Engine coolant is one of the easiest fluids to check and one of the most important in the UAE. When the temperature gauge climbs past halfway in August traffic, coolant is the only thing standing between your engine and a very expensive repair. Yet many drivers never look at it until a warning light forces the issue.
How to check coolant level the right way — where to look, what the level should be, and what to do if it’s low — is a five-minute job once you know how. This guide walks through the whole process, explains what coolant actually does in a hot climate, and covers the warning signs that mean you should stop driving rather than top up and carry on.
Quick Answer
- When to check: once a month, and before any long trip — always with the engine cold.
- Where to look: the translucent coolant reservoir (overflow tank) under the bonnet — not the radiator cap.
- Correct level: between the MIN and MAX (or LOW/FULL) marks on the reservoir side.
- Low level: top up with the correct coolant type, up to MAX — never overfill.
- Never open the radiator cap on a hot engine. Pressurised hot coolant can cause severe burns.
What Coolant Does — and Why It Matters More in the UAE
Coolant (also called antifreeze) circulates through the engine, absorbs heat, and releases it through the radiator. It also lubricates the water pump, prevents corrosion inside the cooling system, and stops the fluid from boiling over. Modern coolants are typically a 50/50 mix of antifreeze concentrate and distilled water — and that “antifreeze” name is misleading here, because in the UAE the anti-boil properties are what matter. A proper mix raises the boiling point well above 100°C, which is exactly what a 48°C day demands.
Losing coolant means losing cooling capacity. Even a slow leak can empty the system over weeks, and the damage from overheating — warped cylinder heads, blown head gaskets, cracked blocks — runs into thousands of dirhams. A monthly level check costs nothing. If your engine does start running hot, knowing how to recognize engine overheating early is the difference between a simple top-up and a tow truck.
How to Check Coolant Level, Step by Step
- Make sure the engine is cold. Check in the morning before starting the car, or at least a couple of hours after driving. Opening anything on a hot cooling system is dangerous.
- Open the bonnet and find the reservoir. It’s a translucent plastic tank (often white or yellowish) connected by a hose to the radiator, with MIN/MAX markings on the side. The radiator cap itself is usually a metal cap directly on top of the radiator or on a pressurised filler neck — leave it alone for this check.
- Read the level. Look through the reservoir wall at where the fluid sits relative to the marks. Between MIN and MAX is correct. Near MIN is a prompt to top up; below MIN is low.
- Check the fluid’s condition. Coolant is usually green, pink/red, orange, or blue depending on type. It should look clear. Rusty, brown, oily, or sludgy coolant means contamination — the system likely needs a flush, not just a top-up.
- Look around for leaks. While the bonnet is open, glance at hoses, the radiator, and the ground under the engine for coloured puddles or dried crusty residue (coolant leaves a chalky, coloured deposit when it dries).
If the level is fine and the fluid looks healthy, close the bonnet — you’re done. If you find yourself topping up often, that’s a symptom, not a solution: frequent top-ups mean a leak somewhere, and the cooling system needs a proper pressure test at a garage.
Topping Up Coolant Safely
If the level is below MAX, top it up — but only with the right fluid:
- Use the coolant type your manufacturer specifies. Coolant chemistry differs by type (OAT, HOAT, IAT — the manual names the standard), and mixing incompatible types can cause gelling or corrosion. Your owner’s manual or the sticker under the bonnet lists the correct specification.
- Pre-mixed vs concentrate: many coolants are sold ready-mixed (50/50); concentrates must be diluted with distilled water before use. Never add plain tap water long-term — minerals in hard UAE tap water cause scale and corrosion inside the system. In a roadside emergency, a little water is better than running dry, but flush and refill properly soon after.
- Fill to the MAX mark, not above. Coolant expands as it heats; the reservoir needs air space. Overfilling causes overflow and mess.
- Recheck after a drive. Once the engine has run to normal temperature and cooled again, verify the level held steady.
For a fuller picture of keeping your car healthy, pair coolant checks with a regular engine oil change schedule — oil and coolant are the two fluids that protect the engine from heat, from opposite sides.
How Often Should You Check and Replace Coolant?
| Task | Frequency |
|---|---|
| Level check | Monthly, and before long trips |
| Condition check (colour/clarity) | Every 6 months |
| Full coolant flush/change | Every 2–5 years or 40,000–80,000 km (follow your manual) |
| Hoses and radiator visual inspection | Yearly, or before summer |
Coolant has a service life — its corrosion inhibitors wear out over time even if the level never drops. Old, spent coolant lets internal corrosion start, which is slow and invisible until a radiator or heater core fails. A full flush replaces all the fluid and is relatively inexpensive compared with the damage it prevents. Summer is the worst time to discover your cooling system is marginal, so a pre-summer check is a smart habit — see our guide on preparing a car for summer for the full checklist.
Warning Signs Your Coolant Is Low or the System Has a Problem
- Temperature gauge climbing above normal — the earliest reliable sign. Learn your car’s normal position so you notice a change; see our guide to dashboard warning lights for the coolant temperature warning symbol.
- Sweet smell — coolant has a distinctive sweet odour. Smelling it in or around the car usually means a leak.
- Coloured puddles under the car — green, pink, orange, or blue fluid where you park.
- White steam from the bonnet — pull over safely and switch off; don’t open anything until the engine is fully cool.
- Heater blowing cold in winter — low coolant can stop the heater working even when the engine seems fine.
- Frequent need to top up — normal systems barely lose coolant. Needing regular top-ups always means a leak.
If the temperature warning light comes on or the gauge enters the red zone, stop as soon as it’s safe. Driving even a few kilometres on an overheated engine can turn a hose replacement into a head-gasket job. Our guide on what to do when a car overheats covers the exact steps — and if your policy includes roadside assistance, calling it is usually the safest option. Check what your car insurance covers for breakdowns before you need it.
Common Coolant Mistakes to Avoid
- Opening the radiator cap when hot — the system is pressurised; hot coolant can erupt and cause serious burns. Always cold only.
- Mixing incompatible coolant types — different chemistries can react and gel, clogging the system. When in doubt, drain and refill with one correct type.
- Topping up with plain water habitually — dilutes the corrosion inhibitors and boiling-point protection. Fine once in an emergency; bad as a habit.
- Ignoring small leaks — a drip today is an empty system next month. Leaks never fix themselves.
- Overfilling the reservoir — leaves no expansion room; the system will push the excess out anyway.
Coolant basics are well documented — engine coolant on Wikipedia explains the chemistry and types in more depth if you want the technical detail.
Frequently Asked Questions (FAQs)
Can I check coolant when the engine is warm?
Reading the reservoir level on a warm engine gives a slightly high reading, but the real issue is safety: never open the radiator cap or any pressurised part of the system while hot. For accuracy and safety, check when the engine is fully cold.
What colour coolant does my car need?
Colour is not a reliable guide — different manufacturers use different dyes, and some coolants with the same colour are chemically incompatible. Go by the specification in your owner’s manual (e.g. the OAT/HOAT standard named there), not the colour on the shelf.
Is it normal for coolant level to drop slightly?
A tiny drop over a year can be normal evaporation through the reservoir vent. A noticeable drop over weeks or months is not normal and points to a leak — get the system pressure-tested.
Can I just add water instead of coolant in summer?
Water cools adequately in the short term, but it boils at a lower temperature, offers no corrosion protection, and hard tap water leaves mineral deposits. Use it only in an emergency, then restore the correct coolant mix as soon as possible.
How long does coolant last in the UAE?
Modern long-life coolants typically last 3–5 years or 60,000–100,000 km, but UAE heat is hard on them — follow the shorter end of your manual’s schedule if you do mostly city driving, and don’t skip the flush just because the level looks fine.
My coolant looks rusty. What should I do?
Rusty or brown coolant means corrosion is already happening inside the system. Book a coolant flush at a garage and ask them to inspect the radiator, hoses, and water pump while they’re at it.
The Bottom Line
How to check coolant level comes down to one habit: once a month, engine cold, look at the reservoir and confirm the fluid sits between MIN and MAX. Top up with the correct type when it’s low, investigate if it keeps dropping, and never open a hot system. In a climate where summer heat pushes every car to its limits, five minutes with the bonnet open is some of the cheapest insurance your engine can get.
Last Updated: 8 October 2026
About the author: Zaviyar Sultan is a UAE-focused writer at Paxi, covering driving, visas, banking, insurance and everyday UAE life. His guides are researched from official UAE government and regulator sources and updated regularly.
Paxi is an independent informational website, not affiliated with the UAE government or any agency mentioned; content is general information only, not legal, immigration or financial advice; verify critical details with official sources before acting.