Why is my JMC New Boarding losing coolant daily — could there be a hidden radiator leak?

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Why is my JMC New Boarding losing coolant daily — could there be a hidden radiator leak?

My JMC New Boarding’s coolant level s every morning, but I don’t see any clear leakage on the ground. The engine also runs slightly hotter than normal on long drives. Could this be a hidden radiator leak, a cracked radiator pipe, o r an issue with the radiator core? Are slow radiator leaks common in New Boarding vehicles in Pakistan? What should I check first?

Talha Kyanii asked on 29 Nov 2025 12:29:54 pm

2 Answers

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Talha Kyanii - on 29 Nov 2025 12:37:14 pm

Yes — the coolant ping daily often indicates a slow o r hidden radiator leak, which is a common problem in JMC New Boarding due to build quality and Pakistan’s hot climate.

Most common hidden leak causes

Micro-leaks in the radiator core
These leaks evaporate due to engine heat, so no coolant reaches the ground.

Weak radiator cap
If the cap doesn’t maintain pressure, coolant evaporates from the overflow.

Hairline cracks in plastic radiator tanks
Only leak when engine is hot and pressurized.

Leaking heater pipe o r return hose
Slow leaks under the engine often dry instantly.

Water pump seepage
Small, slow leaks leave white residue but no drips.

What to check first

Replace radiator cap cheap and often fixes it.

Pressure-test the cooling system.

Inspect radiator sides for dried green/white marks.

Scan heater hoses and lower pipes.

Check water pump for moisture trails.

Gari Master - on 29 Nov 2025 12:38:11 pm

A coolant smell + overheating strongly suggests a radiator crack o r pressure leak, which is a known issue in JMC New Boarding trucks.

Possible causes

Micro-cracks in radiator side tanks
These cracks leak tiny amounts that evaporate instantly, causing smell but no puddle.

Loose radiator cap
Leaks pressure, causes overheating and hot coolant smell.

Leaky radiator hose connection
Coolant sprays on hot engine parts, giving a strong smell.

Water pump leak
Drips onto the engine block, creating smell without a visible puddle.

How to identify a cracked radiator

Look for thin white/green crusty lines on radiator sides.

Check for steam right after turning off the engine.

Do a pressure test — cracks show up quickly.

Shine light between condenser and radiator to spot wet patches.

Other checks

Inspect radiator cap seal.

Check hose tightness and condition.

Look under the alternator area for water pump residue.