What to check on a used turbocharged engine?

August 4, 2011 11:48 AM

What should I look for in a used car with a turbocharged engine? Saab 9-5 2.3T.

I'm shopping around for used cars and I've found an automatic 2003 Saab 9-5 with the 2.3 liter turbocharged engine. If I recall correctly, turbocharged engines need extra care. What specifically should I be checking out to see if it is in good working condition? If/when I go to check out the car, I will most likely have it checked by a mechanic, but I wanted a friend of mine to see if it is worth checking first, and would like to tell him what to look for.

They're asking 5500 for 92k miles with automatic transmission.

posted by czytm to travel & transportation (7 answers total)

As with any engine the single most important thing to look for is religiously frequent oil changes. For that matter a religious devotion to all maintenance. Ideally the 9-5 will have been looked after by the dealer (or other reputable service center) from new and the mechanic will have provided records which will in turn have been saved by the owner. But that usually doesn't happen. Is it a one-owner car? That's a better bet than a multi-owner car, but in any event make the owner convince you that that it has been serviced religiously. Ask to see the car's service book or service records. If the owner's face drops and he stalls, then its probably worth walking away.

Regarding turbo-charged cars...
The turbos themselves are usually well engineered and manufactured for their job. Moreover the car will be fitted with a boost pressure limiting device that will prevent the turbo from delivering too much pressurized air to the engine. Sometimes these are circumvented with a "boy-racer" chip (a different engine computer that allows higher boost pressure from the engine) But I don't think the 9-5 is a big boy-racer car (but I might be wrong).

I've never owned this generation of Saab, but I have owned several classic Saabs (all turbocharged) and they were all fantastic cars. I even had a "boy-racer" chip in one and it ran to well over 175,000 miles (when the odometer failed).

One final comment regarding turbo engines...They do prefer to run on higher octane gas which is going to cost you more. They will normally perform fine on 89 or 92 octane, but if you like to drive hard and get the most out of the turbo then you'll want to plump for the 95 or 98 octane, which could add up. You might want to check around on a Saab owner's forum to see if people recommend spending the extra for high octane.
posted by pandabearjohnson at 12:09 PM on August 4, 2011

Just FYI, that engine was known for oil sludging.
posted by M.C. Lo-Carb! at 12:12 PM on August 4, 2011

Here is the Saab Central website 9-5 forum. I'd suggest its worth an hour of your time to look it over (even if you aren't very technically minded). You'll get a few ideas about what to look for and what to expect.
posted by pandabearjohnson at 12:22 PM on August 4, 2011

Be warned. 2003 is an infamous year for Saab models. It was the first year of a major remodeling, overseen by GM cost-cutters. Do your research carefully.
posted by chicxulub at 3:16 PM on August 4, 2011

In my mind, the absolute minimum checks for a turbo engine vehicle for a pre-sale inspection at nearly 100K miles, are a complete compression check, an electronic engine diagnostic with emissions tailpipe probe, a reading of OBD-II error code history, a thorough visual inspection for coolant and oil leaks around gaskets, and careful check of the exhaust system/turbo plumbing, and of the radiator/cooling system. Prepare to spend about $500 on inspection, and get someone with real knowledge of Saabs, and the time and necessary equipment to do it.

If the engine has been steam cleaned, or the engine bay is too clean to be believable in a 9 year old car, walk away, without further question. If the exhaust manifold/turbo/turbo plumbing/intercooler/cooling system radiator seem newer than the rest of the engine, it had better be extensively documented in the service records. A mechanic's stethoscope is helpful in rough checking a turbo for exhaust system issues, turbo bearing noise, etc.
posted by paulsc at 3:27 PM on August 4, 2011

Seconding paulsc. Compression check on EVERY cylinder. Run the codes, and emissions. Check for any oil leaks at mating joints. Any competent mechanic can do this in thirty minutes or less. But a Saab guru will be priceless and will know and check other things beyond the basic.

FWIW: I run my Turbo Swede (Volvo 940 Turbo) on 89 (US) gas and have no issues with pinging or rough running. It's worth the thirty seconds and awkwardness to ask the owner what grade gas they run, if it's 87 or they don't know, that's a red flag. More compression (almost) always needs higher octane gas. This is not a hard and fast rule, but one trick I use to size up the care the previous owner has taken of any car. Another trick is to see if there's an oil sticker on the windshield of the car, if so, it's a sign the owner is at least somewhat competent about getting fluids checked and basic maintenance, etc. No sticker? Ask what type, how much and grade of oil they run. If they're a shade tree guy they'll know right off the bat. Blank looks and stammered answers means they don't know or care. Scary stuff.

Now: a general checklist.

For you and your shade tree shopping pleasure do this: Walk around it. Notice any dents, scrapes or general weirdness and the condition of the tires. Cracks and dents are bad, anywhere. None of this is a deal-killer but be prepared to negotiate down $200 for each visible blemish in the body, $500 for any crack in the tires. Pop the hood and look at coolant and oil before you even get into the car, if the coolant isn't minty green and the oil seems at all milky or cloudy, run, don't walk. Next: pull the trans fluid stick, and look for pink and smell for sweet. Dark and burnt smelling equals failure and tears. Lastly, start it, having checked that the engine is indeed cold (you were just under the hood, right?) if you see any smoke, make an excuse and leave ("I left my socks in the dryer and my cat is calling me so I gotta go." Have no shame on this point.) Next sit in the seat, make sure the electrics still work and the car stars up without coughing and stuttering. Then drop it in into gear and check for any hesitation or idling issues in reverse or drive. Hit the road and brake and and accelerate hard with your hands off the wheel, note any deviation from a straight line, this is like the Apostle Paul's admonishment to the Corinthians: Any deviation is the way to damnation, and any wavering is merely the precursor to a fall. If after all that you still want it, take it to a mech and let him (or her) sort out the various frailties. When (and it'll always be when, not if) s/he finds other issues with the car, decide what you're willing to put up with. For me, I'm willing to tolerate shoddy interiors and beat bodies, but a transmission issue will make me run far and fast away. But I'm a shade-tree guy and not afraid/ill-equipped to tackle suspension and engine work. Always under-estimate your abilities, if your car isn't a hobby (like my turbocharged volvo) and is required to get you to work on a hot August day (which my volvo also is, but that's my problem, not yours...). Because as boring as work may be, it's making money and it's time not spent under your car spending money to get to work the next day.

This isn't an exhaustive guide, and it's not meant to take the place of real, professional advice from a certified mechanic, but is just enough to get you into trouble. Good luck.
posted by 1f2frfbf at 9:37 PM on August 4, 2011 [3 favorites]

I wouldn't buy a used car with a turbo unless the inspection came back perfect.

The engine will not take advantage of any octane higher than it is designed for. If the owner's manual says 87 octane is good enough, then it is.
posted by twblalock at 11:27 PM on August 4, 2011