Well, we are in the midst of a journey with a 1991 318is here in Austin, Texas.
This is a new (to us) car that my daughter and I are going through before it becomes her daily driver in high school (she’s a junior). While I’m new to e30s I have a few decades of experience working on 2002s. I hope this will be a good foundation.
So on to the car. It has 220k. AlpineWeiss with black interior. I’ve driven the car a few miles and it is in generally good condition. Doesn't blow smoke and no noises from drivetrain. Clutch felt fine, shift linkage loose, drove straight, crappy shocks, buzzy muffler. Car has oil leaks and vacuum leaks. Starts and runs but barely idles until it warms up. No receipts for recent work. To be on the cautious side we are going through all of it (engine, suspension, brakes, drivetrain, steering, interior, etc.), both as a learning exercise and well because it probably needs it. Most importantly, it will be a great memory for both of us. She will do as much of this as possible.
Thought I’d capture it here for posterity. I want to do it right. I’m concerned about doing the work and still have leaks. Also, I want to be able to come back to this thread and do it again if I need to.
Some will remind us that this has all been documented before. It has of course. In preparation we’ve scoured the interwebs (a lot on this site) and there are many many references, threads and great advice, most likely from people like yourselves. It is difficult to convey how much it has helped to read documentation and share your hard-earned insight. That's also the challenge; so many pieces of great advice, all over the place. This one will be what I have found to be an aggregated current best practice, with specific step by steps of all details. I reference links in the steps below.
One note on this M42 top end refresh: I’m choosing not to go to the recommended late M42 front timing chain cover from a 1994-95 e36 318is (removes idler wheel and is recognized as a better design). Why this decision? It’s my first M42 refresh and it adds one or two levels of complexity. It's an added cost. Finally, my daughter won’t be taking this car to redline on every shift (I don’t think). The next M42 I rebuild will get the update (more on that later). I hope by doing this work we will enjoy a “trouble-free” 100k more miles. This decision may haunt me but if it does I’ll own up to it :-).
What I plan to do is document this refresh process before I do it. I’m hopeful that you all can help nudge in the right direction if I seem to be wandering off. I welcome all feedback, always.
Should be fun! So, let's begin.
Goal
Refresh the top end of an M42 in a 1991 318is. Reseal engine. Replace common wear items (timing components, water pump, oil pump, filters, etc.)
Preparation steps (I did it in more or less this order).
This is the “easy” part. YMMV, I didn’t capture every wire and every hose but did try. If there is something obvious I missed let me know. No photos of these steps.


Pleased to see cross-hatching in the cylinder bores.

Head gasket doesn’t seem to have major blow outs.

I'm limited by the number of images I can upload in a single post, so I'm breaking this up into sections.
This is a new (to us) car that my daughter and I are going through before it becomes her daily driver in high school (she’s a junior). While I’m new to e30s I have a few decades of experience working on 2002s. I hope this will be a good foundation.
So on to the car. It has 220k. AlpineWeiss with black interior. I’ve driven the car a few miles and it is in generally good condition. Doesn't blow smoke and no noises from drivetrain. Clutch felt fine, shift linkage loose, drove straight, crappy shocks, buzzy muffler. Car has oil leaks and vacuum leaks. Starts and runs but barely idles until it warms up. No receipts for recent work. To be on the cautious side we are going through all of it (engine, suspension, brakes, drivetrain, steering, interior, etc.), both as a learning exercise and well because it probably needs it. Most importantly, it will be a great memory for both of us. She will do as much of this as possible.
Thought I’d capture it here for posterity. I want to do it right. I’m concerned about doing the work and still have leaks. Also, I want to be able to come back to this thread and do it again if I need to.
Some will remind us that this has all been documented before. It has of course. In preparation we’ve scoured the interwebs (a lot on this site) and there are many many references, threads and great advice, most likely from people like yourselves. It is difficult to convey how much it has helped to read documentation and share your hard-earned insight. That's also the challenge; so many pieces of great advice, all over the place. This one will be what I have found to be an aggregated current best practice, with specific step by steps of all details. I reference links in the steps below.
One note on this M42 top end refresh: I’m choosing not to go to the recommended late M42 front timing chain cover from a 1994-95 e36 318is (removes idler wheel and is recognized as a better design). Why this decision? It’s my first M42 refresh and it adds one or two levels of complexity. It's an added cost. Finally, my daughter won’t be taking this car to redline on every shift (I don’t think). The next M42 I rebuild will get the update (more on that later). I hope by doing this work we will enjoy a “trouble-free” 100k more miles. This decision may haunt me but if it does I’ll own up to it :-).
What I plan to do is document this refresh process before I do it. I’m hopeful that you all can help nudge in the right direction if I seem to be wandering off. I welcome all feedback, always.
Should be fun! So, let's begin.
Goal
Refresh the top end of an M42 in a 1991 318is. Reseal engine. Replace common wear items (timing components, water pump, oil pump, filters, etc.)
Preparation steps (I did it in more or less this order).
This is the “easy” part. YMMV, I didn’t capture every wire and every hose but did try. If there is something obvious I missed let me know. No photos of these steps.
- A few days in advance - spray all nuts/bolts that you can access with PB Blaster or equivalent. For example, exhaust manifold nuts, front timing cover bolts, oil filter housing bolts, etc. Repeat as often as you can before you start the work. It could make all the difference.
- Raise front of car - jack stands at proper jack points (right in front of door hinge, use a rubber slot adapter to rest on the pinch weld). Parking brake on. Blocks under rear wheels, etc.
- Drain oil (17mm bolt). Drain coolant (plastic valve at bottom of radiator).
- Disconnect throttle cable (the plastic bracket that holds the end of the cable is slotted to make it easier)
- Disconnect cruise if your car has it.
- Remove intake manifold (eight 11mm nuts that you see standing at drivers side fender, another two 11mm nuts on the sides, some hose disconnects, disconnect throttle position sensor cable, etc.)
- Remove intake that holds fuel injectors (five 11mm nuts, some hoses, at least one vacuum hose)
- Disconnect electric harness from alternator, etc. and fold up to windshield (two 9mm bolts and one 13mm bolt)
- Remove engine mount nuts (two 17mm nuts).
- Lift engine a few inches (I used this),
- I removed the power steering rack because I am replacing it, but I’m not sure it’s required for this job (if so, two 15mm nuts/bolts and then the steering coupler, won’t go into this now).
- Remove lower oil pan (sixteen 10mm bolts).
- Remove upper oil pan (twenty 10mm bolts, three T12 torx).
- Remove major coolant hoses.
- Remove radiator (two clips on side)
- Remove AC condenser (10mm bolts)
- Remove AC pump and bracket (four 13mm bolts holding pump to bracket, then i believe four more that hold bracket to block, AC hoses are 6mm hex)
- Remove exhaust manifold nuts and pull back from engine (13mm nuts, IIRC)
- Lock flywheel (I used a right-sized punch in the sight hole next to flywheel).
- Remove fan (I drilled two holes in a long flat bar and attached to two of the bolts attaching the fan pulley. The arm rested on padding on the driver’s side fender. Then used a large adjustable wrench to unscrew. Note: Reverse Threads!!)
- Remove crank pulley bolt (22mm socket).
- Remove oil filter assembly (six 10mm bolts)
- Remove spark plug wires (grab carefully and pull)
- Optionally remove ignition module from passenger wheel arch (four 8mm nuts) I did it to clean underneath, not required for this job.
- Remove timing chain tensioner (one 17mm wrench or socket)
- Remove valve cover (fifteen 10mm bolts).
- Set engine at TDC
- Remove upper timing chain cover (eleven 10mm bolts)
- Remove cam sprockets and chain (four 13mm bolts each cam. I first etched an up arrow on cams and took a photo too)
- Remove water pump (four 10mm bolts)
- Remove lower timing chain cover (eleven 10mm bolts, four 10mm bolts)
- Remove head (eight T12 torx)
- The head bolts should be removed in a certain order. First just crack the bolt loose and move on to the next. A good article is here: http://www.m42club.com/forum/index.php?topic=11162.0
- Here is the order: 1 8 10 5 3 4 6 9 7 2
- NOTE: E30 M42s do not have the oil pressure check valve like on e36s More on this: http://www.m42club.com/forum/index.php?topic=2804.0
- Remove front bumper and bumper support (not required but very nice to have direct access to front of engine + clean the area) - misc 10mm bolts, 13mm bolts, two T-55 male torx for bumper, two smaller torx T-15 for bottom of section between fender and nose)
- Remove front timing case (three 13mm bolts, one 17mm bolt, seven 10mm bolts, two 6mm hex bolts)
- Inspect back of timing case for coolant corrosion
- After remove timing case gasket from block, inspect the block for coolant corrosion
- Question: What to do if there is corrosion?
- On the bench - Remove cam holders, cams prior to machine shop.
Pleased to see cross-hatching in the cylinder bores.
Head gasket doesn’t seem to have major blow outs.
I'm limited by the number of images I can upload in a single post, so I'm breaking this up into sections.
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