Rep Power: 0

can somebody post a figure on the location of the radiator air bleeding bolt on a 2005 EX ? i recently drained and refilled my radiator and changed the thermostat and i think that some air got trapped in the system during the process and this is causing my car to overheat at idle. i guess that i need to bleed the air out of the system but i can't find the bleed bolt location

 
Rep Power: 188

I would do this
When engine is cool, fill reservoir and radiator to max levels.

Install radiator cap loosely, set heater level to max heat, and run engine until radiator fan comes on twice.

Turn engine OFF, and top off the reservoir and radiator.

Tighten radiator cap, and the bleeding process is done.

 
Rep Power: 0

Thanks Gunner. I am planning to do this today and replace the rad cap and see if this will solve my problem. The problem started a month ago when the car started to overheat at long idle or in traffic so i drained and refilled the radiator and replaced the thermostat and thermostat gasket, which seems to solve the overheating problem. Now when i drained the rad, it only took half a gallon of collant to fill it up, which i found strange since the capacity of the reservoir should be more than a gallon ??? another strange thing was that after i drained the radiator and the drain plug was still open, i still see the coolant in the expansion reservoir, which means that the coolant was not flowing between the expansion reservoir and the radiator ??? so i refilled the coolant directly into the radiator.
The overheating problem disappeared for a month until today the car overheated in traffic and i saw some coolant on the ground coming out of the expansion reservoir, and when i opened the expansion reservoir i saw some bubbles, and i noticed that some coolant came out under pressure from the radiator hose that goes into the thermostat housing.
could it possibly be a head gasket problem ?? any suggestions ?

 
Rep Power: 193

Did you use an OEM thermostat? These cars are picky with aftermarket thermos.

The whole system takes a little over 1gal, there is about 25% of the fluid in the block and another 25% in the hoses and overflow tank, the rest is in the radiator. When you drain the radiator the overflow tank won't drain, you have to pull it and do it manually.

Generally when coolant overflows out of the reservoir it means a bad HG. Seeing bubbles is another common sign.

Does it idle funny when the motor is cold?

 
Rep Power: 0

I used a Stant thermostat from advance, they said that it has a lifetime warranty . The thermo seems to be working fine though since the fan turns on each time the engine temperature rises up.
I did the bleeding process this afternoon and i saw lots of air bubbles coming out of the radiator and the coolant level in the radiator went down twice in 15 minutes of ideling with the heater on, i added around 50 oz of coolant to the radiator and the temperature gauge stayed at the middle the whole time. I guess that the extra coolant replaced the air that was in the system.
the car idles fine, it's just that intermittent overheating and coolant overflow. I'm hoping that the new radiator cap will fix the problem because i heard that a faulty radiator cap has same symptoms as a blown head gasket. Is there a way to tell if it's the rad cap or the head gasket other than replacing the rad cap and wait and see if the problem is fixed ?
Thanks!

 
Rep Power: 201

If it was working fine until you changed the coolant, air was the problem. With that said though, usually the underlaying cause of a head gasket is a warped head, and usually again that is due to overheats. The best way to ensure you get the air out, though it isn't always needed either, is to either jack the front of the car up so the radiator is the highest point in the car, or if you don't have one you can drive it where the front is up. Turn the heater dial all the way to hot, loosen the radiator cap and let it run for atleast two fan cycles. Shut it off, top it up if needed. Let it cool, top it up again. Until you go through a heat a cool cycle you can't get the degas bottle level exact. The main idea is to put some coolant in it so that if the radiator cap opens to let some in it takes in coolant, NOT air. The intake is on the bottom of the bottle, so you don't have to have it full to do this...

 
Rep Power: 812

coolant drain and fills really need to be done with the heater in cold position so the heater core lines stay full of fluid on this car. otherwise its near impossible to get all the air out. you can do two drain and fills after driving around to mix old and new. the cooling passages, heater core, and radiator are far too small to pour coolant in and be done. bleeding helps, but it took almost a year of driving for all the air to purge from the core. try bleeding the system with the method in the overheating sticky thread. i think using a non oem thermo was a mistake that will come back and cause problems later on.

 
Rep Power: 188

Sounds like your on the right track, Other signs to look for would be smoke from your exhaust, oil in your radiator...and if you have to constantly add more fluid but dont see a leak..

I hope getting the air out and your radiator cap worked for you.

 
Rep Power: 0

I borrowed some diagnostic tools from autozone today and i'll be doing some tests tomorrow and post my findings. hopefuly it's not the head gasket

 
Rep Power: 0

hey guys, so i did some diagnostics for the head gasket but i wans't clear how to interpret some of the things that i saw, especially in the first test. Overall i am now leaning toward a conclusion that the head gasket is fine; not sure though, any suggestion/comment would be great

Test # 1
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with the car completely cool and engine off, i replaced the rad cap with the pressure pump



then i put 16psi pressure into the system and observed the pressure gauge. it dropped by 1psi every 2 minutes; so after 2 minutes the gauge was at 15psi; after 10 minutes at 11psi; after like 40 minutes or so the pressure was almost gone. now i know that the cooling system looses pressure after some time, but is the rate of 1psi per 2 minutes a normal rate ??? does this indicate that there is a leak somewhere ??

the second thing i did was put the pressure back into 16psi and start looking for external leak; didn't find anything. i even sit under the car for like half an hour with a light looking for any leaks, didn't see anything, not a single drop. so if there's a leak it's internal, but this all depends on whether a 1psi per 2 minutes drop is normal or is it an indicator of a leak ??

Test # 2
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Keeping the pressure gauge hooked in place of the rad cap, i turned on the car and watched how the pressure change in the system. The pressure started to rise steadily as the temperature of the car rises up. After about 10 minutes the temperature gauge was at the middle and the pressure in the system was around 11psi. once the pressure reaches 13psi, the fan turns on and the pressure goes back to 11psi and the same cycle continues. I found this completely normal, or is it not normal ?

now after i turned off the car and the temperature started to go down, the pressure was dropping by 1psi every 6 minutes. So after about an hour, the pressure is very low. Is this normal ?

why does the pressure in the system drop 1psi per 2 minutes when the pressure is put by the pump, and 1psi per 6 minutes when the pressure is put by the normal operation ?

Test # 3
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This is the block tester test and it made kind of releived when i saw that the fluid did not change the color after keep sucking air from the system for like 5 minutes with the engine on at normal temperature. These are the pictures of the fluid after the test





it didn't change color, which means that there are no combustion gas in the cooling system .

what do you guys think ? should i worry about the pressure tests as the block tester was ok ? does the pressure tests indicate any problem ?

BTW, that old rad cap was completely blown, that's how the water look like after i pumped it




Thanks

 
Rep Power: 188

Pictures not working...As for the pressure test if it drops there is a leak, when you pump it up to 16 psi look at all your connection and hoses to see if any fluid is leaking out, also check the passanger side of your car, it could be the heating coil that is leaking..the average car operates between 8-12 psi so the test while running is fine, but the first test you did was to test for leaks...which by the dropping would indicate there is a leak...

 
Rep Power: 0

I couldn't find out the location of the leak even after putting some UV dye in the radiator and looking all over the car with the UV light, so i poured a tube of Alumaseal powder into the radiator and drove the car for like an hour then did the pressure test, the system held the 16psi for more than an hour
let's see how long it's going to last, the tube says it's a permanent seal

 
Rep Power: 188

Good deal, Hope this holds up for you..