Schaeffer Manufacturing Co SynShield OTR Plus 5W-40 Full Synthetic Diesel Engine Oil — 1-Quart Bottles (Pack of 12), API CK-4, DPF

Designed for on- and off-road heavy-duty diesel applications, this 1-quart bottle sold in a pack of 12 brings a balanced combination of high-temperature strength and cold-start performance. Formulated to meet API CK-4 standards, SynShield OTR Plus 5W-40 works with 2007 and 2010 emission-compliant systems that use heavy EGR and after-treatment devices such as DPFs, DOCs and SCR. Proprietary friction modifiers and advanced detergency help control soot and deposits so engines run cleaner and more efficiently.

How does SynShield OTR Plus protect engines under heavy duty conditions?

SynShield OTR Plus is built to resist wear and thermal breakdown in high-stress diesel environments. Its full synthetic base provides a stronger oil film at elevated temperatures while additives minimize metal-to-metal contact and reduce abrasive wear from soot.

• Friction modifiers Micron Moly and Penetro form a protective, slippery layer.
• High-heat stability maintains oil strength under heavy loads.
• Detergents and dispersants combat soot-related abrasion and deposits.

Will this oil work with emission systems like DPFs and SCR?

Yes — SynShield OTR Plus 5W-40 is formulated for 2007 and newer diesel engines that use heavy EGR and exhaust after-treatment systems. Its low-ash and soot-control chemistry help maintain after-treatment performance while protecting internal components.

• Compatible with diesel particulate filters (DPFs) and diesel oxidation catalysts (DOCs).
• Formulated to support engines with selective catalytic reduction (SCR) systems.
• Designed to meet API CK-4 requirements for modern diesel service.

How does SynShield OTR Plus perform in cold starts and fuel-efficiency goals?

The 5W-40 viscosity gives reliable cold weather startability while preserving a fluid film that improves mechanical efficiency at operating temperature. The formulation aims to deliver measurable fuel-economy benefits without sacrificing wear protection.

• 5W low-temperature rating ensures easier cranking and faster oil flow at startup.
• Full synthetic base reduces internal friction for improved efficiency.
• Balanced additive package helps maintain fuel economy over service intervals.

What maintenance advantages can a fleet or owner expect from this pack size?

Buying SynShield OTR Plus in a 12-quart pack simplifies inventory and reduces the frequency of reorder for commercial operations. The individual 1-quart bottles are convenient for topping off reservoirs or servicing small-to-medium equipment without bulk handling.

• Pack of 12 one-quart bottles keeps spares on hand for scheduled service.
• Smaller bottles reduce waste and simplify storage in service bays.
• Individual bottles are portable for field technicians and mobile service rigs.

Who is this for? Schaeffer SynShield OTR Plus 5W-40 is aimed at fleet managers, heavy-equipment operators and diesel owners running 2007-and-newer emission-compliant engines who need a synthetic engine oil that balances cold-start performance, high-temperature durability and soot control. It’s a practical choice for mixed-use fleets, construction equipment, long-haul trucks and any application where API CK-4 performance with after-treatment compatibility is required.