1) Diagnose the symptom (what’s wrong and why)
- What to look for: coolant leak at pump/pulley hub, growling/grinding or rumbling from the front of the engine, belt squeal, belt mis-tracking, engine overheating, visible pulley wobble.
- Theory: the water-pump shaft rides on bearings and is sealed where it exits the pump housing. Bearing wear → radial/axial play → pulley wobble and noise and extra belt load. Seal failure → coolant leak and corrosion at the shaft. Pulley misalignment or looseness → belt wear, slipping and belt noise, reduced pump drive and overheating.

2) Safety and preparation (why each is necessary)
- Cool engine to ambient (hot coolant will scald). Disconnect battery (avoid fan/clutch starting and electrical shorts).
- Drain coolant to below pump level or remove only enough to avoid big spills. This prevents coolant loss and contamination of the work area.
- Loosen belt tension and remove the drive belt; remove fan/fan shroud or fan clutch as required to access the pulley. Theory: you must remove all torque/load and clearances so you can remove the pulley without stressing the shaft or breaking nearby components.

3) Remove the pulley (and why it’s done this way)
- Expose the pump pulley bolts or the press-fit hub. On many Toyota diesel pumps the pulley is either bolted or interference-fit on the shaft.
- If bolted: remove bolts while supporting the pulley so it doesn’t drop; if interference-fit: use a proper gear/pulley puller, not a hammer. Theory: the pulley transfers torque from the belt to the pump shaft — removing it lets you inspect and/or replace the pump shaft, bearing, seal or the pulley itself without causing damage.
- Mark belt routing and pulley orientation if you will reuse parts; this preserves final alignment.

4) Inspect components and measure (what to check and why)
- Check pulley for runout/wobble on a dial indicator or visually spin by hand: wobble indicates bent pulley or shaft play.
- Check shaft axial and radial play by hand: any perceptible slack, roughness or grind → bearing failure.
- Inspect seal lip, shaft corrosion, impeller condition inside pump (if visible): scoring or coolant in bearing area → seal failure/corrosion.
- Theory: these inspections tell you whether the problem is the pulley, the pump bearings/seal, or both. A noisy pulley with a solid shaft means the pulley may be damaged; a noisy shaft with play means bearings/pump need replacement.

5) Decide repair method (why choose each)
- Replace pulley only: acceptable if pulley is damaged but shaft and seal and bearings are good. Restores correct belt contact and tracking.
- Replace bearings/seal (if serviceable) or replace entire pump assembly: required if shaft play, rough rotation, leakage, or internal impeller damage. Theory: bearings align and support the shaft; seals keep coolant out of bearings. If either is compromised, long-term reliability requires replacing the failed parts or the whole pump.
- Practical note: on many Toyota diesel engines replacement pump assemblies are the most reliable fix because bearing and seal replacements are labor-intensive and need press-fit tools.

6) Remove and replace the failed part (how the repair fixes the fault)
- If replacing the pump: unbolt the pump housing from the block, remove gasket, clean mating surfaces, fit new pump with new gasket or RTV per spec, tighten in a cross pattern to spec. Theory: installing a new pump re-establishes correct shaft alignment, tight seals and a true impeller so coolant flow is restored and leaks/noise stop.
- If replacing pulley only: press off old pulley and press on new pulley using a hydraulic or mechanical press with protective adapters so the hub and shaft aren’t damaged; align keyways and ensure correct seating. Theory: a new pulley that is true and correctly seated removes wobble and restores proper belt tracking and load distribution to the pump shaft and bearings.
- Use correct tools (puller/press) to avoid scoring shaft or mis-aligning the new part.

7) Reassembly and adjustment (why correct reassembly matters)
- Reinstall fan, fan clutch, and any brackets. Refit belt and set belt tension to factory specification (not too loose — causes slip; not too tight — overloads bearings).
- Check pulley runout and belt alignment visually; spin the pulley by hand to confirm smooth rotation and no rubbing.
- Theory: correct tension and alignment minimize bearing loads and prevent premature failure; smooth rotation confirms the repair addressed the root cause.

8) Refill and bleed cooling system; test run (what to verify)
- Refill with correct coolant, bleed trapped air, reconnect battery.
- Run engine to operating temperature; watch for leaks, listen for noise, check temperature gauge and belt tracking.
- Theory: proper bleeding removes air that can cause local overheating or cavitation; checking under load verifies that the pump is pumping correctly and that the repair eliminated the original fault.

9) How the repair fixes each common fault (summary)
- Replacing the pump bearings/assembly: removes radial/axial play and noisy bearings, restores concentric shaft rotation and impeller effectiveness → eliminates wobble, noise, leakage and restores coolant flow (stop overheating).
- Replacing the pulley: removes bent or damaged pulley that caused belt mis-tracking or vibration → restores belt contact geometry and prevents belt wear and slippage.
- Correct reassembly and tension: prevents reloading and premature failure of bearings/seals/pulley.

10) Practical checks to confirm a good repair
- No front-end growl or rumble at idle and under load.
- No visible coolant leaks at the pump/pulley hub after a cold-to-hot cycle.
- Belt runs true on the pulley and does not walk off edge.
- Engine reaches and holds normal operating temperature without local hot spots.

Safety and workmanship notes (brief)
- Always cool the engine before opening the cooling system; use proper pullers/presses — do not hammer; use new gaskets/seals; torque bolts to factory specs; dispose of coolant properly.

This is the ordered theory-plus-action sequence: diagnose → safe prep → remove pulley → inspect → choose replacement → replace parts properly → reassemble/tension → refill and test. The repair succeeds because it restores correct shaft alignment, bearing support and sealing (or corrects pulley deformation) so the pump turns smoothly, seals coolant in, and drives coolant flow without introducing belt/pulley vibration.
rteeqp73

2H engine [Restoration] Here are some photos of how I rebuilt a 2H Toyota engine.

This week at Mr Landcruiser #14 - 2H Turbo BJ40, 12HT swaps and more! Another week work begins here at Mr Landcruiser, so it's time for another yard update! Join Paul for a tour through the workshop ...

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Tools needed
- Basic hand tools: 1/4" and 3/8" ratchets, short/long extensions, 8–14 mm sockets (common for clamps/cover bolts).
- Screwdrivers: flat and Phillips.
- Pliers: slip-joint, hose clamp pliers or side-cutters (for spring clamps).
- Small pick or awl (remove old grommet/seal).
- Handheld vacuum pump with gauge (for testing PCV valve) — optional but recommended.
- Torque wrench (only if removing valve cover).
- Shop rags, gloves, eye protection.
- Replacement parts and consumables (see below).

Safety precautions
- Work on a level surface, parking brake engaged, wheels chocked.
- Engine cold before removing breather/PCV components (hot turbo/intake pipes cause burns).
- Wear eye protection and gloves — crankcase oil can be hot and dirty.
- If you remove or loosen any electrical connectors, you may disconnect the negative battery terminal to prevent accidental cranking or shorts.
- Do not run the engine with intake or turbo openings disconnected — route and cap lines as necessary during checks.

Replacement parts recommended
- Correct PCV valve assembly or crankcase breather for Toyota 2H / 12H-T (OEM or quality aftermarket).
- Valve-cover grommet / O-ring where PCV inserts (if it’s a pressed-in grommet).
- Crankcase breather hose (replace if brittle, swollen, cracked).
- Hose clamps or spring clamps (replace rusty or weak clamps).
- Optional: valve cover gasket if you must remove the cover.

Locate the PCV/breather
- On 2H/12H-T diesels the crankcase breather/PCV is normally on the valve cover and connects by hose to the intake side (pre-turbo or turbo inlet on 12H-T). Trace the hose from the valve cover to the intake/turbo to find it.

Step-by-step replacement (no valve-cover removal required in most cases)
1. Prepare
- Park, chock wheels, let engine cool.
- Remove air cleaner snorkel or intake piping as required for access. Loosen clamps with screwdriver or socket.
- Put rags beneath the work area to catch oil.

2. Expose the PCV/breather
- Identify the breather hose and PCV valve where it inserts into the valve cover or breather box.
- Use pliers or hose clamp pliers to loosen/remove the clamp holding the hose at the PCV end and at the intake end.

3. Remove the hose and PCV valve
- Pull the hose off by twisting and pulling. If seized, use a flat screwdriver gently to pry and break adhesion; protect the valve cover paint with a rag.
- If the PCV valve is a push-in type, grasp it and pull straight out. If it’s threaded, unthread with the appropriate tool.
- Use a pick or small screwdriver to lift out the rubber grommet if the valve uses one and the grommet must be replaced.

4. Inspect and test the old PCV valve
- Visually inspect for heavy carbon/oil sludge blocking passages.
- Using a handheld vacuum pump on the nipple, apply vacuum and observe. The valve should open and either hold or show a change in flow at a low vacuum — if it’s clogged or stuck, replace.
- If you don’t have a pump, shake-test (rattle) may help on some valves; on diesels the valve can be oily and not rattle reliably — when in doubt replace.

5. Clean the area
- Clean the valve-cover opening and hose ends with rags. Remove loose sludge or oil with a rag — do not spray solvent into the crankcase.
- Inspect the hose for soft spots, cracks or swelling; replace if any deterioration is found.

6. Install new grommet (if applicable)
- Seat the new rubber grommet into the valve-cover opening. Lightly lubricate it with clean engine oil to ease insertion.
- Make sure it’s flush and properly seated — a mis-seated grommet leaks.

7. Install new PCV valve
- Push the new valve into the grommet (or thread in if threaded) until fully seated. For push-in type, you should feel it snap in.
- Orient the valve as OEM specifies (outlet nipple toward hose/intake).

8. Reconnect hose & clamps
- Slide hose onto the valve nipple and onto the intake/turbo inlet. Use new clamps or the original if in good condition. Tighten screw clamps snugly — do not over-tighten and crush the hose.
- For spring clamps, use clamp pliers to set in place.

9. Reinstall intake components removed earlier
- Reconnect any sensors, pipes and air intake parts. Tighten clamps and make sure nothing is pinched or contacting a hot surface.

10. Final checks and test
- Start engine and let idle. Check for vacuum/suction at the hose and listen for hissing or leaks.
- Inspect around grommet and hose ends for oil leaks.
- On turbo models, observe intake join and turbo inlet connection for any leaks or increased smoke. Road test or load test to verify normal behavior.

How each tool is used (quick)
- Ratchet/sockets: loosen/tighten hose clamps, remove small brackets and airbox fasteners.
- Screwdriver: loosen screw-type hose clamps or pry gently to free hoses.
- Pliers/hose clamp pliers: remove and install spring clamps and to grip valve/hose when pulling.
- Pick/awl: remove old grommet or clean out seating area.
- Vacuum pump/gauge: apply vacuum to PCV nipple to ensure valve opens and holds as expected.
- Torque wrench: required only if you remove the valve cover — tighten cover bolts to spec (consult manual) to avoid warping or leaks.

Common pitfalls and how to avoid them
- Reusing brittle hoses or old clamps — replace them. A leaking hose causes unmetered air and oil leaks.
- Not replacing the grommet — old grommets harden and leak; always inspect and replace if firm or cracked.
- Pulling at an angle and tearing the grommet or damaging valve-cover paint — twist while pulling and protect with a rag.
- Over-tightening clamps — can cut hose or distort nipple, causing leaks.
- Assuming a rattle-free valve is OK — diesel valves can be sluggish from sludge; test or replace if uncertain.
- Removing valve cover unnecessarily — avoid if not required; if you must, clean surfaces and use proper torque sequence and values to avoid leaks.
- Installing the valve backwards — ensure outlet nipple faces the hose; some valves are directional.

When valve-cover removal is required
- If the PCV assembly is integral and requires access from above, remove valve cover: disconnect electricals and intake as needed, undo cover bolts with a socket, lift straight up. Replace valve-cover gasket if any evidence of leakage. Clean mating surfaces and torque bolts to manufacturer specs (do not overtighten).

That’s it — replace the PCV valve, grommet/hose/clamps as required, test with a vacuum pump if available, and inspect for leaks after start-up.
rteeqp73