A few EGR cooler/intake tips

I had a P0117 code and an intermittent overheat light, so while I had the cooling system drained, I decided to hit the EGR cooler, intake manifold clean, and oil catch can add. I watched the Nuts about Bolts videos, which were very helpful, but here are some of my discoveries and tips from doing the job. I also replaced the ECT sensor and water pump rotor to address the code, and the thermostat because I was there. Also spark plugs while the cowl was off.

My 2014 Prius is at 190k miles, and while the cooler was definitely dirty, it was not thoroughly clogged. I could see light reflecting through it, but I could not see light directly through it.

1). The Cleaner. I initially thought I would use oven cleaner, as I have used that successfully in the past on cleaning engine blocks and pistons. The problem for this use was that oven cleaner foams and didn't soak deep down the small passages. Some improvement, but not much after an hour plus of messing with it. In googling that evening, I ran across a Motor Trend article on EGR cleaning solutions for diesel EGR coolers. A soak and rinse shootout. Two hour soak, no wires, no ultrasonics. Their winner was Purple Power, which I didn't find locally, so I got a 5g container of Zep Industrial Purple Degreaser at Lowe's. I cut the very top off a 1g empty coolant jug, dropped the cooler in vertically, and filled the jug until the cleaner covered the cooler. I dunked it a few times to make sure cleaner was working its way through the passages, took my wife to lunch, the Indiana Jones matinee (recommended!), and fixed my mother's wifi; a six-hour soak. Rinsed with hot water, compressed air, and hot water again. It looked fully clean. I gave it another two-hour soak while I was doing other work, and the rinse gave no additional crud. No wires after the oven cleaner attempt, and no ultrasonics. The picture is the end result. All passages were this clear. Soaking the intake manifold in a 3:1 Zep cleaner:water ratio in a small trash can gave the same good results on the small EGR passages, though I did follow up with long pipe cleaners in both the small passages and the side EGR pipe port. If I was to do this again, I'd pull the cooler and intake at the end of the day, toss them both into a suitably sized container together, and let it all soak overnight in full strength cleaner. Next morning, rinse, reinstall. Highly, highly recommend the Zep purple cleaner, though I suspect the other purple cleaners will also work.

Search motor trend ego cooler cleaner
We bench-test diesel EGR Cooler cleaning solutions



2) The "Difficult Nut" and others. To pull the difficult nut underneath the cooler, I used a deep 12mm with a 2-1/2in extension on a flex-head ratchet. Broke it loose, put a magnet-on-a-stick on the end of the stud, and spun the nut off with my left hand behind/underneath the bracket. Installation was reverse; put the nut on the magnet, maneuver it onto the end of the stud, spin it on, tighten. I pulled the long stud in the front and the two rear pipe studs with an e-torx socket. I left the "difficult stud" in place. To prevent the pipe gasket falling on removal, I clamped the pipe and cooler flanges with a small vise grip. For installations, when working blind, I often slip a long length of fine string or monofilament line through the piece I'm installing in case I lose my grip on it. That's how I secured the rear pipe gasket to prevent it from dropping into the abyss. I often do the same with nuts, bolts, and even tools, but here, for the rear studs and nuts, I transported them into place with the magnet stick until the threads were started.

3) Oil grunge. I had some pooled oil in the intake, and plenty of caked oily carbon in the head intake ports. Got maybe 70% of the port crud out with brake cleaner soaked paper towels, but I was afraid to get too aggressive with it. I used a 3" length of 3/4" fuel line on the intake PCV port, stepped down to 1/2" fuel line to the catch can with a 3/4-1/2" barb connector sourced from Lowe's (Proline Series 3/4-in x 1/2-in Barbed Splicer Adapter Fitting, Item #877084, $4.88), with 3/8" fuel line for the PCV valve to catch can run.

I hope this helps!

 

I was all ready to use my pressure washer, but with the soak and compressed air, it just wasn't necessary. I wasn't fully clogged, however, so that may have made a difference. I was really impressed with the Zep purple. Now I don't know what to do with these four cans of oven cleaner!

I got the rotor from Amazon. I posted another thread on my p0117/overheat woes.

 

I didn't note any corrosion issues on the inserts, but neither did I check them with a magnet.

 

Yeah, I looked for various plugs, covers, and other means of just filling the cooler interior, but one-gallon jugs was what was in ready supply in my garage.