Inspecting a Porsche 993 for purchase

A 993 is over 25 years old and some examples are subject to aggressive use, have had modifications, and have known age & use-related issues, so evaluating a purchase candidate before a purchase is a big deal!

Importation: If you plan to purchase a 993 outside of the US and import it for use, here are the importation rules that apply to all our cars that have been manufactured over 25 years ago.

Customs: Importing classic or antique vehicles/cars for personal use.

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Pre-Purchase Inspections (PPI):

I do not put a lot of faith in Pre-Purchase Inspections (PPI) by third parties as they will generally only capture gross mechanical issues and miss most wear-related parts and body condition items. Inspections by any dealer or local servicing shop should be reviewed very carefully as items you would consider expensive service work the shop may consider routine maintenance or minor nuisance items and not worth mentioning. 

The way to minimize these issues is to provide guidance to the inspector on what you would like inspected and not have the inspection done by the selling dealer or in the case of a private sale by the seller’s servicing entity.

Most new car Porsche dealers are no longer familiar with these older cars and therefore do not provide any enhanced inspection simply because they are Porsche dealers. Recently Porsche has developed the Porsche Classic Partner program where certain Porsche USA dealers are certified to service older cars like the 993. These dealers may be better suited to conduct an inspection or simply use an independent shop that specializes in servicing older air-cooled cars.

Defining What the Inspection Covers, The CPO Checklist:

The definition of what a comprehensive inspection is, I suspect, varies quite a bit between inspectors. A good starting point in defining the elements of an inspection might be to use Porsche's own Certified Pre-Owned (CPO) inspection checklist. Using this list and adding to it 993 specific known service issues might be something to specify that your inspector use for his evaluation.


Defining What the Inspection Covers, 993 Specific items:

Below is a beginning list of 993 specific known service issues that can be considered when defining the elements of an inspection.  Not all should dissuade you from considering the car and a seller will rarely lower their asking price by more than 10% no matter what condition problems are discovered. However if one enters ownership with their eyes open as to things that will need to be addressed sooner and later, it is always desirable. After reviewing this blog you may want to add additional items:

• For OBD-II '96 and forward-year cars run the OBDC Codes to verify emission testing READINESS is complete and all the emission-related codes are in a PASS state. This is important as clogged air injectors are a known issue and a seller may be unaware of or is covering up this or other issues by recently clearing the codes. The emission codes in a not-ready state indicate the codes were cleared recently and the system's analysis of Pass/Fail Emission status is not yet finished. When the testing is complete and any of the internal emission tests fail the Check Engine Light (CEL) will illuminate. 

• Here is some more information covering On-Board Diagnostics:
• https://993servicerepair.blogspot.com/2020/02/on-board-diagnostic-codes-obdc-notes.html
• Here is the 1996 forward model year known issue related to emissions
• https://993servicerepair.blogspot.com/2020/02/emission-control-systems-horror-of.html

The reason why checking the On Board Diagnostic (OBD) Readiness Statuses is so important has to do with cost to repair. For example if the code is related to an underperforming catalytic converter the replacement part cost alone can be well over $1000 for a used one or $4600 for a new one. 

 

• Turn the ignition on and check to see that during the initial dash light test that all the warning lights including those in the clock and the central waring light ( ! ) illuminate as sometimes bulbs are removed to hide a malfunction or were removed as part of an undesirable modification to the car. 
• Look for no OBD trouble codes displaying for the HVAC system as failed servomotors in the system are quite common and will throw a code. Also, verify the recirculation flap opens when the Recirculate button is pressed, on Late 1995 Model year forward cars it should make a satisfying "thwack" behind the dash when the button is pressed. More information here
• The AC system should run cold. If not it may simply need a recharge. On some cars, the evaporator is found to be leaking an expensive part, and a labor-intensive process to get to it to replace it. There are improved aftermarket evaporators but seeing that the vast majority of examples are original to the car, have lasted over 26 years, and many over 100k miles of use I would not call it an expected problem. Here is a page that discusses known HVAC issues.
• During the test drive force the anti-lock brake system to trigger as it can be inoperative while reporting no OBD codes. This topic is discussed on this page.
• Check that the odometer is working, also a known issue with failed internal gears.
• You have started the engine from cold after sitting overnight and the hydraulic valve lifters work quietly from the get-go, if not their adjuster cartridges will need to be replaced, they are accessed under the valve covers and do not require opening the engine or removing the engine from the car to replace. Here is a page that discusses noisy hydraulic lifter adjusting cartridges.
• The 6-speed manual shift linkage provides for smooth shifting, if not the nylon parts of the linkage, the engine mounts, or the rubber linkage joint may need to be replaced. Here is a page that discusses the shift linkage.
• The vacuum actuators in the engine compartment and behind the CCU properly test cycle during ignition-on start-up signaling the actuators are working properly and the system is developing and holding a vacuum. This is particularly important for 1996 forward Carreras with the Varioram intake system. The simple test is at the bottom of this page;
• That the car comes with at least two sets of keys and fobs where the fobs are mated to the car and work. If not replacement keys can be gotten at the dealer and fobs can be purchased from https://www.ecudoctors.com/ or IMMO BLOC. IMMO BLOCK also offers an electronic fob that allows a backup fob to be cloned from an existing fob.
• The alarm LEDs in the door sills flash properly, slowly in an even cadence, and not in couplets and all the interior lights extinguish shortly after the doors are closed and go out immediately when the car is locked by using the key fob, otherwise, there is a problem with the alarm/immobilizer that needs to be sorted out;
• Verify the struts are not original to the vehicle as if they are they will need to be replaced. The strut section on this page discusses replacing them.
• Test the low-speed fan setting on the oil cooler and the AC condenser coils. How to test is at the bottom of this page;
• Minimal or no rust under the outer windshield and backlight window seals;
• That the Door check strap mounting points on the "A" pillars do not flex or move and or the doors do not make a popping sound when opened and closed. Fixing this will be an expensive Bodyshop repair. See this page for more detail.
• Check that the factory lift/jacking points are not damaged or collapsed. The front left lift point is a know weak spot. It is important that all 4 points are in good shape otherwise one will not be able to use the emergency jack, or lift bars to lift the car, Lift bars are the preferred lifting method if one doesn't have a 4-point hydraulic car lift because the bars lift the car by the factory specified points and does not introduce twisting forces to the body encountered when lifting one point at a time using individual jack stands. Here is a page discussing my experience getting the lift point repaired on my 993.
• If the engine undertray is in place remove it and look for engine leaks. A tray that has recently been wiped clean is suspect. Clear oil droplets forming on the bottom of a cylinder or engine case suggest potentially a leak big enough so it may drip on the floor or the exhaust causing burned oil odors prompting some for the need for repair. Here is a page with a section discussing oil leaks.
• Engine mounts, sometimes called motor mounts are a known service item on a 993.
  Here is a page that discusses how to test and replace them.
• Engines that have a small amount of oil weeping that has attracted dust and grime to the valve covers or the underside of the engine is to be expected and of no major concern. If an oil leak is big enough to drip from a valve cover it will smell as the oil drips onto the exhaust system. On the plus side if a leak is from the valve covers only, the most common source of a leak, it is an easy inexpensive fix. If the oil is clear and golden in color on the dipstick this suggests a recent oil change and if one finds the right side lower valve cover is wet with oil here are the most likely causes.
• Remove the front underbody cover and look for an established leak on the steering rack. A little oily film is ok and normal on the ends, a puddle on the cover is a sign that the steering rack will need to be rebuilt sometime soon.
• The clutch is firm on a 993 and should actuate smoothly however if excessive force on the clutch peddle is required or the clutch slips with aggressive shifting this suggests the clutch may need replacing soon. I find with careful shifting the clutch will last 60K to 80K miles with less than gentle use a lot less. A clutch that doesn't actuate smoothly may need to have the clutch actuation hydraulics or the peddle cluster serviced. Here is a page with more on this topic,
• If when fully warmed the transmission dings or grinds consistently in any specific gear suggests the transmission will need servicing and some of its synchros replaced. This should only be seen in cars with an excess of 80K miles if the transmission gear lubricant is not replaced regularly. More on this topic here. Be aware a 993 requires that the clutch peddle be pressed all the way to the floor during shifting when evaluating the condition of the transmission, if not it will make grinding noises during shifting even if there is no problems with the transmission. If you have not driven a 993 before it may be helpful to slide the seat a little closer to the dash than you would normally do during the test drive. This tends to facilitate pressing the clutch fully to the floor while shifting.
• Leak-down or other similar tests. I do not put too much faith in these.
• Most 993 at this point have had some modifications. Things such as aftermarket exhaust systems, replacement struts, suspension components or bushings, racing brake pads, calipers, engine modifications, emission system alterations or component removals, and any number of other updates. The ability to modify a 993 is one of its most desirable features however many performance or race-inspired modifications may not be the best for a street-driven car and may be expensive to undo so any inspection should include notes as to what has been updated on the vehicle. It is probably a good idea to ask the seller if they have retained any parts taken off the car when swapping out parts as part of a cabin, audio, or performance upgrade.  Do ask for these parts as part of the car at sale. 
• The "gotcha" section at the bottom of this page includes a list of common and in some cases ill-advised aftermarket modifications done to a 993.

Buying the Private Seller:

Trust, but verify (Russian: Доверяй, но проверяй) is a rhyming Russian proverb. The phrase became known in English after Suzanne Massie, an American scholar, taught it to Ronald Reagan, then President of the United States who subsequently used it on several occasions in his discussions of nuclear disarmament with the Soviet Union.

Some buyers ascribe to a "buy the seller"

approach in lieu of inspecting the vehicle in a private car sale even in some cases buying a car sight unseen. Some buyers use this approach by having a discussion with the seller that gives them the opportunity to size up the seller's forthrightness in their car selling and the diligence with which they have maintained their car for sale. Although I see some value in developing an opinion on this anecdotal information many times even an honest seller doesn't understand the condition of his car. For example, he may have subconsciously adapted his shifting technique to adjust for wear of the clutch, transmission, or shift linkage and is unaware of an issue you will need to address at significant expense after the sale, trust but verify.

Mail-order Brides - Buying online from an online or eBay-based independent dealer requires special handling.

The best solution for any remote buy is to negotiate the price contingent on an inspection and then fly down and look at the car. Let’s face it, buying a twenty-five-year-old plus car without personally inspecting it and driving it around a little is a train wreck in the making. 

For any purchase, if at all possible, look at the car yourself with the help of a friendly local PCA or technical forum member as a ride-with who knows how the car should drive and feel. Making a request through the PCA or one of the 993 Technical Forums such as Rennlist online will usually turn up a resource in the geography where the car is located who will be more than glad to assist you.

CarFax is only as valuable as the facts they have in their system.  Originally it was intended to capture fraud via odometer roll-backs that could misrepresent an end-of-service-life car from one that could have many more miles of service left in it.  Once out of warranty, something that happened a long time ago with a 993, they are generally serviced and repaired by their owners' DIY or by small independent mechanical or boutique body shops.  These sources of repair service almost universally do not report anything on their work to CarFax or anyone CarFax uses as an information source.  Here is a quote I picked up on a car enthusiast website that seems insightful:

• "I am a general sales manager [at Carfax] , Carfax's are only what is reported as public knowledge. Carfax's/Autochecks are primarily used to see titling and mileage history. Accident history is probably less than or around 30% accurate." In other words, 70% of any car body or other major mechanical damage repair on a vehicle is not reported in a Carfax report, and for a 25+ year old  993, the percentage is probably a lot higher.

 

Beyond having a salvage title in its history or the items cited above these reports, I feel, are of little value.

If a CarFax or the seller discloses a repair involving the body and there is any question as to how serious the damage was the owner's insurance company has documents and pictures of the damage also the body shop that did the work provided and has records of their statement of work that was done on the car. The seller should be able to provide these and if unable to or unwilling to do so it should raise a red flag to have a competent body shop review the car and its unibody. If this is not possible and no documentation is offered I would pass on the car.

Keep in mind a private seller should be able to give you a good reason for selling, a dealer can end up with a car for any number of undisclosed reasons, some of which are good reasons to not purchase the car.

 

Validating Suspect Odometer Miles using data

stored in the Motronic ECU

The 993 Motronic ECU, like those in all

electronic fuel-injected Porsche keeps track of running hours on the engine. If the miles on the odometer seem to be inconsistent with the condition of the vehicle and the mile entries reported into CarFax do not provide useful corroboration one way to do an indirect evaluation of usage is to read out the running hours information from the ECU. This is done using an OBD Code Reader that supports seeing this information via the real-time or actual data display function.

More information on such a reader can be found here.

The table to the right was developed from the odometer and running hours information from my car. 

My 993 is my primary daily driver, so it sees mostly surface roads and short sprints on the local highways around town. It also has in excess of 100K miles on the odometer so the table is based on averaging the relationship between miles driven & operating hours over many miles & hours of operation. 

For this reason, the table may be useful in conjunction with other information to arrive at if the odometer miles on a purchase candidate car seem reasonable.

 

Salvage Titles:

Salvage titles can be in the history of a car for a number of reasons unrelated to damage or flood recovery.

• For example, a stolen car claim from an owner where the car was towed from the spot the owner illegally parked it while bar hopping and then makes a stolen loss claim with their insurance company.  Six months later the tow lot owner, wanting their back storage fees, gets in touch with the now-former owner who refers them to the insurance company that now has a car to sell on a salvage title. It is surprising how often stuff like this happens especially way back in the ’90s. So having a salvage title in a car’s history can represent an outstanding value or a nightmare in the making. In such cases try to ascertain why the salvage title was issued before considering one of these cars.

If you found this page informative return to the main page and bookmark it for future 993-related servicing, repair, and upgrading guidance & information. If it saved you some time, aggravation or even some coin consider a donation through the button on the top left margin of this page.