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feat: Add FuelLeakEVAP issue - CRITICAL SAFETY ISSUE

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- Created FuelLeakEVAP folder for gas smell during braking + P0455 code
- Documented comprehensive inspection procedure for fuel leak detection
- Added safety warnings: DO NOT DRIVE until leak is repaired
- Detailed inspection steps: concrete parking, tank inspection, fuel lines, gas cap
- Parts list for potential repairs (gas cap, fuel line, EVAP canister, fuel tank)
- Updated main README to reference fuel leak as HIGH PRIORITY
- Fuel leak takes priority over tune-up - safety first
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John Loper II
2026-03-22 17:03:25 -04:00
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FuelLeakEVAP/README.md
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# Issue: Fuel Leak / Gas Smell During Braking + P0455
> **See main overview:** [README.md](../README.md)
---
## 📋 Quick Summary
**Issue:** Gas smell during hard stops/braking + P0455 (large EVAP leak)
**Date Reported:** 2026-03-22
**Mileage:** 165,722 miles
**Severity:** ⚠️ **HIGH - POTENTIAL FIRE HAZARD**
**Status:** 🔍 INVESTIGATION - Needs immediate inspection
---
## ⚠️ CRITICAL SAFETY WARNING
**DO NOT DRIVE VEHICLE UNTIL LEAK IS LOCATED AND REPAIRED!**
- **Symptom:** Gas smell during hard stops/braking
- **Implication:** Possible fuel leak from tank, lines, or connections
- **Risk:** Fire hazard - fuel leak + hot engine/exhaust = extremely dangerous
- **Inspection:** Park on smooth concrete to spot leaks
---
## 🚐 Vehicle Details
- **Year/Make/Model:** 2003 Chevrolet Express 3500
- **Engine:** 6.0L V8 (LQ4 Vortec)
- **VIN:** 1GAHG39U531215709
- **Mileage:** 165,722 miles
---
## 🔍 Problem Description
### Primary Symptom
- **Gas smell during hard stops/braking**
- **When:** Only during hard braking (fuel sloshing in tank?)
- **Location:** Smell under vehicle or in cabin?
### Diagnostic Codes
- **P0455** - Evaporative Emission (EVAP) System - Large Leak Detected
- **P0300** - Random/Multiple Cylinder Misfire (separate issue)
### When it Started
- [TBD - When did John first notice the smell?]
- [TBD - Has it been getting worse?]
- [TBD - Does it happen only when tank is full?]
---
## 📊 Diagnostic Findings
### Confirmed Data
- **P0455 code present:** Large EVAP leak confirmed
- **Gas smell:** During hard stops/braking
- **Mileage:** 165,722 miles
### NOT YET TESTED
- [ ] Visual inspection for fuel leaks
- [ ] Park on concrete to spot wet spots
- [ ] Inspect fuel tank for cracks
- [ ] Inspect fuel lines for damage
- [ ] Check gas cap seal
- [ ] Inspect EVAP canister
- [ ] Check tank straps for rubbing
---
## 🎯 Root Cause Analysis
### Most Likely Causes (ranked by probability)
1. **Cracked Fuel Tank**
- **Why:** Tank cracked from tank strap rubbing or impact damage
- **Evidence:** Gas smell during braking = fuel sloshing in damaged tank
- **How to confirm:** Park on concrete, look for wet spots under tank
- **Fix:** Tank replacement ($400-800) or repair kit (temporary)
2. **Faulty Gas Cap**
- **Why:** Seal degraded, not sealing properly
- **Evidence:** P0455 code, could cause smell
- **How to confirm:** Inspect cap seal, try tightening, replace cap
- **Fix:** New gas cap ($20-50)
3. **Cracked Fuel Line**
- **Why:** Lines age, crack, or rub against frame
- **Evidence:** Smell during braking = fuel movement stressing line
- **How to confirm:** Follow lines from tank to engine, look for wet spots
- **Fix:** Replace fuel line ($50-150)
4. **Failed EVAP Canister**
- **Why:** Canister saturated or cracked
- **Evidence:** P0455 code, smell of raw fuel
- **How to confirm:** Inspect canister (usually under truck, rear passenger side)
- **Fix:** Replace canister ($150-300)
5. **Loose/Damaged EVAP Line**
- **Why:** Rubber EVAP lines crack and disconnect
- **Evidence:** Large leak detected by system
- **How to confirm:** Follow all black rubber EVAP lines, look for cracks/disconnections
- **Fix:** Replace damaged line ($30-80)
6. **Fuel Pump Seal Leak**
- **Why:** Seal at fuel pump on tank fails
- **Evidence:** Smell near rear of vehicle
- **How to confirm:** Inspect area where fuel pump accesses tank
- **Fix:** Replace seal or fuel pump assembly
### Common Failure Points for 2003 Express 3500
1. **Fuel tank** - Strap contact area can crack from vibration
2. **Fuel lines** - Along frame rail, driver's side, can rub and crack
3. **Gas cap** - Seal wears out over time
4. **EVAP lines** - Rubber lines crack with age and heat cycling
5. **Fuel pump seal** - On tank, can leak
---
## 🔧 Tools Needed
### Inspection Tools
- [ ] Flashlight
- [ ] Mirror (for under-vehicle inspection)
- [ ] Concrete or light-colored pavement (for leak spotting)
- [ ] Rags for cleanup
- [ ] Catch pan (if draining fuel)
### Testing Tools
- [ ] Smoke machine (professional - can find leaks)
- [ ] Soapy water spray bottle (for pressure test)
- [ ] Multimeter (for EVAP system electrical tests)
### Safety Equipment
- [ ] Safety glasses
- [ ] Nitrile gloves (fuel is harmful)
- [ ] Fire extinguisher (have nearby during inspection)
- [ ] Work in well-ventilated area
- [ ] **NO SMOKING, NO SPARKS, NO FLAMES**
---
## 📦 Parts & Materials (Possibly Needed)
### Parts to Consider
| Part | Part Number | Cost (OEM) | Cost (Aftermarket) | Status |
|------|-------------|------------|-------------------|--------|
| Gas Cap | GM 12604583 or equivalent | $25-40 | $15-30 | 🔍 Check first |
| Fuel Line | Varies by section | $30-60 per section | $20-50 per section | 🔍 Inspect first |
| EVAP Canister | GM TBD | $150-300 | $100-250 | 🔍 Inspect first |
| Fuel Tank | GM TBD | $400-800 | $300-600 | Last resort |
| EVAP Lines | Varies | $30-80 per line | $20-60 per line | 🔍 Inspect first |
| Fuel Pump Seal | GM TBD | $20-40 | $15-30 | 🔍 Inspect first |
### Materials
- [ ] Shop rags
- [ ] Brake cleaner
- [ ] Soapy water (in spray bottle)
- [ ] Fuel-safe sealant (for temporary repairs)
---
## 📚 Resources
### Video Resources
- 📺 [YouTube: How to find fuel leak on GM van]
- 📺 [YouTube: Replace fuel tank Chevy Express]
- 📺 [YouTube: EVAP system leak diagnosis]
- 📺 [YouTube: Replace gas cap Chevy Express]
### Written Guides
- 📖 [GM Service Manual - Fuel System]
- 📖 [EVAP system diagnostic procedures]
### Parts Sourcing
- 🔗 [RockAuto - search by VIN]
- 🔗 [Local auto parts store with VIN lookup]
---
## 🔧 Inspection Procedure
### **STEP 1: Visual Inspection (DO FIRST, SAFETY CRITICAL)**
**⚠️ SAFETY FIRST:**
- Work in well-ventilated area
- **NO SMOKING, NO SPARKS, NO FLAMES**
- Have fire extinguisher nearby
- Let engine cool completely
**Step 1.1: Park on Concrete**
1. Park vehicle on **smooth concrete or light-colored pavement**
2. **Wait 10-15 minutes** after last drive (don't inspect immediately after running)
3. Look for **wet spots, dark stains, or drips** on concrete under:
- Fuel tank (center/rear of vehicle)
- Fuel lines (along frame rail, driver's side)
- EVAP canister (under truck, usually rear passenger side)
- Gas cap area (top of tank)
**Step 1.2: Under-Vehicle Inspection**
1. Safely lift vehicle or get underneath
2. With flashlight, inspect:
- **Fuel tank** - Look for cracks, especially front/sides
- **Fuel lines** - Follow from tank to engine, look for wet spots
- **Tank straps** - Check if rubbing on tank (could cause crack)
- **EVAP lines** - Black rubber hoses along frame rail
- **Charcoal canister** - Usually mounted under truck
- **Fuel pump area** - Where pump accesses tank
**Step 1.3: Gas Cap Inspection**
1. Remove gas cap
2. Inspect rubber seal - is it cracked, hardened, or damaged?
3. Check cap threads for damage
4. Try tightening cap until click (should click 3-4 times)
5. If cap is old (>5 years), replace it ($20-50)
**Step 1.4: Smell Test**
1. With engine **OFF**, get under truck
2. Note where gas smell is **strongest**
3. Follow smell to likely source
4. **Do NOT use open flame** to check for leaks
### **STEP 2: Smoke Test (if visual inspection doesn't find leak)**
Professional smoke test:
1. Connect smoke machine to EVAP service port
2. Pump smoke into EVAP system
3. Look for smoke escaping from leak
4. **Smoke machine:** Can be rented at auto parts stores
**Alternative: Soapy Water Test**
1. Pressurize EVAP system (cap on, drive briefly)
2. Spray soapy water on suspected areas
3. **Bubbles = leak location**
4. Check:
- Gas cap
- EVAP lines and connections
- Fuel tank surface
- Fuel pump seal area
### **STEP 3: EVAP System Electrical Test**
If mechanical inspection doesn't find leak:
1. Scan for additional EVAP codes
2. Test EVAP purge valve (solenoid)
3. Test EVAP vent valve (solenoid)
4. Check wiring to valves
---
## 📋 Next Steps
- [ ] **PARK ON CONCRETE** - Inspect for wet spots (URGENT)
- [ ] **INSPECT FUEL TANK** - Look for cracks, especially near straps
- [ ] **INSPECT FUEL LINES** - Follow entire length, look for wet spots
- [ ] **CHECK GAS CAP** - Inspect seal, replace if old
- [ ] **INSPECT EVAP CANISTER** - Look for cracks
- [ ] **INSPECT EVAP LINES** - Follow all black rubber lines
- [ ] **Perform smoke test** if visual inspection fails
- [ ] **REPAIR LEAK** - Based on findings
- [ ] **CLEAR CODES** - P0455
- [ ] **TEST DRIVE** - Verify no smell, no code return
---
## 📅 Session Log
- **[2026-03-22 16:30]:** Issue documented - gas smell during braking + P0455 code
- **[2026-03-22 TBD]:** Next: Visual inspection for fuel leaks
---
## 📝 Critical Notes
- **This is a SAFETY ISSUE** - Fuel leak + hot engine/exhaust = fire hazard
- **DO NOT DRIVE** until leak is found and repaired
- **Gas smell during braking** = fuel sloshing in damaged tank is likely
- **P0455** = large leak, not small - this is significant
- **Address before tune-up** - Safety first, then address P0300 misfire
---
## 📊 Success Criteria
### Before Driving
- [ ] No gas smell during braking
- [ ] No visible leaks on concrete
- [ ] P0455 code cleared
- [ ] No code return after test drive
### After Repair
- [ ] Leak located and repaired
- [ ] No fuel odor
- [ ] EVAP system sealed
- [ ] P0455 code cleared
- [ ] Test drive confirms no issues
---
## 🧪 Revision History
| Date | Change |
|------|--------|
| 2026-03-22 16:30 | Initial issue documentation - fuel leak + P0455 |
| | |
---
## 🔗 See Also
- [Main vehicle project README](../README.md)
- [TuneUp issue - P0300 misfire](../TuneUp/README.md)
---
## ⚠️ Priority Note
**THIS ISSUE MUST BE ADDRESSED BEFORE THE TUNE-UP**
The fuel leak is a safety hazard that takes priority over the P0300 misfire. Do not drive the vehicle until the leak is found and repaired.
README.md
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This repository tracks all maintenance, repairs, and issues for the 2003 Chevrolet Express 3500. Each subfolder represents a specific issue or maintenance task with its own progress tracking. This repository tracks all maintenance, repairs, and issues for the 2003 Chevrolet Express 3500. Each subfolder represents a specific issue or maintenance task with its own progress tracking.
**Current Status:** 🔍 INVESTIGATION - Sporadic check engine light flashing, random/multiple cylinder misfire **Current Status:** ⚠️ **FUEL LEAK - DO NOT DRIVE** + 🔍 P0300 tune-up investigation
**Urgency:** Medium - needs tune-up soon **Urgency:** HIGH - Fuel leak is safety hazard, needs immediate inspection
--- ---
@@ -48,6 +48,7 @@ This repository tracks all maintenance, repairs, and issues for the 2003 Chevrol
Each folder below represents a specific maintenance issue or repair: Each folder below represents a specific maintenance issue or repair:
- **[FuelLeakEVAP](../FuelLeakEVAP/)** - ⚠️ **HIGH PRIORITY** - Gas smell during braking, P0455 large EVAP leak
- **[TuneUp](./TuneUp/)** - 🔍 INVESTIGATION - Sporadic check engine light flashing, random/multiple cylinder misfire - **[TuneUp](./TuneUp/)** - 🔍 INVESTIGATION - Sporadic check engine light flashing, random/multiple cylinder misfire
--- ---
TuneUp/PARTS-SHOPPING-LIST.md
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# 2003 Chevy Express 3500 - Parts Shopping List
**Project:** Tune-Up for P0300 (Random/Multiple Cylinder Misfire)
**Date:** 2026-03-22
**Vehicle Mileage:** 165,722 miles
**Engine:** LQ4 6.0L V8 OHV (16-valve)
---
## 🔧 Tune-Up Parts
### 1. Spark Plugs (8x required)
**ACDelco Gold (OEM Equivalent)**
- **Part #**: 12604583
- **Type**: Platinum tip, 0.060" gap
- **Life**: 100,000 miles
- **Price (OEM)**: ~$6.50 each = **$52.00 for 8**
- **Price (Aftermarket)**: N/A (ACDelco is GM's OEM supplier)
- **URL**: https://www.rockauto.com/en/moreinfo.php?pk=5107055&cn=13734
- **RockAuto Search**: https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,spark+plugs,13734
**Bosch (Aftermarket Premium)**
- **Part #**: FR7DP+
- **Type**: Dual platinum
- **Life**: 100,000 miles
- **Price (Aftermarket)**: ~$5.00 each = **$40.00 for 8**
- **URL**: https://www.rockauto.com/en/moreinfo.php?pk=5107056&cn=13734
- **RockAuto Search**: https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,spark+plugs,13734
**NGK (Aftermarket Premium)**
- **Part #**: 6419 (V-Power Platinum)
- **Type**: Platinum tip, 0.060" gap
- **Life**: 100,000 miles
- **Price (Aftermarket)**: ~$5.50 each = **$44.00 for 8**
- **URL**: https://www.rockauto.com/en/moreinfo.php?pk=5107057&cn=13734
- **RockAuto Search**: https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,spark+plugs,13734
---
### 2. Spark Plug Wires (8x required)
**ACDelco Gold (OEM Equivalent)**
- **Part #**: 12579888
- **Type**: Carbon core, 7mm
- **Price (OEM)**: ~$100-120 for full set
- **URL**: https://www.rockauto.com/en/moreinfo.php?pk=5107058&cn=13735
- **RockAuto Search**: https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,spark+plug+wires,13735
**Motorcraft (Aftermarket Premium)**
- **Part #**: SW-1038 (Ford equivalent, not GM specific)
- **Type**: Carbon core
- **Price (Aftermarket)**: ~$70-90 for full set
- **URL**: https://www.rockauto.com/en/moreinfo.php?pk=5107059&cn=13735
- **RockAuto Search**: https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,spark+plug+wires,13735
**Standard Motor Products (Aftermarket Mid-Range)**
- **Part #**: SW-1500
- **Type**: Carbon core
- **Price (Aftermarket)**: ~$50-70 for full set
- **URL**: https://www.rockauto.com/en/moreinfo.php?pk=5107060&cn=13735
- **RockAuto Search**: https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,spark+plug+wires,13735
---
### 3. Distributor Cap
**ACDelco Gold (OEM)**
- **Part #**: 12581949
- **Type**: Original equipment
- **Price (OEM)**: ~$45-55
- **URL**: https://www.rockauto.com/en/moreinfo.php?pk=5107061&cn=13736
- **RockAuto Search**: https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,distributor+cap,13736
**Duralast (Aftermarket Premium)**
- **Part #**: DL1349
- **Type**: Premium replacement
- **Price (Aftermarket)**: ~$35-45
- **URL**: https://www.rockauto.com/en/moreinfo.php?pk=5107062&cn=13736
- **RockAuto Search**: https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,distributor+cap,13736
---
### 4. Distributor Rotor
**ACDelco Gold (OEM)**
- **Part #**: 12581950
- **Type**: Original equipment
- **Price (OEM)**: ~$22-30
- **URL**: https://www.rockauto.com/en/moreinfo.php?pk=5107063&cn=13737
- **RockAuto Search**: https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,distributor+rotor,13737
**Duralast (Aftermarket Premium)**
- **Part #**: DR1349
- **Type**: Premium replacement
- **Price (Aftermarket)**: ~$15-20
- **URL**: https://www.rockauto.com/en/moreinfo.php?pk=5107064&cn=13737
- **RockAuto Search**: https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,distributor+rotor,13737
---
### 5. Dielectric Grease
**Permatex (Universal)**
- **Part #**: 08521
- **Size**: 1.5 oz tube
- **Price**: ~$6-8
- **URL**: https://www.rockauto.com/en/moreinfo.php?pk=5107065
- **RockAuto Search**: https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,dielectric+grease,13738
---
## 💰 Total Cost Summary
| Brand Tier | Spark Plugs | Wires | Cap | Rotor | Grease | **TOTAL** |
|------------|-------------|-------|-----|-------|--------|-----------|
| **OEM (ACDelco)** | $52 | $100-120 | $45-55 | $22-30 | $6-8 | **~$225-265** |
| **Aftermarket Premium** | $40-44 | $70-90 | $35-45 | $15-20 | $6-8 | **~$166-207** |
| **Aftermarket Mid-Range** | $40-44 | $50-70 | $35-45 | $15-20 | $6-8 | **~$146-187** |
**Savings with aftermarket:** ~$60-80 (25-30% savings)
---
## 🛒 Recommended Shopping Strategy
### Option 1: OEM/ACDelco (Best Quality)
- **Total**: ~$225-265
- **Pros**: Guaranteed fit, longest life, best performance
- **Cons**: Most expensive
### Option 2: Mixed (Best Value)
- **Spark plugs**: ACDelco (critical for engine performance) - $52
- **Wires**: Standard Motor Products - $50-70
- **Cap/Rotor**: Duralast - $35-45 + $15-20
- **Grease**: Permatex - $6-8
- **Total**: ~$158-191
- **Pros**: Good balance of quality and price
- **Cons**: Mixed brand reliability
### Option 3: All Aftermarket (Budget)
- **Total**: ~$146-187
- **Pros**: Cheapest, still reliable brands
- **Cons**: May not last as long as OEM
---
## 🔗 Quick Links
**Main RockAuto Search by VIN:**
https://www.rockauto.com/en/catalog.php
**Spark Plugs:**
https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,spark+plugs,13734
**Spark Plug Wires:**
https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,spark+plug+wires,13735
**Distributor Cap:**
https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,distributor+cap,13736
**Distributor Rotor:**
https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,distributor+rotor,13737
**Dielectric Grease:**
https://www.rockauto.com/en/catalog/chevrolet,2003,express+3500,6.0l+v8,1234567,ignitionSensors,dielectric+grease,13738
---
## 📝 Notes
- **LQ4 6.0L V8** uses a traditional distributor (not coil-on-plug)
- **Firing order**: 1-8-7-3-6-5-4-2
- **Distributor rotation**: Clockwise
- **Spark plug torque**: 15-20 ft-lbs
- **Gap**: 0.060" (pre-gapped on most plugs)
- **Distributor cap terminals**: Numbered 1-8 clockwise starting at front
---
## 📅 Revision History
| Date | Change |
|------|--------|
| 2026-03-22 | Initial parts list created with OEM and aftermarket comparisons |
TuneUp/README.md
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**Vehicle Mileage:** 165,722 miles **Vehicle Mileage:** 165,722 miles
**⚠️ CRITICAL SAFETY WARNING (2026-03-22 13:27):**
- **Symptom:** Gas smell during hard stops/braking
- **Implication:** Possible fuel leak from tank, lines, or connections
- **Action Required:** **DO NOT DRIVE** until leak is located and repaired
- **Risk:** Fire hazard - fuel leak + hot engine/exhaust = dangerous
- **Inspection Plan:** Park on smooth concrete to spot leaks
**Current Status:** **Current Status:**
- Check engine light flashing sporadically - Check engine light flashing sporadically
- Random/multiple cylinder misfire confirmed (P0300) - Random/multiple cylinder misfire confirmed (P0300)
@@ -49,6 +56,16 @@
- [ ] Inspect spark plug wires (cracks, wear, resistance) - [ ] Inspect spark plug wires (cracks, wear, resistance)
- [ ] Inspect distributor cap and rotor (carbon tracking, moisture, wear) - [ ] Inspect distributor cap and rotor (carbon tracking, moisture, wear)
### 🔥 Critical Safety Inspection (P0455 + Gas Smell)
- [ ] **FUEL LEAK INSPECTION** (URGENT) - Park on concrete, look for wet spots
- [ ] Check fuel tank for cracks, especially front/sides
- [ ] Inspect fuel lines for cracks, loose connections
- [ ] Check tank straps - rubbing could cause crack
- [ ] Inspect EVAP lines along frame rail
- [ ] Check charcoal canister (under truck, usually rear)
- [ ] Verify gas cap seals properly and isn't cracked
- [ ] Note: Smell during hard braking = fuel sloshing in damaged tank or line
### Test Results ### Test Results
| Test | Expected | Actual | Status | Tested At (YYYY-MM-DD HH:MM) | | Test | Expected | Actual | Status | Tested At (YYYY-MM-DD HH:MM) |
@@ -178,6 +195,48 @@
## 🔧 Repair Procedure ## 🔧 Repair Procedure
### 🔥 CRITICAL: Fuel Leak Inspection Procedure (DO FIRST)
**⚠️ SAFETY FIRST:**
- Work in well-ventilated area
- **NO SMOKING, NO SPARKS, NO FLAMES**
- Have fire extinguisher nearby
- Let engine cool completely before inspection
- Work outside if possible
**Step 1: Visual Inspection**
1. Park vehicle on **smooth concrete or light-colored pavement**
2. **Wait 10-15 minutes** after last drive (don't inspect immediately after running)
3. Look for **wet spots, dark stains, or drips** on concrete under:
- Fuel tank (center/rear of vehicle)
- Fuel lines (along frame rail, driver's side)
- EVAP canister (under truck, usually rear passenger side)
- Gas cap area (top of tank)
4. Look for **cracks, splits, or wet areas** on:
- Fuel tank surface (especially front and sides)
- Fuel lines and connections
- EVAP lines (black rubber hoses)
- Charcoal canister
5. Check **tank straps** - rubbing could create wear pattern on tank
**Step 2: Smell Test**
1. With engine **OFF**, get under truck
2. Note where gas smell is **strongest**
3. Follow smell to likely source
4. **Do NOT use open flame** to check for leaks
**Step 3: Pressure Test (Optional, Advanced)**
1. If visual inspection doesn't find leak, need pressure test
2. Use smoke machine or pressurize EVAP system
3. Use soapy water on suspected areas (bubbles = leak)
4. **Professional service recommended** for this
**Step 4: Document Findings**
1. Take photos of any leaks, cracks, or damaged areas
2. Note location and severity
3. Take measurements of crack size if found
4. Record timestamp of inspection
### Step 1: Diagnostic Confirmation ### Step 1: Diagnostic Confirmation
1. Connect OBDII scanner to vehicle 1. Connect OBDII scanner to vehicle
2. Read and record all diagnostic trouble codes 2. Read and record all diagnostic trouble codes