Heat exchanger defective or leaking? You have to pay attention to this!

Recently updated on October 29, 2023 at 08:45 am

We have just discussed the subject of "The color of the exhaust gas: that's what the exhaust gases reveal!"Reported and as unlikely (but not completely impossible) Cause a defective heat exchanger addressed. But how do you actually recognize a defective heat exchanger? You can find out more about the typical symptoms of a defective heat exchanger, how the replacement works and what costs are incurred in the following report.

How the heat exchanger works

The heat exchanger is part of the Cooling water circuit of the motor. The cooling water circulates, absorbs the heat generated in the engine and transports it to the radiator, where it is then released into the ambient air. So that it is nice and warm in the vehicle, the warm cooling water from the engine flows through the heat exchanger and ensures that the fresh air for the interior is at the desired temperature is heated. To regulate the amount of heated air, a Cooling water valve or it will be electromechanically controlled air flaps used. Normally per car a Heat exchangers are installed, although they are also installed in larger vehicles such as vans, SUVs or minibuses second heat exchanger can be installed for the rear.

How do I recognize a defective heat exchanger?

A defective heat exchanger in the vehicle manifests itself through the following symptoms, among other things. Please note that not all symptoms together must occur to indicate a defect and not all symptoms are mentioned by us.

• Overheating of the engine due to the loss of cooling water
• Air comes into the system despite ventilation
• smelly smoke from the exhaust
• The interior does not get warm
• The interior does not get evenly warm; warm air only flows out of some of the ventilation nozzles
• Cooling water smell in the interior (is often described as sweet)
• Increased humidity in the interior (windows fog up from the inside)
• Cooling water puddle in the interior
• Loss of cooling water recognizable in the expansion tank
• Smoke from the ventilation

Since the repair costs can be very high in the event of a defective heat exchanger, the functionality of the heater and the coolant level should always be ensured. If the heating output drops sporadically from time to time, the heat exchanger should be checked. To test the heater, it is set up when the engine is warm highest step and checks whether from all ventilation nozzles evenly warm air flows.

Possible causes for a defective heat exchanger

• The heat exchanger is clogged with radiator sealant.
• Hoses are porous and leaky
• The wrong cooling water or the wrong cooling water additive was used, which for example led to corrosion.

Attention likelihood of confusion!

It depends on what symptoms are occurring. If several of the above symptoms appear at the same time, there is a high probability that the heat exchanger is really responsible for the problem. But to be on the safe side, one should pressure test with following Visual inspection be performed. If, for example, only the interior is not warm, a defective thermostat, defective interior fan or a defective temperature sensor be the cause. If there is a loss of cooling water, this can also happen to one leaking radiatorto defective water pump or a defective cylinder head gasket lie.

Can I still drive with a defective heat exchanger?

If there is a suspicion of a defective heat exchanger, it should if possible contemporary a workshop must be visited. A leak creates a permanent one Cooling water loss, which in the worst case could result in engine damage due to overheating leads. In any case, the Engine temperature Always watch for a defective heat exchanger while driving Overheating to avoid.

Is a defective heat exchanger TÜV relevant?

Usually has a defective heat exchanger save direct effect on the passing of the general inspection. Should the defect somehow cause the Combustion of the engine impaired are for example in combination with a defective cylinder head gasket, then the Change the exhaust gas values ​​negatively. This is the emission test failed and receives the vehicle no new badge.

Replace or repair?

Whether the defective heat exchanger exchanged has to be or can still be repaired depends entirely on the condition of the component. At a leaking This usually has to be a heat exchanger new part or a working one Used part be replaced. But it should only be one clogged heat exchanger act, this problem can often be remedied by simple means such as radiator cleaner and compressed air.

The more work it takes to remove and install, the more expensive it usually becomes. Therefore, one should carefully consider whether to repair the component or immediately against one new part exchanges so as not to risk another change.

As the heat exchanger on most vehicles between the engine compartment and the interior Sitting under the dash is the change very expensive. First of all, all cooling water connections in the engine compartment must be loosened, then the dashboard is removed. The heat exchanger can then replaced or repaired will. Once everything has been reassembled, it must be ensured that all causal symptoms have been eliminated.

What does it cost to change a heat exchanger?

The material costs for a new heat exchanger from well-known spare parts manufacturers are around 50 to 250 euros. However, this is only the smallest part of the total costs, because due to the complex and time-consuming removal and installation, around 5 to 10 hours of work depending on the vehicle. Depending on the hourly rate of the workshop, labor costs of 500 to 1000 Euro join in. Together with the material costs, there is a total cost of around 500 to 1.250 Euro to be expected. Due to the extreme effort involved, we recommend replacing the heat exchanger with a new part if possible.

Of course that had not happened yet!

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