98 RS
I had a used radiator installed in my car, about a year ago, and I been having the issue ever since, the coolant keeps getting dirty (oxidized), it comes out brown, I took it to a place to have my system flushed, and that worked for about 2 weeks,I bought radiator flush bottle from an auto parts store, and that worked almost 4 days, and the oxidation came back, I flush the system at least once every 15 days, using only water, and it comes out lightly dirty, just to keep the car moving.

What can I do to get rid of oxidation once and for all:
I've found on the 'web' solutions that I'm thinking to attempt:
-Flushing the system with white vinegar.
-Taking the water pump out and cleaning it, changing the thermostat, and taking some chemical (again; radiator flush) and flushing again.

For people who have had this issue, what has worked?
Should I just go to a different shop to have the system flushed again and start from there.

If you keep flushing it and it keeps getting nasty I'd say that you probably have a worse problem than a corroded cooling system. Flushing the corrosion and then putting in new fresh coolant should stop the corrosion dead the first or second time. Are you sure there isn't any oily matter in the coolant?

Originally posted by RoninEclipse2G
If you keep flushing it and it keeps getting nasty I'd say that you probably have a worse problem than a corroded cooling system. Flushing the corrosion and then putting in new fresh coolant should stop the corrosion dead the first or second time. Are you sure there isn't any oily matter in the coolant?

Completly sure, there is no oil residues, new gaskets with some 20,000mi, i personally change the oil. Nothing other the oil comes out of the oil pan, and nothing but O2 rich H2O out of the cooling system.

I'll take some pictures and videos this weekend when I do it, to show in more detail what i mean.

During all of this, you are using distilled water correct?

Not that it is a primary cause, but using tap/hose water is a big no-no and contributes to ionization/scaling/degradation of your system.

I was using only distilled water, until last time I flushed.

I'm flushing again today, has anyone heard or tried the white vinegar approach? - I think I might try it, anyways, I'll post how it goes.

I'm taking the radiator out, and all the hoses, make sure I get to all the nooks and crannies.

And feeding some real coolant into it after I'm done, hopefully it'll stay clean.

So you've been running straight water?

Originally posted by RoninEclipse2G
So you've been running straight water?

yes, for almost 2 weeks...

So here it is...


This is just me flushing the system after 3 weeks of not flushing at all(flushed until water was clear). Making room for a 50/50 vinegar/h2o..
I ran the car with the 50/50 Vin. for about 30 mins, quick trip to the market and back, and I let it sleep overnight.

In the morning, I flushed again and this is what came out:


some other nasty stuff. Again I flushed for about 15 mins with the car running, until water seemed clean.

I took out the radiator, and let it soaking in pure vinegar for almost 3 hours. And then I flushed again.

*I also cleaned all hoses and reservoir container.


I replaced the water cooling line PNC=10113, put the radiator, fans and extras back, and I flushed for another 20 mins. made sure all the vinegar was out. Poured some antifreeze, and it looks good. sorry about the lack of pics for the last steps, but I will post a picture the next coming days to see how clean the antifreeze is, or isn't.

so far it looks promising.

Dude, that is got to be the nastiest looking radiator I've ever seen in my life!!

I would just go ahead and get a new one man. I just replaced my original one that came new with the car last week just because it was going on 12 years old. It's the exact same Denso unit that came from the factory but a lot cheaper ($115 from densoaftermarket.com) Yours might be cheaper because mine is an automattic.

I wouldn't even mess with that thing anymore.

I agree, just get a new radiator. That thing is nasty!

Ugly radiators need lovin' too. But seriously, yeah, I'm getting a new pump and radiator ASAP.

Originally posted by likuitn
Ugly radiators need lovin' too.

No, they're a problem waiting to happen.

This is why I always tell people not to run straight water unless you're on the track.

Change that radiator ASAP...also I'm sure you have some degrading piping and head with all the tap water you been running.

you can flush the system with water but never run water...the corrosion devil has hit.