Hello everyone.
bought a second gen Rx with 183k miles 4 months and 2 weeks ago. Everything was going fine till the other day. Besides having a heat shield rattle poor fuel economy and the rear struts going bad she was running like a champ. Put 19k miles on her and was just due for a 5k mile oil change when on our way home my fiancé turned on the cruise control. The car revved past the set speed and began knocking. Within a mile the check engine light came on as well as the VSC. The oil light had flashed on and off intermittently but the light has behaved this way before we had the oil changed the previous times. Did 7k miles between changes since the car purchase came with free oil changes at the dealership for the first 15k this time was going to do it promptly at 5000 was just about 100 miles over that and had bought a 5l jug of mobile 1 high mileage with a matching filter the day before but due to rain and my dumb idea that I could wait another day here we are.

so now I have a big end knock and I’m quite certain it’s from low oil and shot crankshaft connection rod bearings. There is no leaking oil that I can see, the cam and crank shaft seals are probably leaking some but that shouldn’t account for that much oil loss. Anyway something within the internal lubrication components failed and now I have 6 codes. (
It says seven but one is a duplicate and I only have a ****ty cheap obdII scanner so I’m not certain as to why there are 2 of one code.)

anyway the codes are as follows P0012 P0022 P0430 P0441 P0446 P0455

what are the chances an engine rebuild or swap out would eliminate all these codes or that the bank 2 cat is fried as well?
already have a bunch of tools and have found an engine hoist and stand together for $100. On top of that I’m going to need some engine machining tools/ gauges ring compressor/ expander cylinder bore gauge and calipers. Another $100 or I know someone who will lend me what I need. But I’m trying to keep costs down and want to know if retarded cam timing will lead to evaporative system malfunctions? I would think it’s very plausible since the engine malfunctioning would lead to imperfect combustion and ultimately whatever comes out of the cat would be off but not necessarily mean the cat is bad.
anyone ever have any similar issues and how were they resolved?

We really love this car and want to keep it. And I figure doing an engine swap will give me enough experience so I never need to go to a mechanic again. I’m pretty good with a wrench as is. Not going to lie here, disconnecting an engine and pulling it out does seem overwhelming at the moment but it’s just a matter of organization, labeling and tedious work. A bunch of small steps in sequence to complete a larger task.

any guidance or information would be of great assistance. Been looking for people who have rebuilt a 3mz but haven’t found anything. There is a 1mz tear down on YouTube and I’ve watched some quality engine rebuilding videos that have given me a good idea of the task at hand.
Found a 3mz near me for $1100 and if an engine swap will remedy the codes I was thinking just get that and then rebuild the old one in my free time either to save as a spare down the road or sell to recoop costs.

but anyway, car troubles are fun. But taking the bus is far less fun. How the hell did Matt farah’s ls430 make it to 1,000,000 miles without ever having the engine opened up? Blows my mind.
And where the hell did all the oil go? Did the filter clog? Did the vein gear pump fail? When I checked the dipstick the oil was dark and near the bottom hole. But the only leaking fluid under the vehicle has been from the air conditioning system. thanks for reading regardless.

 

It looks to me you have some electrical problems.

You may have a bad engine and maybe not.

Red flags that indicate electrical problems:

1) The cruise control issue: this is controlled by the engine ecm, dead give away.
2) The multiple codes you have: can also be electrical issue
3) Rod knock: is it a rod knock or a serious fuel & spark issue? need to find out
4) Bad fuel economy: can also be electrical issue causing serious misfire.

I'm not saying you don't have mechanical issues too but you definitely have electrical problems.
Ideas- bad ecm or bad grounds, or bad alternator & charging system, etc, etc.

Before pulling the engine I'd have someone who is good and know what they are doing scope all the signals- crank sensor, fuel injectors, ignition coils, knock sensors, cam sensors, etc- the works!
While they have their scanner out might as well do a "relative compression test" too!

I doesn't cost that much to get a skilled tech if you can find one who does mobile work and can come to you. Will need to drop the glove box for ECM access because this is where the wires will need to be tapped into to scope. Don't hire someone just to read codes on a scanner, you can do that yourself.

 

everything electronic works in the car. Sunroof, windows, auto windshield wipers, heated seats, the mirrors move when put into reverse, the CD player doesn’t work but the stereo system and radio are fine, the automatic back hatch lift and close. It would suprise me to find that this is an electrical issue.

inused to have a 2000 dodge stratus that had rusted through the oil pan and it ended up with bad rod nock and the sound is almost the same.

let’s just discard the electrical ideal, I’m definitely going to have it diagnosed and tested.

but I’m wondering if the cause of the codes is indeed rod knock and we pull and rebuild the engine; will the reparations on the engine clear the codes? Or will I also need to replace cat bank 2 and any affected O2 sensors.

I would love it if this was an electrical issue/ the only electrical issue we have is that there are some weird gurgles and groans emanating from behind the dash board. But from what I understand this is common in the ‘04 and other 2nd gen Rx models.

Thank you for the response and your input!