White Smoke Under Hood from Coolant Leak of Car

Overheating is the most common reason a car would blast out white smoke under the car hood. However, it is not the only cause of this experience. You can also experience white smoke under hood from coolant leak.

Nevertheless, if you’re battling this issue right now, don’t panic. White smoke from a vehicle can be a worrying sign for any customer. It often indicates an engine coolant leak or motor oil leak. When engine oil or coolant comes into contact with hot engine parts, it can cause overheating. The smoke is steam resulting from the heated fluids. Drivers might notice this, especially at a stop light or street corner when their car is idle, the temperature gauge may rise, or an oil icon may light up on the dashboard.

This experience suggests that a visit to a shop is necessary, where a mechanic can assess all the possibilities, such as oil spillage or a motor oil leak, and the exhaust pipe smoke color can give additional clues. For example, if the white smoke is accompanied by a sweet smell, it is likely a coolant leak. Immediate attention from a road service company can prevent further damage to the engine.

A temporary solution has been provided below in this post. Kindly read on to find out what it is to implement the hack before contacting an expert auto technician to fix it thoroughly.

White smoke under hood from coolant leak

White Smoke Under Hood from Coolant Leak -Why?

White smoke from engine coolant leak is simply a sign that the leaking coolant has come in contact with hot engine components. A sweet smell will usually accompany the smoke in most cases.

The coolant leak is usually traceable to a blown head gasket, cracks in coolant hoses, etc. However, when any of these components become defective, the coolant can easily escape and reach out to hot engine parts.

When this happens, it would be best to inspect the problem and contact an expert auto technician immediately. This is because, apart from the circulation of white smoke under hood, your car’s engine may eventually plunge into a more severe problem if you don’t rectify the issue ASAP.

Other Causes of White Smoke Coming from Engine

Besides experiencing white smoke coming from engine due to coolant leaks, several other reasons can trigger the same occurrence.

In other words, identifying the actual cause of the problem is necessary if you must proffer a solution. Some other causes of white smoke from a car’s engine include the following.

Oil Spillage

Oil spillage is one of the other reasons why you may experience white or grayish smoke coming from your car’s engine compartment. The spillage can occur if you’re not careful enough when pouring oil into the crankcase.

For instance, if the oil is poured on the exhaust manifold, it’ll cause white smoke as soon as the exhaust gets hot. Thus, if you’re experiencing this issue at the moment, ensure to turn off your car and rectify the issue.

Burning electrical wiring

Burning electrical wiring can also trigger white smoke from your car under the hood. However, this one comes with a pungent smell. If your car’s wiring conveys excessive current, it will most likely burn, releasing whitish smoke.

Therefore, you may want to verify the cause of the smoke coming from your engine’s compartment whenever you notice this occurrence. This will enable you to spot whether it is due to a coolant leak or any other fault.


Overheating is most likely the first suspect if you suddenly see white smoke coming from a car. An overheating engine is usually due to poor lubrication of moving metal parts in the engine. Meanwhile, this occurrence is traceable to old coolant or low coolant levels, which is also linked with coolant leaks.

Can You Drive a Car with White Smoke?

Of course not! You shouldn’t drive if you suddenly see white smoking popping out of your car’s engine compartment. This occurrence signifies that something could be wrong with one or more of the engine’s components.

Driving, regardless of the occurrence, can cause severe damage to your car’s engine. Meanwhile, engine problems are some of the costliest faults to fix in a car. Therefore, avoiding such an occurrence in the first place would be best instead of risking the damage.

What Are the Signs of a Coolant Leak?

Typically, when you experience smoke popping out of your car’s under hood due to coolant leaks, it is easy to conclude that the problem has just started. However, most sudden vehicle malfunctions are triggered by prolonged underlying issues that were neglected.

In other words, you will most likely see the following symptoms before coolant eventually gets in contact with your car’s engine and trigger white smoke from the compartment.

Coolant puddle beneath the car

Coolant leaks will usually create big puddles beneath a car, especially when parked for a long time. Since the fluid does not have a specific place where the leaks are channelled, it will flow through the engine compartment and reach the ground under the car.

Meanwhile, the flow rate will determine how much coolant gets to the ground. However, in most cases, as the liquid continues to drip from the bottom of the car, it will eventually create a noticeable puddle, especially when you drive out of the spot.

Low coolant level

A vehicle’s coolant is not expected to run out quickly. So, if you keep seeing between low to no coolant in the coolant expansion tank, it is a sign that there’s a leak somewhere. You may want to inspect the tubing to see any cracks.

Meanwhile, it is crucial to note that running a car on a low coolant level is risky. It can result in engine overheating. When this happens, the internal engine parts will suffer catastrophic damages if you continue driving with it for an extended period. Thus, refill coolant if level is too low. Undoubtedly, white stem from the under hood is a sign of engine overheating.

Coolant warning signal display

Modern vehicles are fitted with several warning lights on the dashboard. One of the warning signals is the coolant warning light. Therefore, if you’re running low on coolant due to coolant leaks, the ECU will automatically cause the low coolant warning light to illuminate.

Engine overheating

Again, engine overheating can be linked to a low coolant level in a car. Since the coolant is responsible for cooling the engine, running low on the fluid will reverse the order.

Therefore, if the coolant runs out or becomes insufficient, the engine parts will suffer from poor lubrication, which can trigger engine overheating. Meanwhile, overheating is not the only thing that can trigger smoke from the engine compartment, in case you’re asking – “Can coolant leak cause white smoke?

How Do You Temporarily Fix a Coolant Leak?

If you’re asking, “What should I do if my car is leaking coolant? Using a radiator sealant product is most likely the best way to fix a coolant leak temporarily. So, if you discover a leak in your car’s cooling system, kindly get a recommended radiator sealant to fix the problem.

Once you have the product, turn on your car and run the engine for a short time to allow the coolant to warm up a bit. After that, open the radiator pressure cap, shake the sealant bottle well and empty the content into the radiator.

Then, replace the pressure cap and run the engine for about 10 minutes to allow the liquid to circulate. This will enable the sealant to access the leaking spots and fix them.

How Much Does It Cost To Fix A Coolant Leak In A Car?

A coolant leak repair cost is estimated at around $10 – $300, depending on the faulty part of the cooling system and the vehicle in question. However, if your car is smoking under hood and you suspect a coolant leak, contact a professional auto mechanic to diagnose the issue and fix it.

The price varies widely because several factors can be the culprit. For instance, if you have a small radiator leak, you can fix it with $10 by adding the radiator stop leak product. On the other hand, you can budget $300 or more if a lousy water pump is the culprit.

radiator coolant leak

Meanwhile, there could be a wide variance between fixing the leaks at a dealership or a local independent auto mechanic’s workshop across the street. But, of course, the repair at a dealership will cost more.


White smoke under hood from coolant leak can be a daunting experience if you’re clueless about what to do. However, no matter what, do not overlook this occurrence because it can result in costly engine damage if not rectified.

Therefore, kindly contact a professional auto technician to diagnose the location and cause of the coolant leaks to fix it immediately. Meanwhile, you may want to use the temporal fix strategy above to stop the leaks at first.

Solomon Osuagwu

Osuagwu Solomon is a vetted auto mechanic with over ten years of experience in the garage and five years of experience as a service writer. He prides himself in writing accurate information on professional repair guides, DIY repair guides, buyer’s guides, comparisons, and car reviews. If he’s not in his repair garage, he’s writing automotive blogs to help car owners and fellow mechanics to troubleshoot and proffer solutions to several car problems.

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