How do I know a part fits my truck?

Every listing shows the truck make, model years, side (left/right) and OEM cross-reference numbers. Match any of your OEM numbers to the listing, or send us your number and we will confirm fitment.

Do you ship the same day?

Orders placed before 12PM Central on business days ship the same day from our US warehouse. Transit is typically 2–5 business days depending on your state.

What is your return policy?

30-day returns on unused parts in original packaging. Wrong part shipped by us? We cover the return label and ship the correct one first.

Do you offer fleet or shop pricing?

Yes. Business accounts get tiered pricing, saved reorders and a dedicated line. Open a business account to see your pricing and order online.

Are these OEM or aftermarket parts?

We sell quality aftermarket parts cross-referenced to OEM numbers, plus select OEM-grade lines. Brand and grade are shown on every listing.

Can I order by part number?

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Dayco OE Fan Belt Tensioner, Volvo D13 / Mack MP8 (89935)

Dayco OE fan belt tensioner for Volvo D13 and Mack MP8 engines (2018+). Maintains correct fan belt tension; replaces tensioners with weak springs or noisy bearings.

Brand
- Dayco
Quality Tier
- OEM
OEM Reference
- Dayco 89935
Condition
- New
Warranty
- 1-Year FleetPro Warranty

Wholesale pricing for approved accounts

Open a FleetPro business account to see fleet pricing and order online. Repair shops, trucking companies & dealers welcome.

Request a business account

Terms and Conditions
30-day returns on unused parts
Same-day shipping on orders before 12PM CT

Internal Reference: DAY89935

Same-day shipping before 12PM CT from our Illinois warehouse
Part requests and quotes answered within one business hour
30-day returns
1-Year FleetPro Warranty
Wholesale and fleet pricing for approved business accounts
We speak English, Russian, Ukrainian, Romanian, Bulgarian, French and Polish

Automatic Belt Tensioner, Specifications & Fitment

The Dayco 89935 is an OE-quality automatic accessory drive belt tensioner for Volvo D13 and Mack MP8 engines. It maintains constant spring tension across the serpentine drive so the belt tracks correctly through the full RPM range. A worn tensioner shows up as belt squeal on cold start, belt flutter or chirp, accelerated belt wear, and a noisy or wobbling pulley. Replacing it restores proper grip on the alternator, water pump, and fan drive.

Specifications

Type: Automatic spring-loaded tensioner assembly
Belt design: 12-rib serpentine (K-section)
Pulley diameter: 74 mm
Pulley width: 46.3 mm
Rotation: Counter-clockwise
Spring: Flat coil spring for reduced bearing load and quieter operation

Where it's used

Volvo D13 and Mack MP8 engines across Volvo VNL, VNM, VNR, VHD and Mack Anthem, Pinnacle, Granite, CHU, CXU and GU series. Installs on the front accessory drive, pivoting against the serpentine belt that turns the alternator, water pump and fan hub.

Cross references: Volvo 21714847 • Volvo 21461221 • Volvo 21417563 • Volvo 20582557 • Volvo 20582558 • Volvo 20860873

Product Details

Brand	Dayco
Quality Tier	OEM
OEM Reference	Dayco 89935
Condition	New
Warranty	1-Year FleetPro Warranty