so am I screwed with an engine sludge problem?

[jonathag]

I have a 2000 Avalon xls with 148k on it. Here are the oil change intervals since I've owned the car which was 96k

3792 miles
5210 miles
5629 miles
6485 miles
6660 miles
7761 miles
5429 miles
7053 miles

I drive mostly all highway miles. Today on my home the oil pan light came on. I stopped and checked the oil because I've got a little over 4k miles on this oil change. The oil was fine and relatively clean. Wasn't low at all. It's always relatively clean no matter how often I check it or change it. Our 2000 Sienna has black oil when I change it around every 3k miles.

I also took the relatively clean oil appearance to mean that the engine had no sludge. Now I don't know.

Opinions?

[jonathag]

I should mention too, I use Castrol 5w30 oil all the time. I change it myself.

The car has been sitting for probably 1 to 1.5 weeks without being driven until today. I drove it 150 miles to my destination today, then the oil pan light came on when I first started the return trip home, which was another 150 miles. The light did not stay on the whole time. 98% of the time it was off, it would only flicker every once in a while. The longest it came on and stayed on was probable 2 minutes, then went off.

Is there some type of reputable engine cleaner I can get?

It is also making a loud whining noise when I start it after it sits overnight. It did this last year too when it started getting cold like it is now. After the car warms up and I drive it 10 minutes or so the noise is gone. I don't think the two are related but not sure.

[ChiTDI]

Before addressing the sludge, if there is any, let's look at the oil light. There is a sending unit that you need to check. The electrical connection for one, and then the oil pressure that the engine is producing. You'll need a screw in gauge for that one. Is there any noise? Smell? Abnormal heat? Did the oil level stay up before and after your trip?

[ChiTDI]

A flickering oil light can be a worn oil pump, worn bearings, restricted oil flow, or a bad oil sending unit.
Miracle in a can isn't going to do it.
Find the source of the low oil pressure. First things first. Check the oil level, and then watch for sounds, smell, etc. Note when the oil light flickers - slowing down, idle, cold engine, ...

[ChiTDI]

If the above findings all point to sludge formation, you can change the PCV valve and shorten the oil change intervals. There are some products/procedures that sometimes will help, but you never know.
Auto-Rx and Seafoam are popular chemicals, sometimes the results are good.

[dorman68]

I recommend hooking up a mechanical oil pressure gauge and check the actual oil pressure. If the gauge reads normal then you have a sensor, gauge, or wiring problem. If the gauge reads low then you have a mechanical issue such as sludge, worn bearings and other internal parts, or worn oil pump.

[jonathag]

Thanks a ton for the advice. I'm getting ready to head out again today and drive a couple hundred miles so I'll monitor this some more today. All very good information.

So, were my oil change intervals ok for the type of driving I do? I would just hate to think that I caused a problem by not changing it every 3-4k miles.

[csaxon]

Did you get a YELLOW oil pan level low light or a RED oil pressure low light?

[jonathag]

Red oil pressure, little oil can red light.

When I left the house today, the light was on right when I left, I got no more than 2 miles from my home and I started hearing a loud rattling noise coming from under the hood. I turned around and went home, my mechanic said it was something flapping that had to do with the oil pressure being off, so I may be screwed. He said they have had some success, if there is sludge in the engine, by taking the oil pan off and doing a handful of other things to clean things out-that it was not guaranteed but we could try it first, or we could take the engine apart and rebuilt it, or replace it. He still has to look at it, but it doesn't sound very good.

[jonathag]

Thanks for the advice. Yes, when I bought the car at 96k the dealer replaced the timing belt for me, and it was only a one owner car when I bought it, and they were religious about oil changes.

I'll have my mechanic check it all out, and I'll printout all of these suggesstions and give him too.

Thanks again!

[poolvibe]

Pull the valve covers. Pull the pan. Have a look and clean it up. The oil passages are crucial.

[05DCLB]

Pull the oil pan and clean the pick-up screen.