oil test for sludge???

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Oct 12, 2003
I was looking at the information on oil testing by a couple of the sponsors here. Will one of these oil tests determine if you have engine sludge or not? Specifically, I have one of the engines by Toyota that is prone to sludge and would like to determine if I have a problem, and , if so, how bad it is. Will the oil test help me?
Oil analysis (TS/Ox/Nit/Vis), will tell you how quickly the oil you are using is sludging up, but it won't tell you how much sludge/varnish has already accumulated inside the engine. Pulling the valve covers and/or oil pan is the best way to do this .... If you have a 3.0L engine and you haven't been changing oil every 3000 miles, or using a synthetic,you can safely assume there is significant deposit buildup. I'd do a double AutoRX treat and switch to Mobil 1 or something similar. I use AutoRX myself and consider Frank Miller a friend, it's just an excellent product.
Earlier I posed a question on my "NASA Sludge Detection Test Sequence TK4-6." (Basically, you pull the oil filler cap and stare at the valvetrain with a flashlight.) From others' experiences, how accurate is this oil cap (top end) method in judging sludge build-up down in the crankcase or elsewhere in an engine? [ November 18, 2003, 03:16 PM: Message edited by: TC ]
I have used that when looking at used cars, assuming that you can actually see enough into the area. I have also run my finger under the cover and found enough dirt/crap for me to walk away. Most of the time you will see the yellow varnish indicative of a dino oil being used too long or overextended drains.
I have changed my oil every 5000 miles. Toyota recommends every 7500 miles, but is now telling owners 3000 miles would be better. Kind of late for those of us with 5 year old cars. I cannot see much at all when I take the oil cap off. There is a yellow varnish, but no sludge. The dip stick shows relatively clean oil, even when it is just before an oil change. Some people say that indicates the oil is not cleaning the engine very well.
"The dip stick shows relatively clean oil, even when it is just before an oil change. Some people say that indicates the oil is not cleaning the engine very well." I'd say this is often true for older engines and dirty engines. Worn engines will put more contaminants in their oil, and this should show up as darkening. If the oil doesn't darken, then crud is somehow being kept out of suspension -- the oil is not doing it's "detergent & dispersant" job. If the engine is dirty (sludge is visible through the oil filler cap, for example), and the oil doesn't darken over time, then it's not dissolving the sludge, which is lame. But new engines are often easy on oil since they're still "tight" -- it might take several thousand miles to get the oil truly non-clear and dark. P.S. Your 5 yr old Toyota engine sounds pretty clean. Congrats! Sounds like you've evaded any "sludge monsters." [ November 18, 2003, 05:07 PM: Message edited by: TC ]
I would have thought if your oil is knackered (ie High oxidation) then there is possibility there is sludge in your motor as the oil cant hold up..
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