360jdm

I replace my radiator and thermostat today and the bottom rad hose is staying cold, but top is warming up , is there a certain way the thermostat has to go back in? Or what am i missing here

ibidu1

iTrader: (1)

Did you wait for the thermostat to open up? Theres a certain temperature about 160-200F for the thermostat to fully open up. Also did you make sure to burp the coolant lines? If you have air in the coolant then it will not flow properly.

Do this, and it will ensure you remove the trapped air in the system. Park the car on a sloped driveway or with the front end of the car jacked up. Open the radiator cap (with the engine cold) fill coolant to the top, place your hand on top of the radiator opening where you just filled and block the air with your hand. With your other hand reach to the lower radiator hose and squeeze the hose, when you squeeze release the air and check to see if the coolant level has dropped, if it drops keep adding more coolant and keep pumping out all the air pockets in the engine.

360jdm

done everything today and still no luck!! bottom hose still hold and fans not turning on, also why am i losing coolant from the reservoir tank? i filled it up yesterday and it was almost empty today

360jdm

also is the gs350 a money pit? i thought i done my homework on this car before buying and now im reading all these problems on the forum , ive owned several Lexus and all were very good to me and i still have a 05 Es330 and all i do is change the oil and not one problem

RXGS

iTrader: (2)

^You bought one in horrible shape. Any car is a money pit if its been neglected for 10 years or more

ibidu1

iTrader: (1)

These cars are solid, especially gs350's. The water pumps do go out at 90k miles, have you ever replaced yours? Aisin (rebranded oem) on rockauto can be had for about 80 bucks.

Also when you said the way you installed the thermostat, theres only one way it goes in as the thermostat comes with its own housing. Did you run an oem thermostat? Like this one, https://www.ebay.com/itm/GENUINE-TOY...YAAOSwQzJbzfnO

Did you use an oem radiator? The fans and thermostat both will not work unless the vehicle approach operating temperature. Maybe youre not letting it get hot enough. The secondary fan should kick on when you turn on the ac system.

360jdm

its a aftermarket radiator and a oem thermostat i ran the carfor about 40 min. and no fans turned on , but still dont know why im losing coolant from the reservoir ? there are no holes on the tank!

tghw

If there are no leaks and the coolant is being drawn from the reservoir, you have air in the system. You need to follow the proper procedure to bleed the air out.

tghw

The vast majority of the issues that you read about on this forum are related to the GS300, not the GS350. When well maintained the GS350 is proven to be extremely reliable. They are still +10 year old cars and require regular maintenance to keep them reliable.

If you want something more reliable and cheaper, then buy a new car or a used Toyota.

ibidu1

iTrader: (1)

I wonder if you bought a car with a blown head gasket, look at your tail pipe and see if you see any funky smoke coming out. The only thing I can tell you is that the water pump is shot, and not pumping the coolant. Best thing I can recommend is to take it to either a lexus dealer or toyota dealer and pay for an hours worth of diagnostics.

gs350fan

Does this engine have a bleed procedure?
If that wasn't followed it is possible (I don't know about this engine)there could be damage.

This car is far from a money pit, but ANYTHING on 4 wheels theoretically could be one.

vincewchan

iTrader: (1)

gs350fan

There are special tools that pull a strong vacuum with compressed air and then suck coolant back into the engine.
Some engines get air pockets and are difficult to bleed
Anyway here is the procedure:
https://workshop-manuals.com/lexus/g...ons/page_2213/

Gotcha350

Buy a lisle funnel, google it. It will help bleed air out the system. Also make sure you have the heat on high when bleeding thr system.

just because the fan isn't coming on doesn't mean it's a problem especially if the car is just idling in the drive way. Lots of factors in play, ambient temperature, humidity, wind speed. The top hose should be warm since its returning the coolant to the radiator. The bottom hose should always be cooler and since you have a new radiator the heat transfer efficiency is going to be at it's best when it is new.

gs350fan

I am posting the service manual procedure here for future reference:

6. ADD ENGINE COOLANT

NOTE:
Before adding engine coolant, turn the A/C switch OFF.

(a) Add engine coolant.

Standard capacity:
9.1 liters (9.6 US qts, 8.0 Imp. qts)

HINT:
-

TOYOTA vehicles are filled with TOYOTA SLLC at the factory. In order to avoid damage to the engine cooling system and other
technical problems, only use TOYOTA SLLC or similar high quality ethylene glycol based non-silicate, non-amine, non-nitrite, non-borate
coolant with long-life hybrid organic acid technology (coolant with long-life hybrid organic acid technology consists of a combination of
low phosphates and organic acids).

-

The thermostat open timing can be confirmed by pressing the inlet radiator hose by hand, and checking when the engine coolant starts to
flow inside the hose.


(b) Slowly pour coolant into the radiator reservoir until it reaches the FULL line.
(c) Install the reservoir cap.
(d) Press the No. 1 and No. 2 radiator hoses several times by hand, and then check the coolant level.

If the coolant level is low, add coolant.

(e) Install the radiator cap.
(f) Start the engine and warm it up until the thermostat opens.

NOTE:
Before starting the engine to warm up the engine, turn the A/C switch OFF.
HINT: The thermostat open timing van be confirmed by pressing the inlet radiator hose by hand, and checking when the engine coolant starts
to flow inside the hose.
(1) Maintain the engine speed at 2,000 to 2,500 rpm and warm up the engine until the cooling fan operates.
NOTICE:
-

Make sure that the radiator reservoir still has some coolant in it.

-

Pay attention to the needle of the water temperature meter. Make sure that the needle does not show an abnormally high temperature.

-

If there is not enough coolant, the engine may burn out or overheat.

-

Immediately after starting the engine, if the radiator reservoir does not have any coolant, perform the following: 1) stop the engine, 2) wait
until the coolant has cooled down, and 3) add coolant until the coolant is filled to the FULL line.

-

Run the engine at 2,000 rpm until the coolant level has stabilized.

(g) Press the No. 1 and No. 2 radiator hoses several times by hand to bleed air.

NOTICE:
-

Wear protective gloves.

-

Be careful as the radiator hoses are hot.

-

Keep your hands away from the fan.

(h) Stop the engine, and wait until the engine coolant cools down to ambient temperature.

CAUTION:
Do not remove the radiator cap while the engine and radiator are still hot. Pressurized, hot engine coolant and steam may be released
and cause serious burns.

(i) Check that the coolant level is between the FULL and LOW line.


If the coolant level is below the LOW line, repeat all of the procedures above.
If the coolant level is above the FULL line, drain coolant so that the coolant level is between the FULL and LOW line.

7. INSPECT FOR COOLANT LEAK See: Testing and Inspection