mteele

iTrader: (5)

Well, I have a couple of pressing issues dealing primarily with my sensors on the car. The engine has 186k miles on it, so I guess its time for some of them to start failing.

First off is my problem when I start the car when the engine is cold. Depending on the outside temperature, the engine will idle at an insanely large number, sometimes probably as high as 1700 rpm's. I live in Florida, so its not like it gets down into freezing very often, but still on a normal day in the 70s-80s it will start idling at 1500. I also get a wierd noise when I start the engine up cold. BUT when I start the engine warm, no problems at all, starts up nice, quitely, and doesnt over-idle. Could this be my engine temp sensor...?

Second problem could also be temperature sensor related. This first happened a week ago when I was driving home for my holiday break. My temperature needle would go alllll the way up, onto the red and beyond, would stay ther, go back down, go back up, etc. I was getting no smoke from the engine or anything else that would make me think the engine was really overheating. This happened again last night, and again, no other signs that the car was really overheating.

Ok mechanics, help me out

mikeloc24

I guess you didn't see my post huh? lol. I'm dealing with the exact same thing and my mileage is right about where your's is. In the last 8 months I've changed my radiator, water pump, thermostat, fan clutch, coolant, radiator cap, etc. all in an attempt to fix whatever is messing with my cooling system. My temp needle would still go up and down like what you're talking about. I read a thread where someone said it may be the "fan switch sensor" but I wasn't so sure. I also noticed when I'd start my car up in the morning I'd hear the sound of rushing water behind my dash, someone said it was air in the cooling system. I checked my coolant overfill jug and it was almost empty so I started the car, let it warm for a second, put the heater on full blast, took off the radiator cap, and then added water to the overfill jug and continued to let it run. I did this twice in 2 days and it seems t have fixed my issues (knock on wood). I just need to get some Toyota Red coolant to add to the water in there to make sure the mixture is right. Hope some of this info helps...

SC400Dude

Mike,
Do you tinker with the coolant a few more times?? I'm guessin it kinda helped. I'm still unable to discuss things with Robert about the "fan switch sensor" , but I'm still working on it. We've been so busy in the last few days dude. We have cars sitting in the shop waiting for parts that are on back order. This rainy weather ain't helping either.....

Mteele,
When you turn your car on cold, sometimes I think it's normal for it to idle that high. I've started up a few RX300's here and they've seemed to idle that high as well. Then it drops after the engine is warmed up. Does your idle drop substantially? Like to 800-1,000 rpms???

I have an SC4 and when cold, idles around 1,200 rpms. Then drops to around 700 rpms when warm. It's funny because my car won't drop idle until the temperature needle surpasses a certain point on the gauge. You can actually feel and see it drop idle as it reaches optimum operational temperature (Which is a little above the second hash mark on the temp gauge).

mteele

iTrader: (5)

Thanks for the help Mike, I'll give that a try and see if it fixes my problem.

SC400Dude, yeah it eventually drops, I just didnt know if it should be idling that high to begin with.

SC400Dude

Has it been doing that for awhile?? Or was the cold idle lower than that??? Just monitor it and if it goes well above what you observe now, then something could be fishy....
I'll ask my mechanic and see what he says....I'll pm you when I get the chance....

mikeloc24

Okay, I think I fixed my problem. It was air in the cooling system as evidenced by the sound of rushing water behind the dash. I fixed this by adding coolant to the overfill reservoir while the car was unning and the heater on max hot. My temperature guage seems to have stabilized now as I haven't had any problems for a few days. Check your coolant overflow reservoir level first before buying any parts...

mteele

iTrader: (5)

I'm doing a drain/flush right now, already got the car jacked up and everything. I'll let you know how it goes