Why UAE Heat Changes Everything
The OBS cooling system was designed and tested in Michigan. Not on the E311 in August. The stock radiator is a two-row aluminium unit that was adequate for its original operating environment — but the UAE adds roughly 20–25°C of ambient temperature on top of whatever the engine is generating, and that margin disappears fast under load, in traffic, or towing.
Three components work together to keep the engine in its operating range: the radiator dissipates heat through airflow, the fan clutch pulls air through the radiator when airflow is insufficient (i.e. at low speed or stationary), and the thermostat controls when coolant begins circulating. When any one of these is compromised, the others are immediately overloaded. In the UAE, all three are likely overdue for attention on a 25-30 year old truck.
The fan clutch is the most commonly overlooked. A worn fan clutch freewheels — it spins but doesn't bite — and in stop-start UAE traffic where ram air through the radiator is minimal, it is the difference between a stable temperature gauge and a roadside recovery call on the 311. Ask me how I know.
What You Actually Gain
What You Need
Mandatory — Replace All Three Together
- HD 3-Row Aluminium Radiator (direct fit) CSF 3177 / Spectra CU2155 or equivalent HD unit
- Heavy-Duty Fan Clutch ACDelco 15-4565 / Hayden 2747
- Fan Blade (inspect — replace if cracked or bent) ACDelco 15-80011 or equivalent
- Thermostat — 82°C (180°F) rating ACDelco 131-139 / Stant 45359
- Thermostat Housing Gasket Felpro 35584
- Coolant — OAT or HOAT type, pre-mixed (5L minimum) ACDelco 10-101 or equivalent — NOT generic green
Do At The Same Time — See Guide 1.3c
- Upper and lower radiator hoses Gates 21369 / 21461 or equivalent
- Heater hoses (inspect — replace if soft or cracked) Gates or ACDelco equivalent
- Radiator cap — 15 PSI Stant 10230 or equivalent
Coolant type matters in the UAE. Do not use generic green coolant — it is silicate-based and incompatible with the aluminium components in the OBS cooling system. Use OAT (orange) or HOAT (yellow/gold) coolant only. Mixed coolant types cause accelerated corrosion and gel formation that blocks the radiator. If you don't know what's in there, flush it completely before refilling.
What It Will Cost (AED)
| Item | Source | Est. Price (AED) |
|---|---|---|
| HD 3-Row Radiator | Sharjah Industrial / order online | 600 – 1,100 |
| HD Fan Clutch | Sharjah Industrial / ACDelco distributor | 180 – 320 |
| Fan Blade | Sharjah Industrial | 80 – 160 |
| Thermostat + Gasket | Sharjah Industrial | 40 – 80 |
| Coolant — OAT/HOAT (5L) | Any quality auto parts | 60 – 120 |
| Radiator hoses (pair) | Sharjah Industrial | 80 – 150 |
| Labour | Independent Sharjah mechanic | 250 – 450 |
| Total — Full Job | 1,200 – 2,350 |
HD radiators vary significantly in quality. Avoid the cheapest units — a poor quality radiator will fail within a year in UAE heat. Mid-range CSF or Spectra units are the sweet spot for price vs reliability.
Where to Find the Parts
Sharjah Industrial Area 1
- Bin Duman Auto Spare Parts — radiators
- Yankees Auto Parts — fan clutch, thermostat
- ACDelco distributors — fan clutch, coolant
- Al Haramain — hoses and general cooling parts
Call ahead with part numbers. HD radiators for American trucks are sometimes stocked, sometimes order-in. Allow a day if ordering.
Alternative Sourcing
- Aramex Shop & Ship from RockAuto (US) for radiator
- VEGA Auto — Al Quoz, Dubai
- Carrefour / Autozone equivalent for coolant
RockAuto pricing on radiators is often significantly better than UAE retail. Factor in 7–10 days shipping and Aramex fees against urgency.
Check Yours Before Ordering
Before spending money, test the fan clutch. With the engine completely cold and the ignition off, grab the fan blade and try to spin it by hand. A good fan clutch will have some resistance and spin no more than one or two revolutions. A worn clutch will spin freely with almost no resistance — like a pinwheel. If it spins freely: replace it. No further diagnosis needed.
A second test: with the engine fully warmed up and at idle, listen for the fan. A functioning fan clutch should be clearly audible — a strong, consistent air-moving noise, particularly when the engine is under thermal load. If it sounds like nothing is happening, the clutch is slipping.
The Process
- Allow engine to cool completely. Drain coolant from radiator drain plug into a suitable container — do not pour old coolant down a drain.
- Remove the upper and lower radiator hoses. Remove transmission cooler lines from the radiator if fitted (have rags ready — fluid will drain).
- Remove the radiator shroud — usually two bolts at the top, clips at the bottom.
- Remove fan blade and clutch assembly from the water pump. Note: the fan clutch nut is reverse-threaded on most OBS trucks — turn clockwise to loosen. A fan clutch wrench (available in Sharjah tool shops) makes this much easier.
- Lift the radiator straight up and out. It is not heavy but is awkward — have a second pair of hands if possible.
- Inspect the radiator core for damage while you have it out. A workshop can pressure-test the old unit if you want to confirm it's failed rather than guessing.
- Install new radiator. Reconnect transmission cooler lines if fitted.
- Replace thermostat — drain enough coolant from the block first. Clean the housing face. Install new gasket with no sealant unless the gasket manufacturer specifies it.
- Install new fan clutch onto water pump. Torque to spec — reverse thread, so turn anti-clockwise to tighten.
- Install new fan blade. Ensure it is seated fully on the clutch.
- Refit radiator shroud. Connect new upper and lower hoses.
- Fill with fresh OAT/HOAT coolant. Run engine with heater on full to purge air. Top up as required. Check for leaks at all connections.
Hand This Over
"Replace the radiator with the HD unit provided, replace the fan clutch and fan blade, and replace the thermostat with the 82°C unit. The fan clutch nut is reverse-threaded — clockwise to loosen, anti-clockwise to tighten. Flush the entire cooling system before refilling — do not mix old and new coolant. Refill with OAT or HOAT coolant only — not green silicate coolant. Run the engine with the heater on full heat to bleed air from the system. Check all connections for leaks before returning the vehicle."
This Guide Covers
Verify radiator and fan clutch part numbers against your specific engine — 5.7L (350) and 5.0L (305) have slightly different specifications. The 5.7L is by far the most common in UAE trucks.
Complete the Cooling System
- Related — 1.3b Auxiliary Transmission Cooler — the 4L60E runs hot in UAE traffic. An external cooler bypasses the radiator's built-in transmission cooler, dropping transmission temperatures significantly. Independent job.
- Do Alongside — 1.3c Hoses, Coolant Flush & UAE Maintenance Schedule — while the cooling system is open, replace every rubber hose. It costs little extra in labour and prevents the next roadside incident.