After completing a timing belt and water pump job on a Lexus LS400, the owner has a coolant leak with unknown source, low idle, and weak heat at idle, needing help diagnosing the exact leak point before disassembling again.

Workarounds Described

• posts on Reddit asking for common leak points before tearing everything apart
• uses visual inspection and assumption that coolant is dripping from above

Implied Software Gaps

• Mobile app providing structured diagnostic flow for post-repair coolant leak troubleshooting
• Database of common failure points for specific engine models after water pump replacement

DiagFlow

DiagFlow is a mobile diagnostic assistant for DIY mechanics that provides step-by-step troubleshooting guides for common post-repair issues. By inputting the vehicle model and work performed, users get targeted leak point checklists, pressure testing instructions, and visual references to speed up diagnosis.