Oil Sludge question

This is not about my Caprice but a general question about sludge and since I 'know' and trust the opinions those of you who post on this forum I'd appreciate your input. I'm also going to post this on the Avalon board but I don't 'know' anyone who posts there!

I have a '95 Avalon which has begun using oil (about a qt in 3-4 weeks), lots of blue-white smoke on a cold start. The smoking started about a year ago after I had the valve cover gasket replaced to stop a small leak. The shop that did this told me the car may smoke for a while afterward but didn't go into explaining why. I've been reasonably good about my oil changes - mostly 3000 to 4000 mile intervals – but not obsessed about it. I watch the window stickers to clue me in to the time for a change and check the oil level occasionally. It has gotten a little low, and needed a qt added from time to time, but nothing severe. Some changes have been at a Toyota dealer, but most at quick lube places and some other independent repair shops. Unfortunately, I've not kept receipts for proof of oil changes so I cannot verify how I’ve cared for the car. I've owned the car since summer of '97. It now has 112,000 miles (had 34,000 when I bought it).

I learned when having the car evaluated for trade-in about the settlement Toyota had made relating to some of the Avalon engines doing this (as I understand) due to small cooling channels in the engine block causing the oil to overheat and cause sludge to accumulate. I do mostly short trip, city driving and understand that more frequent oil changes would be best in that situation but have not always done it at 3000. On the other hand I’ve not exceeded 5000 miles either nor gotten seriously low so I really can’t think I’ve caused the sludge problem.

Since reading a bit I think I understand that what probably happened to my engine is that when the shop replaced the valve cover gasket a lot of the sludge was released to circulate in the oil and cause valve damage. I'm not really into pointing any fingers here, but is this something they should/could have anticipated and avoided happening?

I plan to call Toyota and see if they will help with repair costs (which I think will likely be $1200 or more for a car that at best will be worth $3500 after repaired), but I’m not optimistic. Although the mileage is low, the car is 2 years older than specified in their agreement to repair this problem. And, since I cannot prove how often I’ve done oil changes I can’t prove to them that I am not at fault.

Barring help from Toyota, I don’t plan to have the engine repaired/replaced.
I’m also not interested in accusing the local shop (good people) of causing the damage when they replaced the gasket.

So, what options do I have if I want to keep the car?
Trying to clean out the sludge (if that’s even possible) would seem too late for that. I assume irreversible damage has been done.
If I just add oil regularly as it is burned, might the car be expected to run for a couple more years? Or, does this damage progress rapidly and totally trash the engine. The car is in good condition otherwise and I’d like to keep it for my daughter to drive for a while.
I know there are some mystery products out there claiming the help sludge build-up problems but are there really any benefits to using any of these? (Maybe SeaFoam in the oil! – j/k)

I need to buy a new car. If I get an Aura I can get $2800 in trade for the Avalon – a generous offer but not sure I want the Aura. If I buy an Azera I can get $1500. A new Avalon, haven’t found out yet – maybe Toyota would at least give me something toward a new one in lieu of repair costs.

Thanks

A product called AutoRX is the best thing I know for sludge. It works slowly but does work safely.

Another product called "polyalphaolefin" works very well for removing sludge at a relatively controlled pace, and quite thoroughly and permanently. You'll find it is the primary ingredient in true synthetic-base engine oils, such as Royal Purple, Amsoil, Mobil 1, Red Line, and European imported Castrol Syntec. You might also find it is NOT in domestic Castrol Syntec, neither Pennzoil nor Quaker State "synthetics," and their clones which are Group III "synthetic" oils.