Coolant loss- any connection to a fuel injector

Stick a borescope down 1&2 to see if it's been steam cleaned. The coolant just didn't evaporate????? You can just throw a set of plugs at it , but I serious doubt it's going to solve your issue - long term.....

 

Was that the last time you cleaned the EGR system?

 

You also need to clean the EGR valve in addition to the cooler. If the valve is stuck open or closed, that will screw up the amount of exhaust gases going into the intake per unit time.

 

The valve and cooler are two peas in a pod, just for the record; don’t think it’s possible to remove one without the other, they come out together.

 

Dynamic Duo of tests to rule out egr or confirm head gasket

Start with no cost egr block flow test

At about 10:15 in the video he starts talking about the egr valve letting "air" into the intake manifold. He means exhaust gasses.

A blocked egr cooler won't cause death rattle or misfire codes. A sticking open egr-valve can cause rough low speed engine operation. Both will cause an egr code. Neither will cause loss of coolant.

Car Care Nut HG Borescope at 660s

 

I would agree, but wish to mention I removed just the valve assembly from the cooler. It’s not hard and this avoids removing the cowel. It was done by using a thin bahco circle wrench that was able to fit…

I then blew out the cooler with compressed air - in a can and with compressor. Can was better due to very high pressure (my compressor was lame, yep).

Also the manifold and pipe are veeeery important to clean thoroughly, that’s where the oil gets added to the ash via PCV system I assume.

I bought another complete EGR cooler and valve from a junkyard for a Auris - it’s the same OE for many models so don’t focus on Prius only. This auris one was from a 350 000km car and hardly even half as dirty as mine which was replaced by Toyota 2019 (bought my first gen3 this autumn).

 

The 2010-14 Prius engines had low tension rings and more blowby. Most end up burning excessive oil. These factors send hydrocarbons through the egr system, intake and valves causing high carbon buildup. Gen4s by 2016 redesigned these areas making egr cleanings unnecessary.

 

Yes. I am painfully aware. So, never buy a used EGR assembly from a Prius is my tip… if you shop for used complete EGR assemblies use OE number only.

 

But how every available instruction indicated it’s not possible to remove the valve only is beyond me.

It was not hard and Toyota never replaced the coolant part in the ”semi recall”. Check this great TCCN work through even though he removes the cowel he does not remove the cooler, but blows it out:

 

I bought the entire EGR system parts new at the dealership, except the cooler. I bought that one used from ebay and have been trying to clean it. So far 2 overnight soaks in easy off oven cleaner and two more with oxy-clean concentrate. Then washed with pressure washer. I can still see carbon stuck in the holes, though it's improving. So finally bit the bullet and bought a new cooler. All parts going in soon.

 

I hate very harsh, damaging nature solvents, but that me. I used pine oil soap for the manifold and drill brushes.

Since no oil is added into the cooler (unless your engine is crap) - like gets added for the manifold - it’s really dry and I would not recommend any liquid or soaking compared to keeping it dry and blowing blowing blowing.

 

Correct. If the cooler flows you can simply blow it out.

Exactly. The first cooler I did was completely clogged and required a wire chucked to a drill to clear each channel.

 

I understand I am in a counter wind here, but if the clogging is dry ash, it’s not sound to add liquid to this. Use very high pressure if you have the cooler loose, it’s obvious to me in the air how much ash gets removed.

Its very hard to see thru the mesh if not removed, but after being able to blow so much ash out of the front/exit area I feel I removed atleast 50% without any cooler removal.


the other end of the cooler is direct exhaust that has very high temperatures.

 

How much air pressure is needed for this to work? I have a 8 gallon air compressor but not sure if it will be enough. Also what about safety? What is the likelihood those airborne particles are going to hurt anyone around including the operator?

 

I am so fascinated this Koko world cannot have even agreed on ONE air pressure measurement, so since I’m from Europe I have a hard time decipher what 8 gallon is, per what unit?

I would say any compressor with a pressure tank will deliver enough pressure if the nozzle is small enough.

I do agree fully on that this is pre catalytic converter exhaust ash, so it’s not sound to inhale. But basic nature (plants etc) and animals (humans) can handle inhaled ash better than many man-made solvents and their gases. I used a breather mask and you can easily see the ash getting evacuated so avoid being in that area is vital.

 

I hate US imperial units. But here is a translation:

1 US Gallon = 3.96 Liters

So the 8G compressor comes out to approx. 32 L.

 

I’d have it out, the smaller end stoppered (ID is ~21 mm, #4 stopper is suitable), propped up and filled (takes approximately a cup) with lye solution* (either NaOH or KOH, sodium hydroxide or potassium hydroxide), let sit an hour, rinse, inspect and repeat as needed.

I seriously doubt you’re going to budge the build-up in-place, with compressed air. And where would anything loosened be driven, further into the exhaust manifold?

* Use appropriate precautions with lye

 

I understand your doubt this, based on your method and your great instructions. This is just another a bit easier method, it’s not critique, it’s methodology.

If you consider this build-up is dry ash directly from exhaust, as it’s not oily unless the engine is bad, it’s not that wild of a concept. Blowing out the intake manifold would be impossible!

Everyone can evaluate methods. I just like the fact I managed to get them separated in-car and did not use damaging solvents - and I hope this helps someone trying this.

Note Toyota hardly ever replaces this cooler, they blow it out from the front. It’s not just TCCN pointing this out.

Yep, and the exhaust manifold can likely handle 30% of the ash loosened… That’s where it came from after all. If you have the cooler removed, this would not be an issue at all.

Ten minutes of running makes it ashy gain, that does not mean it’s ”clogged”, as the small passages in the manifold actually gets with the added oil from PCV (and the same ash in the actual valve will block the valve from closing. That’s bad galore).

Also, if you leave deposits of the solution in there it may likely attach more ash easily ie forcing more cleaning within a shorter amount of time.

On the used Auris one I could blow out from both sides, it’s now all see thru and ready to get attached next time.