OIL ? SLUDGE ?

I recently read an article about "sludge problems" in the TOYOTA engines....
I'm puzzled.
I thought that modern detergent oils had eliminated sludge problems.
??? <rj>
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

There are several stories associated with this phenomenon: (1) Toyota professes that the sludging damage was largely a result of people's not servicing their cars with oil and filter change as often as required. IIRC, the recommended change interval on some of these cars was 7500 miles. Now, the dealership tells me that this change interval is too long and shorter change intervals are recommended.
(2) Some owners doubt the Toyota version of the story, and there is some support for this position as well. Some on this newsgroup have suggested that engine design and operating parameters are a prime mover. Particularly, some have suggested small oil passages and insufficient PVC functions may be elements.
(3) Some oils may be improved for sludge. I have never heard the quality of oil debated as a cause of this problem. Items (1) and (2) seem to be the prime suspects.
I dont think the blame has clearly landed in anyone's court, although there was a suit against Toyota and they chose to "do the right thing"
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
That was indeed Toyotas first answer to the problem, that they refer to as 'Gelling.' Subsequently, when the 'Gelling' began to appear in engines properly serviced at dealerships, they acknowledged they had a problem in their V6 engines built between 1998 and 2002. Apparently they had changed the head design to enhance emissions. From what I understand they basically changed back to using the previous head on engines built after August of 2003 and began recommending the use of synthetic oil. In addition Toyota instituted an extended warrant of eight years, unlimited mileage on engines that "exhibited signs of Gelling." The warranty authorizes its deanships to "clean, repair or replace, as necessary, any engine that exhibits signs of Gelling."
As an aside there were several other manufactures that were having sludge problems
mike

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

----- Original Message ----- From: mred To: ed machel Sent: Saturday, September 30, 2006 7:48 AM
Engines in question Makes Engine Models and years U.S. engine population* New-engine warranty Audi/Volkswagen 1.8L 4 turbo 1997-2004 Audi A4, Volkswagen Passat 447,000 8 years/unlimited mileage Chrysler/Dodge 2.7L V-6 1998-2002 Chrysler Concorde, Chrysler Sebring, Dodge Intrepid, Dodge Stratus 797,000 None. Chrysler will handle on a case-by-case basis Lexus/Toyota 3.0L V-6 1997-2001 Lexus ES300, Toyota Camry, Toyota Avalon, Toyota Sienna; 1999-2001 Lexus RX300, Toyota Camry Solara; 2001 Toyota Highlander 1,577,000 8 years/unlimited mileage 2.2L 4 1997-2001 Toyota Camry, 1996-99 Toyota Celica, 1999-2001 Toyota Camry Solara 1,757,000 8 years/unlimited mileage Saab 2.0L 4 turbo 2000-02 9-3 hatchback, 2000-03 9-3 convertible 82,000 8 years/unlimited mileage 2.3L 4 turbo 1999-2003 Saab 9-5, 1999 9-3 Viggen 68,000 8 years/unlimited mileage * Source: Analysis from Ward's Auto Info Bank (approximate).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Apparently not is some Toyotas engines. ;)
mike

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.