Description

Scania R, T 1999 Installation Manual – Webasto DW80 Coolant Heater Retrofit

You’ve got a Scania R or T needing a pre-heater install, and the last thing you want is a coolant leak at 3 AM or a fire from a pinched fuel line. I’ve seen aftermarket instructions that skip the routing steps and leave you guessing which grommet goes where. This 40-page factory manual from 1999 is what Scania sent to dealers for the Webasto DW80 retrofit. It tells you exactly where to drill, which cable ties to use, and how to prime the fuel system without introducing air. If you’re working on a truck with ADR (hazardous cargo) equipment, it even flags the alternative control unit location. That’s the kind of detail that keeps you from having to redo the job.

Manual Scope: What’s Inside the 40 Pages

The contents are laid out like a job sequence. You start with General info – left-hand drive vehicles only, ADR notes, VPS control unit positioning. Then the Short work description splits cab work (operation unit, floor harness, instrument harness) from outside work (heater mounting, exhaust, fuel lines, coolant connections). Preparations on page 5 drops you straight into removing interior parts: covers under the dash, central storage boxes, lower bed fall-out-protection with snap-on connections, and the gas damper for the bed. That’s not something you guess – you need the clip locations or you break trim.

Routing of Cable Harnesses – Factory Loom Paths

Chapter 4 walks you through the floor cable harness and instrument cable harness routing. The manual shows you the exact pathways to avoid chafing against the steering column or sharp edges. You’ll also run the fuel pump cable harness along the chassis to the dosage pump. Miss one tie-down point and that harness can drop into the driveshaft. That’s a tow-truck call. If you’ve ever fought a generic wiring diagram, this chapter is worth the price alone.

Fuel System and Fuel Pump – Not Just a Hose Clamp

The Fuel system and fuel pump cable harness section (page 25 in the PDF) covers routing fuel lines from the tank to the heater, fitting the dosage pump to the chassis, and securing the pump harness. The manual specifies the correct fuel line material and filter orientation. Scania doesn’t use universal parts – the dosage pump bracket has a specific location to avoid heat from the exhaust. One mistake here and the pump cavitates or the rubber line melts. I’ve seen it.

Torque Specs and Fluid Capacities – What This Manual Does and Doesn’t Cover

Let me be clear: this is an installation manual, not a full service manual. You won’t find engine head bolt torque values or transmission fluid capacities. What you get are the specific torque values for the Webasto heater mounting bolts and coolant hose clamps. Those are critical – overtorque the aluminum heater housing and you crack it. The manual also shows you how to bleed the coolant system after connecting the heater. Use a proper pressure tester, not your thumb over the reservoir neck.

3 Reasons to Choose OEM Documentation over Aftermarket

First, the OEM manual references Scania’s own part numbers for the heater kit, grommets, and cable ties. Aftermarket copies often substitute generic parts that don’t fit the R/T cab profile. Second, the wiring diagrams are Scania-specific – they show the exact pin positions on the cab connector and the correct wire gauge for a 24V system. Third, the safety warnings are those you can trust: e.g., for ADR vehicles you have to fit a solenoid valve for combustion air. No aftermarket hack mentions that because they don’t know the regulation. This manual was printed by Scania CV AB in 1999 – it’s the real thing.

Who Needs This Manual?

If you own a Scania R or T series truck and you’re retrofitting a Webasto DW80 coolant heater – this is your blueprint. It’s also for fleet shops that need to standardize installs across multiple trucks. A DIYer who can follow sequenced removal steps and has basic mechanical skills can handle this job with the manual. But you’ll need a proper tool list: torx bits, trim tools, a coolant pressure tester, cable tie gun, and a multimeter to check the fuel pump circuit. I don’t hand a rookie a manual and say “go for it” – I tell them to read the Short work description first, then lay out their tools. That’s how you avoid stripping screws on the bed fall-out-protection.

Fuel System – A Closer Look at the Dosage Pump Routing

The Fuel system and fuel pump cable harness chapter (page 25) is where you’ll spend time. The manual tells you to start at the tank, run the line along the chassis rail using the existing clips, then route it up to the heater. The dosage pump (fuel metering pump) must be installed within 15° of horizontal – if you tilt it, you get air locks. The control unit harness connects through a specific grommet in the cab floor that the manual shows with a dimensioned drawing. Run the harness first, then the fuel line. Sequence matters.

FAQ – Installation Manual Specifics

Does this manual cover both the R and T models?

Yes – it explicitly says for R and T vehicles, with and without ADR equipment.

I’m an experienced mechanic – why would I need a 40-page heater installation guide?

Because the ADR regulations vary by country, and this manual cites local regulations for the country in question – you have to observe them. Also, the routing of cable harnesses inside the cab differs depending on whether your truck has VPS (Vehicle Protection System). The control unit mount changes if ADR and VPS are both present. Missing one bracket can cause a fault code on the Webasto. And you get the exact part numbers for the fuel pump cable harness – not a generic “12V pump.” Plus, the coolant connection diagram shows you how to tee into the existing heater hoses without restricting flow to the engine block heater. That’s time saved not chasing wire diagrams.

If you’re retrofitting a Webasto DW80 into a Scania R or T, you need the factory steps. The manual tells you which interior panels come off first, where the fuel line crosses the chassis, and how to test the system before buttoning up. I’ve had guys ask if they can skip the “Using the heater for the first time” checklist on page 40 – I tell them that’s how you get air in the fuel line and a no-start first cold morning. Access the Factory Manual and keep it in your truck’s binder. It’s 40 pages, A4, printed on Scania’s own template – that’s what you pay for.

Related manuals you might need: Scania D1LC Eberspacher Heater Installation Manual for the Eberspächer alternative, Scania CP19 CR19 CT19 Topline Satcom Installation Manual for communication equipment installs, and Scania Fleet Analysis System 2 Installation Manual if you’re wiring telematics. For generic principles on Manual Transmission maintenance, see Wikipedia; for heavy-duty clutch alignment, check Manual Transmission guides.