Codes up tha Wazoo

3rd gen head gasket failures are usually coolant leaking into combustion chamber(s) (per post 20). That test is for carbon monoxide, which may eventually happen, but in the later stages.

borescope inspection of the combustion chambers is the usual DIY diagnostic, preferably with coolant system pressurized, to accelerate leakage. The morning after a drive is opportune time too, gives coolant leaks time to accumulate. You’re looking for exceptionally clean piston top(s), pooling coolant atop piston(s), and coolant tears commencing at the head gasket seam.

 

A negative result for the exhaust gas test in the coolant does not mean the headgasket is not going bad. Early headgasket problems will not result in a positive test result. Exhaust gases will only be detected after the headgasket leakage has advanced further along.

A bad coolant pump will not cause the engine to knock. The knocking is caused by the misfires in the cylinders.

My guesstimate is the engine coolant pump has been getting progressively worse over a farely long period of time. This caused the engine to repeatedly overheat, which caused the headgasket to start to leak. The only true way to check for a bad headgasket is to pressurize the coolant system and use a borescope to check for coolant seepage in the cylinders of the engine. This usually occurs in cylinders #1 or #2 on these Gen 3 engines.

Your car has 220k miles on it. If you confirm that you have a bad headgasket, I would be looking to replace the car rather than put any money into it.

PS, Mendel responded as I was composing this post. We both are saying the same thing.

 

I’m not 100% in harmony regarding the cause of the head gasket failure though: while failing water pump may well be a factor, carbon-clogged EGR would be my first concern.

 

7 Ways a head gasket can fail (Haynes link)

Those 1.8L engines seem to be suffering type 7 on that linked list. Easiest to spot with a temporarily pressurized cooling system and a good borescope camera in the spark plug hole.

 

Missed this (from post 13). Pretty much guaranteed to be head gasket.

 

You can soak it in gas, but it would be stupid to do so!!!! Extremely dangerous!
You can use Gunk, and a .22cal bore brush in a drill to clear them out.
You'll need to clean out the egr cooler also. No point in doing half the job.
And check to make sure the egr valve is functioning correctly.

 

I’d put that first on the agenda.

Have a look at the top two links in signature. (On a phone turn it landscape to see signatures)

 

I think that you linked the wrong video. The one you linked does not even mention the EGR. Did you only disconnect the electrical connector from the EGR, or did you use a putty knife to block off the flow of exhaust gas from the EGR valve to the intake manifold?

You never described in your previous post exactly when the engine knock is occurring. Does it occur in the morning when the engine is cold, and then it clears up after 15 to 60 seconds of running? Does it only occur at idle, or partial throttle, or full throttle after the car has warmed up? Give us a description of when the engine knock is occurring.

 

It sounds like you may have something wrong with the EGR actuator motor or the electrical connection. (I'm assuming the test you did was to temporarily block off the EGR with the putty knife trick.)

Did you replace the EGR valve, get one off of eBay or something like that, or get one from Toyota?

You seemed to eliminate the connections to the ignition coils and injectors, but it's still worth checking these, as those would also cause cylinder misfires. (Do you have an OBD scanner capable of looking at the cylinder misfire counts?)

 

Every engine, no matter how good, can blow a head gasket from overheating.

Asking for the symptoms rather than the miles is far more important.

Car Care Nut HG Borescope at 660s

Car care Nut Egr video with block tube test

 

Typical of head gasket causing major rattles fooling the misfire detection.

It bothers me when egr cooler cleaning is recommended to fix knocking. Blocking the egr flow is easy and will rule out egr work.

It is common for this test to give a false negative.

If it's white it's getting serious.

Classic head gasket symptoms. I would expect loss of coolant very soon.

 

Is the volume splashing out large or small?
From which cylinders is the coolant splashing out?