Having E-Mailed Honda Austrlia , and recieved their answer from their technical department I can say that a 1998 Honda Accord V6 3litre harmonic balancer retaining bolt is 16MM x 1.5MM Pitch. i hope this helps.
John G W
The bolt was incorrectly tensioned.
Counterclockwise.
Use an impact wrench (1/2 inch works best) to loosen the harmonic balancer bolt. If you do not have one, you must keep the engine from rotating while loosening the bolt. Try leaving the serp belt on and add some more tension on the belt; then use a jerking motion to break free the bolt, you might get lucky...if that doesn't work remove the starter and insert something into the flywheel to lock it in place, then try to loosen the balancer bolt.
The water pump is located on the driver side, rear of the engine. It is driven by the timing belt, and is therefore a major project to swap one, and is beyond the scope of many shadetree mechanics. It involves removal of an engine mount, the timing and balancer belts, the harmonic balancer, etc. Consult a factory service manual.
I just changed a timing belt in a buddys 1990 accord and you need to set the marks on the pulleys to same direction as your crank pulley mark is.
The water pump is difficult to access on this car. It's driven by the timing belt, which is located behind the timing belt cover, the pump is on the back side of the engine, near the firewall. It involves removing the driver's side engine mount, the harmonic balancer, the cover, etc.
If it is a 2.3 L 4 cylinder engine, the timing and balancer belt should be changed at 105,000 miles. I would suggest changing the water pump, camshaft and balancer seals at the same time.
it drives the serpentine belt for your accesories like AC, power steering, and alternator. The crankshaft pulley also serves as a harmonic balancer in some cars. It means that the pulley helps to dampen engine vibrations that arise during/between the power strokes especially in diesel engines. When the pulley is aged you will experience engine vibrations accompanied with sone kind of whining noise around the belt area of the engine.
Replace both belts at 105,000 miles. This is an interference engine and as such it is critical that you replace these belts. If the cam belt breaks you will have serious engine damage.
The hole for the timing marks is located on the front of the engine, right below the distributor. You'll have to remove the hood to get a good angle for the timing light (I don't know why they designed it that way).
Remove the wiring harness from the wiper motor. Remove the windshield wiper arm from the wiper motor. Remove the wiper motor retaining screws. Reverse the process to install the new wiper motor.
On retractable headlight models raise the headlightsDisconnect the neagative battery cableRemove the retaining screws taking care not to disturb the adjustment screwsRemove the retainer and pull the headlight out enough to allow the connector to be unplugedRemove the headlightTo install the headlight plug the connector in place the headlight in position and install the retainer screws tighten the screws securleyPlace the headlight bezel in position and install the retaining screws