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Cracked Cylinder Head Symptoms: Causes and Repair Costs!

Before going over the signs and symptoms of cracked cylinder heads, we think it’s important to briefly go over their purpose. The internal combustion engine that powers vehicles contain several cylinders.

The tops of these cylinders, called cylinder heads, play a vital role in the internal combustion process. Unfortunately, their weak design makes them prone to damage.

If the cylinder head(s) get damaged, you need to replace or repair them. However, before you do anything, you need to identify the damage. A minor crack in its initial stages may hardly be noticeable because most larger symptoms will be absent.

Regular inspection is the key to diagnosing a crack in the cylinder head. However, as the crack grows, the symptoms become more apparent and the problem becomes worse.Here are four common symptoms that you can watch out for:

Symptoms of Cracked Cylinder Heads

cylinder heads

1. Weak Engine Performance

Poor engine performance is the first indication of a crack in a cylinder head. When this is the case, you might notice the engine isn’t running as it should because compression isn’t optimal. Compression is essential for combustion engines to burn fuel efficiently. If compression is poor, you may even find that your engine will quit and needs to be restarted often.

2. Oil Leakage

Inside the cylinder head is oil. When there is a crack, you may find oil leaking out. Consequently, this will make the oil light turn on. If that happens, you need to check the engine and look to see if there is oil around the cylinder head.

3. Low Coolant Levels

Each cylinder is surrounded by coolant. In the case of crack, you may notice coolant at the seam of the cylinder head, in addition to oil.

As you can imagine, if you’re leaking coolant, the engine has no way to cool down. The cylinder heads are at the forefront of the thermal stress. As a result, the metal parts will warp and crack.

4. Smoke

A rare, but sure sign of a cracked cylinder head is exhaust gases leaking into the cylinder head, which causes smoke in the engine. If you have this problem, it is likely a severe crack and should be repaired as soon as possible.

There are also other symptoms such as bubbles in the radiator, too much steam in the exhaust, moisture under the oil filler cap, engine misfires, and burnt spark plugs.

Repair Costs

The repair cost for cracked cylinder heads varies, as several factors come into play while calculating the cost.

These days, most vehicles have aluminum cylinder heads, and the cost of repair is lower. On the other hand, some older vehicles will use iron cylinder heads, and in case you own such a vehicle, the repair costs are going to be higher.

The cost of repairing a damaged cylinder head is always less than replacing it. Because when replacing a cylinder head, you need to pay for both the spare parts and the labor costs.

Based on previous experience, you can expect to pay $500 for the repair. With parts and labor, likely around $1000.

Check with your dealer to see if your vehicle is under warranty. The estimate above can easily be $1000+ if the crack is more substantial than you think it is.

Richard Reed
I've been a General Manager of a moving company and I've also been a Professional Mover for over 30 years. I've driven flat beds, reefers, dropdecks, moving vans, heavy machinery, etc. In my time as a Mover I've driven over 1,000,000 safe miles. My days of moving and driving truck are past me but The Vehicle Lab allows me to share the knowledge I've gained over the past 40 years.

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