I need to replace the oxygen sensor that is against the firewall?

CMCKINNEY75

MEMBER
2000 MAZDA

I have a 2000 Mazda Millenia V6 2.5 liter, with 76,000 miles. Can you tell me where the catalytic Converter is located. I need to replace the oxygen sensor that is against the firewall?

Thursday, June 8th, 2006 AT 7:57 PM

3 Replies

COSMO

MECHANIC
347 POSTS

Which one? I think there are three of them

Cosmo. Mazda tech

p.S. Are you sure its a 2.5 and not a 2.3 miller cycle?

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Thursday, June 8th, 2006 AT 11:29 PM

CMCKINNEY75

MEMBER
2 POSTS

Yes I am sure its a 2.5. The problem is. I need to replace the oxygen sensor that is against the firewall on the left hand side if facing the car. I dont know which sensor to buy. Either the upstream or the downstream. Can someone tell me?

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Friday, June 9th, 2006 AT 2:17 PM

JACOBANDNICKOLAS

MECHANIC
109,913 POSTS

Hi,

There are a total of three sensors on this vehicle. If the sensors are under the hood and near where the exhaust manifold and downpipe attach, those two will be upstream. There is a third one further back on the exhaust.

I attached two pics below. In the first one, I highlighted the catalytic converter as well as the sensors. In pic 2 I identified the three as front, middle, and rear. That is how they are identified. The front and middle are upstream.

I hope this helps. Let me know if you have other questions.

Take care,

joe

See pics below.

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