How to fix a car radiator leak

Author: Evgeny Zhivoglyadov. Publication date: December 15, 2022. Category: Automotive equipment.

The radiator is one of the main components of the car engine cooling system. Even minor damage to it leads to antifreeze leakage. And, this, in turn, threatens to overheat the engine (with all the ensuing negative consequences). Therefore, timely elimination of radiator leaks is a measure that must be carried out immediately in order to further safely operate the vehicle. Repairs (both temporary and long-term) of this unit can be completely carried out independently. How to do it? This will be discussed in our article.

Determining the location of the leak

If the coolant “leaves”, you will immediately know about it by opening the hood and finding a drop in its level on the expansion tank below o.

Next, you need to determine the location of the leak. To do this we do the following:

Add antifreeze to normal level.
Warm up the engine to operating temperature.
We park the car on a flat and dry surface.
Let the engine cool down.
We look for where drops of liquid fall under the bottom and carry out a visual inspection of the entire cooling system.

If you are convinced that it is the radiator that is leaking, then it is necessary to take urgent measures to eliminate this malfunction and only then continue to operate the car.

Causes of leakage

In fact, a leaking radiator becomes like this for several reasons. All “breakdowns” are conventionally divided into two categories: mechanical and natural.

Mechanical accidents include accidents with a frontal collision, which result in a breakdown. Also included in the category are repair “interventions” by non-professional craftsmen. Often, after poorly performed work, various parts and assemblies are damaged, which causes leaks.

Natural “strips” include corrosion processes. Over time, even a small scratch can turn into a strong source of corrosion, so you need to respond to such places in a timely manner. Otherwise, a hole will appear in the system through which refrigerant will begin to leak.

There are several ways to check a radiator for leaks:

Before you go on the road, and also while driving, you need to look at the coolant level.

Inspect the system from time to time to detect cracks.

Keep pressure and temperature under control, and respond promptly to warning lights.

If the cooling radiator leaks, what should you do in this situation? If the driver is “on the road”, then you can fix the problem yourself. But if possible, you should contact a service center, where technicians will diagnose and eliminate the leak.

Methods for eliminating identified cooling radiator malfunctions

There are several ways to fix a radiator leak:

The use of folk remedies (only if you are located at a considerable distance from the nearest spare parts store).
The use of special sealing agents that temporarily eliminate leaks in the cooling system.
Repairing a damaged unit using soldering or special adhesives.
Replacing a damaged radiator with a new one.

Important! The first two methods are purely a temporary measure that allows you to continue operating the vehicle without the risk of engine overheating.

What can happen if there is a lack of coolant?

If the radiator leaks or the pipe ruptures, the following may happen:

The engine will overheat;
The cylinder head gasket is deformed;
When attempting to examine the problem, pressurized liquid may splash into the face, causing burns;
The engine will seize.

All these troubles can lead to expensive repairs, and damage to health can be irreparable.

Folk remedy

If a radiator leak is discovered on the road, then you can get to the nearest grocery store, buy mustard powder or ground red (or black) pepper, and use the proven “old-fashioned” method, which was successfully used even by professional drivers when auto chemicals and its developments did not yet have such wide application.

The method of manufacturing and subsequent use of a homemade repair composition is quite simple:

Pour mustard powder or ground pepper into a suitable container (at the rate of 1 g per 1 liter of cooling system volume).
Pour 200÷300 ml of antifreeze or distilled water into it.
We start the engine, let it run until it reaches operating temperature and turn it off.
Carefully open the radiator cap (observing the necessary precautions).
Shake the container with the homemade repair composition and pour the contents inside the unit.
We start the engine again and let it run for another 15–20 minutes.

Particles of organic matter temporarily stop small holes or cracks that have formed in the radiator: this will allow you to safely reach your destination and carry out a full repair there.

Important! After a complete repair, the entire cooling system must be flushed using special compounds, and only then new antifreeze must be added.

Danger of leakage

Many drivers do not know the dangers of coolant leakage. Let's explain clearly.

As soon as a leak forms in the radiator, the antifreeze stops removing heat. As a result, the engine overheats. At the same time, the cylinder head changes configuration, which is guaranteed to lead to gasket failure.

In addition, the “engine” can become severely jammed at one moment, which will certainly lead to a major overhaul. The lack of coolant in the radiator is dangerous for the driver.

If a person opens the hood when a problem is detected, the boiling liquid forms a kind of geyser. Once on the skin, hot drops will cause a burn.

Types of radiator sealants

The modern market for auto chemical products is replete with various sealants for eliminating minor damage to radiators. They are produced in the form:

powder;
tablets;
liquids.

According to their intended purpose, such funds are divided into:

highly specialized;
universal.

The former are intended for emergency repair of radiators made of either copper (for example, Bar's Leaks Block Seal Liquid Copper) or aluminum (for example, Rislone Liquid Aluminum Radiator Stop Leak). Using the latter (for example, K-Seal ST5501) you can eliminate leaks in the entire cooling system. Moreover, they can be used regardless of the material from which the radiator is made.

Reviews of the use of such drugs vary widely: from the most enthusiastic to the purely negative. The truth is, as usual, somewhere in the middle. It is important to remember that eliminating a leak using one of the proposed drugs is a temporary measure: it only allows you to continue using the car for a period of 2–3 days to several months.

Popular sealants for car radiators

Today, the most popular among Russian car enthusiasts are three types of liquid sealants designed to eliminate small leaks in the engine cooling system: “Liqui Moly Kühler Dichter”, “Hi-Gear Radiator Stop Leak” and “Wynn’s Cooling System Stop Leak”.

The method of application for the above compositions is approximately the same:

We warm up the engine to operating temperature (so that the thermostat opens and the coolant circulates in a “large cycle”).
Unscrew the radiator cap (observing safety precautions).
Thoroughly shake the container with the sealant and pour it into the coolant.

We install the plug in place.
Let the engine run for another 15÷20 minutes (until the leak stops).
If necessary, add antifreeze (to normal level).

The cost of one bottle of liquid gemetic (capacity 250÷325 ml), designed for the volume of the cooling system of a passenger car (from 5 to 12 liters) varies from 300 to 400 rubles. According to the manufacturers, the above compositions are compatible with all types of antifreeze currently used in cooling systems.

Liqui Moly

Declared manufacturer: Germany

Approximate price: 200 rub.

Metal-containing drug. The sediment after draining shone with sparkles of all colors. A clear leader in the speed of sealing holes, and the leaks, having stopped, never resumed. The level of residual deposits is average.

+ Best operating efficiency.

- Price.

1 place. Radiator sealant “BBF Super”

Preparatory stage of radiator repair

Before you begin repairing the radiator yourself, it is necessary to carry out a number of preparatory measures:

Drain the antifreeze from the cooling system.

We dismantle the radiator, clean it of dirt and dust and rinse it thoroughly.
We “muffle” all technological openings (inlet and outlet) using improvised means (for example, pieces of plastic film and electrical tape).
We lower the radiator into the bathtub filled with water.
Based on the air bubbles rising to the top, we determine the location of the damage.

When the “problem” areas are clearly identified and the radiator is thoroughly dried, you can immediately begin the repair process.

Soldering a copper or brass radiator

Repairing minor damage to radiators made of copper or brass is quite simple. For this you will need:

Gas burner (the simplest nozzle for a cylinder costs only 200–250 rubles).
Solder paste (for example, ZIL-2 or ST-61).
Tin-based solder (POS-30, POS-40 or POS-60).

Work algorithm:

We clean the damaged areas using sandpaper and needle files.
We warm them up using a gas burner.
Apply a layer of solder paste or acid.
We apply a solder rod to the hole or crack and continue to heat the soldering area with a gas torch.

We make sure that the melting solder evenly fills all damaged areas.
After complete cooling, remove excess tin mechanically.
We close all the holes of the radiator, lower it into a bath filled with water, and make sure that there are no air bubbles in the soldering areas.

Repair of aluminum radiators

Until recently, exclusively special oxygen-free argon welding was used to repair products made of aluminum and its alloys. This was due to the fact that after mechanical cleaning of the damaged area, an oxide film instantly formed on the surface of the material, which made soldering difficult. Nowadays, with the advent of low-temperature solders (Durafix or HTS-2000), designed specifically for soldering aluminum, repairing a radiator made of this metal at home does not present any particular difficulties:

We clean the damaged areas mechanically.
We degrease them with alcohol or solvent.
We heat the damaged area using a gas burner.
We press a rod of special solder tightly against it and carry out reciprocating movements. By doing this, we remove the layer of oxides from the surface, and the solder, which melts upon contact with the heated surface, reliably “blocks” the radiator leak.

Possible problems

It happens that the sealant turns out to be of low quality or completely fake, so instead of sealing the crack you can get:

clogging of thin radiator pipes;
violation of engine cooling, overload and breakdown;
clogging of the radiator stove, disruption of the interior heating;
failure of the pump, thermostat.

To prevent this from happening, you need to purchase sealing compounds from reliable manufacturers, after consulting with the seller, and apply them strictly according to the instructions. This will help to temporarily solve the problem of radiator leaks and get to a repair shop without consequences.

How can you seal a car radiator?

The use of “cold welding” or special adhesive compositions is also a very effective measure to extend the “life” of your car’s radiator. Work algorithm:

Use a narrow screwdriver to widen the crack.
We thoroughly clean it with needle files or sandpaper and degrease it.
We mix the “cold welding” components (“Poxypol”, “Moment”, “Arbo” or the like).
Fill the gap with the prepared solution and leave the knot for a day to dry completely.

We check the radiator for leaks and install it in place.

Damage to radiators (made from a wide variety of materials) can be quickly and effectively repaired using a special Hosch-Kleber repair compound. The delivery set includes two containers:

one with liquid adhesive;
the other with special welding granulate.

How to use this tool to repair a car radiator is described in the video below:

Application of glue

Only two-component adhesive mixtures are suitable for repairing a plastic radiator. They cope well with situations where the crack in the radiator is large enough or it is not possible to connect the parts of the case due to a lack of small fragments. If a small crack is being repaired, simply mix the glue components and apply it to the crack in two layers.

In some cases, a crack appears in a hard-to-reach place. In this case, the sealant is applied along the entire length of the radiator Source Chebo.pro