I have a 99 Accord V6 EX with 165,000 miles. A few weeks ago the oil pressure light was flickering on at an idle and after a few minutes it would come on steady then start blinking. I immediately stopped and checked the oil level, and it was good. I was only about a mile from my home so I drove the car home and so long as I kept the revs up the oil light would not come on. After lots of reading and research I decided to check the clearances of the oil pump.

I jacked the car up, and went through the process of removing the oil pan, and timing belt to access the oil pump. The tolerances of my oil pump listed in the hanes manual were in spec. So after going through all of that the only other possibility was the oil pressure switch. I replaced it, and the light went away.

However after putting the car back together and starting it up to see if the oil pressure switch fixed the light, which it did the car was knocking. The car runs fine/smooth at an idle, however under load (ie going uphill/accelerating) there is a knock. It was not knocking before I put it in the garage to work on it.

I did have a hard time getting the timing belt back on, and it may be off a notch or two. Could the timing belt being off cause the knock or is it the bearings? If it is the bearings can I replace the bearings or do I need a new motor?

 

I would align the crankshaft to top dead center and see if your cam marks are off.

 

I am in the process of tearing it back down to double check my work. I should be able to report back in on Friday night or Saturday morning.

Have you heard of a misaligned timing belt causing a knock? If it is off have I done major damage to the engine by running it with the timing marks misaligned?

 

The short answer is I don't know.

If the belt is off by a couple of teeth, then hopefully the pistons didn't hit the valves. The only way to know for sure is to get the belt properly aligned, then see how the car runs.

If you aren't sure how to install the timing belt and tension it, I would buy a shop manual. I bought one for $21 on Ebay from automanualsource that I could download after the purchase. It was a pdf of the shop manual.

 

Well it looks like the cam shafts are aligned/timed with each other. On the front cam shaft the yellow dot is aligned with the dash on the block and a dash on the cog with a corresponding number 1. The yellow dot on the rear is also aligned with a dash on the block and a dash on the cog. See pictures.





Is there a way to tell if the crankshaft is at TDC without removing the crankshaft pulley? I cant see any dots or marks on the crankshaft pulley itself.

(I dont have the honda crankshaft pulley remover tool, when I did this project the first time around I used pepboys loan-a-tool program.)

When I first installed the timing belt the camshafts kept slipping and thats what was giving me trouble. So since they are both aligned I feel like the timing belt is probably ok. However I still want to check the camshafts when I am certain that I have #1 at TDC

So what is your best guess as to what is causing the knock. Keep in mind it does not do it at idle, only under load (i.e. accelerating or going up a hill)

 

There should be marks or notches on the edge of the crankshaft pulley near the timing belt cover. There will be one by itself (white) and three clockwise from it (red). There should also be a pointer on the timing belt cover. When the white mark is aligned with the pointer, #1 should be at TDC.

Another way I can think of would be to remove the spark plug on the #1 cylinder. Put a long screwdriver in the cylinder and slowly turn the crankshaft until the screwdriver stops moving up.

 

Here are the pictures, I dont know why they did not work before.






Thanks for the tip on the screw driver to find TDC I'll try that tonight after work and see how things look.

 

I had a recent experience w/ my Acura MDX (3.5L V6) which may or may not be helpful.

At 105K I performed timing belt maintenance w/ usual problems; crankshaft pulley bolt, timing belt alignment, etc. But eventually I got everything aligned and back together. I started engine and all sounded fine.

My wife drove for a week before I had a chance to drive. I immediately noticed a noise from TB area. It could be heard while engine was idling. It might be intepreted as an "engine knock". A clonk-clonk sound. My suspicion was that one of the parts, tensioner or idler, was loose, allowing tensioner or idler to wobble a bit and hit timing belt cover.

I re-opened the timing belt covers (almost like doing TB's again) to inspect everything closely. During disassembly I noted one slightly loose bolt on the passenger side motor mount (must be completed disassembled and removed for access). It's a strange arrangement with large metal lug that does not appear to have a function (at least not obvious!).

I inspected all TB hardware and checked TB alignment marks again. All was secure and TB alignment spot on.

After re-assembly, the noise was gone and has not returned so I concluded the loose motor mount bolt was somehow the source of the noise.

My thought was that you may have a similar motor mount arrangement and would have gone through same steps I traced. My suggestion is to check your passenger side motor mount assembly carefully. Particularly the large upper steel lug which looks like a rotation stop but may be for some other reason.

good luck

 

Well I used the long screwdriver trick to find top dead center of #1 piston and verified my timing marks. The timing belt is installed correctly. And the knocking noise is unmistakably an internal engine noise.

If the bearings are toast, would the engine knock all the time - even at an idle? Mine only knocks at increased an RPM and only sometimes. It also gives a rap or two during cranking. Could it possibly just need the lifters adjusted? The car has always had a noticeable ticking noise from under the valve covers.

Or could the noise be attributed to a sticking sticking valve(s)? I've also been informed that it could be the ignition timing. Is that a legitimate possibility, and if so how is that adjusted?

I really appreciated all the input and tips. I will take it into a Honda shop sometime soon and hopefully find out the cause of the noise.

 

I have read other posts on MDX forum indicating that loose valve train may be a common problem on the Honda/Acura V6's. You should be able to distinguish between rod knock and valve clatter. If from beneath valve cover, then sounds like a valve inspection and adjustment is in order.

good luck