CarCareTruth Score
Decent, but it's tough on the environment.
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Prices may varyHealth score is for adult use as intended, per the manufacturer's SDS. It does not model child ingestion, accidental spill cleanup, or off-label use. See the safety panel below for full hazard classification, and /disclaimer for the full editorial scope.
GHS hazard codes are quoted from the manufacturer’s Safety Data Sheet. PPE tiers below translate those codes and the listed ingredient chemistry; they are not CarCareTruth recommendations.
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Translated from the manufacturer’s Safety Data Sheet, Section 2
SDS §2 classifies H319 (causes serious eye irritation). Standard consumer bottle poured into a narrow fuel-tank fill neck makes drip-back realistic · recommended tier per category default.
U.S. regulatory standard
29 CFR 1910.133(a)(1)
“The employer shall ensure that each affected employee uses appropriate eye or face protection when exposed to eye or face hazards from… liquid chemicals…”
ANSI Z87.1 (incorporated via §1910.6)
OSHA standards apply to workplaces. Cited here as the U.S. reference threshold for the underlying hazard class.
CarCareTruth publishes the cited sources verbatim and does not advise what action a user should take. Consult the full SDS before use.
Translated from the manufacturer’s Safety Data Sheet, Section 2
SDS §2 classifies both H315 (skin irritation) and H317 (may cause an allergic skin reaction). The combination of an irritant and a sensitizer at concentrate strength escalates skin tier from situational to recommended.
U.S. regulatory standard
29 CFR 1910.138(a)
“appropriate hand protection when employees' hands are exposed to hazards such as those from… chemicals which produce an adverse effect on the skin or eyes…”
OSHA standards apply to workplaces. Cited here as the U.S. reference threshold for the underlying hazard class.
CarCareTruth publishes the cited sources verbatim and does not advise what action a user should take. Consult the full SDS before use.
Only when: in enclosed space · hot panels
Translated from the manufacturer’s Safety Data Sheet, Section 8
SDS Section 8 names a NIOSH-certified air purifying respirator with organic vapor cartridges only conditionally, for airborne exposure above the established limit or where ventilation is inadequate; Section 4 separately notes that oil mist generated at elevated temperature may cause respiratory irritation. Section 2 carries no respiratory GHS code (no H330, H331, H334, or H335), so this is a ventilation/heat precaution, not a mixture-level inhalation hazard for a normal-temperature pour.
CarCareTruth publishes the cited sources verbatim and does not advise what action a user should take. Consult the full SDS before use.
No PPE specified in published sources for ventilation. Absence does not imply “not needed” — consult the full Safety Data Sheet.
PPE tiers translate the manufacturer’s SDS and U.S. regulatory standards. Not professional safety advice. How we report safety.
Scope of these PPE tiers. The tiers on this page translate the product's Safety Data Sheet where one is published, plus its ingredient chemistry, into a comparable rating. They describe a formulation, not a situation: a tier is not a safety determination for any specific user, task, quantity, or environment. The manufacturer's label and use instructions govern how the product is handled. Where the product is used at work, the employer's PPE program and hazard assessment under 29 CFR 1910.132 decide what protection is selected, not this page.
No warranties. CarCareTruth makes no warranties, express or implied, and expressly disclaims the implied warranties of merchantability and fitness for a particular purpose.
This product ranks #3 of 16 in Fuel Injector Cleaner.
Last reviewed July 8, 2026
TL;DR PEA chemistry confirmed as the active · the detergent class with the most independent research behind injector and intake valve deposit removal. Highly rated on Amazon and a genuine category favorite, with borescope-documented GDI intake valve results in community threads. No independent SAE paper specific to this product.
SI-1 uses PEA (the detergent class most studied for injector deposit dissolution and intake valve carbon removal), confirmed directly in the US SDS. Protocol: full bottle into a near-empty tank for initial cleaning, then half-bottle every 1,500 miles for maintenance. Community evidence is specific: a long-running BITOG thread includes borescope images of GDI intake valve deposits before and after treatment, with follow-ups at 3,000+ miles. No product-specific SAE paper or dyno test found.
Best for owners running non-Top Tier fuel who want a concentrated PEA treatment · one-tank flush for suspected deposits or a 1,500-mile maintenance cadence. GDI owners with intake valve carbon concerns are a strong fit. Skip it if you always run Top Tier certified gasoline, which already includes the detergent package that prevents deposit buildup. Skip it for severe rough idle or stalling · one bottle is not a substitute for professional ultrasonic cleaning.
SDS §2: WARNING with H315 (skin irritation), H317 (skin sensitizer), H319 (eye irritation), and H412 (aquatic toxicity, chronic). No respiratory H-codes appear at mixture level · the low-volatility carrier means inhalation exposure during the pour is negligible. The product listing carries a Prop 65 warning; SDS §15 names the specific Prop 65 substance. The product combusts in the engine · exhaust byproducts are the environmental endpoint.
The US SDS for Red Line SI-1 (document 830019) lists polyetheramine, also written polyether amine or PEA (CAS 224622-34-8), in Section 3 at less than 30% by weight. PEA is the detergent active. The SDS gives a ceiling, not an exact figure, so it confirms the upper bound but not a precise percentage. The carrier is a low-volatility hydrotreated naphthenic petroleum distillate. The SDS revision on file is dated 2018-01-30.
The listing for Red Line SI-1 Complete Fuel System Cleaner carries a California Prop 65 warning. Red Line SI-1 Complete Fuel System Cleaner is a working automotive fluid rather than a passive part, so the warning points at the formulation itself. The manufacturer's Safety Data Sheet is the primary source for what is in it: the hazard classification and the PPE tiers on this page are translated from that sheet, and the full SDS is linked from the safety panel. California requires the warning whenever exposure to any of roughly 900 listed substances is possible. It does not name which substance applies to a given product, and it states no dose or risk level, so it is not on its own a measure of how hazardous this fluid is in normal use.
Marketing copy from Red Line, via Amazon. Not editorial.
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