Water in Engine Oil Causes Symptoms Fix
  • Post last modified:January 12, 2024

Water In Engine Oil Symptoms, Causes, Test & Fix

Swiftly detect water in engine oil symptoms using these 3 steps. As it will affect its performance, seize the opportunity for a quick-fix solution.

Water mixing with engine oil can cause trouble for your vehicle’s performance. Potentially cause significant damage if not addressed promptly. If you’re noticing symptoms or experiencing engine issues there’s a chance that water has infiltrated your oil. This article will delve into the signs to watch out for and emphasize the importance of dealing with this problem without delay.

Understanding the Impact of Water in Engine Oil

When water combines with engine oil it creates an emulsion that compromises the lubricating properties of the oil. As a result increased friction and wear on engine components can occur, leading to performance and even potential engine failure. One clear indicator of water in the engine oil is a foamy appearance when checking the dipstick. This occurs due to the formation of an emulsion between the oil and water. Other symptoms may include overheating and a sweet or burnt smell.

If you suspect that there’s water in your engine oil it’s crucial to have a mechanic diagnose and resolve the issue promptly. Ignoring this problem could lead to repairs. Even requires an entirely new engine altogether. In this article, we will thoroughly explore these symptoms. Also, provides insights into preventing water from entering your engine oil. Don’t disregard these warning signs; uncovering this troublemaker is essential, for safeguarding your engine’s health.

Common Symptoms of Water in Engine Oil

Water contamination in engine oil is a serious issue that can cause significant damage to your car engine. It occurs when coolant from the radiator or cooling system leaks into the oil leading to a contaminated mixture that can cause serious damage to the engine.

The most common signs of water contamination include:

  • Difficulty starting
  • Loss of engine power
  • Increase in engine noise
  • White smoke from the exhaust pipe
  • Milky-colored oil on the dipstick or under the oil cap
  • Milky or foamy oil
  • Increased oil level on the dipstick
  • Overheating engine

This water can cause issues with your car’s engine performance. In addition to that, water accumulation can lead to oil sludging formation and ultimately wear and tear on your engine. If you notice any symptoms of water in engine oil, it is important to take action quickly to prevent the car from overheating and further damage.

How to Detect Water in Oil

The engine oil dipstick and under the engine oil cap are quick and easy ways to check for water in car engine oil symptoms. If you look under the engine oil filler cap and on the engine oil dipstick for a white milky appearance similar to a creamy chocolate milkshake it indicates internal engine problems like a blown head gasket. When you remove the drain plug (sump plug) from the oil pan (oil sump) the water will flow out first because water is denser than oil. Before going car shopping grab my used car inspection checklist to learn more on what to look for before buying a used car.

How to Test for a Blown Head Gasket Using a Block Tester

The car got the sniffles? Check for sneaky exhaust with a coolant tester.

Ever noticed your car running weirdly, maybe overheating or blowing white smoke? It could be a blown head gasket, and that’s not good news for your engine. But before you call a tow truck, grab a coolant tester! This handy tool is like a doctor’s stethoscope for your car, letting you check for sneaky exhaust gases leaking into your coolant system.

Think of your engine like a big ol’ burger. The bottom half, with the pistons and rings, is like the juicy patty. The top half, with the valves, is like a fluffy bun. And in between? That’s your head gasket, the key ingredient holding everything together. It seals in three critical things: water (coolant!), oil, and powerful engine pressure.

Now, imagine a sneaky little straw poking through the bun, letting exhaust smoke mess with the juicy goodness down below. That’s what happens when your head gasket blows. But here’s the good news: a coolant tester can sniff out those sneaky fumes before they turn into a major burger meltdown.

It’s quick, it’s easy, and it can save you a ton of cash and heartache. So grab a tester, check your coolant, and keep your engine humming happy!

Best Combustion Leak Detectors (Block Testers)

(eBay affiliate link)

Before buying a Combustion Leak Detector, double-check that it comes with the necessary test fluid and a sturdy case to prevent any potential damage caused by mishandling. With a comprehensive block tester kit* (eBay affiliate link), you’ll no longer need any extra components; it’s ready to be used out of the box. It contains enough test fluid for about 16 tests and additional bottles are also available if needed.

Before buying a Combustion Leak Detector, double-check that it comes with the necessary test fluid and a sturdy case to prevent any potential damage caused by mishandling. With a comprehensive block tester kit, you’ll no longer need any extra components; it’s ready to be used out of the box. It contains enough test fluid for about 16 tests and additional bottles are also available if needed.

Block Tester Kits are incredibly valuable when it comes to buying a used car too. You can use them to find out if the vehicle has any problems and avoid buying someone else’s problem that could cost you thousands of dollars in repairs. Plus, they make it simple and easy to check for a defective head gasket.

Block testers are used to detect combustion gases in water-cooled engines, such as petrol, diesel, and LPG. They work by changing the color of the blue liquid it contains to yellow when combustion gases are present. This can alert you to potential problems with the cooling system quickly and efficiently.

If you notice a decrease in the coolant levels of your vehicle, it may be due to a combustion leak. The block tester can help diagnose this issue accurately. Also, before deciding to dismantle the engine you could try an easy temporary fix by using a head gasket sealer* (eBay affiliate link).

Before testing the coolant, drain some out from the radiator to avoid any potential contamination of the test fluid.

  1. Place the block tester into the radiator so that it fits snugly.
  2. Squeeze the bulb to check if the testing liquid changes its color from blue to yellow.
  3. A transition from blue to yellow in the fluid is a sign of a combustion leak.

Suppose you’re testing other combustion engines or generators. In that case, it’s handy to have a tool in your garage or tool kit that works on any internal combustion engine with a closed cooling system.

How to Fix Water in Engine Oil (Temporary Quick Fix)

Before dismantling the engine, you could try an easy temporary fix by using a head gasket sealer* (eBay affiliate link).

oil in water symptoms, causes, and solutions

You Can Have Oil in Water Too

Motor oil in water is usually a bigger problem when cleaning the sludge from the engine cooling system and radiator. When you open the cooling system cap or radiator cap, look for oil in the water and around the cap. Also, beware of any quick fixes like the owner or seller using automotive additives or head gasket sealers* (eBay affiliate link). These work like magic in many cases but they are a quick fix.

A Bad Oil Cooler

Oil coolers are relatively uncommon in cars that run on gas engines. However, they are a mainstay of turbocharged vehicles. Leaks from an oil cooler may cause oil to mix with coolant, which would be an indicator of a problem. When oil cooler leaks occur, many assume that the head gasket is blown. However, the engine generally functions normally in such a situation. A damaged head gasket will usually cause the engine performance to become affected. If an oil cooler is leaking, it’s a relatively inexpensive repair job. The replacement parts – the oil cooler and its gasket – need to be installed, and then the cooling system is flushed and refilled.

Leak in the Transmission Cooler

Some cars with an automatic transmission have a dedicated transmission fluid cooler that is typically connected to the radiator. Over time, cracks may form between the two parts, leading to transmission fluid leaking into the coolant system. The coolant can look pink and foamy, which is an indication of a problem. Unfortunately, it might also reach your transmission and eventually cause irreparable damage, requiring a replacement.

Preventative Maintenance Tips to Reduce the Risk of Water Contamination

An engine oil change is crucial because there are a lot of additives in the oil that become dirty and essentially wear out causing the lubricating properties that protect the engine to diminish. This results in some metal parts being eaten away and water being retained in the crankcase which results in sludge.

The sludge mixture will just keep building up by attracting more abrasive particles and then wear down the engine instead of protecting it as clean oil does. This is why changing your oil at specified intervals and more frequently than the manufacturer’s recommendations if you drive less frequently or in abnormal conditions like stop-start traffic is so important.

Oil Change Replaces:

  • detergents
  • dispersant additives

If your vehicle is used a lot for short trips and doesn’t reach operating temperature often before you turn the engine off then it is advisable to change the oil more frequently than what the manufacturer recommends to get the most out of your engine and protect moving parts. This also prevents condensation from building up inside the car engine resulting in oil tarnish and sludge buildup.

When do I need to get my car’s oil changed? You should have your car’s oil changed every 3,000 miles or about six months.

For general driving of the vehicle, every 5,000 kilometers or 3,000 miles (6 months) is a good rule of thumb before you need to change the engine oil.

Non-Synthetic Oil Change Interval

For older cars using non-synthetics, say no more than every 5,000 kilometers or 3,000 miles. (6 months)

Synthetic Oil Change Interval

With more advanced engine designs and better oil formulations like full synthetics, manufacturers are always increasing the oil-change intervals. It is still highly recommended to check the oil yourself frequently and has it changed more regularly too. With newer cars say no more than every 10,000 kilometers or 6,000 miles (12 months) just to be on the safe side.

Car Overheating Causes: 7 Common Causes & What To Do

Car Overheating Causes: 7 Reasons Why Your Car Overheats – See steam, the temperature gauge reading high, or a burning smell? Here’s what to do.

If your car overheats it can be costly. Here you can learn the common reasons why your car engine overheats and what to do. Number 7 is very costly so do these checks to avoid it. You can also learn the different components that make up an engine cooling system and understand their function to help you identify any immediate problems or likely future problems that could be costly.

Don’t Ignore the Signs Of A Car Overheating

A car engine overheats when the coolant (water and alcohol) starts to boil but before it gets to that point there are warning signs that you need to pay attention to and act quickly.

Car overheating causes and warning signs.

Temperature Gauge Rising

If your temperature gauge is showing the needle above its normal position or starts rising then you need to act quickly. Most modern vehicles will demonstrate the needle in the same position irrespective of the warmer months because they use electric fans that come on and off to control the engine temperature. So if you find the temperature gauge showing a different reading than normal you can safely assume something is wrong. This can lead to engine overheating so you need to do some basic checks.

Overheating Car Engine Signs

Also, depending on the amount of carbon build-up on the top of the pistons and in the combustion chamber you may start to hear a pinging sound due to excessive heat. This is the pre-ignition phase where the fuel is igniting too early in the engine cylinders.

Hissing, Whooshing Noise & Steam From Under The Hood

If you hear a splashing noise as the coolant hits the hot parts of the engine and gives off large white steam clouds that come out from under the hood you know you have a problem. The car is already overheating.

Engine Sounds Like Ball Bearings In A Can

This is severe and caused by extreme heat that has made the engine oil thin out and lose its lubricating properties. Damage is being done to the bearings and other surfaces in the engine.

Also, you will start to hear a detonation sound (engine knock) and this causes metal components in the engine like pistons and piston rings to start cracking or melting.

7 Car Overheating Causes

  1. Blockage – The cooling system can fill quickly with rust and corrosion. A build-up of rust or scale can cause a blockage in the radiator cores or water jackets in the engine (mineral deposits prevent proper heat transfer).
  2. Faulty Thermostat – Not opening and restricting coolant flow to the radiator.
  3. Loose Drive Belt – Drive belt slips prevent the water pump from circulating coolant efficiently.
  4. Faulty water pump – Leaking, bearing noise or broken pump shaft are all visible or audible. It’s also common for the impeller of the water pump to become corroded and lose its ability to pump the coolant efficiently through the cooling system causing the engine to overheat at higher speeds.
  5. Missing fan shroud or ducting – Reducing cold air flow through the radiator.
  6. Engine fan problems – Fan clutch or electric radiator fan problems prevent adequate airflow through the radiator.
  7. Major Mechanical Problems –  Possibility of engine combustion leakage into the cooling system or symptoms of blown head gasket like engine oil in water or water in engine oil that shows a white milky appearance.

Understanding Your Engine Cooling System Operation

When the engine is running, a drive belt (fan belt) or timing belt powers the water pump. The water pump is designed to pump coolant around the engine.

While the engine is cold, the thermostat remains closed. This prevents coolant from going to the radiator. Instead, it circulates inside the engine. This helps warm the engine quickly.

When the engine reaches operating temperature, the thermostat opens. The heated coolant then flows through the radiator. Excess coolant heat is transferred to the air flowing through the radiator. This maintains proper engine operation.

Engine Coolant

Coolant performs several functions like preventing corrosion in the engine. If you live in colder climates, a chemical called antifreeze is added. The coolant color can be pink, orange, blue, or green depending on the manufacturer. If the coolant is brown it usually indicates the cooling system needs flushing and the coolant replaced. There are coolant testers that can help you.

Tip: Keep your car’s engine cooling system clean by having it regularly flushed as per the manufacturer’s recommendation. This prevents the coolant from becoming contaminated and causing serious internal engine damage.

Engine Cooling Fan

Most late-model vehicles are fitted with electric fans which use a heat-sensitive switch to turn the fan on to avoid engine overheating. If the engine is fitted with a Thermostatic fan clutch, the fan should slip when cold. When the engine warms, the clutch should engage. You should hear and feel air flowing through the radiator and over the engine.


The radiator transfers coolant heat to the outside air. Cool outside air can flow freely through it. Look for any leaks around the top and bottom tanks. Also around the radiator drain plug. look at the overall condition and age of the radiator by looking for any damage to the fins.

Radiator Cap

The radiator cap performs several functions like sealing the cooling system. It also controls the pressure in the system which allows the boiling point of coolant in the system to be raised. If the pressure in the system is excessive it releases the pressure.

Check the rubber seal or O-ring condition to make sure the radiator cap is sealed.

Cooling System Hoses

Radiator hoses and heater hoses carry coolant between the engine water jackets and the radiator.  Look for coolant leaks before and after the test drive. Other symptoms of a bad radiator hose that may fail shortly are:

  • Swollen hoses or collapsed hoses due to age.
  • Deteriorated hoses due to oil contamination.


The thermostat helps to bring the engine to operating temperature more quickly from cold starts. When the engine is at operating temperature the thermostat opens to allow the coolant to flow more freely through the radiator. When test driving the vehicle the engine operating temperature should be at a constant temperature. Specific temperatures vary for different makes and models.

Water Pump

Usually driven by the fan belt or the timing belt when the engine is running circulating the coolant (water) around and through the different cooling system parts and engine components. Worn shafts and bearings causing noise or leaks are common problems with an old water pump.

What To Do With A Car Engine Overheating In 3 Steps?

  1. Stop the vehicle in a safe place. Turn the air conditioning system off and turn on the heater.
  2. Check to see if there’s any steam or if you hear a whooshing sound. If there’s steam or noises, stop the engine. Lift the hood after the steam goes away and the engine cools down then carefully check the coolant level and cooling system for any leaks. If there’s no steam, leave the engine running and lift the hood.
  3. Check the cooling fan is operating. If you hear the cooling fan is operating, wait until the needle on the temperature gauge starts to fall and then stop the engine. Once the engine is cool you can check the coolant level for any leaks. If you don’t hear the cooling fan operating, stop the engine. Then do the above checks once the engine has cooled down sufficiently.


  • Wait until the steam has gone before opening the hood. The engine bay will be very hot.
  • Do not remove the radiator or reservoir cap if the engine is hot. When removing use a rag or towel and open the cap gently with all parts of your skin and face away from harm.
  • When adding coolant (you can use water in an emergency) wait until the engine has cooled down. You don’t want to fill the cooling system with cold coolant or water to a hot engine quickly as this can cause damage to the engine.

If you’re going car shopping download my free used car inspection checklist to know what other important checks to do.


To maintain the health and performance of your vehicle it’s essential to understand the signs and symptoms of water in engine oil. By detecting these issues early you can avoid costly repairs and keep your engine running smoothly. However, prevention is always better than cure so it’s crucial to adopt maintenance practices that prevent water contamination in the first place. Regularly inspect your engine for internal leaks, use high-quality coolant to ensure long-term sealing, and minimize the risk of having water in engine oil.

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