Welcome to impala! This file contains Frequently Asked Questions (FAQ) as well as a general source of info on the late
model Chevrolet Impala SS and the Caprice models from 1994-1996, and some info on other Caprice/Impala models.
This FAQ also has a wealth of information from actual Impala SS owners who have corresponded on the list about problems, modifications, and experiences. Many thanks to all the impala listserve member who contributed to this FAQ.
Impala Frequently Asked Questions:
1.Where can I get this FAQ?
2.What other sources of Impala SS information are on the Internet?
3.Who is responsible for the design of the Impala SS, and how did it come to be?
4.How many late model Impala SS vehicles are there?
5.What kind of standard features are available on the Impala SS?
6.Where is the Impala SS built?
7.Was the Impala SS recalled?
8.How fast does it REALLY go?
9.Are there companies that make aftermarket modifications for the Impala SS?
10.What's that buzzing sound I hear near the blinker control when I accelerate in my Impala SS?
11.What kind of problems have owners of the Impala SS experienced with their cars?
12.If I bought an Impala SS, is there anything I should do to it right away? *NEW IMPALA SS OWNERS READ THIS!!!*
13.What kind of gas mileage can I expect in my Impala SS?
14.How come the Camaro has a 300 HP LT1, and the Impala SS is rated at 260 HP? What's the difference?
15.What are the differences between the '94, '95, and '96 Impalas?
16.Isn't the Police Package Caprice (9C1) basically the same as the Impala SS?
17.Listings of magazine articles on the Impala SS.
18.What do the numbers in the Vehicle Identification Number mean, and how can I decode them?
19.What can I do to help?
1.Where can I get this FAQ?
This faq can be found via ftp at:
ftp://ftp.crl.com/ftp/users/im/impala/faq
Or via the WEB:
2.What other sources of Impala SS information are on the
Internet?
The best source of up to date information on the Impala SS is the Impala SS listserve. There are over 300 Impala SS owners in this group, and the information is current and first hand. To subscribe to this free electronic mailing list email:
With the body:subscribe naisso youremailaddy:With no subject
EXAMPLE: To: naisso-request@magicnet.net
From: JoeBlo@aol.com
re: subscribe naisso JoeBlo@aol.com
3.Who is responsible for the design of the Impala SS, and how did it come to be?
Chevy 2 studio chief John Albert noticed his neighbor has lowered and customized a late-model Caprice with big wheels and dark paint. He liked it so much he showed it to Chevrolet General Manager Jim Perkins. Perkins instructed John Moss to work up a similar car for the 1992 SEMA show. It was named in honor of the large muscle-cars of the 60's. Because it was such a hit at the show, it was rolling off the production lines 14 months later.
4.How many late model Impala SS vehicles are there?
'94 Impala SS = 6,303
'95 Impala SS = 18,649
'96 Impala SS = 23,000 to 26,000 (estimated)
5.What kind of standard features are available on the Impala SS?
The Impala SS comes standard with the following features:
5.7 liter LT1 engine.
Sequential fuel injection
Four speed 4L60E automatic transmission
Bosch System 5 Four Wheel Anti-lock Disc Brakes
3.08 ratio Limited Slip Differential
17" Aluminum Wheels
BFGoodrich P255-50-ZR17 Tires
Heavy Duty Radiator
23 Gallon Plastic Fuel Tank
Leather Interior, Driver and Passenger Bucket Power seats - Gray Only.
94-95: Digital Speed display with KPH/MPH switchability and digital mileage indicator. 96:
Analog speedometer and tach, digital mileage indicator.
Driver and passenger air bags.
Three point rear passenger seatbelts
6.Was the Impala SS recalled?
There were a few minor recalls for various runs of the Impala SS. The only mass recall to date wasthe Shift Linkage Recall. The other recalls were for specific runs. Check with your dealer for info, go armed with these recall notices:
Date: Wed, 28 Jun 1995 17:51:48 -0400
95-C-23, June 1995. "G.M. has decided that certain (bold)
1994-95 Chevrolet Caprice and Impala model vehicles may have
been built with a defective accelerator pedal assembly which
causes the vehicles to fail to conform to the requirements (of
some govt rule)...Under some circumstances at low temperatures,
there may be excessive friction in the accelerator pedal
assembly. If there is excessive friction in the pedal assembly,
in the event of a failure of a throttle return spring the engine
speed may not return to idle as specified in (some govt rule)."
Date: 09 Jul 95 13:22:33 EDT
Service Bulletin 53-32-05, June 1995
Subject: Horn may honk without driver activation (replace
steering wheel and SIR module assembly)
Models: 1994-95 Chevy Caprice
Condition: The horn may honk without driver activation, usually
when the tilt lever is released quickly, letting the wheel slam
to the "up" position (sometimes called "tilt and toot"). The
horn may also honk when closing a door or when turning a corner.
Cause: The design of the switch is not strong enough to prevent
the contacts from closing when a sharp bump occurs.
A new membrane design switch was introduced in production
approximately May 15, 1995 for base steering wheels and June 15,
1995 for leather steering wheels.
Correction: Replace both the steering wheel and the SIR module
assembly (air bag) following the directions in Section 3F of the
service manual. Be sure to disable the SIR system before
removing any parts, and follow all cautions and notices.
Parts Information:
Item/Description Part Number
------------------------------------------------------------
Wheel Assembly, Steering (Leather), Light Grey 16757633
SIR Module Assembly, Light Grey 16757619
Parts are expected to be available on 7/3/95 at GMSPO.
Warranty Information: For vehicles under warranty, use Labor
Operation E7020.
Service bulletin is # 53-33-02 dated April, 1995.
Models: '93-'95 B-cars (Roadmaster, Caprice, Impala)
The torque specification for the upper and lower steering
knuckle nuts would be as follows:
Tighten:
-Steering knuckle nut (upper) to 83 Nm (61 lb-ft), additional
tightening may be required to insert cotter pin. Do not exceed
60 degrees of additional tightening.
NOTE: The '93 service manual states 61 lb-ft (which is correct),
however the '94-'95 manual incorrectly states 125 lb-ft!
-Steering knuckle nut (lower) to 112 Nm (83 lb-ft), additional
tightening may be required to insert cotter pin. Do not exceed
60 degrees of additional tightening.
NOTE: The '93-'95 service manual incorrectly states 125 lb-ft.
GM Service Bulletin No. 53-34-03
Subject: Rear Wheel/Tire Position in Wheel Well Openings
Models: 1994-95 Chevrolet Caprice/Impala SS
Condition-
Some customers may comment that one rear wheel may appear more
forward in wheel well opening than wheel in opposite side of
vehicle or that vehicle appears to dog track when viewed fro the
rear when in operation.
Cause-
Rear lower control arm frame bracket holes pierced off location
during frame manufacturing.
Correction-
Elongate holes in rear axle control arm bracket per service
procedure
General Motors has decided that certain 1995 Chevrolet
Caprice/Impala model vehicles fail to conform to Federal Motor
Vehicle Safety Standard (FMVSS) 114, "Theft protection". Some
of thesae vehicles have been produced with an improperly
adjusted shift control linkage. As a result, it may be possible
to shift from the "Park" position with the ignition key removed.
This condition may increase the risk of accidents resulting from
unauthorized use or from unintended movement of parked vehicles.
7.Where is the Impala SS built?
The Impala SS, Caprice, Buick Roadmaster, and Cadillac Fleetwood, are all built at GMs Arlington, TX plant.
8.How fast does the Impala SS REALLY go?
The Impala SS in stock condition, on level ground can achieve speeds of around 140 MPH. There is an internal RPM limiter in the Impala SS which would cut fuel at 5500 RPM, or about 157 MPH. Stock 0-60 times as tested in most major magazines show between 6.9 and 7.3 seconds. Stock quarter mile times as tested in magazine articles (and reported by the impala listserve members) range in the high 14's to mid 15's. 14.97, 15.23, 15.55
9.Are there companies that make aftermarket modifications for the Impala SS?
Yes! With the confirmation that '96 would be a large production year for the Impala, marketing products for the Impala and it's iron head LT1 became a profitable venture. A complete list of the products available for the Impala SS is being developed for the web site..the following is some information on available aftermarket products.H
Hypertech, JET, and Z-Technologies , all market PCM reprogramming, or PCM fooling (JET)products. Edlebrock has begun producing headers for the Impala SS. Many companies offer aftermarket exhaust systems, including Borla, which has a pricy cat back system.
There are also literally hundreds of products available to modify the LT1, but use caution. TheImpala SS's LT1 engine is not the same as the Z28 or Corvette. Most noticeably, the Impala comes with an iron head LT1 whereas the others are aluminum. This makes things like roller rockers and valvetrain components for the LT1 questionable as to their compatibility with the Impala. Tests are being done by our impala listserve agents, and information develops daily on these products.
Once again...with things like OBD II and the like, the usability of aftermarket products is still an ongoing topic of discussion, and the best source is the impala listserve!
In addition to aftermarket products for the Impala, there are a plethora of parts available from GM to modify your Impala.
Since the Impala is based on the Police 9C1 Caprice, most of the options found on the 9C1 can be applied to the Impala.
UNDER CONSTRUCTION Here is a list of some of those modifications: FRONT SPOILER
DEFLECTORS FOR BRAKE COOLING TRUNK POPPER WIPER ARMS SPRINGS
BILSTIEN SHOCKS POWER STEERING FLUID COOLER ENGINE OIL TO AIR COOLER
LIFETIME SILICON HOSES TRUNK MAT DRIVERS DOOR LATCH TO UNLOCK TRUE
READ OIL PRESSURE SENDER REAR WARNING LIGHTS - OPEN TRUNK
For a superbly comprehensive list and instructions of Impala Modifications, Visit: Bob Cheek's Impala Page
10.What's that buzzing sound I hear near the blinker control when I accelerate in my Impala SS?
This seemed to be a common "problem" reported by Impala SS owners. There is a small 1" by 1" "cube" of plastic which is part of the steering column. It's located just behind the blinker control adjacent to the tilt wheel adjuster. This part tends to vibrate at certain frequencies of road noise or RPM's. Users have: Removed it and lined it with tiny chunks of "DynaMat" (a dampening material used in auto sound acoustics available in JC Whitney). OR Just press it back in tightly when it finally
loosens up...about every day and a half or so. OR Place a piece of electrical tape on the bottom of the "cube" out of sight.
11.What kind of problems have owners of the Impala SS experienced with their cars?
Unfortunately, the Impala/Caprice carline fell, and continues to fall victim to many quality control problems during it's production. On a positive note, many of these issues can be easily resolved with a small appointment at the dealership. Armed with the following information, however, new owners will be able to inspect the car for the problems and have them fixed prior to delivery! So you're lucky you're here! You're welcome!
Some of the common service issues:
Misaligned body panels. Many new Impalas came with the body panels misaligned as much as 1/4 inch! A quick look at the tolerances on the tops of the doors where they meet the roof, the fenders where they meet the doors, and the closing and opening of all the doors should be all that's needed to see if your Impala is crooked. The rear doors were the most common misaligned panel. Next came the passenger's side fender. The best way to check the fender alignment is to look down the length of the car from the front then the rear. The Progressive Assembly Line Tolerance Error theory was explained to me by my very poor service department about how my passenger fender could be sticking out almost a 1/4 inch. Don't ask.
In most cases this problem was fixed by the dealer subletting to a real body shop who knows how to align body parts. My car was more than satisfactory when returned only 6 hours later. This problem continues into '96, although apparently not as wide spread as in '95. Buzzing around the steering column at certain RPMs. See section 11 of this FAQ.
Power Steering Pump Leaking/Failure/Grinding
Many Impalas develop or are even delivered with badly illing steering pumps. They make noise, leak, even spray fluid in the engine bay near the pump. Curiously, usually only a minor amount of complaining is required to get your dealer to replace a noisy pump or to order seal kits for leaky pumps, which led us on the listserve to believe that they know the pumps are
trash! Yikes. There have been no reports of the replaced pumps being bad, and as of yet, only a few 1996 Impala steering pumps were reported bad, but these were hose leaks to the pump. Stay tuned.
Exhaust Hanger Bolts Missing/Loose/No Nuts.
The dual exhaust system has U bolts and brackets just forward of the rear axle. Many '95 Impalas were delivered without them, or them being loose. Jack up the car for this one, and check it out...Obviously a simply yet annoying fix. The worse thing that happens if you have no hangars is the there is a "clunking" in the rear end as you hit bumps.
This problem appears to be fixed for '96.
Ball Joint Torque.
Two major issues have developed regarding the ball joints...both are potentially very serious. First, the ball joint nuts are supposed to be torqued to the factory specs, and then if necessary, tightened further, just enough to get the cotter pin through the holes that are in the knuckle, and the slots in the castle nuts. Unfortunately, users report that the nuts have been well below the specifications, even to the point of causing play in the joint. Speculation surfaced that the nuts were being backed off for cotter pin insertion...yikes.
The fix is to simply check the torque of the ball joint nuts to their proper specifications:
UPPER BALL JOINT TORQUE SPECIFICATIONS
61 ft-lbs
LOWER BALL JOINT TORQUE SPECIFICATIONS
83 ft-lbs
TIGHTENING PROCUDURE:
Remove cotter pins.
Loosen the castle nuts slightly (This is optional, but a good plan, should the joints be overtightened)
Using a torque wrench, tighten the nuts to the specified torque.
Continue to turn the nut until the next notch in the nut comes clear for the cotter pin to go through the knuckle.
Do not exceed 60 degrees of additional rotation.
This brings us to our next major ball joint issue.
The FACTORY repair manual, and the Helm shop manual, both have INCORRECT TORQUE SPECIFICATIONS listed.
Both list 125 ft-lbs! This, in the case of the lower joints, could actually damage the ball joint!
This was discovered by a police fleet mechanic, who after replacing many ball joints twice figured something was wrong.
This problem continues into '96. Alignments.
As with many other GM cars, alignments at delivery were off in many cases. It's always a good plan to have it checked. Most Firestone service centers will check the alignment for free, and provide a written statement to that effect for your return to the dealer.
Rust.
No undertarring was standard on the Impala SS. Most cars were delivered with a fair amount of surface oxidation on the undercarriage, rear axle, and suspension. Some users reported oxidation in the engine compartment as well, on the dampener and the heads where the meet the intake manifolds. This rust is not much more than cosmetic and cleanable, but still a bummer.
Glove Box Latch
Members report that the little pin that holds the latch shut on the glove box is mounted through flimsy plastic. After some use, the plastic can crack and the glove box will not latch. To fix this, you must REPLACE THE ENTIRE GLOVE BOX ASSEMBLY, as the latch is not available as a single item. Be gentle with that latch, I have and no signs of wear yet. Some members discuss reinforcing the plastic with metal to solve this problem.
QUALITY OVERVIEW:
Several theories have developed as to the reasons for the poor quality control of this car. The Impala was produced as sort of an afterthought. Just after the announcement of it's production, rumors began about the Arlington plant being converted to truck production. The cancellation of the Impala/Caprice/Fleetwood/Roadmaster seemed evident as early as April of 1995. Some rumors indicated that the plant would shut down and convert to trucks at the end of the 95production year (August of 95). GM actually had not made any decisions on the matter, and had a wait and see policy. This may be the reason that little efforts were made to correct plant problems. Why spend time and money to correct problems in a plant that could wind up being completely re-tooled?
In any case, it is the opinion of most of the Users, that the above problems don't detract completly from that fact that the Impala SS is one kick ass car, and most wouldn't trade it for anything!
12.If I bought an Impala SS, is there anything I should do
to it right away?
*NEW IMPALA SS OWNERS READ THIS!!!*
In addition to the common problems listed in section 10 of this FAQ, this section is important to consider. If you look at the rear differential cover, you will notice two small indentations on either side directly in line with the axle tubes. These ndentations are to direct the flow of oil through two holes in the differential case which then flows down the axle tubes to lubricate the axles and the outer axle bearings. The differential cover gasket is also supposed to have two holes in it, which line up with the holes in the case as well as the indentations to allow oil to flow down the axle tubes. Starting in the 1990 model year, GM has been improperly installing differential cover gaskets THAT DO NOT HAVE THE LUBRICATING HOLES!! If you do not change this gasket to one that has the proper holes, your outer axle bearings, as well as the axles themselves, could be damaged by around 70K miles. The damaged (under lubricated) bearings potentially may wear grooves in the
axle shafts, requiring that they also be replaced. If this is left unchecked, the metal bits from the damaged outer bearings and axles will also damage the inner bearings, pinion bearings, as well as cause the spider gears to wear into the differential carrier. GM will not acknowledge this as a warranty or recall issue, because any damage that can occur will only happen well after any warranty period has expired. In addition, the wear that will occur may not be that noticeable until it progresses slowly to the point of rear end failure. All Caprice/Impala SS vehicles produced in 94, 95, and still in 96 (As well as 90-94 B-cars) have the improper gasket. The proper gasket is:
Fel-Pro: RDS 55028-1
Get it replaced!
13.What kind of gas mileage can I expect to get in my Impala SS?
What Kind of a question is that!? Seriously, members report an average of 15 MPG. This is combined city/highway driving in various climates. A member driving on I-5 between LA and San Francisco at an average of 110 MPH got 17 MPG after burning over 19 gallons of 92 octane gas!
(We don't condone this behavior....Well, yes we do.)
14.How come the Camaro has a 300 HP LT1, and the Impala SS is rated at 260 HP? What's the difference?
For the Impala, GM produces an iron head version of the LT1. The Camaro, and Corvette come with a lighter, aluminum head LT1. The camshaft in the iron head LT1 is milder than the ones available in the other LT1 powered GM cars. The basic idea is that such awesome power in the hands of normal America could be dangerous. GM limited the HP rating on the Impala so as not to push it's handling envelope. Here are some major differences:
Item/Description F/Y-car(Camaro) B-car(Impala)
-----------------------------------------------------------------
Heads: Aluminum Cast-iron
Cam/valve lift specs.: .450/.460 (int/exh) .417/.429 (int/exh)
Valve springs: 268 lb/in 393 lb/in
Valve spring od.: 1.300" 1.241"
Valve spring inst. ht.: 1.78" 1.70"
MAF id.: 3.5" 3.25"
15.What are the differences between the '94, '95, and '96 Impalas?
The only outwardly distinguishable differences between the 94 model and the 95/96 is the quarter panels adjacent to the rear quarter windows and the side view mirrors. For 94, a small plastic insert is installed, and the Impala emblem is on the insert. This feature is part of the quarter body panel shape, and not an insert for 95-96 Impala SS/Caprice, with the Impala emblem mounted there. The side view mirrors on the 94 model are mounted to "stalks" on the doors while '95/96 they are
flushed into the front lower corner of the windows. Colors for 94 were black only. '95 and up Impalas can be ordered in two additional colors: dark cherry metallic and dark green metallic. Green was to be replaced for 96 with a silver/gray, but this
idea was scrubbed. Some dealer pamphlets still indicate that as an available color. Contrary to popular lore and superstition, there are no grey (or white!) factory Impalas, Although rumor was that one factory Impala was accidentally painted bright Cadillac emerald green!. Who got this car!? We need to know. 95-up Impalas now have the speed-compensated volume (SCV) stereos standard. 94 Impalas have the "Oil Change" sensor reset in the fuse panel area, and 95-up are reset by
pumping the accelerator pedal three times at ignition "on." There are differences in the amp ratings of the HD radiator cooling fans on the 94-95up Impalas. The 94 fan appears to be a more powerful fan, and was deleted presumably because the efficiency of the cooling system in the Impala LT1 creates no need for such a high powered fan. In 96, major changes occurred to instrumentation and shifter of the Impala SS. The column shifter was deleted and the floor shifter this car was aching for was added. There was no tach for 94-95, which was solved for 96 with analog gauges and a tach. Unfortunately, oil pressure gauges were eliminated for 96. Mixed reviews from Users on the gage cluster. Sales brochures indicate that all Impalas have the 2nd gear start capability. The car, when the shifter selector is in the (2) position, will accelerate from a stop in second gear. This could be advantageous in the snow and ice. The PCM routine for this feature is ELIMINATED from the 95-96 Impalas, and only the 94 models have the 2nd gear start. We still don't know if we can modify the PCM for this.
16.Isn't the Police Package Caprice (9C1) basically the same as the Impala SS?
The following are differences between the Impala and Police Caprice (9C1). Don't fret! They don't have to be differences forever! See the MODIFICATIONS section of this FAQ for info on incorporating 9C1 options into your Impala. EXTERNAL/CHASSIS Besides the obvious external differences such as wheels and tires, grille and trim, and badges, the Police Package Caprice (9C1) is different from the Impala in many ways.While the frames of the Impala and 9C1 are both made from a larger gauge metal than that found on the standard Caprice, the suspension is firmer on the Police Caprice. The springs are heavier and more firm on the 9C1. The 9C1 gets a non-posi rear end of the same 3.08 ratio as the Impala.
INTERNAL/MECHANICAL The 9C1 has an external oil cooler in front of the radiator in addition to a power steering fluid cooler.
The 9C1 Caprice has the green silicone lifetime "superhoses" instead of the black normal hoses for the heater and cooling hoses under the hood. The oil gage in the 9C1 is a "real read" gage and the sending unit on the block sends the actual oil pressure readings to the gage. The stock Impala has a resistor set up which essentially causes a false "always good" reading. It essentially makes the Impala oil pressure gage, an idiot light.
INTERIOR/GADGETS
The interior is not leather in the 9C1, and the floor mats on the 9C1 are usually rubber. The 9C1 also gets a rubber trunk mat, and a "fuel bib" on the rear license plate. The truck popper for the 9C1 is located where the cigarette lighter is on the Impala. The lighter is then located inside the ash tray. The 9C1 has a dash panel light kill, to turn off the speedo and dash lights when the car is blacked out at night. (To prevent the cops from being blinded while they're sneaking around.) The 9C1
driver's door can be unlocked by pulling open the door latch, unlike the Impala. The dome lights do not activate when the driver's side door is opened on the 9C1. The 9C1 is available with a full eads Up Display, Night Vision Camera system, which projects images onto the combined glass display on the windshield. A must have item at around $17,000. Imagine taking that cool country road, no headlights, at night, at 60 mph.
17.Listings of magazine articles on the Impala SS.
Chevy High Performance: Aug, 1994, pp. 112, "New Wheels: Impala SS"
Autoweek: June 13, 1994, pp. 30, "Call of the Wild"
Road and Track: July, 1994, pp. 60, "Chevrolet Impala SS"
Motor Trend: June, 1994, pp. 37, "Chevrolet Impala SS"
Car and Driver: June, 1994, pp. 95, "Chevrolet Impala SS"
Autoweek: Oct 31, 1994, "American Iron", special Impala SS issue
Car Craft: March, 1995, pp.80, "Heavy Metal II", Vortech and Borla install
Chevy High Performance: June, 1994, "Chevy Thunder Insert: Impala SS Returns"
Chevy High Performance: December, 1994, "Chevy Thunder Insert: Super SS"
Car Craft: Nov, 1994, pp. 94, "Real Factory Muscle"
Chevy High Performance: January, 1995, Special Impala SS Issue
Car Craft, April, 1995, pp. 80, "Heavy Metal Lives!"
18.What do the numbers in the Vehicle Identification Number mean, and how can I decode them?
Position 1: Nation of Origin (1 = United States)
Position 2: Manufacturer (G = General Motors)
Position 3: Make (1 = Chevrolet Division)
Position 4-5: Carline
(1994: BN = Caprice Classic LS/Impala SS Sedan)
(1995: BL = Caprice Classic Sedan/Wagon, Impala SS Sedan)
Position 6: Body Style (5 = Four door sedan)
Position 7: Restraint code
(2 = manual belts w/ driver and passenger inflatable restraints)
Position 8: Engine code (P = 5.7L LT1 V-8, SPFI)
Position 9: Check digit position 39
Position 10: Model year (R = 1994, S = 1995, T = 1996)
Position 11: Plant code (R = Arlington, Texas)
Position 12-17: Plant sequence number.
100001 = 1st vehicle
200001 = 100001st vehicle, etc.
A derivative of the VIN is also stamped on the engine and
transmission. This stamping is 9 characters long:
1SR164896
Position 1: Division (1 = Chevrolet)
Position 2: Model year (R = 1994, S = 1995, T = 1996)
Position 3: Plant code (R = Arlington, Texas)
Position 4-9: Plant sequence number (from the VIN)
19.What can I do to help?
You can join the listserve, share your Impala experiences, report on your modifications, email me at
dhardy@crl.comwith suggestions, additions, corrections, insults, and help spread the word about
this really fine car!
This site was written and compiled by:
DAVE of SuperDave Engineering (TM) | dhardy@crl.com
"We make stuff...so you don't have to."