Adjusting the timing belt tensioner post DIY T-belt work


#1

I, myself, recently (3 weeks ago) replaced: timing belt, water pump, coolant, and timing belt tensioner. I could have sworn after putting the cam and fly wheel at TDC that I nailed the tensioner so I buttoned everything up. Either it wasn’t right to begin with or it over tightened some other way.

Now every so often it makes a high pitched whirring sound that changes with rpm. I checked the tensioner and it is indeed too tight. I know I can fix it but I want to make sure I do it right. Is this how I should do it?:

  1. Timing covers off. Serp belt off (Mark direction of rotating for re-installation). Rotate Crank until Cam is at TDC. Check that flywheel is at TDC.
  2. Loosen tensioner. Readjust and check tensioner. Check that everything is still at TDC.
  3. If it’s not: keep loosening and readjusting tensioner until both sprockets aren’t moving off of TDC.
  4. Rotate Crank 2 full rotations with the last 1/4 turn being uninterrupted. Check that the tensioner is still properly tensioned. (If it’s not…?)
  5. Button everything back up and pray.

I don’t suppose I could do an easy way out and forego the TDC nonsense and just loosen and readjust the tensioner?

Am I causing serious damage to the car by driving it this way?

Attached is where my tensioner is at and what I used for instructions.

99’ GLS 2.0L Manual Tranny, AEG Engine code. 86,000 mi

Thank you,
Laura


#2

The timing belts I’ve replaced there’s a specific way to check the tension. On my Pathfinders it’s a feeler gauge. You check the distance between the sprocket and the belt at a specific point outlined in the manual. You either loosen or tighten the belt and use the correct gauge.

The other procedure many mechanics use (because it’s easy)…is the twist test. At the widest point between sprockets…twist the belt. If it can twist past 45 degrees…it’s too loose…if you can’t twist to 45 degrees it’s too tight.


#3

Just loosen and readjust the tensioner.


#4

On my Corolla anyway adjusting the tensioner doesn’t affect the timing mark alignment. That mark alignment (provided the cam and crank gears are aligned initially correctly) is determined by the number of belt teeth between the cam gear and the crank gear, and the tensioner adjustment doesn’t change that relationship.

Every car is different. Ray has said it is a considerably more difficult job to get all this correct when there are two cam gears to deal with, vs one cam gear, like on my Corolla.

In any event, good idea to make sure the timing mark alignment is correct after adjusting the tensioner or doing anything else with the timing belt, before buttoning the covers up. I manually rotate the crankshaft 3 or 4 complete revolutions and re-check.

And always be aware when doing timing belt work that gadgets are moving around like crazy inside the engine even though you can’t see them, so if you rotate the engine crankshaft independent of the camshaft – like if the belt isn’t on there tight and the cogs are slipping – you can damage the valves by bumping them into the pistons.