diff --git a/FuelLeakEVAP/README.md b/FuelLeakEVAP/README.md new file mode 100644 index 0000000..b5db860 --- /dev/null +++ b/FuelLeakEVAP/README.md @@ -0,0 +1,322 @@ +# Issue: Fuel Leak / Gas Smell During Braking + P0455 + +> **See main overview:** [README.md](../README.md) + +--- + +## ๐Ÿ“‹ Quick Summary + +**Issue:** Gas smell during hard stops/braking + P0455 (large EVAP leak) +**Date Reported:** 2026-03-22 +**Mileage:** 165,722 miles +**Severity:** โš ๏ธ **HIGH - POTENTIAL FIRE HAZARD** +**Status:** ๐Ÿ” INVESTIGATION - Needs immediate inspection + +--- + +## โš ๏ธ 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 + +--- + +## ๐Ÿš Vehicle Details + +- **Year/Make/Model:** 2003 Chevrolet Express 3500 +- **Engine:** 6.0L V8 (LQ4 Vortec) +- **VIN:** 1GAHG39U531215709 +- **Mileage:** 165,722 miles + +--- + +## ๐Ÿ” 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?] + +--- + +## ๐Ÿ“Š 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 + +--- + +## ๐ŸŽฏ 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 + +--- + +## ๐Ÿ”ง 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** + +--- + +## ๐Ÿ“ฆ 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 | ๐Ÿ” Check first | +| Fuel Line | Varies by section | $30-60 per section | $20-50 per section | ๐Ÿ” Inspect first | +| EVAP Canister | GM TBD | $150-300 | $100-250 | ๐Ÿ” Inspect first | +| Fuel Tank | GM TBD | $400-800 | $300-600 | Last resort | +| EVAP Lines | Varies | $30-80 per line | $20-60 per line | ๐Ÿ” Inspect first | +| Fuel Pump Seal | GM TBD | $20-40 | $15-30 | ๐Ÿ” Inspect first | + +### Materials +- [ ] Shop rags +- [ ] Brake cleaner +- [ ] Soapy water (in spray bottle) +- [ ] Fuel-safe sealant (for temporary repairs) + +--- + +## ๐Ÿ“š Resources + +### Video Resources +- ๐Ÿ“บ [YouTube: How to find fuel leak on GM van] +- ๐Ÿ“บ [YouTube: Replace fuel tank Chevy Express] +- ๐Ÿ“บ [YouTube: EVAP system leak diagnosis] +- ๐Ÿ“บ [YouTube: Replace gas cap Chevy Express] + +### Written Guides +- ๐Ÿ“– [GM Service Manual - Fuel System] +- ๐Ÿ“– [EVAP system diagnostic procedures] + +### Parts Sourcing +- ๐Ÿ”— [RockAuto - search by VIN] +- ๐Ÿ”— [Local auto parts store with VIN lookup] + +--- + +## ๐Ÿ”ง Inspection Procedure + +### **STEP 1: Visual Inspection (DO FIRST, SAFETY CRITICAL)** + +**โš ๏ธ 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 + +--- + +## ๐Ÿ“‹ 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 + +--- + +## ๐Ÿ“… 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 + +--- + +## ๐Ÿ“ 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 + +--- + +## ๐Ÿ“Š 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 + +--- + +## ๐Ÿงช Revision History + +| Date | Change | +|------|--------| +| 2026-03-22 16:30 | Initial issue documentation - fuel leak + P0455 | +| | | + +--- + +## ๐Ÿ”— See Also + +- [Main vehicle project README](../README.md) +- [TuneUp issue - P0300 misfire](../TuneUp/README.md) + +--- + +## โš ๏ธ 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. diff --git a/README.md b/README.md index 5865977..9c4791c 100644 --- a/README.md +++ b/README.md @@ -39,8 +39,8 @@ 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:** ๐Ÿ” INVESTIGATION - Sporadic check engine light flashing, random/multiple cylinder misfire -**Urgency:** Medium - needs tune-up soon +**Current Status:** โš ๏ธ **FUEL LEAK - DO NOT DRIVE** + ๐Ÿ” P0300 tune-up investigation +**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: +- **[FuelLeakEVAP](../FuelLeakEVAP/)** - โš ๏ธ **HIGH PRIORITY** - Gas smell during braking, P0455 large EVAP leak - **[TuneUp](./TuneUp/)** - ๐Ÿ” INVESTIGATION - Sporadic check engine light flashing, random/multiple cylinder misfire --- diff --git a/TuneUp/PARTS-SHOPPING-LIST.md b/TuneUp/PARTS-SHOPPING-LIST.md new file mode 100644 index 0000000..82deaed --- /dev/null +++ b/TuneUp/PARTS-SHOPPING-LIST.md @@ -0,0 +1,185 @@ +# 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) + +--- + +## ๐Ÿ”ง 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 + +--- + +## ๐Ÿ’ฐ 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) + +--- + +## ๐Ÿ›’ 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 + +--- + +## ๐Ÿ”— 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 + +--- + +## ๐Ÿ“ 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 + +--- + +## ๐Ÿ“… Revision History + +| Date | Change | +|------|--------| +| 2026-03-22 | Initial parts list created with OEM and aftermarket comparisons | diff --git a/TuneUp/README.md b/TuneUp/README.md index 8123469..b8effc7 100644 --- a/TuneUp/README.md +++ b/TuneUp/README.md @@ -14,6 +14,13 @@ **Vehicle Mileage:** 165,722 miles +**โš ๏ธ 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:** - Check engine light flashing sporadically - Random/multiple cylinder misfire confirmed (P0300) @@ -49,6 +56,16 @@ - [ ] Inspect spark plug wires (cracks, wear, resistance) - [ ] Inspect distributor cap and rotor (carbon tracking, moisture, wear) +### ๐Ÿ”ฅ 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 | Expected | Actual | Status | Tested At (YYYY-MM-DD HH:MM) | @@ -178,6 +195,48 @@ ## ๐Ÿ”ง Repair Procedure +### ๐Ÿ”ฅ CRITICAL: Fuel Leak Inspection Procedure (DO FIRST) + +**โš ๏ธ 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 1. Connect OBDII scanner to vehicle 2. Read and record all diagnostic trouble codes