I also own a 2003 Lexus ES300 like your wife's car. It has had regular oil changes from 3000 to 5000 miles since it has been owned. I had a leaking valve cover gasket that I replaced recently and was surprised to see the amount of sludge under the cover. Have you ever taken the valve cover off of your wife's car to look for sludge? I read that it was a problem with these cars. Also, a mechanic suggested that I run a quart of transmission fluid at each oil change ( 4 quarts oil + 1 quart TF). Would this be a good idea?
There's only a problem of sludge at the lazy owners didn't change the oil enough that was the real problem. If you are worried you could use any conventional motor oil flush for five minutes and then change the oil and filter the directions come on the cans like k&w flush
Thanks for the response Scotty. This car has been in my family since 2003 and I have receipts for all the regularly done oil changes. Just curious if you had checked your wife's car. Mine has been a great car, running well with sludge in the engine at over 250, 000 miles!
the valve covers are not submerged in oil, nor do they get a high flow or splashing of oil. That means things will just inevitable build up there, just like on the bottom of the oil filler cap.
Does your car get driven very little? That makes things worse. Try to take it for a good long and hard drive once in a while so it gets hot and dissolves the crud.
Thanks for your comment. We were driving it quite a bit and would never had noticed the buildup unless that valve gasket hadn't started leaking. It's got 250, 000 miles on it. There was a class action lawsuit that included this car regarding sludge build up and I brought it to the dealer just to talk about it, not expecting to get anything after that much mileage. The service manager brought in a tech to talk with me about it and he was the one that suggested using a quart of ATF at oil changes to help clean the sludge. I had never heard of that before. Anyway, the car is still running great. Other than regular maintenance, I've only had to replace the starter and the valve cover gaskets.
How often you changed the oil?
My father in law bought the car in 2003l From the records he gave me, he had the oil changed at the dealership for the first 3 years and then at Express lube until 2009 when he sold it to me. In all cases it was around every 3500 to 4000 miles. When I got it, I started changing it myself every 5,000 with semi synthetic Castrol 5-30.
So, you don’t need to worry. Just do what you plan to do.
Let me guess. The sludge you speak of is yellowish and creamy. This is typical of vehicles driven on short trips where the engine never gets up to operating temperature long enough to evaporate the moisture that has collected in the engine oil. This also happens a lot with cars driven in the northern climates during the winter.
Actually, it was dark reddish brown. I've gotten some K&W flush that Scotty suggested. I might give that a try. I think that engine still has another 100,000 in it.
BTW, BC St, thanks for your help and suggestions.