Catalyctc converter or oxygen sensors?

07durango · Aug 13, 2020

Hi guys i got a 2007 slt 4.7 with the flex fuel.

My durango runs great but i noticed when it is running for a good while it will start to have symptoms of a bad catalytic converter. You know loss of power, uses more gas and runs sounding like a jet engine when accelerating. But like i said it only does it when it gets hot (not the thermostat gauge it does not over heat but just warmed up in general).

So if it WAS a bad catalytic converter wouldn't it be running bad ALL the time? not just when it warms up? sounds like the o2 sensors effecting it because if the catalytic converter was bad it would not work at all right?

Oh and if i buy the catalyct converter can i get one of those universal cheap ones on ebay? 120$ lol but will it throw up codes? Thanks.

Don Fox · Aug 14, 2020

07D
How many miles on your D? When was the last tune up? I would expect a CE light from a post cat 02 sensor for low efficiency or the like if you had a cat issue. Does the engine run smoothly, ie, no misfires?

You say it runs great at some times, so how long of a run time before the issues come up?

Don

07durango · Aug 14, 2020

Don Fox said:
07D
How many miles on your D? When was the last tune up? I would expect a CE light from a post cat 02 sensor for low efficiency or the like if you had a cat issue. Does the engine run smoothly, ie, no misfires?

You say it runs great at some times, so how long of a run time before the issues come up?

Don

Thanks for your response, it's at 190k miles. i changed the sparkplugs and boots at around 170k miles. It drives good for about half an hour before it starts sounding like a jet engine.

I checked the codes and had a pending code for p0432. I cleared the code so now I see no codes but the symptoms persist. I went to autozone and spent 90 dollars on o2 sensors. I got the po432 o2 sensor that called for bank 2 s1 but also got the upstream one cuz i heard it will throw a code unless i replace both.

I have not installed them yet.

I took the car to a dealership a year ago and had the 02 sensors replaced already, but they could of been damaged when i was driving with a broken vaccume egr valve i recently replaced.

Don Fox · Aug 14, 2020

Since the 02 replacement was at a dealer, they should have used oem parts. At 190K, you might have a cat on the way out. If there was a period along the way where it was run with a misfire for a period of time, that may have started the decline.

If the repair was less then 12K or 1 year ago, you might still have a warranty on the repair. You could check with the dealer, or your paperwork from when the repair was done. If you end up throwing a cat on there, I would not go low bid unless you are just fixing it to move it along. The better cats have a longer warranty than the el cheapo models.

Don

07durango · Aug 14, 2020

Don Fox said:
Since the 02 replacement was at a dealer, they should have used oem parts. At 190K, you might have a cat on the way out. If there was a period along the way where it was run with a misfire for a period of time, that may have started the decline.

If the repair was less then 12K or 1 year ago, you might still have a warranty on the repair. You could check with the dealer, or your paperwork from when the repair was done. If you end up throwing a cat on there, I would not go low bid unless you are just fixing it to move it along. The better cats have a longer warranty than the el cheapo models.

Don

Thanks Don. Will the computer throw a code if I use a universal cat?

07durango · Aug 14, 2020

I was running with a misfire when a sparkplug had to be replaced (I had left the rubber boot one 1 of the sparkplugs the last time i changed them and it melted on the sparkplug so I was getting a misfire) It was a pain to get off the melted rubber off the sparkplug I had to blow torch my socket and melt it off.

Would a misfire cause the oxygen sensors to go bad?

Don Fox · Aug 14, 2020

I guess it's possible that a repeated barrage of unburnt fuel could harm an 02. How long of a period did you drive the D this way? A couple of days, or even a week would likely do no harm, but a lot of miles could.

Re the aftermarket cat, as long as it does the intended job properly, I would not expect a CE light.

Don

fabric8 · Aug 15, 2020

I recently replaced the fan clutch on my 06 durango with 4.7 gas engine because it was bad. It wouldn't engage when it got hot so my engine temperature would rise.

But with the new fan clutch and the hot weather we're having and running the AC, the fan clutch engages pretty much when the engine is warmed up driving around town. And when it does, it sounds like a jet engine. When the revs go up, so does the fan noise.

And of course, gas mileage and performance is affected because the engine works harder.

The only experience I've had with a bad catalytic converter was on my dads Audi a4 1.8 turbo. His boost was slowly decreasing over a period of months until it would only make 2lbs of boost (down from 17lbs). I pulled off the CAT from his car and put a test pipe and it immediately returned to making 17lbs. So his CAT was practically completely clogged. It didn't matter if the car was cold or warmed up.

Don Fox · Aug 16, 2020

Fabric:
It is highly recommended that you go with OEM when replacing a fan clutch to avoid the very issue you are having. Many folks have had the same result with an aftermarket FC. I went with oem when I replaced the FC on both my '01 4.7 as well as my '04 5.7. No problems.

Don

fabric8 · Aug 16, 2020

Don Fox said:
Fabric:
It is highly recommended that you go with OEM when replacing a fan clutch to avoid the very issue you are having. Many folks have had the same result with an aftermarket FC. I went with oem when I replaced the FC on both my '01 4.7 as well as my '04 5.7. No problems.

Don

Don, would you happen to have a part number for the fan clutch you got? They list 2 versions for the 4.7L and I believe mine has the heavy duty fan clutch (not the standard). The aftermarket fan clutch I got was from the auto parts store and was the heavy duty version.

Sent from my SM-G950U using Tapatalk

Don Fox · Aug 16, 2020

Fabric:
This was the number (52028992AC) that went into my '04 5.7L. I think the HD spec refers to whether or not the D in question has the tow package. Both my '01 and the current '04 do, so I am pretty sure this is the HD clutch.
Your 4.7 might require a different P/N, or not.

Don

fabric8 · Aug 16, 2020

Don Fox said:
Fabric:
This was the number (52028992AC) that went into my '04 5.7L. I think the HD spec refers to whether or not the D in question has the tow package. Both my '01 and the current '04 do, so I am pretty sure this is the HD clutch.
Your 4.7 might require a different P/N, or not.

Don

Thanks! I found that the correct PN for my 4.7 magnum is 52028994AC.

So now that I'm hearing the fan engage when it's hot, when I didnt with the old one, it makes me believe that this aftermarket one is working well. It's been in the 113's lately in Las Vegas. Summer hasn't been kind. The fan does shut off when on the freeway. But in stop and go traffic, its loud and I'm expecting that's normal because the fan is moving a LOT of air.

Do you think an original fan clutch would slip more and therefore be quieter? But that would also lead to less cooling, right?

My D had been running quite hot when towing our 18ft SeaRay up some hills in this hot weather. It would even run hot at stoplights. That made me change the fan clutch and it hasn't run hot since. But I haven't towed yet since I replaced the fan clutch with an aftermarket one, but I'm planning to this coming weekend.

Catalyctc converter or oxygen sensors?

07durango

Don Fox

07durango

Don Fox

07durango

07durango

Don Fox

fabric8

Don Fox

fabric8

Don Fox

fabric8

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