Blown head gasket/EGR revisited

Be careful comparing Gen 3 and Gen 4 EGR systems. Gen 4 uses "catalyzed EGR", which is a different approach that was being worked out in engineering research between the days of Gen 3 and the days of Gen 4, and no, it wasn't just Frank on a bathroom break saying :"hey, what if we took the gas from after the catalyst?" Tapping from downstream of the cat changes what chemical compounds are in it, which changes the reactions that happen in the cylinder.

On top of that, the catalytic converter has a pressure drop across it. The downstream tap has a lower pressure, which means all of the EGR plumbing had to be upsized just to flow the same volume of gas. That's why it looks bigger.

 

To paraphrase Shakespeare:

Is the 4th gen EGR much less prone to carbon clogging? That is the question.

My money's on yes.

Any 4th gen'rs had a look, and at what miles? That's another question of interest.

And any 4th gen's blowing head gasket yet? Another good question.

IIRC @Raytheeagle's had a look at his EGR, but he's got a Prime, with fairly high EV usage.

 

Most gen3s and especially 2010s burned too much oil. That ends up as carbon and blowby throughout the engine. The gen4 engine has almost everything related to the cylinder reengineered including water jacket changes and a foam insulator. Many of the changes reduce knocking which creates excessive pressure in the cylinder. You have the new block which may pay cylinder cooling dividends in the future. If you can make the gen3 intake and egr work properly.

 

I don't think oil burning is the culprit, at least not a significant factor. Our (2010) had significant carbon build-up in the EGR, at 71K kms, and zero discernable oil consumption.

Same story still, no oil consumption. Last oil and filter change was at 90K kms (almost exactly), and currently at 92300~. Put in 4.2 liters (4.5 US qts), and oil was about 3~4 mm below top mark. Just checked:



pic to come

 

But no head gasket fails. My car did not burn oil until 150,000 miles with above average maintenance.

 

You mean no head gasket fails without engine oil consumption?

I think the engineers are counting on the EGR gasses getting to the combustion chamber, both to reduce emissions and to moderate temps. If you have a mission-critical component bunged up with carbon, that can’t be good.

 

No look at the egr, as it'll be more difficult to extract.

And my EV percentage is on the rise since switching employers now that I am in battery range for work and they have ChargePoint stations there.

Current "tank" is showing 1800 miles and over 380 mpg with 1/2 tank left.

When I get to 120 k miles and the spark plugs are due, I'll investigate and report back, but know the HV percentage at 120k miles may be only 20%.

But it'll be a data point.