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PORSCHE 924 BUYERS GUIDE
Copyright 1999, Obin Robinson

 

What follows is my "buyers guide" for prospective Porsche 924 owners.   There were about 125,000 of these babies made, who knows how many are left.   In any way, there are a lot of them out there.  You don't have to jump on the first one you see, but if you see one that really catches your eye, print out this list and take it with you.  Please do not redistribute this list, or modify it.  If you feel that there are any errors, please e-mail us and it'll be fixed.

Enjoy!

 

Porsche 924, 1976-1982

Points of Inspection:
Here is what to ask the owner of the car about:
1) Is the seller the original owner? Where are the car maintenance records? How complete are they?
2) Is there any rust on the car?
(Surface rust is not bad, as long as parts are not rusted out, or
needing sheet metal. Deep rust or rusted out parts are bad. Floor
pan rust is bad and hard to replace. Rocker panel rust is bad.)
3) Is the car painted in its original colour?
4) Is the paint faded unevenly?
5) Will it need a new paint job?
6) Has the car had regular oil changes at every 3,000 miles?
7) Does the car burn oil?  Note that the 924, like all "real-man's" sports cars, are oil consumers.  You should expect 1 quart of oil every 600 miles.   Get in the habit of checking the oil every two FULL tanks of gas.  Keep a bottle of 20W50 in the back tool area.
8) Did the owner always use 20W 50 oil?  This is the preferred grade for the 924.
9) How is the engine?
Start the engine with the hood up so you can hear everything better. Find out the compression test figures. Knocks point to excessive wear. Watch the lights when
turning on the car and see if the alternator is working correctly.  A knock coming from the top of the engine could point to worn lifters.  Worn lifters may cost as much as $300 to repair.  Don't forget to check for squealing belts (fan, AC, or steering). Ignition troubles with points are a simple fix that can be done for $100 or less.
10) How is the steering?
Check for any peculiarities, or sounds that the steering might make.
Also check the ball joints.  Bent or broken A-arms can end up costing $300-$400 per side!  The steering on the 924 is VERY precise.  It should be fairly easy to haul the car through a tight turn, and by turning the wheel back and forth, there should be no play or wobble at all.  If you feel vibrations at speed, that's the road!   Rhythmic vibrations regardless of road texture should be checked out!
11) Does the transmission feel like it did when the car was new?  Difficult shifting into gear is tricky to diagnose, the problem could be a worn clutch or simply bad transmission oil.  924 transmissions can be found for cheap.  Complete replacement is about $300 (to remove an old one and install a new one).  Don't worry about abusing it.  Our 924 was purchased with a tricky transmission that we thought would need replacement ASAP... 10,000 miles later I'm still trying to get the full life out of the old one before p[putting a new one in.  The fact is, these are tough little units that can take a beating.
12) Are the gears meshing smoothly?  Once in a while, it may be tough to get the car into reverse, don't sweat it, change the oil and see if the problem goes away.
13) How old is the clutch?  (These cost from $150 to $333 for the kit, and labor is about $400 - $600).
14) How does the clutch backlash feel?
15) Are there any gaps or spaces in the body panel fit?  Check to see if the body is sagging.
16) How old are the shock absorbers?  These aren't too hard for any shop to replace.  Go with high-quality ones if you can, and you WILL notice a difference.
17) Any water or fluid leaks?
Make sure that the car does not leak. The problems and costs are as
follows:
Hatch leaks; worn seal: $60
Passenger side foot well; battery leaking: $500
Sunroof leaks; check drain hoses for blockage.
Fluid leakage in engine compartment, look near motor mounts:
Power steering leakage; entire control arm replacement: $300 or more
Radiator leak; $300- $400 (it's not too hard to replace the radiator yourself)
Coolant leak; anywhere from $10 to $200, depending on what hose, and how bad.
Check oil level - do not tolerate a car that leaks oil!
18) Has all the air been bled from coolant system?  This may seem minor, but we almost blew an engine because of this minor oversight (by us, not the previous owner).
19) How old are the motor mounts?
(If engine has excessive vibration @ idle, then disappears @1200 RPM,
then the motor mounts could be bad.)
20) How old is the water pump?
(If there is a noise or there is any leaking fluid, then the pump must
be replaced. We've seen brand new pumps going for as low as $15, so don't worry, they're not the super-expensive 944 type.  Also, make sure the pump hasn't leaked on any belts.)
21) How old and in what condition is the exhaust system?
Make sure to check headers. Blue smoke coming from the exhaust could
be pointing to a bad valve stem seals or ring.)
22) When was the last emissions check done?
23) How old is the timing belt?
You don't have to worry about the expensive 944 timing belt troubles.  Belts are less than $10 from any Porsche supply store.
24) How old are the brakes?
(Make sure to check the fluid in the master cylinder Also check the
hoses for cracks. Check the tubing for rust. Check the calipers for
leaks.)
25) How old is battery?  (You can get a great one at Sears for $70 or less, and they'll check the old one for free!)
26) Does the heater work?
If the heater is not getting hot enough then there might be cooling
system damage or a bad thermostat. Check the radiator fluid with the
litmus paper and ask when the last time the cooling system was
flushed.
27) Does the speedometer and odometer work?
(These aren't hard to fix, but the work is time consuming and kind of annoying.  It sounds kind of funny, but I actually gauge my mileage by how much oil is consumed.   Hey, don't knock it!  It works!)
28) How old is the oil pump?
These are hard to repair and possibly expensive.
29) How is the Capacitive Discharge Ignition?
Listen for a high-pitched whine while the car is on. The CD box is a silver box near the front of the engine compartment on the driver's-side.  If you do not hear a whine, or engine misfiring at high RPMs, then the car may need a new CD ignition. These are easy to fix, but expensive, and there are good after-market options.
30) How old is the alternator?
If the engine cranks slowly and the lights are dim even when engine revs up, then the car may need a new alternator. Always consider a new voltage regulator when replacing the alternator. Alternator replacement is about $250 (including labor and belt tensioning).   Don't worry if the alternator light comes on dimly while driving with your high beams on... the belt may just need to be tightened.
31) How is the starter?
If the starter won't turn over when the engine is hot, then the car might need a starter relay kit. Many starting problems are due to high heat transfer from the engine and transmission causing a voltage loss. This is a very cheap and simple fix needing only simple tools. Also if the engine doesn't turn over when hot, check the engine-to-chassis ground strap. You can get good grounding kits from several places for $15 or less. Replace this part and install a starter relay on all old 924s. This is cheap and easy to do.
32) How is the headlight motor?
This is an easy fix, but about $250 each.  Get them from parts yards for less than $50 each and save the cash.
33) How is the fuel accumulator?
Leaking and defective ones are dangerous. They cause hard starting. They are not hard to fix, but are kind of expensive (around $100-$150) on 1979 and later cars.  Also do this carefully and don't break a fuel line!
34) How is the fuel injection?
Fuel injectors should all be replaced at the same time, if there is anything wrong with them. They aren't too hard to replace, but are a pain. They are about $50 each.  It is very important to check the injection boot. Oil rotted or cracked boots can disable the car! Check these regularly!  If you have some time, clean them up with silicone spray and shine them up like new, you will be able to see any small cracks much easier.  Fix them with regular Permetex black silicone that comes in a toothpaste-tube looking thing.   Get this stuff it at K-Mart for $2.00 or less and save yourself $100 or more!
35) How is the cold start valve?
A defective or leaky cold start valve causes hard starting and rough idle when engine is warm. These aren't too expensive, or too hard to replace.
36) How is the fuel pump?
If engine cranks for a long time before it fires up when hot, but starts fine when cold, there may be a leaking check valve in the fuel pump.  (it could also be a leaky accumulator).  Fuel pumps can run from $90 to $250.
37) How is the sway bar link?
If you turn the wheel all the way to the left (or right) and look at the suspension, you'll see these little "lollipop" bars that attach to the front sway bars.   If these break, or bend, then your car will not handle very well These are easy to fix, and only cost about $50 each.
38) How are the sway bars?
39) How is the fresh air and heater control?
These are not too hard to fix, but are ridiculously expensive and sometimes hard to find.   Get them from a junked car in a yard, or from a parts car you see on the internet, or just ignore it.
40) How does the front nose panel look?
This is expensive because you need a welder, and painting to replace.
41) How is the front valance?
This is easy to fix, for about $125.
42) How is the gas cap?
This is an often overlooked part... that you can get from a VW rabbit for about $5 to $20.
43) How are the lights?
Lights are easy to fix, but are delicate. They are also kind of expensive if more than one must be fixed.
44) Has the car ever been in a flood?  Make sure to check and smell for mildew, check for moisture on flood damaged cars

Engine Data

Engine number on left side of crankcase next to clutch housing.

Compression Pressure
Test pressure with fully open throttle, oil temperature above 140 F,
all spark plugs removed and engine at cranking speed. Each cylinder
should be allowed about 12 compression strokes. Difference between
cylinders should not exceed 43 psi (3 kg/cm 2).

Spark plugs
Gap    .028-.032" (.6 - .8mm)
Torque 21 ft lbs.

High Tension Wire Resistance
6,000 Ohms per wire

Distributor
Dwell Angle
at 1500 RPM    52-70
at 5000 RPM    42-68

Ignition Timing
Adjust by turning distributor until mark on flywheel aligns with
reference edge on clutch housing.

Battery
12 Volt Negative Ground, 63 Amp Hr

Belt Adjustment
Tension is correct when center portion of belt can be depressed
approximately 3/16" to 3/8" (5 - 10 mm) by firm thumb pressure.
Adjustment is made by shifting position of alternator. Remove small
plate from alternator cover for access to adjustment lock screw.

Capacities
Crankcase (with filter)        5.28 qts
Cooling system w/heater    8.4 qts
Manual transmission w/diff. (GL-4)    2.75 qts.
Fuel Tank                 16.4 gals (incl. 1.3 gal reserve)

Engine Cooling:
Cooling System Capacity: 7.4 qts.
Thermostat: opens at approx. 180F
Radiator cap: 12.8 - 16.4 psi
Cooling Fan: comes on at 198F, goes off at 189F.

 

Fuel Injectors:
Porsche 924 Injection system is a Bosch K-Jetronic Continuous Injection
System.

Troubleshooting:
Cold Start Symptoms
-engine cranks but will not start
    check fuel pump and double fuse relay, replace as necessary
-auxiliary air valve does not open
    replace valve
-cold start valve does not operate
    check electrical power to valve, replace as necessary
-cold start valve leaking
    replace valve
-sensor plate and/or plunger sticking
    free up or replace as needed
-vacuum leak
    repair vacuum leaks
-fuel system leak
    repair fuel leaks
-faulty thermo time switch
    replace switch
-"Cold" control pressure incorrect
    replace warm-up regulator if pressure not to specification
-sensor plate stop set incorrectly
    adjust to specs

Engine hard starting
-"Cold" control pressure incorrect
    replace warm-up regulator if pressure not to specification
-auxiliary air valve does not open
    replace valve
-cold start valve does not open
    check electrical power to valve, replace if necessary
-cold start valve leaking
    replace cold start valve
-vacuum leak
    repair leaks
-fuel leak
    repair fuel leak
thermo time switch does not close
    replace

Engine cranks, but will not start
(or engine hard starting)
-"Warm" control pressure incorrect
    replace warm-up regulator
-sensor plate stop adjustment incorrect
    adjust sensor plate stop
-sensor plate and/or plunger stuck
    free up or replace
-electric fuel pump not operating
    check fuel pump and relay fuse, replace as needed
-idle mixture out of adjustment
    adjust mixture to specifications

Rough Idle
-aux. air valve does not open or close
    replace valve
-cold start valve leaking
    clean or replace valve
-injectors, fuel, or vacuum leaking
    replace parts as necessary


HOT ENGINE DRIVE ABILITY
Rough Idle
    -check aux. air valve, cold start valve, vacuum, fuel, injectors, and
idle mixture

Poor engine performance
    -check cold start valve, idle mixture valve, and throttle valve

Excessive fuel consumption
    -check same as above

Engine misfire at high speed
-loose electrical contact at fuel pump
-primary pressure too low or too high
    check specs and adjust
-fuel system leaking

Engine "diesels"
-injectors leaking
-faulty cold start valve

Idle speed too high and cannot be adjusted lower
-aux. air valve does not close
    replace valve

Engine backfires
-vacuum leak, cold start valve leaking, or idle mix out of adjustment
-fuel system leaking


---
Bosch electronic ignition system consists of a control module, a
breaker less distributor, a single or dual resistor, a high output
ignition coil, an ignition switch, and battery. Standard centrifugal
and vacuum advance mechanisms are used.
---
Fuse block is located under instrument panel on left of steering
column. First row is below relays, second row is above relays. Fuses
are numbers from left to right, lower row first.
---


Suspension and Steering Troubles
Hard steering
-tire pressure too low
-front wheels out of alignment
-lower control arm ball joint seized
-gear housing lubricant low
    refill and check for leaks
-insufficient lubrication or abnormal wear on steering linkage
-seized or damaged ball joints
-steering shaft too tight
    readjust
-steering column incorrectly aligned
    realign

Pulls to one side
-cross member broken, cracked, or loose
    replace
-left and right side wheel base uneven
    check frame and repair
-loose or excessively worn wheel bearings
    adjust or replace
-loose wheel lug nuts
    tighten
-brake drag
    adjust
-Pitman arm binding
    adjust or replace
-uneven ride height
    adjust
-loose steering gear
    check for worn parts, replace and adjust

Steering wheel wander
-excessive ball joint wear
-lower control arm and strut damaged
-lower control arm pivot bolt loose or sloppy
    tighten or replace parts
-lower control arm and strut damaged or worn
    inspect bushings and replace as required
-steering linkage loose or worn
    adjust or replace
-worn shaft bearing out of adjustment
    readjust
-loose steering gear housing
    tighten housing

Body roll
-stabilizer broken or damaged
-shock absorbers worn out

Noise
-coil spring broken
-bad shocks
-insufficient lubrication
-components loose or worn
-damaged wheel bearing
-improper tire pressure

Steering hard to control
-broken front coil spring
-defective shock absorber
-loose control arm bushings
-strut assembly loose
-tire pressure
-wheel alignment out of tolerance
-damaged suspension links
(if any of above, replace applicable parts)

Vibration or shimmy
-incorrect tire pressure
-tire out of balance
-worn shock absorbers of springs
-loose steering gear housing
    tighten
loose steering linkage
    adjust or replace linkage

Noise
-incorrect tire pressure
-wheel bearings loose or worn
    repair or replace

CLUTCH
Chattering or grabbing
-incorrect lever adjustment
    adjust clutch
-oil or grease on facings
    check for oil leaks
-loose "U" joint flange
    check "U" joint flange and tighten
-worn input shaft spline
    replace shaft
-binding pressure plate
    check for binding, replace as necessary
-binding release lever
    free binding levers, or replace
-binding disc hub
    replace disc and adjust clutch
-glazed facings
    replace disc after checking pressure plate and flywheel for scoring.
replace as necessary
-unequal pressure plate contact
    check release lever clearance, disc thickness, and pressure plate for
parallelism with flywheel
-bent clutch disc
    replace clutch disc
-uneven spring pressure
    adjust spring tension
-incorrect transmission alignment
    check clutch housing alignment
-loose facings
    replace clutch disc
-scored pressure plate
    replace pressure plate if Warped more than .015"
-worn pressure plate, disc or flywheel
    replace if signs of excessive wear, heat, or scoring
-clutch disc hub sticking on shaft
    check shaft for excessive wear or burrs, replace as necessary
-worn or binding release levers
    replace levers and release bearing
-broken or weak pressure springs
    replace springs
-sticking clutch pedal
    check for worn or mis-aligned components
-incorrect disc facing
    replace clutch disc
-engine loose in chassis
    check motor mounts and replace or tighten

Dragging
-oil or grease on facings
    free release levers
-incorrect lever adjustment
    check for damage and readjust lever
-incorrect pedal adjustment
-dust or dirt on clutch
    disassemble and clean thoroughly
-worn or broken facings
    replace clutch disc
-bent clutch disc
    replace, inspect for cause
-clutch disc hub binding on shaft
    check for burrs or gummed splines
-binding pilot bushing
    replace pilot bushing
-sticking release bearing sleeve
    free sleeve, check for scoring or rough spots
-warped pressure plate
    replace pressure plate if worn more than .015"

Grinding
-dry release bearing
    replace
-worn out or dry pilot bearing
    lubricate or replace
-worn input shaft bearing
    replace

Heavy, stiff pedal
-dry or binding linkage components
    lube
-sticking release bearing sleeve
    check release bearing sleeve for wear, burrs or roughness
-dry or binding pedal free hub
    replace bushings or bearings in pedal hub and lube
-rough, dry or binding pivot ball, or fork pivots
    lube all moving points


Rattling
-weak or broken release lever spring
    replace spring
-damaged pressure plate
    replace pressure plate and adjust clutch
-broken clutch return spring
    replace return spring
-worn splines in clutch disc hub or transmission input shaft
    replace clutch disc or transmission input shaft
-worn clutch release bearings
    replace release bearing, check tips or release levers for wear,
replace as necessary
-dry or worn pilot bushing
    lube
-unequal release lever contact
    readjust release levers
-incorrect pedal free play
    adjust
-warped clutch disc
    replace, check pressure plate for wear and replace if necessary

Slipping
-pressure springs worn or broken
-worn facing
    replace clutch
-incorrect clutch alignment
    adjust clutch
-oil or grease on facings
    replace clutch disc, fox oil leaks
-warped clutch disc
-warped or scored pressure plate
    replace pressure plate if scored, heat checked, or warped more than
.015". test spring tension and replace clutch disc
-binding release levers
    free release lever
-binding clutch pedal
    check for worn or mis-aligned parts

Squeaking
-no lubrication in release bearing
-worn release bearing
    replace
-dry or worn pilot bearing
    lube or replace
-pilot bearing turning in crankshaft
    replace
-worn input shaft bearing
-incorrect transmission alignment
-no lube between clutch fork and pivot
-no lube in torque shaft

Whirring
-incorrect pedal free play
    adjust
-incorrect transmission alignment
    check clutch housing alignment


Adjustment:
Clutch:
Lower end of clutch cable should measure 5.438+/-.078" (138 +/- 2mm)
when measured from lower edge of cable holder to pin at release lever
with release bearing against diaphragm spring. To adjust, turn
outboard release lever on shaft and tighten in position. Adjust cable
with counter nuts on holder to give .8 - 1" (20 - 25mm) free play at
clutch pedal.

Pedal:
1) With engine and transmission warm, depress clutch pedal to stop.
In this position reverse gear must just be able to engage silently.

2) When clutch pedal is fully depressed, clutch release lever should
move .6" (15 mm) to completely disengage clutch. If cable housing
rests on bottom of guide clamp when pedal is fully depressed, inner
cable must be adjusted at yoke end.

3) Measure from threaded cable end of yoke to outer edge of lock nut.
Measurement should be .7 - .9" (17 - 22 mm), adjust if necessary. If
cable housing rests on bottom of guide clamp when clutch pedal is
fully depressed, inner cable must be lengthened at yoke end.

4) If arc of cable is too large, allowing cable to come out of guide
clamp when pedal is released, inner cable must be shortened at yoke
end.

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