What can influence EGR cooler clogging?

Infrequent or even following the 10k miles oil change can lead to increased oil control piston ring wear and clogging of the egr cooler and valve.

Installing an oil cat can can also less the possibility of egr circuit clogging.

 

That milestone is somewhat arbitrary; if it’s on your mind I wouldn’t hesitate to dive in. Do the whole thing too, including intake manifold.

 

we don't know the reason(s)

best practice is regular cleaning and oil catch can. much cheaper than a new head gasket or engine

 

Bad rings

 

but these simplistic explanations don't address the cars that go hundreds of thousands of miles without issue

 

Here's some backstory on our old 2010 that went 200 k miles in various climates and environments for multiple years:

1) Prius bought in august 2009 in Richmond, VA

• Spent 2 years there
• Put 30k miles on the Prius in those two years
• Commute to work was 15 miles one way on surface streets where the max speed was 40 mph
• Climate in Richmond is mostly warm but there were times where snow fell and the summers are hot and HUMID

2) Moved to Wichita, KS in July 2011

• Spent 2.5 years there
• Put 40 k miles on there
• Commute to work was 32 miles one way and a highway
• Climate in Wichita was warm in the summer, cold in the winter

3) Moved to Fairfield, CA in February 2014

• Put 130k miles on the Prius until selling it in April 2019
• Commute to work is 38 miles one way on the freeway. Here there is stop and go traffic in addition to 70 mph
• Weather is nice year round. Hot in the summer (temps approach 110 F in the summer). Winter temps very rarely get to 32 F
• Oil catch can installed after the 175k mile egr circuit cleaning
• Found our Prius consuming about a quart of oil every 5000 miles at 125 k miles
• I did two egr circuit cleanings:
  • One at 120k miles. Found the egr cooler to be coated but not solidly plugged
  • One at 175k miles. This egr circuit cleanse was dirtier than the previous cleaning

So in less miles, I found more plugging, but the oil consumption may have had something to do with it.

Hope my data helps.

 

maybe it's as simple as manufacturing tolerance parameters

 

Maybe Toyota's take on 3rd gen EGR shortcomings is reflected in what they revised in 4th gen: a signif increase in cross-sectional area of the components, and exhaust intake relocated to the downstream side of the Cat. AFAIK they don't come right out and say anything, but judging from their actions...

 

Judging by their actions, they had people reading the published engineering literature on the changed combustion chemistry achievable by taking the EGR from downstream of the catalyst, and they increased the cross-sectional area of the components by the amount corresponding to the drop in pressure when the gas is taken from the downstream location.

 

How much driving does she do annually?

What's the mileage total on the current ride?

70k is early on and she'll have time to pile on more miles and still be ok before egr circuit cleansing occurs.

I knew a courier out here who had a 2015 Gen 3 and he put 375k miles on it before a semi thought he owned the lane the courier was in.

He never cleaned the egr circuit and also his Prius did not consume oil .

Another piece of data to consider.

 

My two cents on the 2012-2014 Prius V, and the fouling rate of the EGR + Cooler:

Oil Quality?

Would using a top of the line Castrol "hi-mileage" 0W-20 oil make a difference compared to Walmart brand? I must confess that I have used Walmart brand 0W20 a few times. Once I discovered that Sears Auto Centers gave Uber Drivers 1/2 Price Oil changes, they did most of my changes. $42 total, and I didn't get dirty. No idea what oil they use.

Now that my Sears Auto Center has closed for good, I decided to spend for the most expensive Castrol "hi-mileage" oil for my most recent oil change on my 2013 at 93K. $10 more than Walmart brand isn't a lot of money extra to spend, and I get just as dirty. I have not noticed oil consumption yet,

I will post some pics when of my EGR cooler cleaning next week.

 

Walmart oil is just fine. It is widely sold under other private brands by Warren Distribution. It is a high quality oil.

High mileage oil is the same as regular oil but infused with rubber seal conditioners. Unless you have seal leaking issues, I'd hold off on using it.

It's not the brand of oil that's important, it's how often it is changed. As long as the oil meets the standard for SAE 0w20, you're fine.

Clean oil helps keep the oil control rings from fouling and pass through the narrow passages that lubricate the timing chain and keeps the engine cooler. Dirt and contaminants coat the walls of these passages and slows heat transfer.

 

High mileage oil is distinguished from regular oil by additives that swell seals/gaskets. The bottles are NOT clear, but really: you only want to use this stuff if you've got runaway oil consumption.

 

The egr valve is easy to clean. Not so much for the egr cooler which is the real culprit.

Four years, ago, when this problem began to manifest itself, I found salvaged egr coolers on eBay for as little as $50 delivered. Now that the issue is widely known, used uncleaned ones are near the $150 range.

I wanted the used one that I got totally clean. I soaked and examined it every week for six weeks. Each successive week resulted in remaining yellowish solvent water. After six weeks, I got totally clear solvent fluid. The cooler was basically like a new one.

I'd get either a used egr cooler and clean it or a new egr cooler, before I started examining the egr system.

You will also need an 8mm e-torx wrench to disassemble the egr system. So, get one before you start.

 

That reminds me; info:
Bad Flywheel | PriusChat

 

I was using Mobil One 0w-20 pre oil burn, so that is some pretty good stuff.

After that, I clubbed up and began using 5w-30 Red Line.

Did help maintain the oil burn, but then at the end I went to Pennzoil Pure Platinum 0w-40. Said the same Mai raining of the oil burn, but at a cheaper cost.

 

You could be damaging your engine to the point of starving the delivery of oil to the timing chain and also be reducing the cooling effect of the oil as a higher viscosity moves slower to reduce the effect of the flow of oil that also cools the engine.

VW switched back to timing belts in their engines due to restricted oil flow, since timing belt systems fo not require narrower oil flow passages. Timing chain damage in VW engines is legendary.

 

Post 16, say Georgina, what solvent did you use?
I liked your idea/ cleaning technique.