Cleaning the EGR cooler. Or Not!

Thanks Wendel, for your very helpful reply. As a ChatGPT addict I asked for further clarification on the issue. An earlier question to it had stated an extreme scenario. You might enjoy seeing its answer to yours, below. (A much longer detailed answer with step-by-step DIY guidance was given. Too long to post here. I can send direct if you like. But none of it likely news to you. Its detail was impressive though. ChatGPT is helpful...most of the time

"The EGR cooler stud can be difficult and nerve-wracking. Breaking it does not doom the engine. Mendel omitted reinstalling it because it is non-critical. Shops over-warn because of liability, not because of real danger. ChatGPT earlier advice leaned toward theoretical worst-case. Mendel’s answer reflects hands-on Prius reality."

 

Hypothetically...

Regarding the problematic stud on the EGR cooler, the one that is oriented perpendicular to the two studs at the end of the cooler. After reading a bunch of these threads it seems that some people leave it off, and some others even cut off the bracket that the stud passes through. Since I think Toyota most likely had a good reason for putting that support there, perhaps a middle ground is possible? After removing that stud with an E8 once, pull out the EGR cooler, then grind a slot into that flange, same size as the existing hole, or slightly larger (not enlarging the existing hole), from that hole towards the rear of the car. Then reinstall the stud. Seems like after doing that one could remove the EGR a second time by just pulling it towards the front of the car (after the nuts are off the 3 studs), and that support point would be mostly intact. About 2/3 of the contact area for the nut would still be present, and the flange/nut would still keep the cooler from moving at all in that region.

I have not done this, but it seems like it should work. Unless maybe there is something in the way that would prevent the EGR cooler from sliding past the length of the slot so that the flange clears the stud.

My first thought was to carefully cut the slot into the flange before taking the EGR cooler out. Then the stud would never need to be removed, so no E8 needed. However, that seemed like it was just begging for a hand slip and serious damage to some part that would not take kindly to a visit from a Dremel or similar cutting tool. Also metal bits all over the inside of the engine compartment, which is rarely a good idea.

 

I can't imagine cutting a slot in that bracket, considering it's location. You can't even see it. I'm not sure why people want to perform surgery, just back the stud out, done.

That said, "just backing the stud out" is not easy, considering the location, and all the blinking cables and brackets in the way. I was JUST able to get a 1/4": drive ratchet with E8 socket on it, and achieve enough wiggle room to get one click at a time, out of the ratchet. It took me about 15 sweaty minutes, click by click, and fighting due to dissimilar metals, all the while. There's no way I would reinstall it.

My take, Toyota did NOT anticipate this mess, neglected to test this new EGR system, didn't appreciate it would be come a mandatory maintenance. So buried it in a morass of cables. We're pioneers.