The Chrysler 2.7-liter V6 is a fine engine with some serious issues. If yours is still running, you need to switch to the appropriate oil before the entire assembly seizes up and dies without warning.
All engines utilize internal passages called galleries to ferry oil around the engine. The 2.7-liter engine's oil passages are a little too small and too close to certain hot spots in the engine. This causes oil to cook inside the galleries and turn into sludge in the engine.
Oil sludge by itself can cause any engine's oil passages to clog up and fail, but the 2.7-liter has a pair of complicating factors. The small oil passages will clog far easier than most other engines, but --perhaps more importantly -- the engine's oil pressure sensor is located in one of the few very large galleries that will maintain pressure even as the rest of the engine runs dry. This means that you'll receive no warning whatsoever if your engine loses oil pressure due to sludge.
Before changing the oil, run an oil-flushing solvent through the engine to dissolve built-up sludge. Drive for fifty miles, drain the oil, then replace it with cheap 10W oil and more solvent. Drain and repeat this procedure till the oil comes out fairly clear and free of sludge. Replace your engine oil with a 5W-30 weight, full-synthetic oil.
