Bad Valve Seals – How To Tackle This Problem DIY?

Bad Valve Seals – How To Tackle This Problem DIY?

July 25, 2021 0 By CarGuy

If your car is making a cloud of smoke in the back when you cold start it, or you apply some pressure on the gas pedal. One of the possibilities is that you are having bad valve seals.

Valve seals are also known as valve stem seals or valve guide seals. They are making sure that no oil from the lubrication system goes down into the cylinder.

If you have bad valve seals, the oil will travel down into the cylinders and burn with the fuel and cause carbon buildup on the spark plugs and valves. If left untreated, it may jeopardize the valve sealing capability and may cause you to lose compression and also burn a lot of oil in the process.

Bad valve guide seals or valve stem seals may cause a lot of trouble in the long run. They can damage your engine and also cause burnt valves. If your valves reach the point when they will start bringing it means that you will pay a lot of extras in order to get this problem fixed.

So, if you are thinking a step ahead and you suspect that the valve seals are bad, this article is the right one for you. In this article, we are going to learn everything about valve seals and how to recognize the symptoms, and also how to replace the valve seals DIY. So, if you are interested and you want to learn more about this problem, follow along.

Symptoms Of Bad Valve Seals

Symptoms of bad valve seals can be many. That’s why it is very important to know them and recognize the problem. In this chapter, we are going to discuss the ones that are most frequent in car shat have bad valve seals.

Ticking Noise

Ticking noise is the first symptom when you have bad valve seals. The valve seals get loose and the valves start making some ticking noise. This symptom is especially prominent when you step on the gas. This is the time when the valves move faster and the ticking sound increases.

You can also try to hear from which cylinder the ticking noise comes from. Although you can’t be really sure until you remove your engine head and start to disassemble things.

Loss On Power

Another symptom is loss of power. You will notice this symptom when you apply the gas pedal. If there are bad valve seals there will be some power loss. Because there is blowby in the cylinder.

When valve seals go bad this is one of the most common symptoms besides the ticking noise.

Loss Of Compression

Loss of compression is also a symptom. If you hear ticking noise accompanied by loss of power it is a good time to start troubleshooting and start checking the cylinders for compression.

In order to perform this job, you will need to remove all of the fuel lines and spark plugs. Make sure that everything is disconnected. Also, you are going to need a special tool to measure the compression. These tools can be found for cheap on Amazon.

Then you need to start cranking the engine and see each cylinder how many bars of pressure are making. Everything below 100 is bad compression.

A compression test is a good idea to do when you are buying a car with a potentially damaged engine. You will have a clear idea of what issues you will probably have to deal with.

Increased Oil Consumption

Increased oil consumption is probably going to be an issue if your valve seals leak. You should regularly check your dipstick and observe the oil level. If your car burns a lot of oil, it can be either bad cylinder rings or O-rings or bad valve seals.

If oil consumption is above 1L per 1000 miles. It means that your engine needs some serious overhaul and the valve seals have to be replaced. In order to prevent carbon buildup and possible engine damage because of low oil.

Valve seal oil consumption repair needs to be performed in order for your car to get the oil consumption in check. In order to save your engine from protentional hazards like burnt or bent valve seals. Also, you will not get worried if you topped out your engine oil every time. Also, your oil spending will be minimal and your car will run perfect once again.

Carbon Buildup

Carbon buildup also can be the case if you have bad valve seals. In the chamber, the oil is burning along the gasoline and it creates sludge that will collect on the top of the piston and the head. If this issue is prolonged and is not fixed, the carbon buildup can become so big that the valves will stop closing.

If the valves stop closing you will have a loss of power and compression. In the long run, this may cause burnt or bent valves. Valves can get bent if they come in contact with the cylinder. And this can cause damage to the head and the cylinder. Repairs will cost a fortune and can possibly scrap your engine altogether.

Blue Smoke Coming From Exhaust

Blue smoke is another symptom that you notice when there is increased oil consumption. If your car develops clouds of smoke when you press the gas pedal it means that it has some issues. If the smoke is white, it means that there is coolant consumption and the head gasket is done.

And, if there is blue or black smoke it means that the car has increased oil consumption. This oil consumption as we said is made possible by damaged piston rings or bad valve seals.

The engine needs to be taken apart and needs to be checked for the issue to be diagnosed and the problem resolved.

Engine Misfires

Bad seals cause misfires also, these misfires will happen pretty frequently if the valve seals are bad. The oil that is injected inside the cylinder will cause the explosions not to be that strong and will cause carbon buildup.

This problem can also develop check engine lights to appear on the dash. Because the O2 sensor will have some different readings that it should have if the combustion is not good.

If you have a check engine light, it is a good idea to connect it to a computer and see the error codes. These codes will tell you which cylinder is affected by the issue and how you can resolve this issue.

OBD scanners come really cheap and you can find them on Amazon. But you should note that you will need a better-equipped scanner to get the codes right. Some scanners have limited options and are not very good for troubleshooting.

How To Install Valve Stem Seals DIY

In order to install new valve seals, you will have to remove the old seals from the head. But first, you need to reach the head and to have a proper working environment. Also, for this task, you will need new valve stem seals and a new head gasket.

Step 1

First, you need to remove all the injector lines and all the coils. This can be a tedious process if you started wrenching. You will probably be going to need a couple of hours just to figure things out, but don’t worry. This is normal when you are learning. Trial and error as they say. After you have done this, then it’s time to remove the headcovers. They are usually held by few bolts that are fairly easy to get to, also they are not torqued a lot and come off pretty easy.

Step 2

For the next step, you will need a torque wrench to untighten the bolts that are holding the head. These bolts are torqued a lot and you need to figure out how much. Look online for your specific engine, they are usually torqued from 65-73 ft ib. But remember that you should not apply that force at once but little by little. There are usually 3 sequences when engine heads are torqued.

Step 3

After you untightened the heads and removed the bolts now it’s time to remove the head from the engine. Remove the head and place it on a table. Clean all the dirt and debris off and check the valves and if there is some play.

Step 4

This is the important part. First, you will need a tool to remove the tension of the spring. After you removed the tension of the spring now it’s time to remove the valve seals. Use a valve stem seal removal tool that is made for this purpose and that will do the trick.

Step 5

After you replaced the valve stems. When putting all back together you will need a valve clearance tool to adjust the valves and make sure that they have the proper clearance. If the valves are not adjusted your engine will run poorly and possibly ruin the valves. So, don’t miss the adjustment process.

Step 6

After you adjusted the valves then it’s time to place the head gasket and mount the head. Torque the bolts up to spec and make sure that you do in three sequences.

Step 7

In the last step, you need to mount the fuel lines and coils. After making sure that everything is well connected you can start your car and see how it will behave. If you did everything as it should. The engine will work very well. If you missed something, it may be required to complete this process again.

How To Replace Bad Valve Seals Without Removing The Head?

Replacing the valve seals without removing the head is also possible. But you will have to turn the engine for one rotation so the piston goes to the highest position. So, the valve doesn’t fall inside the cylinder. How to replace valve seals without removing the head is fairly easy compared to removing all the components in order to reach the valves.

But by using this method you will not be able to know the condition of the valves. Maybe they are burnt or too much carbon buildup is created and they don’t seal properly.

That’s why doing all the work of removing the head is necessary. With this method, you will also have the ability to see all the valve’s overall condition. And replace the faulty ones if there is a need to do so. Also, you can refurbish the heads and clean the carbon buildup in all the cylinders.

Valve Stem Seals Quick Fix

A quick fix for valve stem seal is by using thicker oil. Thicker oil has a higher viscosity and will not travel easily down to the cylinder like thinner oil.

This is a quick fix, so remember that it’s not permanent and your engine will smoke from the back, but a bit less than before.

The best oil for valve seal is the thickest one your engine can handle. There are also some options that Lucas offers like the Lucas oil stop leak valve seals. This oil conditioner/additive will prevent your oil do get down the cylinders but remember that this will not last forever and as soon as the additive goes away. The leaks will start to appear once again.

Valve Seal Replacement Cost

The replacement cost for the valve seals is fairly inexpensive, especially if you do the job at home. You just need to remove the heads and use a tool specific for removing valve seals. This tool can cost around $40-$70 and can be found anywhere online in shops like eBay or Amazon.

Valve seals are fairly cheap and can cost from $15-$50 depending on how much you want to spend on the new valve seals. But remember more expensive means better quality. Not always, but most of the time.

You can also remove the valve seals without removing the head, but that will involve rotating the engine to make sure that your valves don’t drop inside the cylinder while you are replacing the valve seal. This is an even simpler solution than removing the heads and the accessories.

If you take your car to a mechanic’s shop. It will probably going to cost you up to 2 grand. Depending on where you take your car and the mechanic’s expertise and rates.


In this article, we learned a lot about bad valve seals. We learned what are the main symptoms and how to detect this problem in the early stages when there is not a lot of carbon inside the cylinders and also less damage to the engine.

In our DIY section, we explained how this process is done. There are seven steps that involve removing the head and replacing the valve seals. This process is fairly easy, you just need to have the proper tools in order to perform it successfully.

And at the end, we have discussed the cost of this problem. How much are the parts and also how much it can cost you to do this work at a mechanic’s shop.