hey doing a coolant flush tomorrow morning on my car and am wondering the best way to drain the block. they only sell 50/50 coolant at Honda and lordco and if I leave the water in the block the coolant wont be strong enough.... is there a plug or something to pull?

thank you

 

There is a block drain bolt above oil filter. it may not be necessary to rinse a coolant system; just drain and refill.

 

^^And you may find it difficult to remove that drain bolt on the block once you find it. Maybe not, but maybe. Therefore, my method of "coolant flushing" has been to drain and replace the coolant from the radiator and the reservoir, run the car for three on-off cycles of the radiator fans, then drain and replace the coolant again. Sometimes I do a step with distilled water. Don't get me wrong. I admire your ambition here, and I may do the block drain myself the next time, but not without a spare block drain bolt and washer (jus' cuz I'm the kind of Boy Scout who likes to be prepared). By the way, the '07-'08s have a bleeder valve on a hard pipe that is located against the firewall. But you know that, right?

 

Thanks for the info, I was able to get the plug out and back in using a magnet insert in my socket. I didn't use the bleeder valve screw thing tho as I used a vacumm filler to fill it.

 

Drain. fill ,, run top off done.. This car is easy compared to 2 others in the garage..
I dont flush the system unless I see buildup in there.. (White chalky stuff.. )

 

Don't over-think this,


Honda's recommendation is just a drain and fill of the radiator. No, you don't get all the old coolant out.

That is why the interval is half the time/mileage after the first drain. (IIRC: first time: 100K miles or 5 years, every 50K miles/3 years after that. It's difficult to keep track with the Maintenance Minder)

So, just get under there, drain the rad with the petcock, and refill. The most difficult thing is getting air out of the system. HINT: Run the engine 15 minutes, shut down, then wait 30 minutes so that the T-stat heat-soaks and opens. THEN the system will fully 'burp' it's air out.



BTW, for those that like to Mix Their Own, un-diluted Honda Type II coolant is available from motorcycle dealers (or Amazon/Ebay).

 

So, how difficult was it to remove that bolt on the block?

 

@Carbuff2: I respect what you're saying, but I think the Service Manual recommended interval of 5 yrs./100k mi. is too long. Two or three years feels better to me. But I am not an expert, and I am not basing my practice on any hard facts.

 

Wasn't to bad I got a socket with extension, the thing was very tight tho for 56ft lb probably never done from previous owner or it was over tightened possibly. Then putting it back was a pain but with the magnet insert in my socket I didn't have to worry about dropping the plug.

 

The trick with "flushing" is its almost impossible to get a drained block, as long as you use clean filtered water your ok.. If you try and use chemical flushing, after the flush is in you have to run the engine for a long time pumping clean water through it till you've washed all the chemicals out. Then you still want most of the water out, or accounted for. The antifreeze compatible with the honda engine is only widely available in pre-mix 50-50. So its hard to get concentrated stuff to top off to the actual 50-50 ratio.

After a flush (About a week later) you can test your work buy sending a sample to a lab to see if your mix is right. (Some of the oil test labs do this... )

Much like oil changes if you keep on the maintenance and don't let it go too long, you'll always be ahead of the game and won't need to flush the system.

BTW I just had to change the radiator in my 07 fit. Inside the radiator was perfect.. But the plastic on the tanks had gotten hard and cracked from age, which funny enough is a regular problem on both my BMW's so keep an eye on it.. The radiator may need to be considered a service item at 10 years or 150K miles or something like that.. We shall see.

 

Ya my rad looks ok right now I've got 103000 km and its 08

 

Can you make a write up of the radiator change DIY?

 

I just did a drain and refill of the coolant, but I noticed that the radiator reservoir didn't drain out when i opened the petcock. Is this normal?

I opened up the pet a little bit, but not very far, and then undid the radiator cap. should I have left the rad cap on to get the reservoir to drain first, or is this an indication of a blockage of some kind in the tube that goes back to my radiator?

Judging by sloshing sounds I could hear in the engine bay in the past, I think I had a decent amount of air in my system (but I can't be sure), would that possibly also indicate an issue with the reservoir hose?

 

Best practice (for me anyway) is to remove the coolant reservoir and clean out the inside. That way you don't get fooled by the buildup of crud inside, and think that there is coolant in there, when there isn't.

That said, I haven't tried to remove the Fit's overflow tank. (I know that some car's are more difficult than others to remove.)

I have known car brands where loose reservoir hoses allowed air, rather than coolant, to be sucked back into the system during cool down. If this possibility worries you, cut the stretched end of the hose off and reconnect, using a non-hardening sealant such as Hylomar or Permatex Ultra Blue Silicone Gasket Maker.

 

I appreciate the quick reply! yeah, i didn't clean out the reservoir or attempt to remove it- i just did the drain and fill with the wheels on the ground. i would imagine it wouldn't be that difficult to remove if the front was up on ramps and you removed the splash shield. i might do that next time.

but would you say the fact that the reservoir didn't also drain when i opened the petcock is a cause for concern? or is that expected behavior for the fit?

 

I don't think this is an issue. It's normal for the rad to drain but not the un-pressurized reservoir.

If you are determined to replace the fluid in the reservoir, use one of those $10 USD fluid pumps to suck it out, then refill to the max line (cold).

After you purge all the air out of the cooling system, just check the coolant (cold) in the reservoir by shine a light through the plastic. It should be between the MIN and MAX lines.

 

that makes me feel better, thanks! i found an image of our coolant reservoir, and what looked like a hose line off the bottom on the engineering drawings appears to actually just be a little plastic nub, probably to stabilize the reservoir, so that makes sense that it wouldn't drain along with the radiator.

i think i'll grab one of those fluid pumps like you mentioned, just to do as complete a job as i can - i'm pretty good with maintenance, but somehow let the car go 9 years before the first coolant drain and fill. luckily the drained fluid was only slightly darker than the normal blue of the new coolant, no signs of anything like rust, etc

anyway, thank you again!!

 

1st off thanks to all of you for talking on this subject, My Fits oil has been changed when my car tells me, a couple of times , I have let it go to 2,000 miles past, the reminder, I have mostly owned American made cars, this is my real 1st Honda car - have own many of their Motorcycles and still due, a 83 boxer Goldwing runs like a clock.


I haven't done my radiator fluid yet, the car has 135,xxx,xx, still runs great!, I checked the radiator fluid and it still looks new, and the reminder hasn't come on, but I want to change it, cause I really like this Car and wouldn't want it to blow up due to heat, As mentioned before, the BMW's reservoir can cause a meltdown to the engine, this did happen to my family member. Do you guys think I should change mine, Lots of Great info on the topic, Gentlemen , thanks again

 

I think it's a good idea to replace the coolant.

As you have seen, the blue Type II coolant is very robust and does not react to the aluminum like the older green coolants do.

Still, the additives DO wear out, and that is why Honda recommends a drain & refill on older cars at a TIME period as well as a MILEAGE interval.

 

If you pull the water pump it goes a long way to really draining out the block, The mess I had to clean up recently proved it to me.. The drain plug above the filter is on there pretty tight..