I decided to drain my radiator and refil it with fresh Prestone dexcool compatible coolant. After draining the radiator I looked inside with a flashlight. It looked great. I refilled it and checked the overflow. The overflow was a gunky tan colored mess. I used a small brush to try and clean as much out as possible and then added some water and coolant to dilute it. I'd preferr to not have to remove it and totally clean it out if that's possible. Is it an issue if it's somewhat nasty looking?

 

I guess you know you should really use distilled water only.???

 

Doesn't that gunk usually only form when someone leaves the original dexcool in for too long, or tops it off with older eth glycol coolant, mixing the two?

 

The gunk is the product of either:

- Dexcool left in the system for too long, or

- Improper coolant level (air in the system).

 

In another thread I read on this forum, someone explained that there is a chemical reaction between something in Dexcool and the chlorine that is in city tap water and this reaction causes Dexcool to turn nasty. Not sure if it's true, but I remember reading it a while ago.

 

Hence the reason for the distilled water versus what came out of your hose. I use Dexcool and distilled water and I do my own work on stuff like that to make sure it is done right. Water is water to most service guys.

 

I agree. I use the prediluted dexcool, which is mixed with distilled water as stated on the back of the bottle. I've never had any gunk build-up issues.

 

prediluted FTW!!!

 

I agree, I'm a lazy bastard!

 

me too.

 

Well, why we have great smarty pants remarks, I'm certain none of this will actually help you understand your problem.

I am not an expert, but I will share my situation with you. Take it for what its worth, but it might help you understand it better. I have the same issue.

- I just purchased my vehicle a yr ago. Though I remember checking it, I was a newb...didn't know any better. looked fine at the time.

- I acquired the same red clay/tan stuff I think you speak of (see picture below).

- As I'm sure there will be comments about "you should have changed it" fact is, for whatever reason, it wasn't. My/your bad. But I can tell you that I personally haven't added ANY additive, distilled water, extra coolant....notta!

- There is a really recent thread about it where people just call stuff out and argue, but it does make sense on SOME parts. The clay/tan gunk, if left untreated potentially may eat the seals and cause leaks. (that thread is long and most of it is crap, but I suggest reading it, it will let you know, at least how "few" people there are....there are in fact having issues). You are right, you probably need to get it out (common sense right?)

- I actually took my car in to service the other day. Payed $79....yeah, thats right $79 to flush it out and use a different coolant.

- It didn't work. I took it to a place that flushed it, but didn't have the capability to "power flush it" or actually spray it. I took it back and learned that they didn't have that capability, and most friendly neighborhood shops now a days don't because putting pressurized liquid/coolant..etc might still harm the "internal components." I guess heres where we get raped by overly sensative people that cried it hurt, but when you need it...its not there. Damned if you do, damned if you don't.

- So I'm actually trying to work a solution now. But I did finally get out of one of the service guys that there are a FEW places that are willing to actually get in there and "spray/scrub" it. You're going to really have to ask around though.

- So, this is just my opinion, but I think the best option is....yes, you really are going to have to get in there and use that elbow grease. To me, its just such a simple thing. I am not that familiar with my car, yet, so I am anxious to learn something, but scrubbing something out that shouldn't be there in the first place. Yeah, I guess its just frustrating, but it is my reality right now. I"m going to have to find a way to do it, as I am thinking you might.

For me, once I figure out how to ensure its cleared out (thats my issue...step at a time!), then I will probably stay with something similar to it, but I really do think above all, simply not leave it in for 5+ years. I'm thinking 2-3 yrs I'll get it switched out. Oh, it might make a little difference for you to consider, but this is my thoughts as I keep my vehicle in storage over the winter months.

This is all just my experience though, however not an expert one. I know there will be posts after me "correcting" this, and I hope you do, for both your and my sake, but I hope its with actual useful advice too. I would certainly like to take care of this problem too! good luck!

 

Couple things- the fluid has been changed once before so it is well within the 5 year mark. Second, I can't remember if I ever added any tap water to the overflow so that may have been a factor. SOLUTION- What I did was I disconnected the overflow hose from the radiator and placed it into an empty coolant bottle. I had my dad use the portable air tank (100PSI) with a long air nozzle into the overflow tank. He took a rubber glove and sealed it as best as he could. The air tank blew most of the old gunk out. I reattached the hose and filled it.

 

Here is another recent thread on this. Read it over, and decide for yourself.

https://ls1tech.com/forums/advanced-engineering-tech/676288-thoughts-dexcool-v-s-green.html

I still have yet to see any compelling evidence that dexcool is any more harmful than green stuff, assuming you change both regularly. If anything, I've had more cooling system issues with my green coolant cars.

I'm sticking with dex.