east302
Full Access Member
Truck is a 1998 K1500 (350) with 225k and it’s had a rough life. It’s my teenage son’s truck, so I’m of a “keep it going long enough until he’s out of high school” mindset versus my Tahoe.
The left head cracked and locked up #5, so I replaced that with a reman head. The right head was also cracked but wasn’t leaking (yet) so I swapped it as well. It must have overheated when the previous owner had it.
It took about two hours to burn the coolant out of the bank 1 exhaust when I started it up after the repairs. It has a true dual with a small crossover before the mufflers. Coolant was dripping out of the exhaust flange downstream of the catalytic converters, so…yeah.
Here is a plot of the bank 1 (which had the hydrolocked cylinder) and bank 2 O2 sensors. Am I seeing a dead cat on bank 1 and a good one on bank 2?
The flange downstream of the cats (which is upstream of the bank 1 downstream oxygen sensor) is shot; you can feel the exhaust coming out of it after the coolant finished leaking from it. I’ll look for another gasket this week and swap it out. Kind of hoping that it remedies everything but you know how that goes.
Would this exhaust leak downstream of the cats (and upstream of the downstream Bank 1 O2 sensor) cause these readings or did the converter say “I’m out of here” after getting flooded with coolant steam?
And as for negative LTFT, can y’all help me interpret it?
No DTCs are stored. Thanks for any help, I’m looking forward to finally getting this out of my garage
The left head cracked and locked up #5, so I replaced that with a reman head. The right head was also cracked but wasn’t leaking (yet) so I swapped it as well. It must have overheated when the previous owner had it.
It took about two hours to burn the coolant out of the bank 1 exhaust when I started it up after the repairs. It has a true dual with a small crossover before the mufflers. Coolant was dripping out of the exhaust flange downstream of the catalytic converters, so…yeah.
Here is a plot of the bank 1 (which had the hydrolocked cylinder) and bank 2 O2 sensors. Am I seeing a dead cat on bank 1 and a good one on bank 2?
The flange downstream of the cats (which is upstream of the bank 1 downstream oxygen sensor) is shot; you can feel the exhaust coming out of it after the coolant finished leaking from it. I’ll look for another gasket this week and swap it out. Kind of hoping that it remedies everything but you know how that goes.
Would this exhaust leak downstream of the cats (and upstream of the downstream Bank 1 O2 sensor) cause these readings or did the converter say “I’m out of here” after getting flooded with coolant steam?
And as for negative LTFT, can y’all help me interpret it?
No DTCs are stored. Thanks for any help, I’m looking forward to finally getting this out of my garage
Last edited:
