Vortec Cylinder Head Crack Symptoms 
well this past fall I purchased some used 062 cylinder heads from a scrap yard with the hopes of switching out the stock heads on my 350 tbi small block. Apparently the vortec heads, specifically those made between 1996- 2000ish with casting #'s 062 and 906 are the bees knees when it comes to cheap high performance cylinder heads. From my reading they should give a modest increase in horsepower due to better porting and combustion chamber design. As well compression ratio is also increased due to different combustion chamber design, all good things when running on wood I assumed.
Vortec Cylinder Head Crack Symptoms
Engine blocks contain the cylinders, as well as a number of other major components of the bottom end of a motor. When an engine block is properly functioning, it allows the pistons inside the cylinders to move up and down, which then turns the crankshaft. The turning of the crankshaft then allows the wheels to move. Engine blocks are designed to last for the lifetime of a vehicle. Unfortunately, things can and do go wrong, leading to the formation of cracks in the engine block.
You'll find these issues on generation two and generation three Chevrolet V8 engines from the mid-1990s through the 2007 model year.Although these are the two most common reasons to remove the upper plenum and lower portions of the intake manifold, these are not the only ones. In fact, anytime you remove a cylinder head or perform any kind of major engine work you'll need to remove the intake manifold. What you see when you first take off the part might surprise you. From the factory Chevrolet used a composite intake manifold gasket made of plastic and silicone. Since the gasket is delicate and could crack from over tightening, General Motors uses a very light torque spec measured in inch pounds.
Therefore, the symptoms between the two situations becomedifferent. With a cracked manifold you see white smoke from thetailpipe and the engine runs rough. These often crack on the inside making it hard to see.
One of the most common causes of cylinder head failure is cracking. This will most likely cause you to need a replacement head, because machine shops aren't always able to repair them very well. This causes the cracks to reoccur soon after a rebuild, putting you in the exact same position, but out the money for the initial repair.
Frequently, cracks appear between the valves, one of the weaker spots on the head, but that's not always the case. The operating conditions play a large role in how the damage occurs on the cylinder head.
The most common cause of cylinder head cracking is overheating. The rapid heating of the engine causes the head to expand and then contract as the engine cools. This puts a large amount of stress on the cylinder head, leading to cracks. Similarly, stressful operating conditions can lead to cracks, along with other engine problems. This is especially true if you have an engine model where your engine block and cylinder head are made of different materials. A common combination is a cast iron block and aluminum head. The two metals expand and contract at different rates, causing cracks in the lighter aluminum head more quickly.
A number of issues can arise from a cracked cylinder head. Coolant can enter the cylinders and engine block through the crack. This can contaminate the oil, causing other major engine problems. It could also cause pitting and damage to the engine block. If the coolant enters the cylinder itself, it is often burned off in the exhaust, while damaging the cylinders. If this damage occurs, it's likely that more than just the head and head gasket will need to be replaced to regain a proper seal for combustion and prevent further damage.
Cracks in your cylinder head is not something you want to ignore. They obviously aren't going to go away on their own, and more than likely they will lead to further damage on your engine. If you find yourself in need of a new cylinder head, we offer a large selection of both new and remanufactured heads.
Our certified techs would be more than happy to help you find the right cylinder head for your engine, or any of your other diesel engine needs. Request a quote online or give us a call at 844-304-7688 and let us help you!
The cylinder head on this engine was made by Castech. And due to a manufacturing defect, it would end up cracking. This crack would cause the coolant to leak. It was also hard to tell that the coolant was leaking and as a result, the engine would suffer. Fixing this is a costly affair as it involves replacing the cylinder head.
Firstly, the many versions of the 5.3 Vortec use iron blocks while the LS generally uses aluminum ones. The engines are also quite different in terms of size. Other internal differences come in the form of crank bearings, water pumps, ignition systems, and cylinder heads. The architecture of the engine is also not the same.
Another misnomer is that a cracked cylinder head will cause overheating. Again this does not apply in this instance. A crack in the combustion chamber may cause overheating. This crack is in the top of the head and coolant oozes into the oil. Combustion gasses are not involved and unless the engine runs low on coolant, overheating will not result.
Cylinder head cracking and coolant loss often begins around 130,000 miles, but could be much sooner. We have seen the problem as low as 60,000 miles and as high as 200,000. Some engine last much longer and many never have the problem.
Head cracking is a common issue, but does NOT occur on all engines. Many last hundreds of thousands of miles and never have the problem. Several other coolant leak areas are common on these vehicles and give similar symptoms. Many people have misdiagnosed this issue and gone to a large expense for no reason.
A very common leak point is the water pump gaskets. Leakage trickles out between the pump and the engine block and a casual inspection may not show it. The heat of the engine evaporates the liquid and it may never drip to the ground. Always carefully inspect this area, with a mirror if necessary, before suspecting the cylinder heads.
Often General Motors vehicles, with the 5.3L and 4.8L engines have come to us because they continue to lose coolant. Normally the owner has tried in vain to find the leak and sometimes, multiple auto repair shops have been unable to find a source. It's strange because no outward signs of coolant leakage can be found, yet the coolant reservoir keeps going low. Knowing where to look helps and often a cracked cylinder head is the source of the problem.
Between 2001 and 2006 GM manufactured millions of engines, many with defective cylinder heads castings. The cylinder head castings are weak in the area where the head bolts pass through. Over time, the heating and cooling cycles of the engine take a toll and the head may crack. The cracks most often appear around the center row of head bolts. This is under the engine valve cover, and we cannot see it from the outside. This makes the problem more difficult to diagnose. Coolant is leaking into the engine oil and a great deal of engine damage can quickly occur.
The affected heads may be identified by a casting mark, just above the intake port. Cylinder heads with this mark are the ones that may be prone to cracking. The cracks usually will be found in one or more of the five head bolt/oil drain areas, under the valve cover.
On this stripped-down and cleaned head we can see the crack. With the head on the engine and assembled, the cracks may be more difficult to see. A pressure test with the valve cover off helps to verify the problem. With pressure on the system, we may see coolant or air, seeping from the crack. Finding the crack is easier when we add a fluorescent dye to the coolant and use a black light to find the traces.