A lot of visible smoke after going down a large hill when engine kicks in at end under acceleration. White smoke and seems to be oil like. Odd thing is that it doesn't smoke around town and only after coasting down the mountain. I don't know if anything can be done except an engine rebuild but I thought I'd check. Bad valves? Blow by on the rings? I have replaced the pcv valve thinking it could be a crank case pressure issue but it didn't change anything. 2007 Prius with 170k miles.
Have you checked the coolant level lately? Does the smoke smell or have a bluish tint? If there are no thrown codes (or lights on the dash) it might be time to check the spark plugs for deposits. Has the engine ran low on oil lately (or not be changed very often), if it overheated your head gasket could be going,
1. Check the radiator coolant for the presence of engine oil. 2. Check the engine oil dipstick for the presence of engine coolant. 3. Did the engine overheat at some point in the past due to insufficient coolant or engine oil? 4. Your engine probably has a leaking cylinder head gasket. Usually that fault develops after the engine has overheated. 5. If you decide to take action on this, it probably would be less costly to install a used engine than to try to fix the original engine, assuming that it did overheat and the cylinder head and block are warped.
Both of the 2005's I've driven did this. These engines have blow by. Check your oil often! They run perfectly fine with blow by. It's a slight inconvenience to check your oil, but that's a part of being a car owner. I noticed this a few years ago in my 2005 after coming down a long grade, it actually had me very concerned. But now, here in 2017 that same car is still being driven by my sister at over 300,000. Still uses oil, still puts out a puff of smoke after a long decent. This isn't coolant. Very normal for the 1.5 after a "few" miles.
Thanks everyone for useful info. I've owned for a year and have gone from 130k to 170k. Had spark plugs changed when I got it. I have maintained the car well - the previous owner had all maintenance from Toyota - there was a huge binder with every oil change at 5k on the dot and all other maintenance in the book. So more than likely maintained well. I don't believe it ever had an overheating problem but who knows. Coolant is not leaking or has ever gone down. Does not appear to have oil in coolant or coolant in the oil. It does seem to burn some oil - perhaps 1/2 to 3/4 quart per 2,500 but I'm trying to get a more exact number. Maybe I'll get an oil analysis and perhaps a leak down / compression test and check out spark plugs. I do take out of town sometimes- so maybe I could spot a major issue like partially blown head gasket. If it just blow by oil then I'll just run it. A curiosity question - do these engines generally burn some oil at higher mileages? Just wondering what to expect. I got lucky with my 2005 accord and it has 230,000 and burns no oil.
Yes, I would say it is "normal" to see some engine oil consumption after 100K miles on the odometer. It is not normal to see visible exhaust emissions. Did you look in the engine radiator itself (not just the overflow reservoir)? An engine compression test is an excellent idea to help you assess its mechanical condition.
Do you still have the car? If so, has the problem changed? I have a 2006 with 332,000 miles on it and have noticed the same symptoms for about a year now. I drive down a two-mile grade each morning, and there's usually a puff of smoke for about five seconds. Longer grades cause more smoke.
