Toyota Repair: low oil pressure, google search engine, sludge problem

Question
QUESTION: hi, i have a toyota avalon 2000 conquest. its 1,73,000 km. i have recently have done a major service on 1,70,500 km including engine oil. suddenly , today the low oil pressure light is turned on while i was driving. luckly i was close to my home & i parked the car at my home. pls let me know what could be the reason for this ? thanks a lot.

ANSWER: Have you checked the oil level of the engine? Are there any obvious oil leaks?

---------- FOLLOW-UP ----------

QUESTION: Hi thanks a lot for your reply.Yes, i have checked the oil level today & it was very very low. so i put extra oil & now its ok.but the fact is, there is a lot of sludge in my engine.its very sticky.pls advise me how to fix the engine sludge problem & how to clean it?do i need to clean the sludge of the engine very often ?  what type of engine oil  should i use?  finally , as i drive with my kids in this car , is it a risk for the car ? pls advise as i am very new driver.thanks again.thanks a lot.

Answer
You will need to contasct a toyota dealer, there have been some known issues causing sludge in the engine and in some cases toyota takes care of the problem under a special policy adjustment but you will have to contact the dealer to inspect and see if this problem you are having applies to this policy.For a lot more information type in "toyota oil gel" into the Google search engine.