pilotshark

While draining my cooling system for replacement, I removed my old radiator hoses from the water pump assembly. I noticed a greyish silt like substance running out with the remanants of the water that was in there. I am concerned because I have let the car sit for several months with periodic start-ups. I just replaced my old radiator with a Devek radiator. I am expecting all the hoses for my cooling system Wednesday. Do I need to flush out my system with a super flush product before filling it with Prestone antifreeze? The prestone is the orange phosphate/silicate free stuff with the "dex-cool approved by GM" in the corner.

I have read all the achived posts regarding dex-cool. Reading those posts prompted me to ask you guys about this. I am aware of "mixing" dex-cool in a system with the green stuff is a bad idea. I am however esentially going to use it in a "new" cooling system with all new hoses, radiator etc. My concern is #1 what the hell was that greyish crap coming out of my thermostat housing? #2 is the engine block going to be ok if I add this new antifreeze without flushing first? I don't really want that crap getting in my new radiator and hoses and thus cycling all over again. How can I make sure I got it all when I rinsed the system following removing the hoses?

I want to thank you guys in advance.

Normy

Gregory-

I just changed my coolant for the second time this year [I installed a new fan switch and 75 degree thermostat], and my coolant came out clean. I would hope so...

Last spring, I changed the coolant after the requisite 2 year interval [and changed a leaky reservoir] and noticed only a very small amount of "scale". However, when I bought the car in 1999, I changed the coolant then and what came out of the engine looked like pea soup- kind of a greyish green. I have no idea how long that stuff was in there...

-I think that it is normal for a small amount of scale to develop. Changing the coolant regularly will help prevent this from getting bad, of course.

Though I suspect that Dex-Cool is probably perfectly safe to use in our cars, some people have raised questions about it. Then again, I use Prestone Lo-Tox, which is virtually non-toxic since it is based on propylene glycol [a food additive...] instead of ethylene glycol, and have had nothing but good results. I run about a 70/30 mixture of distilled water and coolant here in warm Florida, and add two bottles of Water Wetter to the recipe. My temperature needle stays at the first line, only rising to the horizontal position in traffic with the air conditioner on. I have the Devek radiator as well.

AS to flushing the system...this is a good idea. When I change my coolant, I usually just put the garden hose down one of the hoses and let it run for 10 minutes or so, flushing the system with some distilled water before refilling it. My system is quite clean, so I can get away with this but if you don't think yours is, then a good flush with a cleaner is a good idea.

Good luck-

Normy!
'85 S2 5 Speed

pilotshark

Thanks Normy, I think I will flush anyway before I fill. I also bought some distilled water. Probably too much in fact. I got like 10 gallons of distilled water and about 3 or 4 gallons of prestone coolant. My thermostat is almost brand new and with the exception of the expansion take (the cap is new) everything else is brand new. I am anxious to see my needle position as it has overheated before but not a regular phenominon.
Thanks for the reply!

John Krawczyk

[quote]I am anxious to see my needle position as it has overheated before but not a regular phenominon.<hr></blockquote>

Did you rehab the fan clutch too or have you switched over to an electric fan? Part of you periodic overheating, ie hot while stranded in traffic, but cool when moving maybe fan related.

[quote]I changed the coolant then and what came out of the engine looked like pea soup-kind of a greyish green.<hr></blockquote>

Mine looked the same also when i drained it. Probably more than two years old. My first thought was head gasket failure, but i have no symptoms of it, car runs just fine. I flushed with distilled water then refilled with 50/50 Autobahn and distilled water + Redline Waterwetter. But i'm smelling coolant in the back on the passenger side and I periodically have to put fluid in, maybe a cup here and there. If it would stop raining here on the weekends i could find out what it is. I am starting to miss that drought...

Thom1

Hi Gregory,

You absolutely must flush the system very thoroughly to switch over to Dexcool. It even says that on the container. Otherwise, the mixture will be corrosive. WallyP said that Dexcool is OK for our closed systems. Systems with air in them can be damaged. Burp the air out with the hoses. Keep it full.
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pilotshark

Thanks fellas! Rennlist comes through again. I will post some pics in a day or two with the new hoses vs the old ones (among other stuff).