Loctite 37535 Dielectric Tune-Up Grease
Priced as of May 22, 2026
4.8(464 ratings)Buy on AmazonSaved to your guest loadout. Sign up to also save to your Cabinet (consumables) or Kit (tools you own).
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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.
From the Safety Data Sheet
Full SDS ↗ (rev. 2025-11-12)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.
EyesSituationalMfr. SDS §8Skin—No PPE in published sourcesLungsSituationalMfr. SDS §8Ventilation—No PPE in published sourcesShow details for all categories ▾Hide details ▴
From the manufacturer’s Safety Data Sheet, Section 8
“SDS §2 (Rev 004.1) carries no H319 classification. Back-of-bottle 'May cause eye irritation' is pre-2025 label copy not reflected in current GHS classification. Situational tier from splash_risk — incidental eye contact during handling is the only residual pathway given boilerplate-only language.”
— Loctite
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 skin. Absence does not imply “not needed” — consult the full Safety Data Sheet.
From the manufacturer’s Safety Data Sheet, Section 8
“No inhalation H-codes classified in SDS §2. Silicone paste is non-volatile at application temperatures. Situational tier for enclosed spaces per health.md — not_needed is schema-invalid for chemical products.”
— Loctite
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.
The Podium · Top 3 in Dielectric Grease
See the full ranking →This product ranks #4 of 6 in Dielectric Grease.Three above it ↓
CarCareTruth's Analysis
Last reviewed May 25, 2026
TL;DR Solid protection for spark plug boots, trailer connectors, and battery terminals; community satisfaction is high at 4.8 stars across 464 reviews, though no multi-season community teardown data is available to confirm long-term hold.
What it is and how it performs
This Loctite tube lays a moisture-proof silicone barrier on spark plug boots, trailer hitch connectors, and battery terminals, blocking salt, dirt, and water to stop pin oxidation and voltage leakage. A thin coat inside a boot or on connector pins takes under a minute. The standard 80ml tube works well for routine home service; apply sparingly to avoid flooding multi-pin connectors.
Who should buy this — and who should skip it
Best for anyone doing a spark plug service, maintaining trailer or tow-vehicle connectors, or protecting battery terminals in a wet climate. The tube format is cost-effective for multi-vehicle households. Skip it if you only need one connector's worth; a single-use packet from a generic brand costs less.
Safety and environmental impact
The 2025 SDS carries no GHS hazard classifications; the signal word is absent. A California Prop 65 listing appears in SDS §15, related to a substance in the formulation. Lungs: situational (enclosed space). Eyes: situational (splash risk).
Frequently asked questions
How does Loctite 37535 Dielectric Tune-Up Grease score on CarCareTruth?▾
CarCareTruth scores Loctite 37535 Dielectric Tune-Up Grease at 7.2 out of 10 on the composite CCT score, with a health sub-score of 8.8/10. The CCT score blends real-world effectiveness, ingredient health impact pulled from the manufacturer's safety sheet, and environmental footprint against a published category rubric. See the methodology link on this page for the full scoring breakdown.
What's in Loctite 37535 Dielectric Tune-Up Grease?▾
Per the Safety Data Sheet ingredient disclosure: Silica, amorphous, fumed, crystal-free (CAS 112945-52-5): 5–10% — thickening agent. Silicone Resin (PDMS base, proprietary, no CAS): balance. Source: SDS Rev 004.1, 2025-11-12, Henkel API (IDH 495549).
From the manufacturer
Marketing copy from Loctite, via Amazon. Not editorial.
- •Provides a moisture-proof barrier that lubricates and protects electrical connections and wiring from salt, dirt and corrosion
- •Extends the life of bulb sockets
- •Prevents voltage leakage around electrical connections
- •Typical applications include marine and automotive electrical connections, spark plug boots, trailer hitches and battery terminals
- •Resistant Properties: corrosion-resistant, dirt-resistant, salt-resistant
- •Fit type: Vehicle Specific
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Manufacturer videos
Manufacturer images
Manufacturer specifications
- Manufacturer
- Loctite
- Brand
- Loctite
- Model
- LOCTITE
- Item Weight
- 3.2 ounces
- Product Dimensions
- 8 x 3.81 x 1.05 inches
- Item model number
- 495549
- Is Discontinued By Manufacturer
- No
- Exterior
- Machined
- Manufacturer Part Number
- 495549
- OEM Part Number
- 37535
- Viscosity
- Semi-Solid
- ASIN
- B003XZFIF6
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