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I have had a cooling problem for quite a while now. So today I changed the thormostat thinking that what it was. After I changed it I went for a drive. Drove around for about an hour, everything was fine. Turned on the heat to see if there was any heat because before there would be no heat and the engine would start to over heat. So once I turned on the heat the temp guage started to rise. Don't know what the deal is someone please help.


Also the cooling fans don't turn on all the time.

 
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When I had that problem in my old s-10 it was the water pump going out. I hope it's something cheaper than your water pump.

 
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Yeah me 2

 
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water pump isnt that much, just a bitch to put in.

 
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When you open up the cooling system you get air in it. To get rid of it, open the radiator cap, turn the heat on high, and let it run while you keep topping off the coolant. Some hondas had a bleeder screw right at the head to blead air out. Having an air bubble in the system can cause overheat.

 
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Yes you need to do that. There were tons of air bubbles in my coolant after swapping the head. Same happens changing thermo or changing fluid. Air doesn't cool nearly as well as liquid.

 
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Would air bubble make my engine overheat when I turn on the heat? Shouldn't turning on the heat cool down the engine. Will do that first thing tomorrow though.

 
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yes air bubbles lower the cooling ability. Turning the heat on does route some coolant to the heater core, but not enough to really notice, especially with bubbles.

 
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i thought it was the ac you were supposed to turn on?

 
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No, you have to turn on the heat so you can purge the air out of the heater core as well. If you don't do this, and you later turn on the heat, you get a big air bubble into the engine. Shops actually use a vaccum pump to draw all the air out of a cooling system.

Hondas are notorious for getting air trapped in the cylinder head. My last accords all had a bleeder at the thermostat housing to purge air. Looked like a big brake bleeder bolt. It was at the highest point in the cooling system. Always bleed with the heat full on so you don't miss the heater core.

 
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okay time to do it again then.

I did it and got a few more bubbles out, but the coolant level in the radiator is about an inch lower than the cap. Does that matter? Should I have filled to the top? Also I noticed my reservoir tank is nearly full, way past the max line. Okay? Thanks.

 
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Yes, fill the radiator to the top. Take some out of the overflow if you can, or it may spill out when it's hot. It won't hurt anything, but make a mess.

 
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Guys,

I've had the throttle-body heater bypass - DIY done for quite some time. However now, when I've put it back to normal - I've got air in my cooling system! Our 7th gens don't have a bleeder valve do they?

I've already tried the following:

Swiched the car on from cold - with cap off waiting for it to warm up and put the heater on, but the car never got warm enough for the coolant to start flowing?

Then last night after a 30min of driving from the city - I pulled over switched the car off, opened the cap and switched it back on, however coolant just cam rushing out of my radiator so I switched it back on again?

Dahm how do I go about doing this properly?

 
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well of cource if you have been running the car for awhile, the cooling system will be at operating tempature, thus the coolant will have expanded and when you open that cap, coolant will overflow coming out. that is why you dont open the cap when the system is hot. it says it on the radiator cap.

Now if you have air in the system, when the car is cool, pull off the radiator cap, turn the heater on, and turn the car on. As it warms up, you will see small bubbles appear at the radiator neck and let it keep running untill there is no more bubbles. You said you did this method, but it never got warm enough, then you didnt let the car run long enough.

 
Rep Power: 812

yes also you can rev the car slightly to make it warm up faster. I found that turning on the ac (and fans) caused more bubbles to come out. But you should do the heat as well.

 
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Thanks guys! All Done!

I took it for a short 10 min drive - let it cool down for about out 5 mins and then turned it on. With the radiator cap off.

I could actually hear from inside the radiator skipping/popping - as it tried to get the air through the plumbing. Once it's caught on - a **** load of air came through for around 5 minutes it was constant air bubbles. Then it stopped - however there was still no hot air coming through my air vents. So I figured there still must have been air in the system somewhere. So I constantly revved the motor for another 2 mins and again heaps of air bubbles came through. Then finally that stopped I stuck my head through my window and the air vents were pumping out hot air! All good - “Isn’t it nice when things just work”