I don't think an overheating engine would damage the cat, at least not directly as a result of a faulty thermostat. Perhaps indirectly if somehow that led to improper fuel/air mixtures. More likely related to the o2 sensor issues you experienced or simply age.

 

The after cat 02 sensor does not affect air/fuel ratio, it only tests the efficacy of the catcon.

 

So here's an update as promised. I still haven't solved my crappy MPGs totally but I'm almost sure it has SOMETHING to do with my Cat-Con as I believe it's broken. I haven't found a way to do a back pressure test yet becasue I can't find a place to buy a PSI gauge that is sensitive enough to rig something up. and I'm too cheap to buy a kit to use once.... Anyways when you whack the Cat you can hear some hefty rattling within. It's old as dirt anyways.

I still have yet to use my Actron diagnostic tool. found the manual online and need to take some time and learn how to use it to confirm my beliefs.

I am gonna start a new thread soon because I just changed my valve gaskets, they were pretty leaky, (and very gummy and chunky inside... maybe that lucas I was warned about ... haha) and I was able to take care of some hose vacuum leaks but since doing that i believe my oil intake in the oil pan is clogged (due to the loosened chuncks flowing through the engine. The gauge intermittently says "check gauges" and the oil pressure goes to zero now. When I get running for awhile it stays at zero which is scary. I changed the oil Sender sensor and it behaves like the old one. So its not that. Also going over bumps, revving engine and changing gears sometimes seems to have an effect on the oil pressure coming back or stopping. I guess it's being jarred enough the mess with the flow.

I changed my oil yesterday (10w-30 full Syth) hoping it will remedy this prob and break up the sludge but it hasn't after a little driving. maybe it still will but i'm not gonna count on it. today I will drain and filter the new oil and put it back in. hopefully some gunk will come out.

I will be posting questions about dropping the oil pan in my van soon / don't wanna split thread too much as my issues seem to be morphing - but the haynes manual says I have to unhook the transmission from the engine, take off timing cover, unhook exhaust, unhook mounts and hoist the motor up to gain clearance for the pan. yikes... Im an amature in a driveway... and the housing association has already given me a few warnings and having the hood up... eh... but i read a lot of posts with guys saying that's unnecessary to go through this and the pan can be jigged loose. I can't find a straight answer on my van (2000 ram 1500) - seems like some of the ram trucks it's an easier operation. I wanna clean/replace the intake hose and check the oil pump over but it would be hell getting that pan off and not even having enough room to replace the gasket...

 

Sorry I didn't have time to read the thread...


Did you ever compare the coolant temp sensor data in the PCM to the actual temp @ the sensor base with an infrared thermometer?

 

No not yet- that's another tool i don't have and am too cheap to buy until i can find more uses.

 

the factory service manual for my 02 (and it should be the same for yours)
says to


remove exhaust pipe
remove left engine to transmission strut
loosen the right side engine support bracket cushion through bolt and raise the engine slightly. remove oil pan by sliding back


I had a tech do this job for me. With the symptoms you are describing, you may need a new oil pump while you are at it.

 

You will find more.

 

Thanks for this. I'll be doing the best I can in my driveway... ended up buying a new pump. it was $6 more then the kit. No brainer.

 

The oil pan can be removed by unbolting the drivers side engine mount and carefully lift or jack the engine a couple of inches, that is all you need. The pan will need to be wiggled a bit but it will come out, I have done it several times over the years.

 

Im about to have a nutty...

have been efffing with that oil pan for hours. Ran outta sun yesterday...
its jacked as high as possible, (so much I think I sprang a leak on my AC pump) detached everything, already pulled the old gasket and oil pump, crancked the shaft all around. Even detached tranny lines to make room. I just cant get it off. it's a nightmare. milli inches we are talking. This morning I feel like I played tackle football i've put so much static muscle pressure into this.

im thinking about cleaning the pan and underneath best i can while it's on there and just going for it. I hate cutting corners but if this "repair" gets the oil flowing again and can get me to maine in june Im home free as Ill be pulling the engine up there...

never hit a wall like this.

throw anything my way you think i might be missing...