspired me to go look in person at what’s actually going on. It reminds me of when I worked at an automobile assembly plant (not for BMWs, sadly). The production control folks had recently managed a change by which cars of a particular model would be fitted with chrome tips on their exhausts. The parts were ordered, brought to the production line, and the assembly instructions were changed to tell workers to put the chrome tips on. But, at the end of it all, my job included being the reality-check person, to go see if in fact all of this planning had actually resulted in chromed-tip exhausts on cars exiting the assembly line. For me, there’s nothing as solid and reassuring as seeing something first-hand.

So, today’s project involved Mass Air Flow Meters on the M30 engine. I own a 1980 BMW 633 CSi, a 1992 BMW 735i, and several models in between, including a 1984 BMW 633 CSi and a 1984 BMW 733i. My tech and I inspected the mass air flow meters on all of these cars, and checked the part numbers. Of course, it’s possible that some of these parts were not originally on the car, but I’ve personally driven each of these cars so I know that the part at least works on that car.

Although the 1992 car has a pretty plastic cover on top of the mass air flow meter, when the cover is removed, the part is the same as on all the other models we analyzed. And so, now we have a good handle on mass air flow meters for the M30 engine.

There are still a million things we DON’T know for certain, but it’s nice to have a fairly good handle on at least this tiny part of the puzzle.

That’s the sort of confidence and certainty that we enjoy.

Fixing a “Limp Home” Mode Issue

The E32 750iL uses an electronic connection between the driver’s right foot and the throttle plate opening. No more mechanical cable.

This system is named “EML” which is an acronym for Elektronische Motorleistungsregelung which is … electronic motor output regulation. I think. German is my first language but my Oma didn’t teach me BMW tech stuff.

An EML light in the instrument panel should come on briefly when the car is started. This shows all is well. When there is a problem, the system would rather not go crazy and maybe accelerate when you didn’t want it to. So, if it self-detects a problem, it shuts down. That means the car goes into a mode where whatever your right foot does has a very minimal effect as to engine speed, bringing it from idle to barely above that, and also the transmission in “drive” mode is in third gear. This tends to enable you to get home slowly but surely, sort of like a wounded animal limping home.

As to troubleshooting: it’s either a false alarm or not. The former means that a bad EML light can actually trigger the problem. Troubleshooting this aspect is probably the easiest. The ideal is to have another good, running similar car and to swap instrument panels, and to draw conclusions from what you observe as a result. If that doesn’t make for a quick fix, you can diagnose the instrument panel. The later ones have a self-diagnoses built-in. The earlier ones require a lot more work, and the risk of breaking parts, and the need for an ohmmeter.

The instrument panel for the E32 BMW came in three versions. The first one had a gray back plate. This was used until 2/89. The second one had a white back plate.  This was used from 2/89 to 9/90. The third one had a blue back plate and that was used from 9/90 until the end of the production run.  The colors imply different internals and non-interchangeability specific to the gray back-plate, though the white back-plate and blue back-plate versions are very close. The latter two save the car data on a chip that can be moved from instrument panel to instrument panel.

Basically, our BMW 1989 750iL car is in “limp home” mode. This mode is announced by the EML light in the instrument panel not coming on. This could be due to a fault in the instrument panel, or elsewhere.

To check the instrument panel, I got another gray-back-plate instrument panel and installed it.  The problem did not go away.

Perhaps both instrument panels are bad, perhaps it’s time for me to stop suspecting the instrument panels. 

I have started dismantling the original instrument panel. There is a back half and a front half, and they hinge together. The hinge comes loose, and so I’ve split the two halves. The rearmost half, into which the EML lights fit, has a light gray plastic housing and a circuit board. I’m assuming that the component-measuring I need to do is from behind, so I need to remove the circuit board from the gray plastic housing.

I found it hard to do this. I pried loose the 4 little feet that affix each plug base to the circuit board. it loose but it doesn’t seem like that’s the right way. I’m trying to figure out how to get these apart safely.

I’m enthused about this because one of the two EML lights seems blown (black glass) and the other might be unhappy too. I’m trying to rule out electronic causes before I start unbolting expensive parts … two blown light bulbs would explain the issue away, 100%.

Next hurdle: how to remove the printed circuit board from the back plate.

I want Empathy when I Buy Parts, Dammit

The local BMW dealer parts counter guy seems to be a nice man, but … sad. I can guess why. Day after day, he deals with the following two sorts of dialog, many times a day:

“Hey, I’m looking for an alternator for a 1992 BMW 735i.”
“What’s the VIN?”
“I don’t know. I don’t have it with me. I’m at work. The car’s at home.”
“I need the VIN to look up the parts.”
“Well, I don’t have it.”

… and it doesn’t get better after that.

Ironically, the parts guy (and his boss, who made the policy) is aware of subtleties most customers ignore, but will probably nevertheless be upset about if not addressed, so it’s a no-win situation for the parts guy.

I’m clear that as a 7-series parts owner, you don’t care about 3 series BMWs but the best example I know involves the 1987 BMW 3-series. Imagine you’re buying a replacement glove box. All the 3-series glove boxes appear to be identical … but they’re not, in a subtle way. The early US models came with L-Jetronic or Motronic 1.0 which has a certain number of strands in the wiring harness that runs from the engine compartment through a grommet in the firewall in the vicinity of the glove box area, to the engine management computer located above the glove box.  In 1987, some models got Motronic 1.1 which has many more strands of wiring, hence a much thicker wiring harness as such … thick enough to chafe on the inboard rear corner of the glove box, and that could damage the engine wiring harness, so the BMW engineers made a notch in the glove box at that location.

Who would have thought that a glove box is tied to fuel injection … and yet it is.  So ironically the parts guy behind the counter is treated by many customers as if he’s an idiot when  really he’s being commendably cautious.  In the customer’s defense, sometimes the VIN really doesn’t matter and the parts guy shouldn’t be asking.  It’s good to know when to ask and when not to ask.  We typically do, so that might well be another reason to buy from us.

Anyway, back to our hypothetical situation.  Assuming the customer does have the VIN, the next conversation goes something like this:

“How much for the alternator?”
“Say, what?”
“For the alternator?!”
“Wow! The entire car cost me maybe $3K and that had a working alternator. That’s crazy.”
… and it doesn’t get better after that.

Aftermarket prices are often better, and sometimes not by much. Sometimes, when I heard the price, I thought “Forget that,” or some less-polite variant.

Seems to me that whoever comes up with these prices has no idea of the basic viability of someone who’s not made of money, trying to keep their E23 or E32 or E38 going. There seems to be a basic disconnect when the parts prices are so high that a customer reacts with incredulity. Basically, the vendor and the customer don’t relate to each other. They’re are not on the same page. There’s no empathy.

* * *

BMW parts prices can suck, but there’s a parallel to that: software.

How often have you used software that sucks, because regardless of how technically cool it might be, it sucks for you because it doesn’t work for you? Whoever made it didn’t empathize. As to whatever your situation was, they didn’t “get it.”

There is a better way. In the software industry, it’s called “Eat your own dog food.” Wikipedia defines it as: Eating your own dog food, also called dogfooding, is a slang term used to reference a scenario in which a company (usually, a computer software company) uses its own product to demonstrate the quality and capabilities of the product.”

It’s a great idea.

That might be the best reason to buy your used parts from my little company. What’s in it for you? You’re understood. That’s it. We also drive old 7-series cars and we’re trying to keep them going, with a tight budget. We empathize.

For a while, I’ve driven a 1992 735i whose front door wouldn’t open, so I got in the passenger door and clambered over. And, I survived. I didn’t have money for the “new parts” solution.

My little used parts business is not the world’s smartest when it comes to E23 or E32 or E38 cars. We haven’t been in business the longest. We don’t have massive depths of technical insight. We don’t have a huge inventory. We often mis-estimate the time it’ll take to get a part into inventory.

But, dammit, we relate. We have our own little sad fleet of several floundering old 7-series cars, and we struggle to keep them going on a tight budget that includes wondering how we’re gonna pay the rent this month. We get personally stranded when a main fuel pump dies, and we have to walk home and figure out what’s wrong, how to remove the bad part without causing a fire, and how to replace it without paying three figures.

This struggle makes us relate to customers who struggle, just like us.

We need to buy food, pay the rent and somehow keep viable, as transportation, decades-old cars that most people have given up on, long ago.

We tenaciously refuse to let these cars die. We make plans, we find money, and we pull through — so that we can keep driving these magnificent pieces of engineering, even if the dash lights don’t work and the heater fan is broken. At some point the way we’d just not lock our E32 because the battery was iffy and we didn’t wanna get locked out of the car due to its electric lock issues. But, dammit, we kept it going until we could figure out a better way. We’re still in the game. We’re fighting and if driving the car one more day is victory, then we’re winning.

If you like that mindset, buy your stuff from because you’re dealing with someone who “gets” you.