kevl3xus

Hello there CL,
Im new to the site and not so familiar with it but I hope you guys here can help me out.
I own a Lexus GS300 and currently having some issues with it. What im experiencing here is coolant lost. I'll have coolant in the radiator and add some in reservoir but it will complete eat up all the coolant in the reservoir after 30min-1 hour drive. I check it out myself seems like no leak what so ever and I even took it to the shop they wasnt able to confirm what was the issue and by that they didnt take any charge$$$. Now the car havent over heat "yet" drive smoothes no issues at all just the coolant lost.

Any opionions? suggestions? or any forum about this issue is much appreciated.

GS300LUV

I guess since you are not finding any leaks you could check to see if your head gasket has gone bad. Check your oil to see if it still looks good. If it looks kind of like mocha, thick looking, and not the usual light to dark brown, then you have a bad head gasket. This occurs when your coolant mixes with your oil. Also if that is the case you have quiet a bit more smoke coming out of your exhaust which will be white in color. Now when you say your loosing coolant, could it be possible you are just very low? This would be much better than a bad head gasket. How much have you added since discovering you are loosing coolant? What type of coolant are you using? Are you using the recommended Toyota Red coolant or equivalent? I would park the car for a bit over a good size piece of card board placed under the engine. Let it run for while just to make sure you have no leaks. This usually helps me vice parking it on the street and looking for leaks. One other thing you could do and it might be a long shot is to see if your heater core is leaking inside the car. I dont know the extent of your knowledge of cars so if im telling you things you already know, sorry.
Good luck. Let us know what you find out!!!

KA8

iTrader: (1)

Sounds like you have a hairline crack on head gasket and coolant is slowly getting burnt. I went through same ordeal on ls400. As long as you keep adding coolant it won't overheat but it's very annoying, good luck!

GS300LUV

That sounds about right too. A hairline crack is a PITA.

99 GS3

iTrader: (14)

You need to pressure test the coolant system, this is the first simple troubleshooting procedure.

You can usually borrow one from advance/autozone loaner tools for free. Simple test to do, just remove cap, attach hand pump/gauge and pump it up to 20psi and let it set, watch the gauge and see if it goes down. You can also put the radiator cap on the pump attachment and make sure it holds and opens properly after testing the radiator system.

Sometimes it can be something simple like a waterneck gasket, hose, or clamp that is leaking a tiny bit but the motor burns it off as your driving and you can't find the evidence as an obvious drip or huge residue spot.

If you don't have oil in coolant or coolant in oil, and the pressure test holds 20+psi for 20-30min or longer then its a good chance the head gasket may not be the issue.

Repeat the test on both a cold engine and a warm engine then compare results.

A cylinder leakdown test would be the next thing to move forward with after the pressure test if the head gasket is still in question.

GS300LUV

So true on the radiator cap..... Before I did my swap i was loosing a small amount of coolant for a few weeks just from the cap. But it sounds like hes loosing quite a bit more.

99 GS3

iTrader: (14)

I know you know what I mean, and thats true a cap is sometimes a simple culprit of radiator issues.

But just to verify for the OP or others and make it completely clear the goal is to pressurize the radiator and all water flow paths in the engine, either it holds or it doesn't, and alot of times this test will force a clamp, hose, gasket, freeze plug, block draincock, radiator neck/body/endtanks, etc to hiss/bubble/dribble/etc and you may find potential leaks. If you find no leaks but the pressure goes down then you may be looking at a headgasket and then you move onto the leakdown cylinder test.

But yes a ****ty radiator cap can cause issues for sure, and that's why I mentioned to also test the cap itself in conjunction with the full system test.

kevl3xus

Thanks for the suggestions and opinions. Im still currently working on the issue and wasnt able to respond in time. Still dont know what is the issue but im sure I will get to the bottom of it and ill keep the suggestions in mind.

Blanco

iTrader: (8)

So was there ever a resolution to this??