Toyota RAV 4 cylinder head gasket
Toyota RAV 4 cylinder head gasket is metallic and non-metallic. Toyota Rav 4 cylinder head metal gasket is made of copper sheet with insert rubber seals. The metal cylinder head gasket has the greatest wear resistance and serves several times longer than a non-metallic one.
Toyota Rav 4 non-metallic cylinder head gasket is asbestos and non-asbestos. Asbestos cylinder head gasket Toyota RAV 4 basically contains paronite, which forms a rubber mixture with the addition of powder components. Asbestos-free cylinder head gasket, made of rubber and synthetic fiber.
Different gaskets are used for the same Toyota Rav 4 model, depending on the modification and engine size. We recommend managers who will take the block head gasket according to the VIN number of the car.
Signs of a defective cylinder head gasket:
- in the expansion tank, violent gas formation, bubbles or oil stains have appeared;
- unstable operation of a heated engine;
- running problems in the cooling system, which led to overheating of the engine;
- white smoke from the muffler.
Cylinder head gasket
One of the most important sealing elements of any internal combustion engine is the gasket between the cylinder head and the cylinder block. Modern trends in increasing the liter power of the engine, due to the high compression ratio, force the manufacturers of gaskets to constantly modernize and improve their products.
The cylinder head gaskets must tightly seal the combustion chamber for gases and at the same time reliably seal the oil and coolant passages.
Requirements for modern block head gaskets:
1. Reliable and long lasting macro and micro compaction
2. Resistance to media such as gas, water and coolant (antifreeze and antifreeze)
3. Resistance to temperature differences and high pressures of fuel combustion
4. Stability and high elasticity when aligning distortions of the contact planes, the cylinder block to the block head
5. Resistance to shear and rupture at the bulkhead
6. Maintaining the forces when tightening the bolts of the block head
7. Heat flow in the sealed joint
Modern technologies for the manufacture of block head gaskets:
Soft head gasket (classic) - Composite cylinder head gasket
The head gasket is made of soft elastic material and is a flat compression seal. It consists of a perforated carrier sheet on which a soft material is rolled on both sides. Metal edging seals the combustion chambers and protects sensitive soft material from overheating. The impregnation of the outer surface prevents fluids such as oil, water or antifreeze from leaking through the contact surface. The so-called "Viton" - elements made of elastomeric materials provide an increase in the specific pressure at the locations of the channels with high oil pressure. Due to the specific pressure, the working material is deformed in such a way that it fits perfectly on the sealing surfaces. Sealing requires very high bolt forces with low springback properties. The minimum width of the lintel is 6 mm in order to withstand high pressures and temperatures during combustion.
When installing soft cylinder head gaskets with Viton element, care must be taken to ensure that the cylinder head gasket and cylinder head are precisely positioned. Due to incorrect positioning, the Viton element can be pressed in with too much force and cut with the sharp edges of the parts. Additional sealing compounds (sealants) are only required if specifically prescribed by the manufacturer.
Multi-layer steel (MLS) cylinder head gaskets
They were born as an alternative to asbestos-containing gaskets banned for use in the late 80s. Multi-layer steel cylinder head gaskets consist of two to five sheets of carbon, spring steel, sandwiched in a cylinder head gasket.
For reliable sealing of gases and media, grooved molding at the combustion chambers, as well as at the places where oil and water passages, increases the local pressing forces (macrosealing). Full-surface or partial elastomeric coatings further enhance the sealing effect. Multi-layer steel seals, thanks to their special design, adapt well to any roughness of the outer surface, provided that the quality of the outer surface is within the tolerance ranges described. High-quality MLS head gaskets optimally smooth out, thanks to the controlled pressing pressure, unevenness and warpage of parts.
Head gaskets made from soft materials and gaskets made from sheet steel make the same demands on the quality of the outer surfaces. When installing, do not take into account any special differences, except for the tightening method.
Repair gaskets.
In the course of prolonged operation of the engine, due to a violation of the temperature regime, detonation and the use of poor-quality fuel and antifreeze, the contact planes of the cylinder block and the block head are deformed. Especially for in-line many cylinder motors. As a consequence, milling or grinding of these "mating" planes is required, which leads to a decrease in the volume of the combustion chamber. In cases where the height of the combustion chamber is significantly reduced during processing, in order to avoid a change in the compression ratio, it is envisaged to install a repair gasket for the head of the block with an increased thickness.
Breaking the cylinder head gasket is an extremely unpleasant thing. Most often, the fault is the overheating of the Toyota Rav 4 engine. Accordingly, in most cases, before dismantling the head, we will not be able to say whether it will be limited to replacing the gasket or not. It may be necessary to grind and even replace the behavior of the cylinder headю
Toyota RAV 4 cylinder head gasket replacement technology:
The hood of the car rises, the upper plastic protection of the engine is dismantled, the side timing covers are removed, as well as the valve cover
The tension of the chain or timing belt is loosened, the camshaft is removed
The cylinder head bolts are unscrewed, then it is removed from the block
The head is checked for tightness
A new cylinder head gasket is being installed
The head is clamped without fail using a new set of bolts
The car is being assembled according to the reverse algorithm
