--- product_id: 585925504 title: "AS503 Engine Oil Tester - Optical Transmittance Analyzer for Gasoline & Diesel, 31.5-inch Flexible Probe, 2.8-inch Backlit LCD, Oil Temperature Gauge in °C/°F" price: "¥11165" currency: JPY in_stock: true reviews_count: 13 url: https://www.desertcart.jp/products/585925504-as503-engine-oil-tester-optical-transmittance-analyzer-for-gasoline-diesel store_origin: JP region: Japan --- # ±0.01% optical sensor accuracy 2.8-inch backlit LCD real-time display 800mm flexible probe for hard-to-reach spots AS503 Engine Oil Tester - Optical Transmittance Analyzer for Gasoline & Diesel, 31.5-inch Flexible Probe, 2.8-inch Backlit LCD, Oil Temperature Gauge in °C/°F **Price:** ¥11165 **Availability:** ✅ In Stock ## Summary > 🔧 Don’t just change oil—know when. Stay ahead with precision testing. ## Quick Answers - **What is this?** AS503 Engine Oil Tester - Optical Transmittance Analyzer for Gasoline & Diesel, 31.5-inch Flexible Probe, 2.8-inch Backlit LCD, Oil Temperature Gauge in °C/°F - **How much does it cost?** ¥11165 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.jp](https://www.desertcart.jp/products/585925504-as503-engine-oil-tester-optical-transmittance-analyzer-for-gasoline-diesel) ## Best For - Customers looking for quality international products ## Why This Product - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Precision You Can Trust:** Advanced optoelectronic sensor delivers lab-grade oil contamination and transmittance readings for both gasoline and diesel engines. - • **Universal Compatibility:** Tailored testing modes for gasoline and diesel oils guarantee accurate assessments aligned with industry standards—no guesswork needed. - • **Ergonomic & Flexible Design:** Lightweight handheld tester with an 800mm PTFE hose and silicone grip ensures effortless single-handed operation even in tight engine compartments. - • **Instant Oil Health Insights:** Backlit LCD screen shows real-time oil temperature and quality status (OK/Replace) in °C or °F, empowering proactive maintenance decisions. - • **Hassle-Free Operation & Support:** Three-step testing process delivers instant results, backed by a 3-year warranty and responsive customer service for lifelong peace of mind. ## Overview The AS503 Engine Oil Quality Tester is a handheld device equipped with a high-precision optical sensor and a backlit 2.8-inch LCD that measures oil transmittance and temperature in real time. Designed for both gasoline and diesel engines, it features an ergonomic grip and a flexible 800mm probe for easy access to hard-to-reach oil fill ports. With simple 3-step operation and industry-standard testing modes, it provides instant, reliable oil health status to optimize engine maintenance. Supported by a 3-year warranty and dedicated customer service, it’s a must-have tool for proactive vehicle care. ## Description Product description AS503 Engine Oil Quality Tester AS503 Engine Oil Tester instantly checks oil health! High-precision optical sensor measures transmittance & temperature. Compatible with gasoline & diesel oils. Features a handheld design with flexible probe & 2.8-inch backlit LCD for clear OK/Replace results. Essential for smart car care. AS503 Engine Oil Tester CAUTIONS Pro Tip The probe should be wiped clean before each measurement and Clean the old oil in the pipe, otherwise it will affect the next test result. The temperature of the engine must be below 60°C. AS503 Oil Quality Tester Functions AS503 Lubricant Tester Packing List 1pcs AS503 Engine Oil Quality Tester Main Unit 1pcs Manual 1pcs Packing Box How To Test Engine Oil Quality The depth of the engine of different models is different. If the tester probe cannot be immersed in the oil, please take out the engine oil for testing. Some models do not have an oil caliper so the probe cannot be inserted for testing, and the oil also needs to be taken out for testing. What is the Difference Between the Engine Pressure Tester? AS503 AS502 AS505 AS506 AS507 Is this easy to use for someone who's not a mechanic? Absolutely! It's designed for everyone.Just wipe the probe, select your engine type(gasoline or diesel), dip it in the oil, and press the button.You'll get a clear "OK" or "Replace" result on the large screen in seconds—no technical knowledge needed. Is this easy to use for someone who's not a mechanic? Absolutely! It's designed for everyone.Just wipe the probe, select your engine type(gasoline or diesel), dip it in the oil, and press the button.You'll get a clear "OK" or "Replace" result on the large screen in seconds—no technical knowledge needed. How accurate is it compared to just looking at the oil color? More accurate than the human eye, our optical sensor analyzes microscopic oil contaminants to give definitive percentage and temperature readings—eliminating maintenance guesswork. How accurate is it compared to just looking at the oil color? More accurate than the human eye, our optical sensor analyzes microscopic oil contaminants to give definitive percentage and temperature readings—eliminating maintenance guesswork. Does it work on both old and new cars, and for diesel trucks? Yes! It is universally compatible with the majority of gasoline and diesel engine oils on the market. Separate testing modes ensure accurate assessment for each engine type, whether it's your daily car, SUV, or diesel pickup truck. Does it work on both old and new cars, and for diesel trucks? Yes! It is universally compatible with the majority of gasoline and diesel engine oils on the market. Separate testing modes ensure accurate assessment for each engine type, whether it's your daily car, SUV, or diesel pickup truck. Why should I buy this instead of just changing my oil regularly? It helps you change oil smartly,not just regularly.It prevents you from changing oil too early (saving money)or too late (preventing engine damage).It's the fastest way to know if your oil is still good,optimizing both engine health and your wallet. Why should I buy this instead of just changing my oil regularly? It helps you change oil smartly,not just regularly.It prevents you from changing oil too early (saving money)or too late (preventing engine damage).It's the fastest way to know if your oil is still good,optimizing both engine health and your wallet. How do I know this is a reliable brand? The AS503 is built with professional-grade components like a PTFE-coated probe and a robust optical sensor. It comes with a clear manual and is trusted by DIYers and professionals for its simple, dependable readings. Your satisfaction is guaranteed. How do I know this is a reliable brand? The AS503 is built with professional-grade components like a PTFE-coated probe and a robust optical sensor. It comes with a clear manual and is trusted by DIYers and professionals for its simple, dependable readings. Your satisfaction is guaranteed. Review: A good mechanics tool - Works well let's you know if its time for an oil change for diesel or regular gas powered engines not to expensive easy to use Review: Excelente - Excelente herramienta ## Features - 👍 HIGH-PRECISION OPTICAL TEST — KNOW EXACTLY WHEN TO CHANGE OIL AS503 measures oil transmittance 0-100% in just 2 seconds via advanced optoelectronic sensor. Clear OK/Replace/Warning indicators help detect impurities or metal particles before they cause engine damage. Ideal for DIY owners checking oil health before road trips. - 👍 GASOLINE & DIESEL DUAL MODE — PRECISE ASSESSMENT FOR ANY VEHICLE Separate sampling and measurement algorithms for gasoline and diesel oils ensure optimized accuracy. Whether you drive a sedan, a heavy-duty truck, or a weekend project car, AS503 delivers consistent, reliable readings every time. - 👍 800mm FLEXIBLE PTFE PROBE — TEST HARD-TO-REACH DIPSTICK TUBES WITH EASE The 31.5-inch flexible hose slides easily into narrow or angled dipstick paths. Made of oil-resistant, oxidation-proof PTFE material, it withstands repeated use and lasts significantly longer than rigid probe alternatives. - 👍 BUILT-IN TEMPERATURE SENSOR — VERIFY OIL TEMP BEFORE TESTING FOR ACCURACY Integrated gauge displays current temperature in °C/°F with a single press. Confirm your motor has reached proper operating warmth before measurement to ensure the most accurate transmittance reading possible. - 👍 2.8-INCH BACKLIT LCD & ERGONOMIC GRIP — CLEAR READINGS, ANYTIME, ANYWHERE Large high-resolution screen stays visible in low-light garages or bright sun. Silicone-lined body (only 363g) provides a secure, comfortable single-hand hold. No confusing codes — just straightforward OK/Replace results. - 👍 THREE YEARS WARRANTY, LIFETIME MAINTENANCE For the damage caused by non-human factors, we promises to resend the parts for free within 3 years. For any demand, we warmly welcome you to contact us, and we will reply you as soon as possible within 24 hours. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0CG99ZLX7 | | Brand | QPKING | | Customer Reviews | 4.4 4.4 out of 5 stars (109) | | Date First Available | August 22, 2023 | | Item Weight | 13.1 ounces | | Item model number | AS503 engine oil tester | | Manufacturer | QPKING | | Manufacturer Part Number | AS503 Motoröl-Qualitätsprüfgerät | | Model | oil quality tester | | Package Dimensions | 10.04 x 5.59 x 2.32 inches | ## Images ![AS503 Engine Oil Tester - Optical Transmittance Analyzer for Gasoline & Diesel, 31.5-inch Flexible Probe, 2.8-inch Backlit LCD, Oil Temperature Gauge in °C/°F - Image 1](https://m.media-amazon.com/images/I/61J2FHUeZsL.jpg) ![AS503 Engine Oil Tester - Optical Transmittance Analyzer for Gasoline & Diesel, 31.5-inch Flexible Probe, 2.8-inch Backlit LCD, Oil Temperature Gauge in °C/°F - Image 2](https://m.media-amazon.com/images/I/71HNvkH99mL.jpg) ![AS503 Engine Oil Tester - Optical Transmittance Analyzer for Gasoline & Diesel, 31.5-inch Flexible Probe, 2.8-inch Backlit LCD, Oil Temperature Gauge in °C/°F - Image 3](https://m.media-amazon.com/images/I/71K4yX7kjXL.jpg) ![AS503 Engine Oil Tester - Optical Transmittance Analyzer for Gasoline & Diesel, 31.5-inch Flexible Probe, 2.8-inch Backlit LCD, Oil Temperature Gauge in °C/°F - Image 4](https://m.media-amazon.com/images/I/71azZM-mblL.jpg) ![AS503 Engine Oil Tester - Optical Transmittance Analyzer for Gasoline & Diesel, 31.5-inch Flexible Probe, 2.8-inch Backlit LCD, Oil Temperature Gauge in °C/°F - Image 5](https://m.media-amazon.com/images/I/61BjIHDeKhL.jpg) ## Questions & Answers **Q: Is this easy to use for someone who's not a mechanic?** A: Absolutely! It's designed for everyone.Just wipe the probe, select your engine type(gasoline or diesel), dip it in the oil, and press the button.You'll get a clear "OK" or "Replace" result on the large screen in seconds—no technical knowledge needed. **Q: How accurate is it compared to just looking at the oil color?** A: More accurate than the human eye, our optical sensor analyzes microscopic oil contaminants to give definitive percentage and temperature readings—eliminating maintenance guesswork. **Q: Does it work on both old and new cars, and for diesel trucks?** A: Yes! It is universally compatible with the majority of gasoline and diesel engine oils on the market. Separate testing modes ensure accurate assessment for each engine type, whether it's your daily car, SUV, or diesel pickup truck. **Q: Why should I buy this instead of just changing my oil regularly?** A: It helps you change oil smartly,not just regularly.It prevents you from changing oil too early (saving money)or too late (preventing engine damage).It's the fastest way to know if your oil is still good,optimizing both engine health and your wallet. **Q: How do I know this is a reliable brand?** A: The AS503 is built with professional-grade components like a PTFE-coated probe and a robust optical sensor. It comes with a clear manual and is trusted by DIYers and professionals for its simple, dependable readings. Your satisfaction is guaranteed. ## Customer Reviews ### ⭐⭐⭐⭐⭐ A good mechanics tool *by J***N on February 24, 2026* Works well let's you know if its time for an oil change for diesel or regular gas powered engines not to expensive easy to use ### ⭐⭐⭐⭐⭐ Excelente *by E***O on February 5, 2026* Excelente herramienta ### ⭐⭐⭐⭐⭐ Excelente *by V***7 on October 23, 2025* De buena calidad y duradero ## Frequently Bought Together - Engine Oil Quality Tester AS503 Engine Oil Tester for Gasoline Diesel Vehicles With 2.8"Screen High-Precision Detection Probe,Transmittance&Oil Temp.Display,Compatible With Various Lubricant Standards - TYRAREX Automotive Transmission Fluid Tester Oil Analyzer Detector with Temperature Sensor, Gasoline & Diesel Gearbox Oil Diagnostic Tool with 31.5in Hose 2.8in Backlight Display (T20) - Brake Fluid Tester, High Precision Car Brake Fluid Detector, Hydraulic Fluid/Liquid/Oil Moisture Analyzer with LCD Screen Audible Alarm DOT3 DOT4 DOT5.1 Tester,Automotive Replacement Level Sensors --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.jp/products/585925504-as503-engine-oil-tester-optical-transmittance-analyzer-for-gasoline-diesel](https://www.desertcart.jp/products/585925504-as503-engine-oil-tester-optical-transmittance-analyzer-for-gasoline-diesel) --- *Product available on Desertcart Japan* *Store origin: JP* *Last updated: 2026-05-20*