New Memeber w/ Lexus ES250

[jtmoney]

Hello all,

I am new to this forums, but very well aquainted with Toyotas. I have a Toyota Matrix, and am registered with matrixowners.com. The reason I am posting here however is that my old man has a 1991 Lexus ES250. It is his daily beater. We bought it for $400 because it has quite a few problems, that I saw to be easily fixable. I am posting here because, clublexus.com has pretty bad support on the 1st generation ES. This car is basically a rebadged 2nd generation Camry V6, so i figured here is better. It was running nice at first, but was getting about 19mpg. I used to have a 1990 camry v6 and remember getting up to 30 mpg. I knew something was wrong. started with a basic tuneup: spark plugs, wires, air/fuel filter, distrib. cap/rotor, timing adjustment, PCV valve, oil change, and seafoam treatment. good improovement, but not perfect. did a fuel pressure test, and a-ha. fuel leakage. repaired, and now she is great, but not perfect. The engine is running real smooth after the seafoam, but now i am on the trans. its a 4spd auto, and it started to shift rough into 2nd a little after we bought it. after the engine was good, i removed and cleaned the pan, drained the fluid, replaced the filter, and refilled with a bottle of lucas oil stabilizer and dexcron III. now it shifts like a lexus (smooth as silk), but here is my main problem. When it was cold, i noticed the rpms were at 2800+ when cruising at 65. Now that its getting hotter out, i have seen it get as low as 2650 rpm at 65. when it is cold it has gotten worse gas mileage, so i am leaning toward this cause. I don't remember the rpms at 65 in my old camry, but i know 2800+ is wrong. i am a manual trans guy, so i am not to good with autos. i just did what a buddy told me to do with the other stuff, and it worked. my guess is that the trans oil cooler is causing the fluid to stay cold, and that in turn causes the tranny computer no to enable lock up on the torque converter. The same thing happens on my moms 2003 mazda mpv, but after about a few minutes in really cold weather, it drops down the rpms, and it also has a trans oil cooler. I don't remember if my old camry v6 had a oil trans cooler or not. I really want to fix this, as it makes a few mpg difference and every little bit helps. I am thinking of ditching the cooler, but want to verify if the camry v6 had one or not. Any feedback is greatly appreciated.

[Kep]

I boiled it down to:


i am on the trans. its a 4spd auto, and it started to shift rough into 2nd a little after we bought it. after the engine was good, i removed and cleaned the pan, drained the fluid, replaced the filter, and refilled with a bottle of lucas oil stabilizer and dexcron III.



When it was cold, i noticed the rpms were at 2800+ when cruising at 65. Now that its getting hotter out, i have seen it get as low as 2650 rpm at 65. when it is cold it has gotten worse gas mileage,


I believe that the Lucas makes the fluid more viscous and might keep the fluid from being able to flow through passages enough to kick in the TC Lock. Other than it seemed like a good idea, was there a reason you added the Lucas? I think I would try draining out the fluid and replacing with good quality Dexron III. Since you won’t get it all out at once, you might need to do this 2 or 3 times to get rid of most of the Lucas. If you drain it once and notice an improvement then do it more. If you don’t notice an improvement I may be all wet (I often am).

Kep

[jtmoney]

well i did the drain and refill with lucas after i noticed the TC problem. I did it, because a friend of mine who is pretty good with auto trannys told me. i was planning on the drain and refill with filter change anyways, but the lucas he suggested it, so i said what the heck. plus i have used lucas oil stabilizer which is great as well. your suggestion makes sense as the lucas was real thick, and might have caused a problem, but i don't think so because the rpms are a bit lower in colder temperatures were they were higher. if anything i actually think the lucas helped with both shift quality and the TC. Thats why i am leaning toward the tranny cooler. i wish i could just find out instant tranny fluid temp to help diagnose the situation.

[Kep]

Yeah, if it was acting up before you added the Lucas the Lucas probably isn't hurting (or evidently, helping).

I'm no expert on trany temperature(s) but there are cheap infrared thermometers that you could point to various parts of the transmission case to get temperature readings at those points. I got one on sale at Harbor Freight for about $10. They had a more sophisticated one for under $50. It gives you an almost instant temperature of any surface that you can point the "light" to.

Unless you're doing something out of the ordinary I don't understand why this trany would overheat any more-so than any other unless there is a restriction or the trany is working harder than it should for some reason. A cooler might resolve the temp problem but might not cure the underlying problem.

Kep

[nicokpe]

ok, just want to say: welcome to forum

[jtmoney]

I think you misunderstood. The car already has a tranny cooler. I beleive the cooler is keeping the fluid too cold, and preventing the torque converter from locking up, which is keeping my rpms higher and causing decreased mpg. i am considering ditching it, or maybe covering the air damn in front of it. I just want to know if the camry v6 has the tranny cooler. if it doesn't than i know the trans can work fine without it.