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Replacing 3.0 engine on my 2005 mazda6

6K views 43 replies 8 participants last post by  mikeykuk 
#1 ·
I am replacing my engine, after my pre cats killed my last one. I am going to buy headers and I have already bought a new engine. I bought a few sensors (camshaft sensors and crankshaft sensor) I was wondering what other sensors I should buy/replace. The car has over 100k miles on it now. Any help in this matter would be greatly appreciated!
 
#4 ·
access to the alternator requires removing the rear exhaust manifold and 2/3s of the header system. it really isn't a fun job to do, and doing it down the road would be no biggie, but the removal process makes it worth doing.

best bet is to ask locals. most electronic motor shops will rebuild them for ~ 100 bucks or so. for an additional tip they will even bump up the power output.
 
#5 ·
Right on, well I'm thinking I might try to do it myself...I like the bragging rights lol. Has anyone tried this before? Is it very difficult? Also, what is your opinion on deleting the front O2 sensors all together? Maybe pushing them further back even?
 
#6 ·
Remember to re-route the EGR valve on the new engine
 
#8 ·
I am glad I asked. I will call some local shops and see what they say. I really appreciate the advise guys. What do you mean "re-route" the EGR valve? I've heard about cutting the tube down, but that's about all I have heard. Also I took my engine out of the top. I know a lot of people are hesitant to do so. And all of the build ups show out the bottom. It was pretty easy, I must say.
 
#10 ·
Yeah, it was way easier to just pull the engine, as oppose to dropping it with the subframe. I'm use to rear wheel drive classic cars, so I figured why not try to use knowledge I already have haha. Anyway, I started taking apart the front end. And I can say...it was pretty damn easy, with the exception of the CV shafts lol. Today I finished pulling everything off of the old engine, cleaned it, then put it on the new engine. I very much looking forward to painting my valve covers!
 
#11 ·
You mentioned on your first post that the pre cats were the culprit on your engine's death.
Rerouting the EGR will prevent that in the future
 
#13 ·
Right, I get the point of rerouting the EGR. Instead of exhaust gas being routed into the intake manifold, it puts clean air into the manifold. The part I dont get is, the benefits. I was under the impression that exhaust gas is more combustable than fresh air...? I also know that, of course, exhaust gas has more carbon, which is not so good for internal components...but is that all?
 
#14 ·
exhaust gases are LESSS combustible than fresh air, as they are NOX and not 02 compounds.

in our cars cases, when the cats fail, there is a possibility instead of them clogging the 2ndary cats(creating excessive back pressure), that the dust created instead will travel up the EGR and be returned into the engine. Leaving your intake runners and combustion chamber full of failed cat..... (See: metal particles)
 
#23 ·
I'd bet good money it does not. My 2006 6s (built in 2005) does not have an engine oil cooler.

But my 2004 MPV has the Duratec 3.0 and it is equipped with an engine oil cooler. I suppose if you really want one, you could salvage the hardware from a MPV.
 
#24 ·
Right on, I mean took apart the entire front clip and didn't see one. I just wondered if maybe it was built into the radiator...even though I did not see an oil line lol. I ask, because I would really like to get a 'speed6 front bumper, and an aluminum oil cooler would look good in the lower grill. Just curious. Thanks guys
 
#27 ·
So today, I started taking apart my dash and center console. First of all...that shit was DIRTY lol. But after taking apart the stereo (purely out of curiosity) I finally found out there is an empty spot where a tapedeck would be. So I have come to the conclusion, I am going to fabricate a "cubby hole" for my ipod.
 
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