EGR Cleaning: What did I get myself into?

Just did mine and you guys were a ton of help. my notes. Fully clogged, Brake cleaner was a pain (literally to the skin, it dissolves silicon gloves and got me almost nowhere with the cooler. Will be using it to finish for final clean. Tried pressure washer at DIY car wash, nada. Did an over night soak with ammonia with ends wrapped in plastic wrap and rubber bands soaking the whole part in a stock pot of hot water. Next morning a lot of black came out. Read about OxyClean and using a wire in a drill. Tried several wires until I found the Holy Grail...a thin bicycle spoke. Fortunately I had a spare that had broke. If you don't pop over to a bike store or REI, buy one, they are not expensive. Cut off the bent end and leave it with that chisel like sharp end. Threaded end into the cordless. OxyClean soak and drill. Rinse and repeat. The sharp end of the spoke cuts up the clogs. Might not be able to get some of the very side holes behind the throat of cooler but the rest are very easy. I repeat mine was fully clogged. My maintenance schedule will be based on the 30k coolant change as having no coolant in the car makes it easier to pull the cooler. Did the spark plugs as I had the wiper assembly and I was surprised the car could run they were so bad. New plugs are supposed to be good for 150,000 miles, the old ones had 90k on them. Hopefully this cures all the issues. 263,000 miles on it.

 

So that was the first time you did the EGR cooler? Has your 2011 run OK for your 263,000 miles?

 

Bought the car used with 169,000 on it four years ago. A former Uber car. It had been in an accident and he had put a salvaged motor in it. So, this was the first time I have done it. Milage had been falling over these last two years. Had some over heating on steep hills in summer that we didn't have the first two years. Two shops I use (not Toyota) didn't have any good advice. Got the engine light with the 'low EGR air flow" and started searching the web and that is when I learned all my issues were common not odd. Found a vid which is where I learned 1. my oil loss is typical not some mystery leak or bad rings. Over heating probably caused by the EGR cooler clogging up. Fuel millage decrease also. So excited as all hell to now. My biggest negative for the car is the blind spot in front of you caused by the rear view mirror. Considering how little I have done to it in nearly 100,000 miles (oil, brakes, and AC) the thing is very reliable. (knocking on wood)

 

The EGR might have come over from the salvage engine, and it might have had less miles. It might have even been cleaned, or half-@ss cleaned, at the time of swap. Hard to say.

 

Brake cleaner is not the best for that. Carb cleaner would have been better.
But oven cleaner is the best. Since yours was completely clogged, you would have to
spray and wait 30 minutes several times. But it does a great job to dissolving the carbon build up.

You can always search the junk yards throughout the country and find a used one.
Mine was $55, delivered!

 

Clogged EGR hurts the fuel economy but it should not overheat the engine. Where's the thermostat located?

 

1. Engine overheating
One of the first symptoms of a potential problem with the EGR cooler is engine overheating. If the EGR cooler has any issues that restrict the flow of exhaust gases through the cooler it can cause the engine to overheat. Over time, carbon can build up on the inside of the EGR cooler and restrict flow through the cooler. This can cause the unit to overheat, at which point it will not be able to cool the exhaust gases, and the engine will overheat as a result. Engine overheating can lead to knock or a ping, and even serious damage, if the issue is left unattended. From yourmechanic com as an example explanation.

 

One of EGR system's stated purposes is to lower combustion chamber temps. It reduces oxygen available during the explosion.

That said, I doubt it would behind a gross raise in coolant temp.

 

On top of that, I don't think any codes are thrown for a clogged EGR. If so, that is a huge oversight on Toyota's part.

 

There is a code, AFAIK. The valve is driven by a wired connection, and if grossly clogged I believe the associated computer can detect problems, throws a code. That said, it seems to be too little too late.

 

Ok...but it doesn't trigger a CEL? Maybe that is what I was thinking...Or maybe it has been too long since I last looked into it.

 

You know what's bad..., when you know the code by heart, lol:

P0401

I also know our dentist's number (by heart)...

 

P0403 is the code when the computer detects a problem with the wired connection.

P0401 is when the routine flow check, opening the valve while you're decelerating with no power, is not confirmed by the manifold absolute pressure reading going up the right amount.

 

Does this verbiage actual show/up on the dash screen?......

 

My cooler was completely clogged, literally nothing would pass through, and I never saw a code.

 

I wonder if P0401 maybe doesn't get checked for as often in a hybrid as in a conventional car. How it's programmed to check for the code is to wait for some time when the engine is warmed up, you're cruising along, and you lift your foot from the go pedal so you're decelerating with engine power cut, and the ECM sneaks in a little test where it opens up the EGR valve and watches to see the manifold-absolute-pressure reading change.

That's obviously a pretty positive kind of a test, not very much to go wrong.

Unless maybe they just kind of copied that programming from one of their conventional ECMs, and nobody paused to think "wait a minute, those conditions we look for to sneak in the test, aren't those the same conditions where in a hybrid the engine is just going to turn off?"

So it might be that the ECM is still programmed to do the same test, but it happens way more rarely because it can only happen when all the required conditions are seen and the engine hasn't turned off.

If it's a code that needs to see a failed test on two consecutive drives (and it is, 'ccording to the manual), that might be a higher bar to clear than they intended. (So there might be times, if you connected with Techstream and asked, where you would see a P0401 pending code, but it wasn't confirmed on the next trip, so never gave a check-engine light.)

That might be a good argument for doing the manual check with Techstream every now and then. It isn't hard to do, and is essentially the same test as the built-in one, only you do it at idle instead of while driving.

 

Ok good...this reinforces my memory of other discussions where folks were seeing a completely clogged EGR while never seeing a code. ( i.e. - I'm not going completely nuts ).

Also, the fact that doing EGR maintenance isn't exactly easy...and Toyota doesn't list EGR maint at all as a maintenance item reinforces the thought that Toyota never intended the need for it...an obvious design flaw. Following that logic, I think any 'EGR checks' done by the computer wouldn't be all that robust.

 

Other than the possible issue suggested in #276, have you thought of a way that opening the EGR valve and checking the change in manifold pressure wouldn't be a robust test?

 

On the "average" car, they don't have a cooler, and the egr system doesn't need any maintenance.
The Prius is different. But it certainly isn't hard.

 

My mom's 1979 Colt (a mopar imported from Mitsubishi) needed its EGR reamed out every time you turned around.