Ren

Hi all,

I am here to help out my brother with his Lexus

Week ago he bought Lexus GS300 and it was all fine but I have noticed that after driving, something is boiling under the hood.
Told my brother, he said "never mind, its normal for the car this age" and forgot about it. I googled it and found out about the problem with air being in the cooling system.

Today we went to the sea because it was hot, and while driving I asked if him engine temperature was fine, we checked and it was fine. After 1 or 2 minutes it was on the highest mark and we stopped immediately, there was some steam coming.

Opened the hood and the reservoir with coolant was boiling and blasting water out...not just that, it made a hole on the side of reservoir. lol!

After a bit of thinking, we though, should there be any air in the reservoir? My guess was no but I am not a specialist.

On his coolant reservoir he has a cap with a hose, but the hose is not connected anywhere, just hanging allowing air to go into reservoir????

So, my main question is, should this pipe be connected anywhere?
He is now buying new reservoir and should he get a cap with no hoses, just totally closing reservoir????
Or would you please show where it should connect and why.


Anyway, sorry for the long post, but hope to hear any advice or comments.


Thanks guys!

YupImJOee

i dont think the res is your problem.

might be headgasket, if your head gasket is blown it will cause those symptoms you have.

but first check your radiator cap, go buy a new one for like 6 bucks. if your rad cap is faulty, it will cause those exact symptoms. i've had both happen, hopefully its just your radiator cap.


mine was exactly like yours, melted a hole in my res. i just JB welded and got a new cap. now im good.

Ren

Thanks for your help, will try this out.

How you got the hose on the reservoir cap? If yes, is it connected to anything?

Also what is the best way to check if the headgasket is blown?


Thanks!

ProjektS13

Could be faulty water pump,sticking thermostat,faulty rad cap, air in cooling system, clogged radiator,Last but not least blown headgasket.

Check your oil to see if you have coolant in your oil (it looks like thick chocolate milk) and also check your coolant for the same thing, if you do see the mixture of oil and coolant then sadly your headgasket is gone.

Running straight water with no coolant also can cause the problem to arise quicker since water by itself has a lower boiling point causing the water to boil over into the res, plus running straight water can actually damage your cooling system with rust and mineral deposits.

Ren

Thank for you replies guys!

I don't think I have a faulty headgasket symptoms from what you have said about coolant in the oil.

But I still want to know if the hose on the reservoir lid should be connected somewhere?

lanthern22

iTrader: (1)

Hello, hope this helps,
I had the same problem and i changed thermostat, rad cap, water pump and next was radiator. but i notice that with the radiator cap off and the car running their was too much pressure, I was trying to bleed the coolant system and couldn't came to find out that #5 and #6 cylinder have compression loss. so check your coolant w/out the rad cap and car running, and check for never ending bubbles.

and the hose from the radiator should be connected to the reservoir at the top of the cap.

Ren

Thanks once again for the replies guys!

He wanted to change radiator anyway, so he is buying one on friday.
Is it hard to replace radiator our selves? Thermostat and reservoir?

We have some knowledge and skill about car mechanics but never experienced any work on the cooling system.
Would we need any special advice or anything special to know?

ANY advice about changing these parts would help

Thanks guys!

BarberMike

Hey dude hope this helps, I'm currently having the same problem as you are.

That hose coming from the resevoir cap is just a drainage for excess coolant/antifreeze. It doesn't go connected to anything.

Now I've changed my fan clutch and thermostat and I STILL have this problem. I drained my cooling system when I did this and found a grey/brownish goo on my thermostat hose and inside my radiator, I drained the system and most of the build-up is gone. I'm sure some of this build-up got into the water pump and is restraining it's flow so my next step is the waterpump but I'm actually starting to think it could just be air in the cooling system.

Hope this helps!

YupImJOee

Mike, have you checked your radiator cap? lol, it would suck to change everything out to find out its only the cap.

Ren

Thanks for help, he is planning to change everything anyway, so we'll see how it goes.

But I am still confused if the pipe on the lid should go to radiator or not, because some say yes some say no

BarberMike

lol sorry forgot to add that!

Yeah I changed the cap two days ago, I'm changing the water pump regardless cause I'm sure that gunk got in there too!

BTW the pipe on the reservoir lid is for drainage it faces towards the windshield of the car!

kene

iTrader: (2)

I have the same problem.
For me I think its the head gasket. I checked by taking off the radiator cap and revving while the engine is running. The coolant shot out of the radiator. When I get home tonight I'm gonna try this again with the engine cold. If it is that same thing then its most definitely the head gasket.

YupImJOee

uhh you opened the radiator cap while the engine was running/hot? very dangerous.

if your trying to burp the system start with a cool system, open the cap, and start her up. let her idle for a minute and slowly give it gas(just to get things moving)

Diemellz

great advice guys, im having the same issue now, its just my coolant not bubbling, its disappear every time i refill it? with no signs of leakage? i got a headgasket anyway cause im sure that's the source, could be wrong but im sure its thats part of the issue

YupImJOee

try all other options before headgasket, thats kinda a pain in the *** to change out.