Coolant has slight discoloring (pic)

[ErikTande]

I've been having some temp issues (nothing serious, but hotter than I'd like (210-215 even in cool weather). A few weeks ago I did a full coolant flush and put about a 50/50 mix of coolant and distilled water back in. I also replaced the thermostat.

I did the flush to make sure that wasn't the issue, and it wasn't, I'm still running the same temps. So I picked up a used Mishimoto dual core, and I'm installing that now.

I just drained the coolant, and this is what it looks like. It's hard to tell from the picture, but it has a very slight brown discoloring to it. It's only a three weeks old.

Should I worry about this? I probably shouldn't re-use it, right?

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[lasershark]

coolant is so cheap I never reuse it, it might be getting a tad bit of oil in with it and that wouldn't be good

 

[johneclipse]

How old is the radiator? When you flushed it, how did the coolant look? Could possibly be a rusted radiator and your seeing the rust in the coolant.

 

[ErikTande]

Yeah, I definitely won't re-use it.

How old is the radiator? When you flushed it, how did the coolant look? Could possibly be a rusted radiator and your seeing the rust in the coolant.

I don't recall. I didn't pay too much attention to the color when I was flushing it, I probably should have.

I've only had the car for just over a year, I'm not sure how old the radiator is. That's a good point though, I had a 91 GSX in 2005 that the connector at the top completely disintegrated it was so rusty.

I'll post some pics of this radiator when I have it out.

 

[johneclipse]

Honestly I would run some hot water through it and check the color as the water is leaving. Truly sounds like a rust issue. Would explain the color and "higher than normal" temps.

 

[ErikTande]

^^ Sounds good, I'll do that in about 30 minutes when it's out.

 

[ErikTande]

Some of the fins have some surface rust on the outside, but it looks in pretty good shape. I flushed it with a gallon of hot water, by the end it was coming out pretty much clear.

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*EDIT*

I just noticed my pan that I caught the the drained coolant has a bit of grime in it, and it was spotless when I started. I'm wondering if it wasn't some of the coolant hitting the dirty undercarriage before it hit the pan, washing in some grime.

 

[lasershark]

that'd be pretty funny, and a quick fix

 

[ErikTande]

Quick question, when I switch the lower coolant temp sensor to the new radiator, do I need to use anti sieze or teflon tape or anything?

 

[ErikTande]

I just realized I had coolant left in my coolant overflow, and that's perfectly clean. It must have been the coolant hitting the dirty car before it made it to my pan.

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[901gtsi]

Quick question, when I switch the lower coolant temp sensor to the new radiator, do I need to use anti sieze or teflon tape or anything?

I used a little bit of RTV on the threads of the sensor when I replaced my radiator. I'm sure Teflon tape would do the job too.

 

[johneclipse]

I used a little bit of RTV on the threads of the sensor when I replaced my radiator. I'm sure Teflon tape would do the job too.

I'm never a fan of Teflon tape, too easy for a piece to find its way loose. I used a VERY small amount of RTV then gave it an hour to dry before adding fluid. Granted mine was for an "extra" drain that had to be blocked off

 

[crimsondragon]

FYI there's no steel in modern radiators. It's either aluminum or copper. That brown discoloration you see in old coolant is caramelized coolant. Antifreeze is essentially a sugar, hence it's sweet taste, and sugar exposed to heat turns brown. The only time I see rust color from the cooling system is from prolonged use of water in an iron block. That stuff is just nasty.

 

[DSM1G90]

Last time I did a flush on my Laser (and shortly after I bought it with the coolant looking like that dirty green):

Took the radiator out and pressure flushed it out with a nozzle on a garden hose - both the inlet and the outlet. One should have seen the sediments that I flushed out of the bottom of the radiator. I flushed it out completely where I had clear water going in and out in both openings.

Took the "T-stat" out and flushed out the block using the same pressure flush task. More sediment came out of that block. I flushed it out for the duration of a good 15 minutes where clear water was going out the lower radiator hose, and when I reversed the flow by shooting water in the lower hose, I had clear water coming out of the fluid fill.

Put it all back together, with new T-stat, gasket and cap. Filled with 50/50 mix, checked levels in both radiator (one fills the coolant fill to the lower inside lip and fill the overflow to the "Full" line.

Fluid has since remained clean looking when I remove the radiator cap.

This was three years ago when I did this. This summer is the time to do the pressure flush again.

-DSM