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NL Published on 10.06.2023
If high pressure builds up in the radiator, this can be recognized, for example, by rock-hard, partially inflated radiator water hoses, the formation of bubbles in the cooling water during operation and strong back pressure when the cooling water tank is opened.
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How does pressure develop in the radiator or exhaust gases in the cooling system?
If exhaust gases or CO2 enter the cooling system, this is due to a leak in the engine, usually Cylinder head gasket or cylinder head. Specifically, there is a crack between a cooling water channel and one of the engine's compression chambers. A CO test with a reaction fluid would confirm this. If the test is positive, i.e. the reaction fluid becomes discolored during the tests, the suspicion of cylinder head gasket damage hardens. Very often, the coolant tank also smells unpleasantly of exhaust fumes when the cap is open and the engine is running. This symptom is therefore a clear indication of a leaking cylinder-head gasket.
CO test with reaction liquid
What visible symptoms occur when there is pressure or exhaust gases in the cooling system?
However, if the existing back pressure in the cooling system is already so high that increased bubble formation or strong bubbling in the cooling water can be observed when the engine is running at idle speed and the expansion tank is open, we recommend the second method.
This method involves completely isolating the back pressure from the combustion chamber by simply switching off the affected cylinder during the application.
What to do if there is pressure or exhaust gases in the cooling system?
What should be done if the cooling water smells of exhaust fumes, forms bubbles or runs out of the top of the expansion tank and too much pressure builds up in the cooling system? And what needs to be considered when using Steel Seal? We show you in this video:
Problem: The compression pressure from the combustion chamber is a disruptive factor when using Steel Seal, as it creates back pressure at the leaky point to the cooling water channel and prevents Steel Seal from carrying out the bonding process effectively. Therefore, the pressure in the cooling water should be minimized or even completely isolated.
Solution: The easiest way to avoid this Pressure in the cooling system To counteract this, the radiator cap or the cap of the expansion tank should be removed during the application of Steel Seal. This allows the built-up pressure in the expansion tank to escape from the cooling system and the coolant pressure allows Steel Seal to reach the defective areas of the cylinder-head gasket more easily. In our experience, this measure is completely sufficient in 2 out of 3 cases to achieve a successful result.
"Very fast delivery! In the meantime I have used Steel Seal on a VW T5 according to the instructions and lo and behold, no more CO2 in the coolant! I'm going on vacation next week. I can only recommend Steel Seal."
Successful use of Steel Seal in the event of overpressure in the cooling system
And this is how it works: First, you determine which cylinder is causing the back pressure. This can be done using a compression tester or, if one is not available, using the exclusion principle - in which one cylinder at a time is tested in turn. Spark plug (for diesel: "glow plug") one after the other, start the engine and observe in which cylinder the bubbling or bubbling subsides. This allows you to identify the leaking cylinder.
After removing the spark plug (or glow plug) from the relevant cylinder and, if possible, the injection line to this cylinder so that no unused fuel enters the combustion chamber, start the engine and simply carry out the process with Steel Seal on the remaining cylinders. If the engine struggles to reach operating temperature during the application, as it is now running with one cylinder less, you can easily step on the gas at idle and increase the engine speed during the application. The injection line and spark plug will of course be reinstalled after the application!
Using this procedure, it is also possible to achieve a successful and cost-effective cooling system despite disturbing exhaust gases in the cooling water and pressure in the cooling system. Repair with Steel Seal to be carried out.
Do you still have questions or are you not sure whether Steel Seal® is the right product for you? Give us a call! We will be happy to advise you without obligation at the local rate at +49 (0)9101 9018160 (EN) or +43 (0)1 9962116 (AT) from Monday to Friday between 09:00 and 16:00.
