3L V6 - replaced the front oil seal, timing belt - Belt noise

so any testing done with the fuel system throttle body --fuel delivery -pressure--etc---trans check ---any pending or active codes

A leaking front seal will allow oil to get into the area where the timing belt is located. This will cause oil to get on the belt and can cause damage. Since the timing cover must be removed to access the front seal, it is recommended to replace the belt while you are in there. Also, the water pump is driven off the timing belt. Replacement of the water pump is always recommended when replacing the timing belt for two reasons. First, it is easily replaced at this time and it is good preventive maintenance. Secondly, the water pump bearing is under tension from the timing belt and develops a wear pattern. Replacement of the belt without replacing the pump will cause the new belt to wear the bearing in a different pattern, often causing leaking in a very short time after the replacement. This would then result in having to repeat all the labor again to replace the pump. It is easy to see that for $400.00 labor, you don't want to do that again in only 2-3 months. as far as the VTEC valve is concerned, I don't see a relationship to the oil leak. It could just be something else the mechanic found during the inspection. I can find nothing in the remove/replace procedures that requires replacement of the oil pan gasket. Again, maybe something additional that is needed from visual inspection, but not needed for the front seal.

Sounds like the seal either did not get put on right or else it slipped during assembling the front cover back on. If you are concerned about where the leak is coming from you can put dye in the oil and check for a leak with a black light to make sure it is the timing cover leaking.

oil seal failure is the main killer of rubber timing belts . Oil can come from the crankshaft seal --the cam shaft seal/s and the hydraulic belt adjuster.. So if you have the front off and am replacing the timing belt then it is fools economy not to replace the seals and any idler pulleys at the same time.

timing belt idler pulley could be loose causing timing belt to slap.

It sounds like the oil is coming from the oil pump or oil pump seal. The oil pump is driven by the timing belt and is usually overlooked during routine service.

Oil pan gasket or crank shaft seal its going to be one or the other you just have to get down there and see which one it is.

Which engine? 4 cylinder (2.4 lit) or V6 (2.7 lit)? Two different procedures as well as different belts. The 4 cylinder also has a balance belt. See next image:

Here's the 2.7 V6 belt:


The replacement procedure is nearly the same at the start (removing, accy drive belts, pullys, support engine & remove front engine mount, remove T.B covers, disconnect Cam Position Sensor & Crank Position Sensor connectors, etc.). When you get to this point on the V6, you also have to remove the front engine mounting bracket from the front of the engine (4 14mm bolts, also a 12mm bolt which bolts the dipstick tube to the side of it) Put crank shaft at TDC (top dead center w/ALL timing marks aligned) remove hydraulic tensioner (2 12 mm bolts), then remove the belt. You'll need to recompress the hydraulic (auto) tensioner in a vise and insert a retaining pin through the pin-holes at the top (through the tensioner piston) to keep it compressed when you reinstall it. Otherwise, you won't be able to install it. Assembly is reverse order of dissassembly. Inspect your pullys while you're in there (check for pully bearing noise, leaking grease, smooth rotation, also the water pump pully, etc.) Replace components as needed. Careful not to damage Crankshaft Position Sensor wire harness.

The 4 Cylinder is quite different. You not only change the timing belt, but also the countershaft (balance) belt, which is behind the crank position sensor blade. IMPORTANT: ALL TIMING MARKS ALIGNED BEFORE REMOVING ANYTHING) There are two (2) counter-shafts (balance shafts). one driven by the timing belt, the other by the crankshaft sprocket behind the timing belt sprocket at the front of the crankshaft.

do you have a 3.1L V6? The timing cover gasket seals the timing components, it is located behind the belt drive system (alt, a/c, p/s etc.) all of these components must be removed to change this gasket, also the oil pan lower seal gets changed at the same time. The oil pan gasket includes the rear pan seal and the side seals and on for the rear of the pan, the engine must be lifted out of it mounts to change this gasket. It takes time to do these repairs and each shop has an hourly rate per hour on labor. The cost of the parts will be relatively the same at any shop, labor will differ. I hope this helps to answer your questions.