# BMW 840Ci E31

> The free buying guide from Last Real Engines, updated 2026-10-13. Web version: https://lastrealengines.com/840ci-e31/free-guide/ · full guide: https://lastrealengines.com/840ci-e31/
## The story

*What this car is, and the six questions that decide whether the one you are looking at is a good buy*


## 1 · Who built it, and what they built

A grand tourer with **pop-up headlights** and **pillarless side windows**, built between February 1990
and May 1999. This guide covers **1995 to 1999** — the second half of its life.

In those years you could have it as the **840Ci**, with a 4.0 V8 and later a 4.4 V8, or as the
**850Ci**, with a 5.4 V12 — and, until November 1996, as the **850CSi**, with a 5.6 V12 developed by
BMW M.

### What is unusual about it, specifically

It was engineered as BMW's flagship at a moment when nobody was asking what it cost. Wind the windows
down and there is no pillar between them, front to back. The headlights are hidden until you need
them. And at the top of the range, twelve cylinders.

**It was BMW's flagship coupé, and it was priced like one.** It is not priced like one now, and that
is the entire reason this guide exists.

### One question decides this car, and it is not the year

**The 4.0 M60 V8 was built with Nikasil-coated cylinder bores — and so were early 4.4 M62s.**
Where sulphur-rich petrol broke the coating down, the piston rings wore the bores, the engine lost
compression, and the usual cure was a new short block. BMW changed the M62 crankcase from Nikasil to
Alusil, at different times in different countries.

It is the engine risk the V8 is known for, and it sits in one number.

**The trap is that neither the build year nor the engine code answers it.** BMW dates series production
of the 4.4 to 1996, but early 4.4s were Nikasil too, and BMW also built Alusil exchange
engines for the 4.0. BMW tells the two apart by the part number cast into the crankcase — where to
find it, and which numbers mean what, is in the buying guide.

**So the question you ask is not "what year is it", or even "which engine".** It is *"which crankcase
is it, and does the engine still hold its compression".*

### How the figures in this guide work

There are no prices in here, and that is deliberate. A workshop rate differs by a factor of two or
three between countries, so a figure we cannot verify for you is worse than no figure. What does not
move is **how much work a job is** — that follows from what has to come off the car.

So every item says whether it is **an hour or two**, **half a day**, **a day**, **two or three
days**, or **a week or more in the workshop**, and whether the money sits in the part or in reaching
it.

---

## 2 · The six questions that decide whether *this* car is a good buy

**1 · What is the engine code — from the registration document or off the block?**
The start of the question this whole guide turns on: on a V8, the code alone does not settle it,
because early 4.4s were Nikasil too, and the number cast into the crankcase does. A seller who
answers it precisely has owned the car properly.

**2 · If it is a Nikasil engine, has anything been done about it?**
Ask it directly. A rebuilt or replaced engine with an invoice changes the car completely.

**3 · When was the cooling system last touched, and what was replaced?**
Water pump, expansion tank, radiator, hoses. On this car they are a set, not four separate jobs.

**4 · May I watch the temperature gauge while it idles?**
A few minutes standing still, and it costs nothing. Almost nobody does it, because a test drive
hides exactly what you are looking for.

**5 · Has it ever overheated?**
Ask it plainly. Apart from the Nikasil question, much of what gets expensive on an E31 starts with a
cooling part that was cheap.

**6 · How often is it driven, and when was it last out?**
Cars of this complexity that stand develop faults that cars that are used do not.

---

## 3 · Which years, which specification

**The car ran from February 1990 to May 1999.** This guide covers **1995 onward**, which is probably the
half with the revised cooling parts behind it, and the half with the later engines available.

**The eight-cylinder cars.** 840Ci, first with the **M60 4.0** and later with the **M62 4.4**, both
of 286 PS; the 4.4 has more torque. Which of them is the one to want is not decided by the engine
code, and the buying guide explains why.

**The twelve-cylinder cars.** By 1995 the 850Ci had the **M73 5.4**; BMW replaced the M70 5.0 in
autumn 1994. The **850CSi**, with a 5.6 V12 developed by BMW M, was built until November 1996, and
this guide does not cover its M-specific parts. Magnificent, and every job on a V12 costs more
because there are two of most things and access is poor.

**A note we are not going to fake.** BMW gives 1996 for the start of series production of the 4.4.
But the date that matters is a different one — the changeover of the 4.4's crankcase from Nikasil to
Alusil — and it fell at different times in different countries. **Since the answer is cast into the
crankcase, check the crankcase.**

---

## 4 · What it is worth

Not in money, but in the only currency that matters when you are standing next to one.

**An E31 is priced as an old coupé and repaired as a flagship.** Two things decide the value of a
specific car, and neither of them is the mileage:

- **which engine is in it**, and whether that answer is documented, and
- **what the cooling system has had done**, and whether it has ever overheated.

A 4.4 with a folder full of cooling work is worth substantially more than its advert suggests. A
cheap 4.0 with no history is a car whose bores nobody has tested yet.

---

## 5 · What it is actually like to own one

Enormous, quiet, and much faster than it feels.

The E31 was built to cross a continent, and that is what it is good at. The V8 is unstressed. The V12
is smoother again and asks for twice as much of everything. With the windows down there is no
pillar in the way, front to back.

What it asks in return is that you keep the cooling system honest and that you use the car. Cars of
this complexity that sit develop faults that cars that are driven do not.

**The honest summary:** an E31 is a flagship at coupé money, and the cheap ones are cheap because of
one bore coating and one cooling system. Both are knowable before you buy.

---

## The buying guide — €24

Everything above is what the car is. This is what you check.

Six faults that belong to this car, taken apart one by one, with
how much work each repair is and how to tell which of them you are looking at.
Eleven things that are simply thirty years old, every one
with how much work it is, what tells you about it at a viewing, and whether it has to be done now,
within a year or two, or not at all. What an E31 shell and its two mechanisms do with age, and where to look first. Why the number cast into the crankcase, and not the build year or the engine code, decides which car you are buying, and why a stored E31 is worse than a used one. The viewing in eight steps, including the
three moments that come only once. The sentences you say to the seller, and how to build an
offer out of what you found.

And a card you print and take with you — nineteen lines, in the order you do them.
That comes as a separate file, because nobody wants to print a whole guide to take a few pages to a
car park.

### This is what one of the eleven looks like

**1 · The engine, and which one it is**
**A week or more** · only on a Nikasil crankcase, and only if the bores have gone
Chapter 5.1. Nikasil-coated bores broken down by sulphur-rich petrol; the usual cure is a new short
block, not a repair. The 4.0 M60 and early 4.4 M62s were built with them, and neither the build year
nor the engine code tells you which crankcase you are looking at — the number cast into it does.

Now: the engine code on the telephone, before you travel, and the crankcase number at the viewing.

### And this is how the card reads

- [ ] Standing, before you start it
- [ ] Running
- [ ] On the move
- [ ] Afterwards

### What €24 buys, put next to what it saves

The 4.0 M60, and early 4.4 M62s, were built with Nikasil-coated bores that sulphur-rich petrol could break down, and once they have gone it is **a week or more in the workshop** for a new short block. It is also cheap to settle: the part number cast into the crankcase tells you whether it is Nikasil or Alusil. The guide is **€24**. It will not stop any of that from being needed — but it does
tell you which of them you are looking at before you agree a price, and that is the whole of the
difference between paying for a car and paying for someone else's postponed maintenance.

### Why there are no prices in it

Because a price we cannot verify is worse than no price, and because a price would be wrong for most of
the people reading this anyway. Workshop rates across Europe differ widely, and so do parts prices. A quote from a specialist in one country tells you nothing in another.

**What does not change is how much work a job is** — that follows from what has to come off the car.
So every point in the guide says whether it is an hour or two, half a day, a day, two or three days, or a
week or more in the workshop, with a labour figure where a source gives one. And it says whether the money sits in
the part or in getting to it, which is what lets you tell a fair quote from a bad one.

If you want a figure, ask any workshop one question — *what is your hourly rate?* — and every effort
level in the guide becomes your own number, in your own currency. One question, and the answer is actually true
for you.

### How this guide was put together

Because you should know before you pay for it.

- Every fault and symptom comes from a source the guide names, the manufacturer's own documents first. The
  effort levels are our assessment, unless a source gives the hours.
- The guide says plainly that on an Alusil crankcase the most expensive chapter does not apply to you at all — that the engine code alone does not tell you which crankcase you have — and that on a Nikasil engine a compression or leak-down test decides whether to buy rather than what to pay.
- The effort of every job is counted item by item and checked against the list before every edition.
- It says as plainly what you can leave alone as what you have to do. Three of the
  eleven age points start from *leave it*.

Leave your email address at the checkout and both files arrive straight away: one guide and one card,
as two pdfs. No subscription, no account.

[Buy the BMW 840Ci E31 guide — €24](https://lastrealengines.com/840ci-e31/)

*Have every car inspected before you buy by someone who knows this engine. This is general information
about the model and not advice about a specific car.*