mcnelson

Ok, I need to change my engine coolant (it is a merky kinda green) the local place says they can't do it because they use alot fo pressure and that will mess up my intercooler for my turbo. So I was going to do it myself. Any concerns I need to be aware of? I believe there are 2 spots that I need to drain it, 1 being the bottom of the radiator, and 2 being the main drain plug. Then I was just going to dump fresh stuff throught the resevoir a bunch of times until it is coming out the drain clear (well green). Then put the 2 plugs back in, dump new stuff in the radiator until it won't take anymore, and then fill up the resevoir until it is at the proper level in there. Any idea how much fluid it will take for a 94' GS300? Is this the way that I should do it? Do I need to do anything with the intercooler or anything else that I didn't mention. I have never changed the coolant on a car before, and for sure not on a turbo car. ANy help would be greatly appreciated. Thanks, Matt

Oh yeah, and changing stuff like oil, and I am sure with this on a lowered car is a b*tch, you can't hardly get anything under there to catch the fluid. What do you guys use?

Also, I am changing out my rear rotors as well. I was told they were too thin by a shop. I also feel a "wobble" or "rotating" feeling if I am starting or coming to a stop very closely, this has gotten slowly worse (considering they told me this 2 months ago, but I have been really busy). The pads are fine, so I am guessing it is the rotors hopefully, they look fine, but maybe they are warped??

mcnelson

I almost forgot, the new pads I bought don't come with shims? The old ones are rusted and crappy. Do I need shims, and if so what the heck do I do? I am almost positive on one of my old cars it was the same thing, I bought new pads from Auto Zone and they didn't come with shims, I replaced them and there was no problem. What should I do? These are just my stock rear pads/rotors, only my front brakes are upgraded.

wwest

If you change your own coolant and then the engine starts to overheat you have probably created a "vapor lock" within your air to water inter-cooler.

mlevk

When changing coolant , you probably will create a air pocket or vapor lock as wwest described , thus overheat only in certain situations , like idling in one place for a long time.

I don't know how to go about purging the air out.

I think ...
If the thermostat is normally open, then the pump will circulate the coolant and empty the air pocket. If nornmally closed , then you will have to wait for the car to get hot and the t-stat will open but screwing around with hot fluids is not wise.

You can buy the shims and spings seperatey from Lexus but using non-Lexus pads will probably not fit quite right.
The shims and springs keep the squealing down , and keeps the pads "loaded" correctly on the caliper. They will still work without them though, use the "blue" stuff on the back of the pads, that helps somewhat with the squeal.

mcnelson

So does that mean I shouldn't attempt to do this myself because I could get this vapor lock, and don't know how to purge the air out of the system?

tpynckel

My kid's Mitsubishi 3000GT had the vapor lock thing....of course he was in the middle of nowhere, Texas, leaving school at Texas Tech. What the manual for that car says is to park the car on a slight incline and run at high idle while slowly pouring in coolant/water mixture until the periodic air bubbling stops. After cooling off the engine for an hour or so, we did this top-off thing and it ran fine all the way back to Houston. The shop where he had the radiator flushed evidently can't read and only filled up the radiator until it overflowed.

SharpLS-96

To prevent that vapor lock, after you refill it keep the cap off the overflow(To let the air out) (Keep hood open as well) ....sit in the car, start it up and rev the engine for about 5 minutes at around 2000 rpm. Turn your heat on high also. Your thermostat will open eventually (hopefully regarding you have a good thermostat) Keep an eye on your temperature guage also. Your temp guage should be right in the middle once the car has warmed up. Shut the car off, recheck the overflow and add fluid as needed. Cap off the overflow and after you have driven the car for a day or so recheck the overflow. You might have to add some. Keep an eye on your temp guage for a day or so when driving around just in case but you should be good to go. That should take care of any vapor lock!

mcnelson

SharpLexusLs400, thanks for the info. When you say "overflow cap" what exactly do you mean, I want to be sure I do it right. Do you mean the resevoir cap, or the cap on the radiator?

SharpLS-96

No problem, I mean the resevoir cap.

wwest

removing th reservoir cap, the reservoir isn't sealed, it's the radiator that's pressure sealed with the spring in the cap.

mcnelson

I agree so, which is it? The radiator cap would make more sense, but ?????

SharpLS-96

Oops, I meant the radiator cap not the reservoir cap!! I type so fast sometimes that I forget what I am typing and they both begin with "r" Vapor lock occurs in a closed system so leave off the radiator cap! Sorry for the confusion!