Mkot9

What would cause the coolant to blow out if the overflow. I watch the temp gauge constantly but got home the other day and it was on hit and after it cooled I looked and the hose was blown off of the overflow and there's coolant allover that side. Is the thermostat stuck or can I get lucky and it's just a hose? Thanks for your help.

uksparky

Getting hot thermostat would be first choice... refill radiator and fit hose ..start engine, let it warm up and feel the top radiator hose for heat.... if the temp gage goes past the middle, and the hose is cold, water is not flowing.... Thermostat.... is the water pump ok ?

Mkot9

While I'm trying to fill it up with water it's leaking out but I can't see from where.

uksparky

pull the top plastics off the engine see where its coming from

Margate330

For sure!
Find the leak or get a blown head gasket and maybe a cracked head too, just ask my neighbor I tried to warn him.lol

Harbor freight sells a coolant pressure tester and it will find any leak, a pressure tester is what the pro's use but be careful not to exceed the pressure ratings on the radiator cap or you can have new problems.

DennisMik

Lexus service manual says to use 17 psi for cooling system test.

Margate330

I replaced my radiator cap with an "oem" from ebay but when I just looked I'm doubting it's oem.
Pressure rating says 88kpa which converts to 12.76psi but I haven't looked to see if this meets the psi specs in the manual.

If cooling testing presure is 17 psi thats approx 3 psi higher than my cap and that sounds about right I think.
I cringe every time I do a pressure test with every pump of the tester over 14 psi cuz never know wher the coolant will starts leaking but it finds the problem fast.
The last time I had a leak I couldn't find it was the coolant valley plate seal and it was a darn good thing I had some RPG on hand because the pressure tester blew what was left of the seal when it started raining coolant on the ground like someone broke the dam so there was no going back until it was fixed. lol

DennisMik

The spec for a new radiator cap is 13.5 to 17.8 psi (93.3 to 122.7 kPa, 0.95 to 1.25 kgf/cm2) while a used cap should be 11.4 psi (78.5 kPa, 0.8 kgf/cm2,)

Mkot9

So my 2005 RX 330 started overheating. I checked around and found a crack in the housing on the side. I used some of that steel putty stuff for a quick fix, refilled the coolant and it seemed to be working. Now, it's getting hot, like all the way up, when I put on the heater high the air is cool. BUT here's the genie in the bottle, all of a sudden the needle will go all the way down to cold. It's still hot when I turn the engine off, but what the heck is going on? It's making me insane!!!!! Please help. Thank you.

DennisMik

It could be that there are air pockets in the engine. If the temperature sensor unit is not in liquid, it will not give an accurate reading. When the engine is cold, remove the radiator cap and add coolant if needed. Then start the engine and let it run until it reaches operating temperature and the thermostat opens. When the thermostat opens, the air bubbles should come out. CAUTION - these air bubbles can come out with force, spraying all over the place. This means don't be looking into the radiator. 200º coolant on the face is not nice.

Once air bubbles stop coming out, add coolant if necessary until air bubbles stop coming out. Having the front of the car slightly elevated may help.