Thanks in advance for any input given, this club has already saved me a ton of $$$...
My issue is that, i noticed my car seems to have a possible coolant leak. I noticed that my a/c wasnt getting as cool as it should when idle, but while driving was just fine. I took a look at coolant levels and noticed coolant resavoir was empty. Radiator and both fans were replaced w/brand new oem replacements 4 months ago... I topped off with coolant last night and it took 3/4 a full bottle to get it full. Car still hasnt ran hot, but this morning on my work commute i noticed a steady stream of coolant coming from what looked to be the passenger side lower radiator location.. I did happen to re-use the same hoses, and i am hoping that is the reason and maybe a hose replacement is all that is needed. A buddy of mine told me it could be a heater core problem though. Is it a pretty easy job to replace that hose? or do i have to remove the fan motor shroud and all that to ivestigate further or change it... any input would be helpful as i am still at work and just thinking of possible problems i might be getting ready to deal with.. I did manage to have more coolant on me to at least make it back home.. but any advice from u guys will be greatly appreciated.... thanks in advance....

-devan

 

ok i took my first break, and noticed that when the car was running, it is leaking from the small overflow hose on top of the radiator resovoir. It was bubbling as if it was kind of hot and it was causing the fluid to come out.. My friend said he thinks the thermostat was'nt opening properly and he thinks that could be why the overflow hose was leaking the fluid.. Now that i think about it. I didnt replace the thermostat, or the hoses when i got the radiator put in. I only got the new fluid, radiator, and fans... Also the fact that for the last few months, it has been 100 degrees plus outside and im 1800 miles over my oil change... Maybe that could be the culprit. I plan on getting a new thermostat and fresh penzoil ultra oil change today or tommorrow. but if anyone wants to chime in w/input, i would be more than appreciative... thanks

 

the hoses arent that hard to change, i would recommend them given the age of your car. replace the clamps too. the stock toyota/lexus spring clamps begin to lose tension the more they get spread open.

a/c refrigerant is different than engine coolant.

also the car wont know its overheating if there isnt any coolant in it to tell the sensor the temp of the coolant.

i would definitely investigate the coolant leak before driving it.
also you may want to change the thermostat on the car if it has never been done.

 

so if it is the thermostat that is seized up on it.... the car wont indicate on on the dash that it is overheating? i thought it would?

 

a thermostat is a thermally controlled valve. it is not electronically controlled. change your hoses, t-stat, and look for any other obvious coolant leaks. MAKE SURE ALL THE AIR IS BLED OUT OF THE COOLING SYSTEM. you could have had a large air pocket.

 

I just installed the new thermostat and hoses_ fans_ and radiator 100 percent intact and functioning. But I still have the coolant bubbling out of the overflow tube on resovoir. I don't know where else to look and I'm not familiar with bleeding out the air on the cooling system. Exactly how do I do that? The car still hasn't overheated yet_ but it's slightly barely over the middle tempature when it is normally below the half way point.. Any advise would be very very appreciated. Coolant was filled to full line..but after idling with a/c on for a while..bubbling occurs maybe the air pocket mentioned might be the problem... Thanx

 

Air conditioning and engine coolant are not connected. The only connection between those two systems is the fan switch, which is ran through for the high speed fans for AC, again not connected to coolant level or function.

Lets break this down, coolant is bubbling out from the overflow tube on reservoir. At all times or only when the car comes to operating temp?

As you drive, how much coolant do you lose? fill coolant to full line when engine is completely cold, then start and let idle, watching reservoir. Let us know what happens and when. What tends to happen when coolant constantly bubbles out of reservoir is usually caused by a faulty waterpump, as coolant is not being flowed through the motor, keeping it from circulating, so pressure builds up and overflows.

Since thermostat is replaced, clearly that is ruled out. To ensure there is no air pocket, go to the top radiator hose and squeeze it (with glove as it will be hot when car is running). That will circulate coolant, again, i doubt your problem, the overflow bottle takes care of air pockets for the most part.

 

First thing to replace is go get a brand new radiator cap. If the cap is bad the whole system will not work right. If the new cap doesn't fix it take it to a good shop and have the system pressure tested to see if it hold pressure - if you have a leak it won;t hold pressure. Also you may just have a bad termistat even if it is new, it may be the wrong one, or installed incorrectly. As other posters noted could have air in the system - there are bleed screws on the motor specifically for that, your hoses could be soft and partially collapsing when hot, or you may have intermittent fan problem not coming on or running right.

 

The overflow tube on top of resovoir doesnt start bubbling over, until it gets to operating tempature. I can hear the thermostat opening and closing, and the car still hasnt actually overheated..

After i let the car run last night with the radiator cap off until it got to operating temp and start to bubble out, i figured that may help if there was an airpocket situation. I checked all fluids this morning and fluids were normal. I went on a drive across town and back, no problem as far as tempature reading in car.. all was normal, but when i got back home and looked to inspect.. I once again saw the coolant bubbling out of the overflow hose and gushing onto my driveway.

I will get a new radiator cap, i did notice it was a little difficult for it to screw on, but it wasnt leaking from the cap site and i figured it was fine..

anyone want to suggest what there next step would be in this situation, pressure test? at a radiator shop maybe? any input would still be greatly appreciated....thanks

 

I would test to see if the engine head / engine head gasket are still in good order.

The bubble story is happening when engine head gasket is due for a change or the engine was overheated so the heads need to be skimmed (however the car is usually overheating as well)...

The test is very easy & cheap, you put fluid in your coolant reservoir and see if it changes color...if it does, you will know for sure
Read here (5.) http://www.ehow.com/how_5609019_prop...ad-gasket.html

Sorry, English is not my first language so I don't know the correct terminology

 

I'm having a similar problem with my son's '04 Lexus ES330. Got a call from his wife last night said the car overheated. Went and looked at it today and coolant level was about a gallon low. No leaks noted but did notice that there is evidence of dried coolant around overflow tube and surrounding areas of the car. After driving the car and coming back to the house noticed that with the car running the reservoir was starting to fill up. Before it more then 3/4 of the way full the fan came on and the coolant level started to drop until the reservoir was almost empty. When the fan shut off the reservoir would start to fill again. Back in January I replaced the water pump when I did the timing belt and also the thermostat. Car has ran fine up until this point. Also didn't notice any evidence of coolant in the oil when I pulled the dip stick. Not sure if maybe the radiator is somewhat clogged but looking for some input on what to check and a possible culprit. Thanks in advance for all your help and input.

Scott

 

After experiencing the coolant bubbling out of the resovoir, i went out and bought a new radiator cap with the pressure release valve on it.... Once installed, the bubbling out of the resovoir stopped happening... i recently replaced the radiator which came with no cap, and one of the fan motors as well as thermostat prior to this issue happening... After i replaced the cap... bubbling stopped, but i did notice that the car would still run a little hot on occasion... 3/4 line to overheating... I took it to a repair shop and they said gaskets were good.. Then after inspecting passenger side radiator fan motor, I'd tap it and it will kick back on..

Too bad these motors are just about 200 bucks everywhere i look.. Even with part number i cant find it anywhere cheap online..

One question though? When at idle my a/c alot of times does not get cold.. But when driving it is fine... I am hoping when i replace the fan motor this will fix the issue.. I read other posts in the forum describing the same issue...

 

Did you get this fixed? If so what was the cause? Im having the same problem with my 2001.