5 signs it’s time to replace valve stem seals
- July 25, 2023
- 0
Any of the five symptoms that motorists say valve stem seals need replacing can indicate other engine failures as well. However, when everything comes together, there is no
Any of the five symptoms that motorists say valve stem seals need replacing can indicate other engine failures as well. However, when everything comes together, there is no doubt: it’s time to change.
To prevent engine oil from entering the combustion chambers from the crankshaft area, clever people came up with special valve seals. Motorists usually refer to them as oil caps. However, nothing more than valve stem seals is firmly anchored in the mass. Basically, the reason for their existence is simple. In addition, the purpose goes beyond the name: valve stem seals provide a seal where the valves of the gas distribution mechanism fit into their own guide bushes.
As they move along the valve stem, these compact oil seals “lick” the oil off the valve stem, preventing lubricant and fuel from mixing. There is also a fairly digestible definition from the textbook: “… a sealing element of the gas distribution mechanism … a rubber cap mounted on the guide sleeve and valve stem to prevent engine oil from entering the combustion chamber.”
Basically, valve stem seals are reinforced bushings made of dense rubber with a rigid metal base and a spring that presses the sealing edge of the cap against the valve stem (stem). From time to time, due to heavy loads and high temperatures, valve stem seals wear out, lose their shape and elasticity – they become oak. And then, once it’s an intake valve, they start directing engine oil into the combustion chamber, where the oil burns along with the fuel, turning the cylinder cavity into a locomotive furnace and the piston into a blackened ember.
If the exhaust valve cap “drips”, the picture is different, although no less deplorable: under the influence of exhaust gases, the oil also burns, but already on the upper part of the valve “plate”. Soot forms on the valve, which over time prevents it from returning completely to its place – the tightness of the combustion chamber is broken.
To determine the malfunction, it is important to at least partially understand the processes in the engine. If oil burns over the exhaust valve, the valve and head parts will quickly become corroded by carbon deposits. But when the oil along with the fuel already burns in the combustion chamber, carbon deposits are already forming on the walls of the cylinder and the upper surface of the piston. The result is coke formation, increased engine wear and a decrease in efficiency. How does this manifest itself in practice?
Reduced compression, loss of traction and economy. Combustion products clog the grooves of the piston rings, depriving them of their mobility. Check the oil consumption after finding the above symptoms. Although in practice you will sometimes quickly find the oil burner, and not the increased fuel consumption. It’s too early to panic, this is not a reason for the “capital”. You also need to make sure that the reason is the caps and not the cylinder-piston group. Making a diagnosis is quite easy.
One way: Let the engine idle for a few minutes, then abruptly lower the accelerator pedal to the floor. If, when working with “idle” caps, the oil is not retained and enters the combustion chamber, the aggressive gas with a large amount of the mixture will cause it to burn out. At the same time, you can watch how a puff of gray smoke will fly out of the exhaust. And if, returning to “idle”, the flue disappears, then the caps need to be replaced.
Seasoned mechanics are always careful in their assessments. Smokiness and maslozhor albeit a true, but not yet complete picture of the death of caps, characteristic of other “diseases” of the engine. The problem is that until you remove the head from the block and “dry out” the valve, it’s too early to run to the shop for a set of new valve stem seals. After all, the problem may turn out to be even more serious and cheap valve seals will not get rid of it …
Photo by globallookpress.com
Photo by globallookpress.com
Photo by globallookpress.com
To prevent engine oil from entering the combustion chambers from the crankshaft area, smart people came up with special valve seals. Motorists usually refer to them as oil caps. However, nothing more than valve stem seals is firmly anchored in the mass. Basically, the reason for their existence is simple. In addition, the purpose goes beyond the name: valve stem seals provide a seal where the valves of the gas distribution mechanism fit into their own guide bushings.
As they move along the valve stem, these compact oil seals “lick” the oil off the valve stem, preventing lubricant and fuel from mixing. There is also a fairly digestible definition from the textbook: “… a sealing element of the gas distribution mechanism … a rubber cap mounted on the guide sleeve and valve stem to prevent engine oil from entering the combustion chamber.”
Basically, valve stem seals are reinforced bushings made of dense rubber with a rigid metal base and a spring that presses the sealing edge of the cap against the valve stem (stem). From time to time, due to heavy loads and high temperatures, valve stem seals wear out, lose their shape and elasticity – they become oak. And then, once it’s an intake valve, they start directing engine oil into the combustion chamber, where the oil burns along with the fuel, turning the cylinder cavity into a locomotive furnace and the piston into a blackened ember.
If the exhaust valve cap “drips”, the picture is different, although no less deplorable: under the influence of exhaust gases, the oil also burns, but already on the upper part of the valve “plate”. Soot forms on the valve, which over time prevents it from returning completely to its place – the tightness of the combustion chamber is broken.
To determine the malfunction, it is important to at least partially understand the processes in the engine. If oil burns over the exhaust valve, the valve and head parts will quickly become corroded by carbon deposits. But when the oil along with the fuel already burns in the combustion chamber, carbon deposits are already forming on the walls of the cylinder and the upper surface of the piston. The result is coke formation, increased engine wear and a decrease in efficiency. How does this manifest itself in practice?
Reduced compression, loss of traction and economy. Combustion products clog the grooves of the piston rings, depriving them of their mobility. Check the oil consumption after finding the above symptoms. Although in practice you will sometimes quickly find the oil burner, and not the increased fuel consumption. It’s too early to panic, this is not a reason for the “capital”. You also need to make sure that the reason is the caps and not the cylinder-piston group. Making a diagnosis is quite easy.
One way: Let the engine idle for a few minutes, then abruptly lower the accelerator pedal to the floor. If, when working with “idle” caps, the oil is not retained and enters the combustion chamber, the aggressive gas with a large amount of the mixture will cause it to burn out. At the same time, you can watch how a puff of gray smoke will fly out of the exhaust. And if, returning to “idle”, the flue disappears, then the caps need to be replaced.
Seasoned mechanics are always careful in their assessments. Smokiness and maslozhor albeit a true, but not yet complete picture of the death of caps, characteristic of other “diseases” of the engine. The problem is that until you remove the head from the block and “dry out” the valve, it’s too early to run to the shop for a set of new valve stem seals. After all, the problem may turn out to be even more serious and cheap valve seals will not get rid of it …
Source: Avto Vzglyad
Donald Salinas is an experienced automobile journalist and writer for Div Bracket. He brings his readers the latest news and developments from the world of automobiles, offering a unique and knowledgeable perspective on the latest trends and innovations in the automotive industry.
