Super cold (around 15 degrees) start this morning, engine started very rough

With the 3rd gen, EGR and intake manifold is like death an' taxes; just do it. First couple of links in my signature have some info and links.

I dropped in on a local Priuschatter when he was doing his, in a driveway, sunny but around freezing point. I concur, not a fun time of the year to take this on. Do you have a garage, or can you get time in one?

Some cold weather strategies:

1. Remove the very-hard-to-access lower hold-down nut on the EGR cooler in advance, and leave it off (forever). Take off the stud too if ambitious: the latter requires an E8 socket. And you want to go slow, it may be stubborn, due to dissimilar metals.

2. Remove the top/front nut and stud at the EGR valve. Apply a thin coat of antiseize on the stud, then reinstall.

3. Check out the aforementioned links in my signature, get together all the stuff you'll need.

4. If you have to, break the job up into two sessions: the EGR components one time, the intake manifold another time.

I think you'll find it takes more than 3 hours. Myself, I think in all it dragged out over 3 days, due to learning curve, struggling to find an effective cleaner for the cooler, fighting with the lower cooler nut, and on and on.

 

More than likely, just judging from the odo miles.

I hear you about the garage: ours used to be two-car, but now the side typically unoccupied by a car has been filled with the "procrastination pile"....

Don't waste time dumping cans of brake cleaner through the EGR cooler. Going the Oxi-Clean route, you can bring it inside, let it bubble out the carbon in laundry sink. (see links in my signature)

Also, read the tips (in sig links) about coolant tactics; clamping hoses is ineffective and a mess. There's a few tricks that can avoid any spill, speed things up.

 

Just go to LKQ or Chicago Auto parts and buy the cooler the intake manifold and I think that's all you need send that to the machine shop and have it tanked and cleaned when it's handed back to you that stuff will be whistle clean you'll be able to see daylight through all the parts and passages and ports throw that over in the corner until things get worse than they are now and it makes you more nervous then you just swap out the cooler and the intake manifold even in 20° weather it won't take you that long and you leave off that bolt that the nut that you're worried about and you're good to go for a long time generally speaking just buy the parts have them clean you'll get them cheap LKQ will almost give them to you and then the set you take off you get them cleaned put them up and if the car really makes it with you like mine and you're taking it to 600,000 you'll probably be doing it again. In the second time it will go quick as all get out

 

I had a talk with my mechanic. He saw his first blown head gasket, and since I own two Prius' he thought it was something I should be aware of. I told him that I am a member on PriusChat and I had seen hundreds of blown head gaskets [nationwide], and that it is loosely connected with a clogged EGR. he said that if the EGR clogs it 'should' trip a diagnostic code. I asked if it would be a good idea to pull and inspect the EGR once a year as a preventative. After checking the labor fees for pulling an EGR, he suggested instead to use 'SeaFoam' in the vacuum intake, that it should flush the EGR.

I take each of my Prius' in every six months for an oil change and tire rotation. [We run summer tires in summer, and studded winter tires in winter] So for my next maintenance we have scheduled a SeaFoam flush.

 

Rough starts with Atkinson engines, especially in cold weather is common. It doesn't happen consistently and if it does you have something more than normal to address, but please don't waste your time if nothing is wrong. And yes an EGR cleaning and tune up is wise, but keep it in perspective.

 

We normally anticipate -20F temps in January and February. Our Prius' are not intimidated by cool weather.

15F is T-shirt, shorts and flip-flop weather.

 

I doubt that'd do anything.

Just clean everything every 50K miles.

If it's down to say absolute zero, you say "It's nippy today, where'd my coat get to?".

 

mid week looks great, start tuesday, finish thursday

 

Nobody can predict whether it will make it through the winter without major trouble, especially not without more information. 95 k is a bit early for bad EGR clogging, but not unknown. These cars have a history of occasional rough starts even when there's no clear cause.
I suggest you clean out the EGR passages of the intake manifold (much easier than unclogging the EGR cooler, and likely more critical) and use the OBD2 port to ask the car whether the EGR path is badly clogged overall.

 

That makes zero sense.

 

Bill norton said back while ago he did an Italian tune up and it took care of clearing the egr.

 

Since knocking isn’t an on going issue and coolant level wasn’t mentioned, it’s just moisture in the combustible engine that formed over night and it’s just getting knocked around and sucked out to the egr.

 

[Duplicate post; see #18 below.]

 

A one time start up cold soak knock can sure create an avalanche of posts

 

The truth is likely between those extremes. The "hype" of your first paragraph started with the previous (2004-2009) generation, which didn't have as many head gasket and EGR issues. Certain members do have a slight tendency to "catastrophizing." Your car might go another 94k with no serious problems---or might not. Your odds will be better if within the next several thousand miles, you clean out the EGR passages of the manifold (under half a day, including generous learning curve, if you're modestly mechanically inclined) and check overall restriction of the EGR system (5 minutes with a scan tool or other OBD device).

At over 136k, my car has had none of the hyperexpensive problems, although clear coat is pealing off its roof already. I haven't bothered tackling the dreaded EGR cooler yet, because the EGR restriction number still looks good.

 

I wouldn’t buy this car again if cost fuel efficiency price of gas and maintenance values were constant when I first bought mine. In fact my next car won’t be a Toyota, that’s how untrustworthy this vehicle is.