




ATS Chemical 505 CRO Oil System Treatment is a 12 oz engine oil additive formulated to dissolve sludge, free sticky valvetrain components, reduce emissions, and help restore smooth idle and performance in gas and diesel engines.
Designed for use during an oil change or added to existing oil, this concentrated formula targets varnish and deposits that build up in high‑mileage engines. It works with conventional and synthetic lubricants and is meant to address common oil‑system blockages without requiring disassembly. Use as directed to improve oil flow, reduce mechanical noise, and help the engine run more efficiently.
The formula contains solvents and detergents that break down hardened deposits and suspend loosened sludge so it can be drained out with the old oil. It loosens sticky rings and lifters by dissolving varnish that restricts movement, helping restore normal oil circulation.
By cleaning oil passages and freeing sticking components, the treatment can reduce oil burning and incomplete combustion that contribute to visible smoke and higher tailpipe emissions. Results depend on the engine’s condition; severe internal damage may limit improvement.
Yes—clearing varnish and restoring oil pressure to valvetrain components often reduces tapping and rattling noises and smooths idle. It’s most effective when noises are caused by restricted oil flow rather than worn mechanical parts.
Add the recommended 12 oz dose to the crankcase during an oil change or into warm running oil as instructed on the label. Allow the engine to run for the specified soak period before draining so solvents can work; some users notice quieter operation and better responsiveness after one treatment, while heavier deposits may require repeated use.
Who is this for: ATS Chemical 505 CRO is intended for owners and technicians servicing high‑mileage or deposit‑laden gasoline and diesel engines who want to address sticking valvetrain parts, reduce oil‑related smoke, and recover smoother idle and performance without teardown. It’s suitable for vehicles showing symptoms of restricted oil flow—noisy lifters, sluggish phasers, or elevated oil consumption—but not a substitute for repairs when mechanical wear or hardware failure is present.
Q: Is ATS Chemical 505 safe for turbocharged engines?
A: Yes, when used as directed, it’s compatible with turbocharged gasoline and diesel engines and helps clear deposits that can affect turbo oil flow.
Q: Can I add 505 CRO to existing oil between oil changes?
A: You can add it to warm running oil for a soak, but follow label dosing and run the engine the recommended time before draining for best results.
Free shipping across Canada on every order, with no minimum. Orders are processed within 1 business day and standard delivery across Canada usually takes 2 to 5 business days after processing, with tracking by email. See the shipping policy.
Free 30-day returns. You have 30 days from delivery to start a return. Return shipping is free: email us your order number and we send a prepaid label. See the return & refund policy.
Not sure it fits? Email northtrailauto@gmail.com with your year, make, model and engine and we reply within 1 business day.










