I have a 05 chevy z71 with 5.3 and 119,000 miles between oil changes I have had to put in 5 quarts of oil. it isnt leaking and no loss of power what could it be

Oil being a quart low is not the problem. 160,000 miles is the problem. Give it up!

Check your oil pan, did you run over something? That many quarts of oil has to be leaking from somewhere. Headgasket blown would likely show as water mixing with engine oil(no loss of water would likely remove likelihood of blown headgasket).

If there is oil in water, then there may be a head gasket leak. However, half a quart of oil loss every 15,000 mi. is not bad. If van runs perfectly, then I wouldn't worry too much about it. Maybe try some Bar's Leaks Head Gasket Repair for $30 or so to fix the slow leak in the coolant system.

could just need a simple oil change, an depending on how many miles are on this engine it could just be over worked. the 5.7 350s that came in these trucks ran forever but unfortunatly would start burning oil an have a loss of power

My 1993 voyager is like that. It may burn some , it definitely leaks some , and it could be just sending some through the PCV valve. Oil leaks and burning oil causes pollution . If you can fix it with a new seal or a valve cover gasket it is easier than constantly checking your oil. Temperature, trailering, speed, outdoor temperature, and engine RPM all can be factors if you are losing oil. If your engine is a quart down, the engine oil consumption rate doubles or triples. In other words the lower the oil level the faster it disappears. High mile cars will drive for years as long as you add oil when it is needed (keep the oil level between the marks). Fix any obvious leaks. Then determine your oil change interval (3000 miles, 4000 miles, 5000 miles). I change between 4000 and 5000 miles. If i am a quart low at 3500 I add a quart. If I am a quart low at 4500 miles I just change the oil in the car. A good practice is to carry a quart of oil in your vehicle just in case you need it. It is far cheaper to add a quart when needed than to go to the dealer once to maybe fix a problem that they may not be able to find or fix. Older engines (even some newer ones) just use oil , especially in hotter climates. Fix the obvious and carry a quart.

valve cover, intake manifold, front crank seal,timing cover, a quart per 1000 miles isnt a small leak.

if you are using a quart of oil every 1000miles,that is NORMAL FOR A MODERN ENGINE.thats why they last so much longer than the old technology.you could try 20/50 oil when you next change as that will help.but worry when it gets to pint every 350 miles.

Have you tried running conventional oil and see how much it burns? If it is truely burning that much oil, you have a problem with the rings not seating, or PCV system sucking in too much oil. If it doesn't burn that much with conventional oil, I would stick with that. If it does, you have a bad motor issue.

Add enough oil to get the stick reading back to the full line. Oil can't disappear...so either you are burning it or leaking . If you used more than two quarts in 400 miles, if it's burning it it definitely should be fouling plugs and smoking. If leaking, there has to be wet oil under the engine somewhere. Check everything over again to verify either condition.

how much oil is loosing? a lot or just a little be? because belive it or not a little oil losse is normal on engines but not a lot.