Skip to product information
Usually ships in 2–4 business days.
Air Heater 129100-77501 129120-77502 For Thermo King Yanmar Engine 4TNV 84 88 94
$214.99
Sale price
$214.99
Regular price
Available to Order
This intake air heater is a dependable aftermarket replacement for compatible Thermo King and Yanmar applications and helps improve cold-start performance in compatible diesel engines.
Not sure which part fits your equipment?
Our Northline Parts team can help you find the right replacement. Support Hours: Monday–Friday, 8:00 AM–5:00 PM CT | Live Chat: Available 24/7
I reached out for some replacement head bolts and they responded quickly with a few questions and cautionary information and is sending me some bolts. Great customer service! Thanks
Edward H. — Verified customer
Product Overview
The intake air heater warms incoming air during cold starts so diesel fuel can ignite more reliably. A failed heater may contribute to extended cranking, white smoke, or difficult starting in low temperatures.
Verify 129100-77501 or 129120-77502 on the original component, along with the part number, voltage, thread or mounting style, terminal location, and engine application.
Key Features & Performance
- Supports cold-weather starting
- Heats intake air before combustion
- Designed for compatible diesel electrical systems
- Replacement for a failed intake heater
Fitment & Compatibility
Compatible with select Thermo King Yanmar Engine 4TNV 84 88 94 applications. Serial-number breaks, production changes, or equipment options may affect the required part.
Technical Specifications
- Product Type: Intake Air Heater
- Compatible Brand: Thermo King, Yanmar
- Part Number(s): 129100-77501, 129120-77502
Frequently Asked Questions
Q: Can a failed air heater cause hard cold starts? A: Yes. Cold-start problems can also involve batteries, fuel delivery, compression, and control circuits, so diagnosis is recommended.
Q: Is this an original OEM part? A: This is an aftermarket replacement; brand names and part numbers are used only to identify compatibility.
Model listings are a guide only. Compare the original component and all available fitment details before purchase.