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Ok, I have been searching through hundreds of posts about changing engine coolant and here are my questions. I hope someone can help. I am assuming that following the directions in the owners manaul is best, correct? SO is there a need to mess with the thermostat? Also has anyone removed the engine bolt without problems, if not, what tools did you use to remove it. Thanks alot. If there are any other things I need to know, let me know.

 
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I can only speak for my opinion, so here's what I did:

I followed the shop manual and drained my coolant by opening the petcock at the bottom of the radiator. This drains coolant from the radiator.

Following the shop manual, I then drained the coolant from the block via the block drain plug located next to the oil filter (I have a non VTEC 1.7L motor). I believe it's a 19 mm bolt (could be a 17 mm though). It's very, very difficult to remove as its sealed in with threadlock and because there's little room to use a long wrench.

By opening both drain plugs you are able to drain out coolant from the system on both sides of the thermostat, negating the need to pull the thermostat.

Once that's done, reapply a threadlock to the block drain bolt, tighten the radiator drain petcock, and refil the radiator with Honda safe coolant (OEM or any non phosphate). Keep checking your coolant level in the radiator (not in the overflow tub) for several thermal cycles of engine operation. Like many newer car engines the 7th gen Civics tend to have a lot of air trap points.

Good luck!

Velocifero

 
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Question.. once the bolt is removed, does the coolant pour out quickly, as in do I need a large catch can underneath to catch all the fluid that comes out? if it does, I'm wondering how can I go about doing it without getting coolant all over the back of the engine bay.

 
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is it okay to just drain the bottle and re-fill it again?

 
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What tools did you use to get the drain bolt off next to the oil filter. I can probably get it off, I just dont know what tool to use.

 
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huh? your probably referring to the overflow bottle, but what about it?

 
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yeah, the reservoir bottle...

well, if i just simply drain that bottle, will that do any good?

 
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streetglower: I used a 3/8" drive socket (19 mm or 17 mm, I don't recall which), u-joint, 4" extension, and a 3/8" breaker bar. It's tight in there so I found that I needed the u-joint to get proper access. BTW, my breaker bar is about 16" and it took all of my strength to loosen the socket.

zen_master: just draining the overflow tank won't do you much good. You really need to completely drain out the old coolant, as over time, the coolant will lose its anti-freeze and corrossion inhibiting properties. Also, particulate will accumulate over time as well from precipitation of solids such as aluminum oxide falling out of solution. These particles are hard on your coolant pump seals.

 
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thanks

 
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For mine, they just unplugged the radiator drain plug and squeezed the hose to get more fluid out. Then just add new coolant. It's probably not the right way, but at least alot of it comes out. I wonder how the dealer does it, cause for tranny fluid it's just a drain and refill.

 
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I want to do it myself and was thinking about just draining the radiator and resovior, but want to get the rest out. With the tranny, if I have more money I would get all of it flushed.

 
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Well, similar to how you do a drain and fill of the A/T, you could just drain via the radiator petcock and overflow reservoir and replace with new coolant. It's better than nothing and if you do such a partial replacement, just do it more often, and it will in all likelihood, be as good as a full changeout.

If you did it that way, all you'd need is a 10 mm wrench to remove the battery and gain access to remove and empty the overflow reservoir.

You'll just end up using more coolant in the long run.

 
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hm....i wonder when i should change em..

well, the dealer where i bought said they just change it....so.....
that was at 24K...now my car is at 29K....when should i change em?

 
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It is a lot easier and better for your system to just drain and refill the radiator and overflow tank once a year or every 15,000 miles instead of everything every 24,000 miles...just my bit of info...saves the hassle of draining the engine block and your coolant never gets old...

 
Rep Power: 283

Just drain the radiator and overflow, refill. Drive it around that day, and do this again. You'll use more coolant but if you're that worried about the thermostat or engine bolt, this would be better for you. And, don't power flush your transmission.

 
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zen_master: Take jahernandez' and Sickboy's advice. A radiator and overflow tank drain and refil done often is just as good as a full drain and refil done less often.

 
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if your really lazy and dont care much about your car thats not a bad idea, it will work i guess. however flushing is still the best way to go. by just draining the radiator and overflow tank your not getting all the deposits, contamination, and other funky stuff out of the coolant. it will all just accumulate. no doubt you will get a little out, but not all of it.

 
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Actually, deposits usually settle at a systems lowest point, this being the radiator of a cooling system. If one were to simply drain the radiator and refill at 15,000 miles, one could say the coolant that was drained was far from lifeless. In essence, you are not giving the coolant a chance to age, similar to my "ATF change more often" post. Scaling and rust usually form when the coolant is getting old. (Lacks the certain properties that prevent rust and scale from forming.) Granted, that is not to say someone will experience a rusty radiator for no apparent reason. I don't want to make anyone mad with my reply, but I have done this for 10 years and have never had any cooling system problems.