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Autopapyrus · Hyundai Tucson D4HD 2.0 CRDi (2021)
https://autopapyrus.com/guides/hyundai/tucson/engine-overhaul/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Hyundai Tucson D4HD 2.0 CRDi (2021): Engine Overhaul

The D4HD (Smartstream D 2.0 TCi) is a second-generation diesel engine with an aluminum block, an 83 mm cylinder bore, a 92.3 mm piston stroke and a 16:1 compression ratio. An overhaul includes removing and disassembling the engine, inspecting all components, boring the block (if cylinder wear exceeds the allowable limits), grinding the crankshaft, replacing the pistons and bearings with oversize parts, replacing the valve stem seals, resurfacing the cylinder head, assembling with all clearances and torque values checked, and installing a new timing belt. The job requires a high skill level, specialized equipment and adherence to factory procedures.

Difficulty: Hard Time: 40-60 hours (depending on the scope of work) Steps: 13 Tools: lift or inspection pit, socket and box-end wrench set, torque wrench, pullers (pulley and bearing), micrometer, bore gauge, feeler gauge, piston ring compressor, seal installation drivers, specialized cylinder boring machine (engine machine shop), cylinder head resurfacing machine.

Part

  • 🔩 oversize pistons, piston rings, oversize crankshaft bearings (main and rod), valve stem seal set, gaskets (cylinder head, oil pan, valve cover, intake manifold), seals (front and rear crankshaft, camshafts), timing belt with rollers, tensioner and water pump, oil pump (if worn), hydraulic lifters (if worn), engine oil (6 L (6.3 qt), 5W-30), oil filter, coolant, flange sealant
There's a full repair manual for this car Every system, wiring diagrams and torque specs — not just this job. Haynes AutoFix (online) and 2 more. See manuals →

Step by step

13 steps
  1. Remove the engine from the vehicle. Disconnect the battery, drain the oil and coolant, and remove the exhaust system, intake system, high-pressure fuel lines, electrical connectors, turbocharger coolant lines and intercooler hoses. Separate the transmission from the engine. Secure the engine to the hoist, unbolt the mounts and carefully lift the powertrain out of the engine bay.
  2. Disassemble the engine on a stand. Remove the accessories (alternator, A/C compressor, starter, sensors), the intake and exhaust manifolds, the turbocharger, the oil pan, the oil pump and the front timing cover. Remove the timing belt and the camshaft and crankshaft pulleys. Remove the cylinder head (loosen the head bolts in the reverse of the tightening sequence, working from the edges toward the center), then take out the hydraulic lifters and camshafts. Turn the block over, remove the connecting rod caps and main bearing caps, and take out the crankshaft and the pistons with connecting rods.
  3. Inspection and measurements. Use a bore gauge to measure the cylinder diameter at three heights and in two perpendicular planes to determine out-of-round and taper wear. The nominal cylinder diameter is 83 mm; if wear exceeds 0.15-0.20 mm or there is scoring, the cylinders must be bored to an oversize (usually +0.25 mm, +0.50 mm, +0.75 mm or +1.00 mm). Use a micrometer to measure the crankshaft journals (main and rod). If out-of-round exceeds 0.02-0.03 mm or wear exceeds 0.05 mm, the journals must be ground for oversize bearings (usually 0.25/0.50/0.75/1.00 mm sizes). Check the cylinder head flatness with a feeler gauge and a straightedge. The allowable warpage is no more than 0.05-0.10 mm; if it is exceeded, resurface the head. Inspect the pistons for cracked skirts, burned crowns and worn ring grooves. Check the rod bearing clearance and the hydraulic lifters for play.
  4. Machining the block and crankshaft. Take the cylinder block to a specialized engine machine shop to be bored to the required oversize (all 4 cylinders must be bored to the same size). After boring, be sure to wash the block with hot water and detergent and blow out all oil passages with compressed air, because abrasive dust will destroy the bearings at the first start. Have the crankshaft journals ground (if the measurements showed it is necessary), then wash it and clean the oil passages. Resurface the cylinder head on a machine if needed.
  5. Selecting and checking parts. Buy oversize pistons (the size must match the block bore, usually marked +0.25/+0.50/+0.75/+1.00 mm), piston rings of the same oversize, and main and rod bearings in the oversize that matches the crankshaft grinding. Check the piston-to-cylinder clearance with a feeler gauge or micrometer (usually 0.03-0.08 mm for a diesel). Check the piston ring end gaps in the cylinder with a feeler gauge. Compression rings are usually 0.20-0.40 mm and the oil control ring 0.25-0.50 mm (exact values are in the piston manufacturer's catalog).
  6. Replace the valve stem seals in the cylinder head. Mount the cylinder head on a stand, compress the valve springs with a valve spring compressor to remove the keepers, and remove the springs. Remove the old valve stem seals with pliers or a special puller (do not damage the valve guide). Before installing the new seals, lubricate them with engine oil, place an installation sleeve over the valve stem (to protect the seal lip from damage), and press the new seal on until it seats fully on the guide. After reinstalling the keepers, check the valve stem installed height.
  7. Assemble the rotating assembly. Wipe the main bearing seats in the block and caps with a clean lint-free cloth. Install the main bearing shells dry (the locating tab on the shell must seat in the notch in the bore), then lubricate the shells with clean engine oil. Lay the crankshaft in the block. Install the main caps with their bearings (orient them by the marks, and do not mix up the caps). Tighten the main cap bolts with a torque wrench in two to three stages from the center outward (the torque values for the D4HD are not published in open sources. The typical range for diesels in this class is 80-110 N·m (59-81 lb-ft) plus an angle turn of 90-120°. Use the exact value from the factory manual). Turn the crankshaft by hand. It should rotate freely, without binding. Install the pistons with connecting rods. First fit the piston rings into the grooves (oil control ring first, then the two compression rings, watching the "TOP" marking), and stagger the ring gaps 120° apart. Compress the rings with a ring compressor and insert the piston into the cylinder (the mark or arrow on the piston crown must face the front of the block). Seat the connecting rod on the crankshaft journal, install the rod cap with its bearing, and tighten the rod nuts/bolts in two to three stages (the typical torque for diesels in this class is 50-70 N·m (37-52 lb-ft) plus an angle turn of 60-90°. Use the exact value from the factory manual). Repeat for all four cylinders.
  8. Install the oil pump and oil pan. Install a new or inspected oil pump (the D4HD uses a gear-type pump at the front of the block) and tighten the mounting bolts. Clean the mating surfaces of the block and oil pan of any old gasket residue and degrease them. Apply a thin layer of sealant to the block flange or use a new oil pan gasket (depending on the design). Install the oil pan and tighten the bolts evenly in a crisscross pattern (the torque is usually 10-15 N·m (7-11 lb-ft)).
  9. Install the cylinder head. Clean the mating surfaces of the block and cylinder head (do not let debris or dirt get into the cylinders, and cover them with a clean rag while you work). Install a new head gasket (check the orientation: the "TOP"/"OBEN" marking must face up, and the cylinder alignment marks must line up). Set the head onto the block and insert the mounting bolts (lubricate the threads and bearing surfaces with engine oil). Tighten the head bolts with a torque wrench in three to four stages following a center-to-edges pattern (the torque values for the D4HD are not published in open materials. The typical procedure for modern diesels is an initial torque of 40-50 N·m (30-37 lb-ft), then a main torque of 80-100 N·m (59-74 lb-ft), then angle turns of 90°+90° or 120°+120°. Follow the exact procedure and sequence strictly according to the factory manual, because any deviation will warp the head or blow the gasket).
  10. Install the camshafts and timing drive. Lubricate the camshaft bearing seats in the cylinder head with engine oil and lay in the camshafts (the marks on the sprockets/pulleys must line up with the marks on the head, and do not mix up the intake and exhaust camshafts). Install new hydraulic lifters (soak them in engine oil for 10-15 minutes first) and insert them into the head bores. Install the camshaft caps and tighten the bolts evenly in a crisscross pattern (the torque is usually 10-12 N·m (7-9 lb-ft)). Install the front timing cover with a new gasket. Install the crankshaft pulley (the center bolt torque is usually 120-150 N·m (89-111 lb-ft) plus an angle turn. Use the exact value from the factory manual). Set the No. 1 piston to TDC (the mark on the crankshaft pulley lines up with the mark on the timing cover or block) and align the marks on the camshaft pulleys with the marks on the head. Fit the new timing belt over the crankshaft pulley, camshaft pulleys, water pump, tensioner and idler rollers (observe the direction of rotation shown by the arrow on the belt). Tension the belt with the tensioner (check the tension by belt span deflection or the tensioner indicator, since the procedure depends on the tensioner type). Turn the crankshaft two full revolutions and make sure the marks line up again. If the marks are off, reinstall the belt.
  11. Assemble and install the accessories. Install the intake and exhaust manifolds with new gaskets, and the turbocharger (check that the turbo oil and coolant lines are clean, and replace the gaskets). Install the valve cover with a new gasket (the bolt torque is usually 8-10 N·m (6-7 lb-ft)). Install the alternator, A/C compressor, starter and sensors (temperature, oil pressure, crankshaft position, camshaft position, knock). Connect all electrical connectors, the high-pressure fuel lines (the fuel line fitting torque is usually 20-30 N·m (15-22 lb-ft). Do not overtighten, or the threads will strip), and the cooling system and intercooler hoses.
  12. Install the engine in the vehicle. Secure the engine to the hoist, carefully lower it into the engine bay and align it with the mounts. Secure the engine mounts (torque 60-80 N·m (44-59 lb-ft)). Mate the transmission to the engine and tighten the mounting bolts. Reconnect the exhaust system, coolant hoses, A/C lines and wiring. Fill with fresh engine oil (capacity 5.6 L (5.9 qt), viscosity 5W-30), and install a new oil filter (prefill the filter with oil and lubricate the rubber seal). Fill the cooling system with coolant and bleed out the air pockets.
  13. First start and break-in. Before starting, crank the engine with the starter for 10-15 seconds with the injectors disabled (or the fuel pump relay removed) to build oil pressure in the system. Reconnect the injectors and start the engine. On the first start, let it idle for 5-10 minutes and watch the oil pressure and temperature and check for unusual noises and leaks. After the engine reaches operating temperature, check the oil and coolant levels and the tightness of all threaded connections. Break-in for the first 1,000-1,500 km: do not exceed 2,500-3,000 rpm, avoid hard acceleration and prolonged driving in a single gear, and do not tow a trailer. After break-in, change the oil and filter (the oil may contain particles from parts wearing in). Run a diagnostic scan to confirm there are no fault codes, and check the cylinder compression (the normal value for the D4HD is about 28-32 bar, with no more than 2-3 bar variation between cylinders).

Common mistakes and warnings

  • An engine overhaul is a complex job that requires a high skill level, specialized tools and machining equipment (boring and grinding machines). Incorrect assembly, failure to follow the torque specifications, or incorrect timing belt installation will lead to another engine failure (in the worst case, valves hitting the pistons and destroying the pistons and cylinders). If you have no experience overhauling diesel engines, take the work to a specialized engine machine shop. Pay special attention to cleanliness during assembly: abrasive dust, dirt or metal shavings getting into the oil system is critical to the life of the rebuilt engine. The D4HD with its aluminum block is sensitive to overheating, so after the repair, keep a close eye on the cooling system (thermostat, water pump, radiator cleanliness). When buying parts, confirm the oversize: the pistons, rings and bearings must match the block bore and crankshaft grinding exactly.
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