I have a problem with my 2003 LS. 84,000 miles. When the engine is warmed to run condition, the enine has a very loud knock above 2100 RPM. I first thought it was the oil control valve for the VVT so I bought a new one. The CEL ( 0012) stopped coming on, but still the noise. I changed the VVT unit, did a complete belt, water pump and all seals. NO change ! I understand that a PCM condition (and replacement by Mazda) is in effect. I run 5W-30 syn. oil. Could this really be a PCM problem ?
Jasper
The first problem is to determine where the noise is coming from. Head area or lower block area. A mechanics stethoscope may be of help.
An actual oil pressure reading (Not fun to do) may also be of some limited help. I have a 99, and have used full synthetic oil (10W30) for years. The mileage is about 89,000, and the engine has been turbo'd for about 60,000. Minimal oil usage, and due to the turbo, oil changes are usually frequent.
VVT Noise The VVT rotating assembly on the end of the cam may be the culprit. Seems that there is a pin assembly that can cause noise. (Service Bulletin, etc.) I'd attach a picture, but my news server is not accepting attachments for this group.
On 6/28/2010 10:33 PM, jasper wrote:
Sounds to me that you will need to really determine exactly where the noise is the strongest. On an engine without plug wells, I'd pull the valve cover and run the engine. Not so easy to do on a Miata. Not having a VVT, I don't know what the Gotchas might be.
So the dealer hasn't a clue either. That's not too unusual, since dealers usually replace engines rather than repair them.
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