How to flush the stove radiator with your own hands without removing it

How to flush the stove radiator with your own hands without removing it

October 27, 2019

Likbez Do it yourself

Do not rush to disassemble half the car and change the heater to a new one: the problem can be solved faster and cheaper.
Photo by Artyom Kozoriz

Artyom Kozoriz

Lifehacker author, mechanical engineer


What you need to know before flushing the stove radiator

Why is the stove radiator clogged

It looks like a blockage from the inside /

A clogged radiator is one of the most common causes of poor heater performance. Most often this happens due to low-quality coolant, mixing two antifreezes of different composition, or using water.

All this leads to the formation of plaque on the walls from the inside. Dirt tightly clogs the already thin radiator tubes with swirlers, disrupting circulation, and there can be no talk of any heating.

How to understand that the problem is blockage

Checking if the stove radiator is really clogged is quite simple. You need to find two thin pipes going into the cabin through the partition of the engine compartment, and feel them. If one of them is hot, and the second is barely warm or cold, then this is a blockage.

In some cases, cold air will blow from the heater even if both nozzles are hot. This may indicate the following: inside everything is so clogged that the heated antifreeze enters the radiator tank and, bypassing the honeycombs, immediately leaves it without having time to give off heat.

What to do with it

The standard solution to this problem is to replace the radiator with a new one. This is what the auto repair shop recommends. Here you have to fork out, because the cost of work is added to the price of a new radiator, and this is 2-3 times more expensive than the spare part itself. In modern cars, getting to the radiator is very difficult: you need to remove the trim and dashboard, unscrew the air conditioning pipes, and then refuel it.

The second option is flushing directly on the machine. In this case, everything is much simpler and you do not need to remove anything. It is enough to disconnect the pipes going to the heater, connect a pump with hoses instead of them and drive the flushing solution through the radiator.

How effective is flushing the stove radiator

Radiator cleaning is much easier, faster and definitely cheaper than replacement, but this procedure has its drawbacks. Flushing is not a panacea, the chances of success are about 50 to 50. In advanced cases, there is sometimes no effect.

Again, on older cars, the radiator may only leak because the deposits that have blocked the holes in the tubes are washed away. Well, there is always the possibility of re-ingress of dirt from the cooling system into the washed stove.

And yet, before changing the radiator, many car owners prefer to flush it first.

How to flush the stove radiator without removing it

1. Prepare everything you need

Almost everything that is needed for cleaning can be found in any garage, bought in addition at the nearest auto and household store.

  • 150–200 g of citric acid;
  • a bucket of 8–10 liters;
  • container for draining antifreeze;
  • hose about 3 m long;
  • clamps;
  • wires;
  • mesh, gauze or nylon;
  • water;
  • antifreeze for topping up;
  • transfer pump;
  • boiler or stove;
  • spanners;
  • screwdrivers.

2. Get to grips with the process

The principle of flushing the stove radiator is as follows. The heater is disconnected from the cooling system and a pump with hoses is connected to it. In a separate container, the chemicals are dissolved and heated, and then, using a pump, the flushing liquid circulates through the radiator. This allows you to dissolve and wash out all the accumulated dirt.

So that the garbage does not get inside again, it is collected at the exit and removed using an impromptu filter made of gauze or old nylon tights. Then the radiator is washed with clean water and the regular hoses of the cooling system are installed in place.

3. Remove the terminals from the battery

When removing the radiator hoses, you may have to disconnect several wiring connectors. Therefore, in order to avoid errors in the control system, it is better to de-energize the on-board network by removing the terminals from the battery. First negative, then positive.

First make sure that the heater is set to maximum heat. If the control is carried out using a valve, then in the closed position it will block the flow of fluid and interfere with flushing.

4. Drain the coolant

The heater is filled with antifreeze. So that the liquid does not leak out to the floor when you remove the pipes, it must be drained into a previously prepared container through the cork on the main radiator.

Since the stove is not the lowest point in the system, not all antifreeze can be drained, but only a part. With due care, this can be done directly through the nozzles during removal.

5. Remove the pipes from the stove radiator

Locate and disconnect the two thin pipes that go into the cabin. They are located between the engine and the bulkhead of the engine compartment. Usually they are easy to detect, but if it doesn’t work out or you are afraid to make a mistake, check the documentation for the car or search the Internet.

Then simply loosen the clamping clamps and remove the tubes by rotating from side to side. Be prepared for some more coolant to leak out of them.

6. Connect hoses and pump

Take any hoses that are suitable in diameter (usually 16 or 18 mm in diameter), put them on the heater pipes and fix them with clamps. Connect the free end of one of the hoses to the pump, wrap the other with gauze and lower it into …






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