Next issue with my car. I know hondas are picky with coolant. I put mostly distilled water in the system with waterwetter since the weather is warmer. Ive had to deal with a burst hose though and this time, after replacing it, I tested the water since it looked a bit funny.

I was hoping not to see oil in there but I think I saw a little in the radiator... But there was also sediment as you can see in the photo. The coolant I put in is green, it comes out the hoses green. (light green cuz its mostly water) but in the photo, from the radiator drain it comes out brown. I hope I dont need to do a head gasket replacement. There arent any other symptoms like coolant or oil in the exhaust.

The coolant was drained and replaced not too long ago but not properly flushed. Does it look like I should go ahead and do that?

 

That looks like rust to me.

A 50:50 mix of coolant:water should be added for several reasons, and you should not dilute it at all. The reason is that the coolant you buy has other additives the prevent rust and scale from forming. You are basically diluting those components out and not gaining anything from doing it.

Get the radiator flush stuff, and run that according to the directions. Then add just water, run it through the system, then drain. Do this a few times with water to flush everything out.

Finally add the premixed 50:50 stuff you can buy at the part stores. Or mix it yourself using DI water.

 

Waterwetter is the substitute for the additives. I looked into this a lot and found the best is an 80:20 ratio with waterwetter and a slightly higher pressure cap. Still keep coolant in there for this environment but as long as the temp is warm I put more distilled water in.

I looked more into it and yeah, seems like rust. I guess ill flush it out. I have the radiator flush.

Now my next question is that when I went to look for it last time I could not find the engine block coolant plug. 'Directly left of the oil filter' but I couldnt find it on my car. Am I missing something? Im only able to drain from the radiator from what I can find on my car.

 

That plug was a PIA to remove. Actually, I ever was able to remove it.

Liquid will drain to the lowest point, and I think the bottom of the radiator is the lowest point, but some will remain in the engine.

You can measure how much you drain and subtract from the capacity which is 6.9 liters (7.4 quarts) to find out how much remains.

Since you have rust in there, the additive stopped working. Something is corroding in there, so I would rather use the recommended radiator cap and coolant than risk having an overheat and damaging the engine.

 

i just put the waterwetter/water mix in there actually. This was something I noticed when first draining the coolant a month ago (before the waterwetter when the mix was 50:50) but its caught my attention since theres less green coolant in the system so the color is more brown.

Im prepared for overheating risks. I monitor the temps since Im doing this based on research and not experience and I keep supplies in my trunk.

However I will do the coolant flush sunday since I have good reason to, seeing that its rust deposits in the system. Thanks. I think Ill just drain it from the radiator and forget about the block plug then.