Strange knocking when I start

**boom_box** · July 14th, 2009 10:03 AM

Hi People, I have a 2005 Mazda 3, over the warranty na. Recently lang, when I start my engine it goes into its normal high RPMs while malamig pa yung engine. In the past 2 weeks, I heard a strange knocking sound coming from the front. The RPMs are normal, it started with 1 click and the car runs smoothly. Yung knocking sound lang. I tried to listen up front to pinpoint the exact location kung saan ng galing yung sound pero by the time I get to the front of the car wala na. The sound does not always come out. It happened twice palang in the past 2 weeks. Any clues?

**oj88** · July 14th, 2009 10:19 AM

Do you hear the sound...

1. While the starter is still turning?
2. Immediately after you turn the key out of "Start"?
3. First few seconds of the engine running at fast idle?

Can you describe the sound in detail? How fast is it? (ie. takatakatak vs tak---tak---tak, etc.)

**1D4LV** · July 14th, 2009 10:23 AM

naka timing chain ba ang mazda3?
the reason i asked is because na-experience ko ito sa B14 ko. the culprit is the upper tensioner for the timing chain. sira na. nung pinalitan, nawala na.

**boom_box** · July 14th, 2009 10:31 AM

oj88- Yes to all three question, yung sound is a fast takatakatakatak. Tumatagal sya for a few seconds lang. in fact, when it happend for the first time I revved my engine while the sound was there. There was no hesitation at smooth yung akyat ng RPMs pero yung sound hindi na wala till about 2 seconds later.

**boom_box** · July 14th, 2009 10:33 AM

1D4LV- hindi ako sure pero alam ko timing belt yung Mazda 3.

**boom_box** · July 14th, 2009 10:36 AM

Originally Posted by boom_box

oj88- Yes to all three question, yung sound is a fast takatakatakatak. Tumatagal sya for a few seconds lang. in fact, when it happend for the first time I revved my engine while the sound was there. There was no hesitation at smooth yung akyat ng RPMs pero yung sound hindi na wala till about 2 seconds later.

To be more exact, it is when the engine starts talaga, as in right after I turn the ignition at kumagat na yung engine.

**jaymd** · July 14th, 2009 10:49 AM

kun malamig pa engine mo baka sa valve tappets yan. have it checked sa casa. try mo din higher octane gas na 95+ RON

**oj88** · July 14th, 2009 11:05 AM

Originally Posted by jaymd

kun malamig pa engine mo baka sa valve tappets yan. have it checked sa casa....

That's the likely cause. These things rattle like crazy for the first few seconds since the oil takes some time to reach these parts to pressurize and dampen the noise. The rattles increases in time as the surfaces wear off.

**boom_box** · July 14th, 2009 11:08 AM

Originally Posted by jaymd

kun malamig pa engine mo baka sa valve tappets yan. have it checked sa casa. try mo din higher octane gas na 95+ RON

Actually tama, the sound only occurs pag bagong start yung engine during warm-up. Ano tingin mo sir, factory defect ba yan or was i negligent at some point sa pag aalaga? Kasi I try to baby my car and now lang ako nag ka problema. The reason I ask is gusto ko lang maiwasan lumaki pa ito or umulit pa yung problems.

**jaymd** · July 14th, 2009 11:14 AM

Try checking yun manual mo. Our old mazda 626 had a tapping noise on start up and it was stated in the manual that cold engines may have that noise. It would disappear after a few minutes of warming up. Madali lang naman i-adjust yan sa any reputable shop kun valve tappets nga yan.