Thanks for the detailed explanation! Since your Bosch dishwasher, model SHX68T55UC/01, doesn’t start leaking until about 30 minutes into the cycle, when the water gets very hot, I suspect you’re dealing with a sump seal that’s no longer sealing properly as the dishwasher heats up.
The fact that you’ve already replaced the circulation pump and heater, but the leak continues, makes the sump gasket or sump housing a more likely cause.
Here’s how I’d narrow it down before ordering more parts.
1. Check the sump gasket and housing
First, disconnect power to the dishwasher and shut off the water supply.
The sump assembly is the plastic housing attached to the bottom of the stainless steel tub. A gasket seals the connection between these two surfaces.
Over time, that gasket can flatten, harden, or become distorted. As the dishwasher heats up, expansion of the plastic housing and stainless steel tub can expose a weak seal.
I’d recommend checking the following:
- Look for any cracks or warping around the plastic sump housing.
- Inspect the gasket for flattening, deterioration, or areas where it may have shifted.
- Check the stainless steel tub around the sump opening for damage or distortion.
- Make sure the sump housing is seated evenly against the tub.
One important point: I wouldn’t tighten those four mounting screws any further. Overtightening can distort the plastic housing and actually make the leak worse.
2. Confirm exactly where the water is escaping
Before replacing the gasket, I’d want to make sure the leak isn’t coming from somewhere just above or beside it.
A circulation pump connection, hose connection, or seal can sometimes leak when hot, allowing water to travel along the sump housing and drip from the lowest point.
With the dishwasher safely accessible, you can use a flashlight to look for the first sign of moisture during operation. Keep clear of energized wiring and moving components.
If the water is definitely appearing along the seam between the stainless steel tub and plastic sump housing, that strongly points toward the sump gasket or housing.
3. Check for sump movement
With the dishwasher empty, cool, and disconnected from power, remove the lower spray arm and filter assembly.
Gently check whether the sump housing has any noticeable movement relative to the stainless steel tub.
If the housing isn’t seated properly, the gasket may not be compressed evenly.
Also, inspect the area around the four mounting screws for cracked plastic or damaged mounting points.
4. What I would replace
If you confirm that water is escaping directly between the sump housing and stainless steel tub, I’d start with the sump gasket, provided it’s available separately for your model and the housing is undamaged.
If the housing is warped or cracked, replacing the gasket alone may not correct the leak. In that case, the sump housing assembly may need replacement.
I wouldn’t recommend applying silicone sealant around the sump. That could temporarily hide the leak without correcting the underlying problem.
5. About the AquaStop activating
The water collecting in the dishwasher’s lower base is activating the flood protection system. That’s why the dishwasher stops operating.
Once the leak is repaired, any water remaining in the base will need to be removed before normal operation can resume.
Avoid running additional full cycles until the leak is corrected.
One question that will help narrow this down
When you see the water dripping, is it coming directly from the circular seam where the plastic sump meets the stainless steel tub, or is it running down the outside of the sump housing before dripping off the bottom?
That distinction is important. If it’s coming directly from the seam, I’d concentrate on the sump gasket and housing rather than the new circulation pump.