bigmitch

Having a problem with my son's '04 Lexus ES330 losing coolant from overflow tube. 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 and slight amount of bubbles coming out of overflow tube at bottom of reservoir . 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

Megafast13

The problem is somewhere else. My car has a little bit of dried overflow and it is perfectly fine. I would have it looked at. If it is a serious internal leak, have it looked at ASAP and drive it as little as possible.

bigmitch

It's not an internal leak, as you can see where the coolant has been coming out of the reservoir overflow tube on top of the cap from the reservoir becoming to full. I've been over the car top to bottom with no leaks detected. I guess I'll have to go to autozone and see if I can rent a coolant pressure tester and a block tester to see if I have any leaks or possible head gasket problem. Probably will throw a new coolant cap on it just to eliminate that as a problem. Any other info on what to consider would be of great help.

hypervish

It sounds like a head gasket, because of the bubbles. But, yeah a coolant cap is worth a dry. Have you tried "burping" the system?

bigmitch

If you mean bleeding the system of air, I haven't. Not sure if there is a bleeder screw or something to that effect that I can open to bleed any air. Or is there another way to bleed/burp the system.

hypervish

Yes, bleeding the air out of the system.

I generally burp the system, by removing the coolant cap (make sure the car is cold, do this before you start the car for the day). Then fill the coolant to the top of the radiator if necessary. Then start the car with the cap off, and wait till the thermostat opens. Then start to fill more coolant as there will be more room "opening up" in the radiator. Don't rev the engine because it will cause coolant to come out of the radiator. After that shut the car off and put the cap back on.

DO this with EXTRA CAUTION, it can be dangerous if you burn yourself.

bigmitch

Thanks for the info I'll give that go tomorrow. I bought a new radiator cap to try and also got a coolant pressure tester and a block tester from Autozone loaner tool. So I should be able to see if either of the head gaskets are shot.

Hayk

iTrader: (1)

You can also purchase one of those non-spill funnels from Amazon for 25 bucks.

bigmitch

Well the news is better then I thought, I landed up finding a leak around the thermostat housing and after pulling the housing found the thermostat stuck open. Changed the thermostat and gasket put on a new radiator cap, burped the system real good and so far everything seems good, no more bubbling into the reservoir. Also did a pressure check and held pressure solid for 20 mins until I bled it off. Also started the car with the pressure gauge hooked up and pressure built up slowly, where as I think it would've built up quickly with a blown head gasket. Also got a block tester and checked for gasses in the coolant for signs of a blown head gasket and the test fluid stayed blue where it would've turned yellow if combustion/exhaust gasses were present. Hopefully that was the culprit of my problems, if it was I consider myself lucky. Temp indicator never went above half way with outside temps at 110 degrees. I'll be driving it the next couple of days to make sure everything is functioning properly before I turn it back over to my daughter in-law.

hypervish

I'm glad to hear you found the problem and it's now fixed!