[manuawal]

Hey guys,
I have seen on these forums about the 6's having clogged Pre-cats. HOw to check if mine is clogged and how to fix it? Cz the metal housing outside is welded to the piece.
Why i think that its clogged is because there is a clicking sound coming from it when the engine is cold. Just as other people have posted on this site.

Thanks for reading
Manu

 

[The Great NY]

clicking, rattling typically means the cat is either broken apart or clogged. only way to really check it is to remove it and inspecct it

 

[Fatty04]

what are some other signs? Oil consumption, CEL come on?

 

[The Great NY]

oil consumption can happen yes. CEL wont come on all the time. you can have diminishing power, sulfur smell and etc

 

[snakoil]

my local muffler shop checked it for me with a laser sensor for no charge while replacing a gasket

 

[manuawal]

Thanx for all the replies guys.
The pre-cat is kinda bent in. Possibly from a previous owner accident. It makes really annoying rattling sounds when the engine is cold. I am just thinking of getting headers. Just did a swap. from an 04 to an 05 V6 motor. The only codes I am getting is the ABS light and traction control. Do you think an OBDII reader can determine why?
Thanks

 

[The Great NY]

Check your wheel speed sensors on the front wheel hubs. Make sure they are bolted down properly on the hub. Also being as you just pulled the motor you may have put some pressure on the connector.

Starting at the hub....follow the speed sensor wire back away from the hub until you get to a portion that is a bit thicker in gauge than the rest of the cable. IIRC that's where the sensor connects to the harness. Press in towrds the middle and try to make sure its seated all the way.

Do this on both sides.

Since you removed the motor you probably took the tranny out with it. And in turn took the axles out, so undoing the hub at the ball joinnts make the hub/spindle hang or lean putting abnormal pressure on the speed sensor cable....causing it to either pull away from the plug or break connection in the wire internallay.

Just check the speed sensors and associated cables.

 

[drewskii]

Engine failed due to clogged precats

so bought the car used in december of 2009 with 36000 miles. its a 2006 v6 with six speed auto. the owners before had the engine replaced due to a transmission glitch that made the transmission shift into first gear going highway speeds. so i thought this was a good deal and all the paper work was there for the new motor and tranny that mazda installed under warranty. i just knew i was going to be happy with the car. fast forward a year and a half later with 54000 miles and my mazda is sitting at the mazda dealership. why? because they want 6200 dollars to replace the engine that is knocking due to precat failure. this is a damn shame. dont know what to do because the warranty is up. probably the last mazda i ever own.

 

[GerryB]

Funny- precat failure for the '06+ is actually pretty rare. And this is not a problem that is isolated to Mazda. There are others.

 

[oregonducks]

yeah usually the precat issue is for the 03-05's...rotten luck.

 

[Blackpearl]

Dead Mazda6 V6 Engine

OK, I am new in here and I have been reading all these posts about sludge & timing chains & pre cats..., I don't know which one I am having problems with! Please help me...

I just bought my daughter her 1st car a couple of weeks ago, a 2003 Mazda6 V6 with 112K miles. The car looked to be in very good shape and ran very well. We had it a grand total of 3 days & 60 miles and then it starts running really rough and won't idle. I limped it to an import garage & they said the engine was loaded with sludge. He drained & flushed oil 2x, added some oil additive to try & repair piston walls, changed spark plugs. No go, won't stay running and smokes now. Only getting full compression on 2 cylinders. He says the engine is toast.

I take it to a different mechanic that is a friend of a friend. He says right off the bat the timing chain is very loose & is jumping. He also says engine is trashed. He is getting a used 2004 6 engine, or most of an engine. He is going to have to use some of my current parts like alternator, etc...

What do I need to watch for on the replacement engine? Do I need to tell him to check the pre cats? (not even sure I know what those are)

What else?

 

[chilimax21]

I would complain to the previous owner and get some/all money back.

 

[Blackpearl]

I am already working on that. I think I will get some money back.
Back to my original question, What do I need to be looking out for on the replacement engine?