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Hey guys, about a week or two ago I did an oil change on my 04 ex and noticed the coolant in the reservoir was kinda dark. I pulled it off and poured it into a clear jug and it looked like pea soup. Color wise. It is a little thicker then new coolant, but not like pea soup thick. I did a drain and then refilled the rad. What could be the cause? Is it just old or do I maybe have a hg leak? I don't see coolant in the oil or vise versa, and I doubt the car has ever had a proper flush done. Thanks!

 
Rep Power: 245

Someone could have put green coolant in it at one point and it mixed with the blue. Combine that with age and I could see getting pea soup.

I would keep an eye on it to see if the color changes. You put Honda fluid in it right?

 
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No I didn't...I used peak 50/50. I didn't have any honda fluid. Also, can you drain, refill with ro/distilled water, drain and refill to get out the remaining stuff?

 
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I had a similar issue with mine when I noticed the seller had run the overflow bottle dry, so topped off with some Prestone 50/50... that was before I'd found modern Hondas don't like aftermarket coolant. The mix that resulted was pretty cloudy -- it was 16 oz (1/2 qt) in a gallon or more of fluid -- but wasn't anything like pea soup, fortunately.

 
Rep Power: 211

i wouldnt put anything but honda coolant in there and that includes water, just drain it and fill it with honda coolant, make sure you drain the rad AND THE BLOCK, there is a drain plug on the back of the block make sure you use it!

 
Rep Power: 519

Have you ever tried to remove that S.O.B. plug?

 
Rep Power: 187

F'ck that. I'd rather remove the water pump than F with that S.O.B plug. I've heard nothing but bad about that plug.

 
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yes.....twice actually

 
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All comments dully noted. I'll drop by the honda dealer after work since it's like next door. The color change though, is that normal for old coolant or could it be something more?

 
Rep Power: 519

The original long life coolant fill very well could have been dark green. Very dark green.

The current long life coolant from Honda is blue (type 2).

 
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Alright cool. And yes I knew about the sob plug, but really didn't want coolant running down my engine. I know someone said no, but I couldn't use distilled water to flush out the old stuff?

 
Rep Power: 519

If you use water, how will you get it all out?

If you refill with prediluted coolant (Hondas type 2 is pre-diluted 50/50), the water you left in the system will further dilute the new coolant.
If it is too diluted, your freeze/boil protection is reduced.

 
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So if I wanted to do a full flush should I just pick up an extra jug, run the new stuff to dilute the old, drain then add new stuff again and enjoy?

 
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^This was the way I plan to do it: flush with coolant, not water.

There's only apparently a bit more than a gallon of coolant for the entire system... so yeah a residual few pints of water will considerably dilute it. Being that this damned D17 has such an appetite for head gaskets, I spent the extra dosh and got a flush gallon.

Can understand why flushing with water was a question, though. I've worked with 210-hp/liter, 14:1-compression, full-aluminum race engines that run fine with plain water and a surface tension product like Water Wetter, due to track regulations banning ethylene glycol coolant (it's very slippery, even wiped up). This car engine can't, apparently, which is frustrating. But you don't run a moto race in freezing temps, nor do you commute on one for ten years. Best to flush with coolant.

 
Rep Power: 519

I personally have no problem with using water to flush, but I do check and adjust antifreeze concentration before I let it go. I have no problem estimating leftover water and using undiluted antifreeze.

 
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Oh -- so Type 2 comes undiluted? That would make things a lot easier... next swap. :P

 
Rep Power: 519

No no no, type 2 is PRE diluted. 50/50. (Google image search and read the label if you need to)

I was just saying I can work with whatever I need to. If I have to flush an engine with water, I know what's still in there. I can estimate and add an appropriate amount of straight antifreeze, then test to make sure I got the concentration adequate for freeze protection.

Some people I work with seem to have issues with the concept: Block is full of water, they add prediluted type2 and can't figure out why it tests weak.

 
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Ah ok -- that's what I thought... didn't think Type 2 was offered in anything but premixed, but you confused me... so I asked.

Yeah, for engines that aren't as particular about the coolant they're given, sure just flush with DISTILLED water, drain as much out as possible, then see how much premixed I have to add to fill the system. Say it fills with 0.75 gal premixed... so there's 1 quart of water in there. I drain 2 quarts of what's in the engine back out, then replace with two quarts premixed. That insures the dilution is at a minimum. But for Hondas with their stricter requirements... I'll just flush with an extra couple quarts of Type 2 rather than water... just as easy, if not as cheap.