Leave it to a traveling salesman to come up with an innovation that would irrevocably shape the 20th century.
Nikolaus Otto, purveyor of teas and kitchenware, got around to building the first practical four-stroke internal combustion engine, dubbed the “Otto Cycle Engine.”
His working model demonstrated that a four-stroke design could work reliably in an engine compact enough to power a motorcycle and, eventually, an automobile.
His motor, introduced in 1876 as the first genuine alternative to the steam engine, remains the basis of today’s high-performance, low-emissions engines. Some 134 years of development and refinement have made our contemporary engines technological marvels – but mistakes can happen.
There are at least eight mass-produced engines today that have caused owners a lot of anguish, according to their grievance reports on the Internet.
If you’re looking for a used vehicle, think twice before you buy one powered by any of these. Old Nikolaus would not have put his name to this lot.
Chrysler 2.7 L V6
The small but powerful 2.7 L V6 commonly found in the 2004 and older Chrysler Intrepid, Concorde, LHS and Sebring/Stratus models is notorious for oil sludge formation.
Motor oil would collect and cook in the engine’s tight passages, forming sludge and constricting circulation. Eventually, the engine would seize due to oil starvation.
Then there’s the water pump that was incorporated inside the engine. The pump’s shaft seal had a reputation for failing at the 100,000-km threshold and barfing a large quantity of coolant into the crankcase. The resulting chocolate milk mixture is a sure sign of exorbitant bills to come.
Chrysler made some design changes in later engines, but anyone with this lump under their hood should monitor oil level frequently and perform oil changes religiously.
Audi/VW 1.8T Four Cylinder Turbo
The 1.8 L turbo four cylinder from Volkswagen was found in almost everything the carmaker sold at one time, plus some models of Audi, including the A4 and TT coupe.
Unfortunately, the engine is a rolling disaster with sludge formation being a real threat.
Apparently, Audi/VW may not have informed owners that the engine required synthetic oil, so owners (and dealers) proceeded to use conventional oil after the break-in period. The usual coke/sludge issues appeared and engines failed in considerable numbers. Models from 1997 to 2004 are affected – essentially any car wearing the 1.8T badge.
Add to this high oil consumption and frequent coil pack failures – one coil pack sits atop each cylinder and serves as the ignition coil firing the spark plug – and you’ve got one troublesome motor.
Way to go, German engineering.
Toyota 3.0 L V6
Toyota’s 3.0 L V-6 is prone to clotting with oil sludge and seizing up in 1997-2002 models with this engine, although Toyota is apt to blame owners for not changing the oil often enough or for using the wrong oil.
Many experts disagree, suggesting a defect in the breathing or circulation system is the likely culprit.
The affected models include V6 models of the 1997-2002 Toyota Camry, Avalon, Sienna, Highlander and Solara. The Lexus ES300 and RX300 used the same ill-fated 3.0 L V6. After 2002, Toyota made some improvements that appeared to solve the problem.
Toyota settled a class-action lawsuit in 2007 that covered an estimated 2.5 million Toyota and Lexus models made between 1997 and 2002 susceptible to engine sludge. The automaker agreed to repair sludged engines for up to eight years after leaving the factory.
General Motors 3.1 and 3.4 L V6
GM’s 3100 and 3400 V6 engines were too clever by half, built with a composite intake gasket and new, long-life, Dex-Cool antifreeze. Original formula Dex-Cool reacted with the nylon/silicone gasket material, eating a hole between a coolant passage and oil drain, allowing the engine to fill rapidly with coolant. The result was a seized engine.
The defect affected numerous GM models made between 1995 and 2003.5. GM eventually caved in to the lawsuits and announced a settlement that specified the replacement of the lower intake gasket within seven years or 150,000 miles of the date of initial delivery.
Technicians have noted that once the faulty gasket is replaced with a steel carrier-type gasket, these engines can rack up 300,000 km and more with no problems.
But orange Dex-Cool has been blamed for other costly repairs, including corroded cooling-system components.
Saab 2.0 and 2.3 L Four Cylinder Turbo
Saab has extended warranties on its turbo engines made from 1999 to 2002 due to a nasty oil sludge problem. The poorly thought-out service recommendation for 16,000-km oil changes, using conventional motor oil or semi-synthetics, has ruined many four-cylinder Saab motors.
Sludge and coke (carbon) buildup on the very fine oil pickup screen in the oil sump can starve the engine of oil, resulting in complete engine failure. Experts suggest this may be due to the catalytic converter being mounted below the sump, cooking the oil at high temperature.
Currently, Saab recommends removal of the sump and doing a complete cleaning. That’s if the engine is still running. Then there’s direct-ignition cassette failures and cylinder-head gasket leaks to contend with.
Affected models include the 2000-03 Saab 9-3 and 1999-2003 Saab 9-5.
Nissan 2.5 L Four Cylinder
The pre-catalytic converter built into the exhaust manifold of Nissan’s 2.5 L four cylinder engine can reportedly disintegrate as it ages. The ceramic material gets sucked back into the motor, causing increased oil and coolant consumption and, eventually, engine self-annihilation.
It’s a big problem among 2002 and 2003 2.5 L four-cylinder Altimas, as well as Sentras with the same motor. Then came word Altimas and Sentra SE-Rs equipped with the same engine built between January and May 2006 may experience unusually high oil consumption. This can lead to premature engine failure and possibly a fire.
Owners of any 2.5 L Nissan engine are advised to check their engine oil level frequently. This motor also reportedly loves to ingest the screws from the butterfly valves in the intake runners, another hazard that can score the cylinder walls.
Ford “Modular” 4.6/5.4/6.8 L Engines
Two-valve 4.6 L and 5.4 L V8, and 6.8 L V10 engines found in many 1997-2004 Ford, Mercury and Lincoln vehicles have an issue with stripped or missing spark plug threads in the cylinder heads.
Owners have reported spark plugs blowing out of their engines and, in one instance, right through the hood (!).
Ford acknowledges this issue in TSB 07-21-2. Ford’s authorized repair procedure for out-of-warranty vehicles prescribes an aluminum insert and tool kit. Reportedly, the 5.4 L “Triton” truck engine is the worst.
The opposite problem may also appear. Found in many 2004-2008 models with the same size engines (but with three valves per cylinder), a unique spark plug design with a two-piece shell has been known to separate, leaving the lower portion stuck deep in the motor. Ford distributes special tools for removing the seized plugs. Repairs can be surprisingly expensive – and frustrating.
Mazda “Renesis” 1.3 L Rotary
For all its renowned simplicity and performance, Mazda’s lightweight, new-generation “Renesis” 1.3 L rotary engine has displayed a number of teething problems since its debut in the 2004 Mazda RX-8.
It has a voracious appetite for motor oil; 2004 and 2005 RX-8s, along with some 2006s, may sustain damage to the catalytic converter due to oil migrating downstream.
Without copious oil, the engine’s apex seals can wear prematurely, resulting in lower compression and requiring an engine rebuild at a relatively early age.
The RX-8’s battery and starter are reputed to fail in cold climates. Owners have also been frustrated by the motor’s propensity to flood if it is started and shut off in a brief period, such as during a parking manoeuvre.