Prius Reliability Statistics - Stay away from the 2004 Prius?

krousdb, I think you ought to consider new spark plugs and a pcv valve. If nothing else, for the adventure of excavating for access to the pcv.

Always interested in the appearance of old prius spark plugs, especially pitting of the ground electrode.

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We can probably all agree that 2001 is the worst NHW11 and 2004 is the worst NHW20. But at the same time, I think that both have shown to be quite reliable and satisfactory vehicles, compared to the rest of the fleet.

 

Doug,
As you know I have a habit of pushing the envelope and the spark plugs and pcv are just a few of many examples. In certain states, the change interval for the plugs is 150k. I would like to wait until 300k to see if there are any ill effects. Have you ever seen spark plugs after 300k in service? Neither have I. I'm sort of looking forward to it.

 

If you have bad spark plugs, this will cause engine misfire and impaired mpg. However this probably won't result in permanent engine damage unless you continue to drive the car for an extended duration after the check engine light comes on.

If you have a clogged PCV valve, this will result in engine sludge buildup. It appears that you observe extended oil change intervals, so that will worsen the sludge buildup. This will not become apparent to you until you remove the valve cover to look at the valve train, or until the sludge gets bad enough to cause a lubrication failure, which will result in a destroyed engine.

 

Love my 04 have almost 60K carefree miles

 

Do I need to remove the valve cover or can I just look for sludge through the oil fill opening?

 

If you look at the oil fill opening, all that you will see is an aluminum baffle plate whose purpose is to prevent lots of oil being splashed up if the oil filler cap is removed while the engine is running. So that won't help your efforts to look for sludge. You would have to remove the valve cover to inspect the valvetrain. If you are going to exert the effort to do that you'd might as well replace the PCV valve while you are at it.

Attached is a photo of my 2001's valvetrain taken when the car had ~60K miles. Also attached is a photo of the underside of the valve cover so you can see the baffle mentioned above. The last photo shows the top of the removed valve cover. Note the new PCV valve installed in the upper right corner.

 

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I would like to wait until 300k to see if there are any ill effects.

I noticed a miss under heavy acceleration several seconds from a stop at around 120,000 miles , new plugs cured that. Suggest to push the engine occasionally to make sure there is not lowered performance from the old plugs.

I extend the oil change interval, mainly because my car is running 6 hours a day on the job-postal and the oil seems to stay 'clean' /eg light colored. I do use a magnetized oil plug for additional insurance. I forgot about checking the PCV valve during the last spark plug change, an ideal time to do that. Another thread I read linked dirty oil (black) with a clogged pcv valve, so I may be okay as is. Is there is an easy way to check the valve ,say pinching the right hose?, the valve appears buried underneath plastic cover and a wire bundle. related thread for more info- PriusOnline.com • View topic - 2002 Prius with a possible sludge issue?
and for replacement - http://www.priusguru.com/2009/03/prius-pcv-valve-replacement/

 

Sparkey ... helo o o o o o o . . . are you listening?



Over here! ... somewhere between 80Kmiles & 90K miles ... still going strong. Yes your thread looks to mean PRE 2004 versus 2004 and older. Oh well, I'm no grammar guru myself.

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