I noticed recently that my antifreeze is dirty..at the top of the resevoir its clearish orange like new..but lower in the tank where it tapers down its dark and mucky..any suggestions why?...I had all of the coolant hoses replaced about a year ago and had the radiator flushed(supposedly)...could this be possible UIM failure?...the oil looks fine though i'm due for a change and its a bit black..i've noticed the temp rising more than normal just after overdrive is used...other than that the running temp is fine but the oil pressure has been lower than normal staying around 40-50 at highway speeds....any ideas?

Check your oil dip stick to see if it'* milky.

the oil seems fine..thats the first thing i checked..well i check it every week..i'm thinking a radiator flush and an oil change is in order :?

It is possible that green coolant was mixed with your orange dexcool coolant. The result is ugly looking.

I agree with your plan..flush and fill with one clean color. (On a side note...I used a can or two of brake clean and a red shop rag to clean my overflow.. it looked like a sewage container before I started. Then rinsed it super well with clean water.

[quote="klystronik"]I noticed recently that my antifreeze is dirty..at the top of the resevoir its clearish orange like new..but lower in the tank where it tapers down its dark and mucky..quote]

You don't say if the cooling system had been rinsed and DexCool changed before. Have you owned the car since 1997 or do you know?

If it hadn't been changed and the coolant recovery tank brushed out, it'* probably just normal accumulation of gunk and the antileak material put in at the factory when the car was new. That material is ground up walnut shells or some organic material like that which will catch in seeping areas and tend to grow catching other particles to block the leak.

My suggestion is to look at the coolant inside the radiator cap opening. If it looks good, I'd remove the overflow hose at the radiator cap, use a bottle brush, to rub the inside of the overflow tank with dishwashing detergent ( Dawn), and then let drain through the tube at the radiator cap. I repeated and rinsed thoroughly a couple of times to remove all detergent.

This avoids having to remove the bolts to get the tank out (I'm lazy when possible).

Then watch to see if the crud shows up again.

Change DexCool every 24 months. Leaving it in longer may cause problems (or may not depending on who you believe). It'* cheap to drain and replace it yourself.

If the radiator was flushed a year ago, it should have only DexCool in it. If you think it may have had green stuff in it, accidentally or on purpose, before that flush and change,
I'd do a second flush just like BillBoost says. Then you KNOW for sure.

thanks guys! ...it had never been flushed or changed before a year ago..a leak developed before i had all the hoses changed and green coolant was mixed in..i'm pretty sure thats the problem..there are black specs in the tank as well so that all makes sense now.

Does mixing the green stuff and the DexCool cause particles to actually show up? I've never seen the result (hope I don't have to see it)?

To my understanding (never done tests) mixing green and dex cool only results in a muddy look. Never heard about black particles, but that only means I've never heard of it. Maybe some others will chime in if they have or haven't.

Make sure you empty and flush your coolant system to get rid of all the mixed coolant types. Mixing the two types is NOT good for your system.