The Car Care Nut uncovers an exhaust pre-heater leak

So the TSB came out in 2019 so anybody with older Gen 4's need to be aware of the possible issue...check that coolant level often (at least weekly) and also look for white smoke out of the exhaust.

I wonder how many folks had their head gasket replaced when that's not the root cause? Yikes

 

AND test the coolant (like the maintenance schedule calls for) and change it when the test results indicate degradation of the coolant (ie: preform coolant system preventive maintenance). Regardless of the year.

 

so i guess the answer is, dealers can't read

 

I just change it out every 5-years and did the 2017 last summer...only took a gallon and a half for both radiator and traction system.

 

Car Care Nut was late to the party on Gen3 Head Gaskets as well. In some of his early videos he stated he never saw one while working at the dealership. Of course relatively few bring their high mile cars to a dealership.

In this case the gen4 heat exchanger problem is emerging, it’s not an infant mortality flaw, it is a higher mileage failure.

Several clear distinctions from a hg; all four cylinders steam cleaned, fast coolant loss and the engine does not rattle on startup. Plus copious white smoke from exhaust which is only late end stage on a hg.

If it were my car it would be bypassed and the thermal exhaust heat exchanger valve would be clamped open to the free flow state.

Gen4
(*1 Engine, *4 Exhaust Pipe Gas ControlActuator, *5 and *6 catalytic_converters, *9 Heat Recirculator, *e Exhaust Flow Control Valve )


Pic from gen3


Full TSB

One open question in my mind is how the exhaust steam made it back to the very steam cleaned cylinders? He speculated it was late closing Atkinson cycle exhaust valves scavenging exhaust/steam; I wonder if it is not the gen4 egr_valve with its pickup after the cats?

 

Perhaps a little of both. But once again, an ounce of prevention is worth a pound of cure. Rust and rust failure in a coolant system can easily be prevented.

 

I kind of wonder, if you say "whoa, look at this piston, it's been steam cleaned", and you end up saying that about all the pistons in the engine, were they maybe just clean?