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Toyota Prius Engine Problems



  • pathstar1pathstar1 Posts: 1,015
    "Back in the day" when slick 50 actually added Teflon, it did work wonders. I added it to a Subaru (the old push-rod flat four). Before adding I needed a wrench to turn the engine when adjusting the valves, after I could do it by hand. Slick 50 were forced to change their formula. I heard via the grapevine they were cut off from using Teflon. I tried it once after the change and it did nothing (to another vehicle).

    Just use Mobil 1, which is a good synthetic oil, or if you're really enthusiastic, try Royal Purple. I think it's the "better" type of synthetic. From reading several forums it appears use of synthetic will not result in measurable fuel economy increases in the Prius. Perhaps any improvement is buried in the "noise" of background variations. ;)
  • acdiiacdii Posts: 753
    True, no increase for MPG will be seen with Mobil 1 in the Prius, and you really wont see any in any other car for that matter, this isnt the reason to use a synthetic. The true purpose of a syn is much better protection than any dino oil. Over time Dino breaks down in all factors, additive packaged, lubricity, holding suspension etc. Synthetics can last much longer in Lubricity and suspension, two key factors in the use of oil. Lubricity to keep the parts free moving, and suspension to carry the waste particle of combustion to the filter where it is removed. In addition, the additive packages last longer due to the properties of the synthetic blends. The additives help bind to the metal parts, adding to their life span. Zinc is one of them, ZInc is a babbit material on bearings, and having zinc in the oil helps deter from the wear(at least that was how it was explained to me in class, ASE Cert) that occurs. With Dino, the lubricity goes away after time, due to the compressions the molecules go through with each rev of the crank, Synthetics have more resistance to breaking down from compression. What Mobil 1 can do for the prius is extend the oil life from 5000 miles to 10000 miles with just a filter change at 5000 and topping off the oil. Some guys who have diesels have a bypass filtration system installed and change their oil every 15-25K miles with nothing my oil changes every 5K miles and topping off the oil. Big savings when you have 4 gallons of oil to change out, but not realy that much with the prius.
  • pathstar1pathstar1 Posts: 1,015
    Well, actually my 2001 Pathfinder has a 10% increase in fuel economy with Mobil 1. Perhaps it only shows up on larger less fuel efficient engines. The increase in fuel economy pays back the extra cost of the oil three times over in the 6000 km change intervals (stock recommended change intervals). I will not extend the change intervals.

    Don't get me started on the silly "fuel efficient" oils (5W30) the Pathfinder came with new. Warm engine, idling, I hear rumbling (oil film breakdown - crankshaft touches bearings). Never heard it again once I switched to 10W30 (proper viscosity) oil. Sometimes people think too hard.
  • acdiiacdii Posts: 753
    There is a reason manufacturers are recommending the lighter weight oils these days. It helps them meet CARB specifications, that basically is the only reason. Engines have tighter tolerences today as well, so lighter oils work better in the newer engines, but is not needed. One thing to be aware of with Synthetics, dont use them in an old engine with 100K on it, or you might find yourself burning oil when you didnt before. Synthetics have tremendous cleaning powers, probably the reason you saw an increase in MPG. WHen you put this in an old engine, the carbon deposits behind the rings will dissolve, loosening the rings and giving them a larger gap, then you start to burn oil. Newer managed engines will less likely have this problem with lots of miles on them, but can still have similiar results, just depends on how well the engine was maintained and how it was driven.
  • pathstar1pathstar1 Posts: 1,015
    I doubt it was carbon on the rings in the case of the Pathfinder. It was the third oil change from new (18,000 km). On the first oil change I went to Penzoil 10W30 (fixed the rumble when hot and idling - in fact I did the first change because of that 500 km early when I first noticed it). Used the same oil on the second. On the third went to Mobil 1 10W30 to see what all the fuss was about synthetic (this was back in 2001 - yeah, I'm slow to adopt "bandwagon" things) ;). Saw the 10% improvement, and it has remained at the improved fuel consumption rate ever since (I stuck to Mobil 1 10W30). I keep detailed records. ;)

    I've also seen (heard) the viscosity breakdown rumble on other vehicles using 5W30 oil (non-synthetic). Only when the engine is hot and idling. Scary stuff hearing the bearings loose material! With the other vehicles it happened a long way from home and I couldn't do anything about it right away except raise the idle. With the Pathfinder it happened in my garage, and I changed the oil right then!
  • acdiiacdii Posts: 753
    In your case, no, carbon build up is not an issue, the carbon issue is on older engines, especially pre fuel-injected engines. In your case though I bet it was a number of factors that showed your increased fuel economy, the first being you hit the magic mark where all the parts are working in harmony. The second being the better lubricity of the Mobil 1. Your tires may have also hit their mark where the wear patterns on them give them the least rolling resistance. Some happen right away, others take some time to wear in.
  • Mobil 1 0w-20 is what I use in my Ford. They want 5w-20, and this is an official substitute. Have been using Mobil 1 since '86 - no problemo.
    Never fold a wet soft top, don't leave it out in the intense sun ( Texas ), and do not use unapproved cleaners/detergents. Ford has a list of approved products.
  • stevedebistevedebi LAPosts: 3,788
    "So - any ideas out there? I doubt that it was ice (we do live in Minnesota - but haven't seen that much ice). Was it a software glitch?"

    The early 2nd Gen had a software problem that sometimes caused people to be stranded. It was fixed, but maybe your model doesn't have the fix?

    I started a thread a couple of years ago for Prius Software errors; the thread is closed but you can still view it.
  • stevegoldstevegold Posts: 185
    I'm stuck in front of my house. All dash lights come on including the big red triangle and the car/lock icon but the ready light is not on and the car won't go.
    If I power off, the P,B,D,R cluster stays on, without the READY light, as does the big screen which displays "CAUTION - Transmission "P" lock mechanism is abnormal. Park in a flat place and apply brake."
  • pathstar1pathstar1 Posts: 1,015
    Sounds like the parking pawl is jammed. It it on a hill? If so, apply some force against the hill (push the car up the hill, apply parking brake) and try again.
  • stevegoldstevegold Posts: 185
    I couldn't do anything in the dark last night so I purposely left the lights on to fully discharge the small battery. This morning, I jumped the small battery, using the easy to get at terminal under the front hood. It started right up like normal. (It probably re booted the various micro processors.) I will have Toyota check the error codes later this week.
    If it didn't start this morning, I was going to disconnect the battery (in the back, right side) to force a re boot. I think because I let the battery run out, that wasn't necessary this time.
    This could have been a major problem if my wife was using the car and/or was out of town.
    I will downgrade my Prius from the best car I've ever owned to just OK because of this. (unless Toyota has a good explanation or there was a service bulletin that I did not take care of.
  • chadxchadx Posts: 153
    Just a clarifying are talking about two oils of the same operating weight. 30 weight. The fact that one is a 5w and the other a 10w contributes nothing to their breakdown (at least not in the length of time oils are normally used in an engine). All engines can only benefit from using the lowest winter weight available. Meaning the first number in the name. 0w-30, 5w-30, and 10w30 in a good synthetic oil like mobil 1 all perform the same at operating temperature (like a 30 weight). The first number is how it acts when at room temperature. And then, the lower the number the better because it will flow through your engine faster on startup (in both hot and cold weather).

    A 5w-30 (vs. 10w-30) oil will not make an engine have knocks or other oil starvation sounds on startup. Just the opposite. You are more likely to hear that from the heavier oils because your oil pump can't pump the thicker oil as easily to your engine components. Use a good synethetic oil of the lightest weight your vehicles owners manual recommends. That is usually a 0w or 5w. I don't know of any modern engines that recommend a 10w although they can be run in hot weather. It's just not nice for your poor engine to have to try and pump that 10w on a 32 degree day. Do your Pathfinder and change to 5w-30 (or even 0w-30) in your preferred synthetic. Easier on the engine that 10w-30, even in hot weather, but especially in anything less than 50 degrees.

    On a note unrelated to viscosity or weight. another reason synthetic is better because it leaves a film on internal parts, after shut-down, longer than conventional oils, so it is easier on an engine at startup (which is when, arguably, all engine wear occurs).

    Though some drivinge mileage increase may be apparent in certain engines, most of the mileage gains are from the time of first startup and then the miles put on until the engine warms up. This is also why, in many vehicles, the mileage improvements, when using a synthetic vs. conventional oil, are higher or more noticable in the winter time. Of course the biggest mileage killer in the winter time is people idling their cars for 15 minutes before they leave. Park your car in your garage (rather than having it full of junk) and think how much gas the country would save every winter day! hehe.
  • pathstar1pathstar1 Posts: 1,015
    Actually, you are correct in theory, but in practice, with non-synthetic oils, breakdown of the oil film did occur with 5W30 in the Pathfinder and a previous Landcruiser. Once I switched to 10W30 -standard- oil (non-synthetic) film breakdown did not occur. This film breakdown never occurred at startup, only when the engine was hot and idling. A rough rumbling/grinding sound that would start after a few seconds of idling.

    I currently use 5W30 in my Prius and don't see any evidence of breakdown, but I'm using Mobil 1.
  • You can sense my outrage. Traded in my completely reliable 2000 Honda Civic for a more responsible Prius and now it won't start after a measly 6,000 miles.

    All the dash lights go on, including the check engine (I got an oil change etc at the recommended 5,000 miles) and nothing happens. Had it towed and of course did not hear from the dealership all day.

    I'm sorry I didn't buy another Honda. What I want is reliability AND responsibility.
  • Sorry to hear about your problem. Kindly post what happens here when it's finally fixed. I have had 2 or 3 similar experiences but was able to get them cleared myself without being towed but not without a lot of stress.
  • On a recent trip to Mammoth Lakes the car drove well but when I came out next morning, the engine would not run after an initial 15-20 seconds. Trouble lights came on. If I accelerated in the initial start period it would continue to run but lights stayed in alarm. This continued and engine would not operate properly. The next morning I decided to take it to Bishop, the nearest dealer and wait until they opened Monday morning. 15 miles down the hill, it began to operate correctly and has not had another problem. Is it sensitive to the cold or perhaps altitude?
  • Hi, I was at 7,000 feet in about 20 degree weather with my 2002 prius and all the emergency lights went on and the gas engine wouldn't kick in. I had it towed back to Berkeley, at sea level and 60 degrees, and the next morning it started right up. The dealer replaced some electronics because a code had been tripped, but I don't have a lot of confidence to return to the mountains. Any one had a similar problem, or a suggestion. thanks.
  • mm517amm517a Posts: 3
    After turning on my 2002 Prius, 4 warning lights came on although the engne was running. I looked in the manual and it said to take to a Toyota dealer. The lights did not go off for a distance of 5-10 miles. I was told that they need to replace the start relay motor. Has anyone else had this problem and does this sound reasonable at a cost of $230 for parts & labor?
  • kimfckimfc Posts: 1
    2004 Prius has started making a sreechy noise only when the gas engine is running. Maybe a belt or bearing? It seems too soon for these parts to be going. Any ideas?
  • I have a 2008 Prius with about 5200 miles. At times when the brakes were applied I had the sensation that the car accelerated. When I took the car in for initial service they could not duplicate the problem. I don't know if it is a coincidence but 2 weeks later my car would not start. When the power button was pushed the information screen came up but the car did not turn on. If I held the power button down for a 2nd time the warning lights came up for brakes, check engine, etc. The car would only shift into neutral. I started over several times but could not get the engine to start and it was towed to the dealer. I am awaiting a response, but if anyone has a similar problem I would appreciate your feedback. Really concerned !!!
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