Engine sludge problem

Chemical flushing is not "bad" but in many cases it will not remove all of the crud and sludge. So you end up with areas where you still have sludge but now that sludge may be "loose" because the chemicals softened it. That could break free and plug a bearing oil feed or block oil flow to a camshaft.

Tearing it down takes more time and money but you can also check the parts, replace things like the timing belt or chain, water pump and gaskets. When it goes back together those parts that are "service items" are now done and you know the inside of the engine is clean.

Thanks a lot Steve. The problem is, in my area it is very hard to find a good mechanic who will carryout a good job in cleaning the engine mechanically. If I do a chemical flush and replace the engine oil some what frequently (at about 1500 km for couple of times), will it be a good decision?

It should not hurt it. It depends on how dirty the engine is currently and where the deposits are. You could even do the flush run it a bit and do it again. I have always been a fan of, tear it down and clean it because there are areas (piston ring lands) where the flush does not reach very well. But then again I also wear a leather belt and attached suspenders for my pants, really do not like "mooning" the folks. :-)

Where are you located (country and city are fine) maybe someone on here knows of a good shop nearby or at least some to avoid.

Here is a write up on it.
http://www.toyoland.com/sludge.html

:D yup got it. I am from Colombo, Sri Lanka.

Oh right next door.... :-) Sorry to say I know of no shops there...