Exhaust leak Hino 258

natsys · Sep 9, 2023

Used the exhaust brake the other day and heard a hissing like a giant air leak. Checked around under the hood and saw a pile of soot on the right side of the engine. Found a good size leak in the forward flex joint in the pipe shown that runs from the rear of the exhaust manifold to the intercooler.

What I can't seem to find is a replacement part or even what it's called. The engine is a J08E and the truck is a 2011 258 LP. Anyone know what it's called or have a part number lmk. Or maybe the flex joint can be replaced?

greasytshirt · Sep 9, 2023

That's an EGR pipe. I don't have a way of looking up parts at home.

Just hope the bolts in the exhaust manifold don't break off because it can get ugly.

natsys · Sep 9, 2023

Ok. So it's not the intercooler, it's an EGR cooler?

It looks like the cooler bolts will come off ok, but I have the same reservation about the manifold end. It is 12 years old, but still only 60k on it so maybe it won't be too seized up.

At least I know what to look for.

Thanks again.

danthewolf00 · Sep 10, 2023

Use a rust remover solvent before you try to remove the bolts.

natsys · Sep 22, 2023

Can't. Bolts are threaded right into the exhaust manifold casting with no through hole.

Watched a few YouTube videos and got some free advice from a Hino tech who happened to wander into the parts department while I was picking up the new pipe ($600 for the pipe and gaskets -Holy smokes!). He said he starts with a cold engine and uses a torch to heat the exhaust manifold but not the bolts. I used mapp gas and a plumbers torch to heat below each bolt where screwed in and then put steady pressure with a 1/2 inch ratchet and got all 3 to break loose.

Including removing the air cleaner and inner skirt it took about an hour. Really glad nothing broke.

greasytshirt · Sep 23, 2023

Awesome, that's the best possible outcome.

natsys · Oct 26, 2023

Seems like this is related so I'm posting on this thread.

Since I changed that egr pipe my DEF usage has shot up substantialy. Sometimes when the truck is idling you can smell ammonia. It went through 3 1/2 gallons in about 500 miles. Previously that would last me almost 5000 miles.

There aren't any codes or CEL, and regens have stretched from around 120 miles to 160, and they take a lot longer.

Can't find too much on this subject anywhere so if anyone has any ideas on what to check let me know. I have Hino DX software so I should be able to investigate if I know where to look.

greasytshirt · Oct 26, 2023

Since you have DX, I'd do a def solution addition test. You'll do this through the DCU. Remove the def injector (leaving all the lines connected) and put it into a graduated container like a paint mixing cup. There are three steps to the test. DX tells you the proper volumes . Then do the leak test to see if the injector is leaking.

I'd also be interested in what the NOx sensors are doing. Do this after the truck has sat for a few hours. Using DX, set the soot to 2.5. Go to data monitor and monitor the NOx values. Start it up and hit the regen button. It'll take several minutes for the sensors to wake up. The readings will bounce around for a few seconds, then the readings will stabilize after a few minutes. If one sensor continues to oscillate wildly it should be replaced. Then in a nutshell the inlet reading should be higher than the outlet. Negative on the outlet is ok. If the outlet is equal or higher than the inlet towards the end of the regen then maybe trouble is brewing.

While you're in there find the DPR inlet and outlet temps listed in system protection data.

Also download the burner event log and look for things like lost flame, failure to achieve temperature, temp sensor faults, emergency stop, and see if the flame temp has ever recorded a temp in the 4000f range.

Does it need to be manually regenerated frequently?