As for those problems, if you want a Catera shop carefully. Within days of buying mine, in November 2006 at 48,000 miles, I had to have the Heater Bypass Valve replaced after it puked most of the engine's coolant. I didn't do my homework. Had I known about the Catera's inherent problems I'd have had the dealer inspect and replace it prior to my taking possession. I saw a pretty car at a great price. A German Sport Sedan in Cadillac trim. I later had the leaking camcover gaskets replaced. The crankcase breather was clogged which increased internal pressure, forcing oil past the gaskets and onto the exhaust heatshields where it smoldered. Two years later the Crankshaft Position Sensor (CPS) failed and left me stranded. AAA to the rescue. The '97 - '98 Cats had the most problems. Some were addressed, but not necessarily cured, in '99. The 2000 - 2001 models are less trouble prone but not perfect. When you find a Catera that looks good on the outside, here's what to look for on the inside.
• Have Cadillac check the VIN for the cam-belt tensioner bulletin #02041A. This is critical. If the tensioner seizes the belt will break and the pistons will bend the valves. All 24 of them. This service must be done every 5 years/50,000 miles or sooner.
• Replace the Crankshaft Position Sensor (CPS). If it fails your Catera will stall and not restart until the sensor cools. Eventually it will quit altogether and strand you. Located near the oil filter, it's easy to replace and fairly inexpensive for a Cadillac part.
• Check the engine oil for coolant contamination. It will appear as a cream colored emulsion residue under the oil filler cap and maybe the dipstick. Wipe it off and drive the car at operating temp for 30 minutes. If it doesn't reappear it was probably normal water condensation and boiled off. If it reappears it could be antifreeze in the oil. Another indicator is oil in the coolant reservoir. They all indicate the oil cooler is leaking and needs replacement. Left alone it will burn your engine's bearings and clog the radiator and heater core. A laborious but relatively cheap repair (for a Cadillac) if you do it yourself. Improved coolers were introduced in '99.
• With the engine running, check the coolant tank for bubbles or an exhaust smell. That's probably a blown head gasket. It's not that common but does happen. We suspect worn out coolant is to blame. Acids in the coolant attack the gaskets.
• Have the Heater Bypass Valve (HBV) behind the engine replaced. It's not expensive as Cadillac parts go and the labor is DIY easy. If you wait and it leaks it will puke all your coolant, the engine will overheat, and the aluminum heads will warp. The spilled coolant can also damage the DIS ignition pack on the '97-'98s.
• The cam cover gaskets can leak and drip oil on the exhaust heatshields and create smoke. Cleaning the crankcase breather relieves the excess crankcase pressure that blows oil past the gaskets so you must clean it out. This is very expensive if you let Cadillac do it. They charged me $750 including the gaskets. Order the gaskets and have a trusted local garage do the work or DIY.
• Check for tire wear front & rear. Cupping or feathered edges indicates worn/split front & rear control arm suspension bushings. OEM replacement bushings are available as well as some polyurethane substitutes. New front suspension arms come with the stock bushings and ball joints already installed so that's an option too. Whichever fix you choose you'll need a wheel alignment. There's an aftermarket eccentric bolt available that will extend the front camber adjustment's range by +/- 2 degrees over stock to help bring it to where the tires wear more evenly. Eccentric rear suspension bushings for the Pontiac GTO, G8, or Opel/Vauxhall Omega, adjustable for camber and toe-in, will do the same for those tires.
There are other things like weak door stays, cracked brake light switches, EBTCM failure, cracked radiator end caps, and HVAC control malfunctions. Search the forums for more info. Most irritating are the computer gliches and sensor failures which leave you stalled and stranded. Given the level of electronics in cars today and the harsh environment they operate in I doubt the Catera is worse than other cars. A failure is never an easy thing to endure but this is the 21st century and electronic controls are here to stay. Thanks to the database, on this and other Catera/Omega sites, information is available and you can go to your chosen service facility armed with knowledge.
My car has suffered the HBV, CPS, radiator leak, and EBTCM failures. I did have the timing belt & tensioner replaced plus the serpentine belt and its tensioner. The lower control arms were rebuilt swapping their front/horizontal bushings for polyurethane ones, as well as new rear/vertical bushings and ball joints. The front anti-sway-bar received polyurethane bushings too plus new anti-sway-bar links. All the cooling system hoses, all filters including the crankcase breather box, all fluids including the differential oil, and the cam cover gaskets were replaced. I haven't had the Transmission fluid changed yet because it shifts so sweet but at the first sign of trouble she'll get new fluid and a fresh filter. UPDATE: The transmission refused to shift into 3rd and 4th gears so I had it replaced with a used 4L30E transmission. So far so good.
You'll notice that most those were maintenance items. And that's my point. The Catera has many faults but most are due to lack of proper upkeep. Owners neglect the car's regular maintenance and blame her when something goes wrong. One legitimate design flaw, however, is the robustness of its suspension parts, or lack thereof. European roads tend to be smoother than our pocked and bumpy ones and no allowances were made for them in the Omega's transformation into the Catera. The price we pay is frequent suspension repairs like worn bushings, broken springs, and premature tire replacements. The desire for better and longer lasting suspension bushings drove me to find polyurethane ones. I found them, plus high performance dampers, springs, brakes, and more. I've since swapped my Catera's dampers for Koni Sport struts & shocks. GTO front brakes too.
My Catera Sport now handles like she's on rails, and stops on a dime. Energy wasted scrubbing the tires into black dust by worn suspension bushings is now directed towards speed and handling. I drive her hard like I'm sure many of you do and that's taking a big chance if you don't address past abuse and neglect. Don't forget, these cars are over 10 years old. Most are older. Lots of potential problems waiting to bite us in the A** if the previous owners didn't perform the scheduled maintenance properly and timely. You want a more dependable Catera? Then you'll have to bring her neglected maintenance up to date.