Edit: Rust in Coolant Flush

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Chemical flushes will erode the insides of your steel coolant lines, eat the aluminum oxidation from the aluminum parts, exposing pits and potential leaks,
Geeze, how long do think people are leaving these flush chemicals in for? And what chemical?

The most common seems to be citric acid, and Thermocure doesn't contain any acids. You should be able to run Thermocure as long as you want without damaging any metal in your cooling system.

Also, if there's a leak that's only been sealed by corrosion or sealant, I would want to know about it.
 
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Geeze, how long do think people are leaving these flush chemicals in for? And what chemical?

The most common seems to be citric acid, and Thermocure doesn't contain any acids. You should be able to run Thermocure as long as you want without damaging any metal in your cooling system.

Also, if there's a leak that's only been sealed by corrosion or sealant, I would want to know about it.
So, if it means that it will cause a head gasket leak, you're totally ok with that? Because that's a distinct possibly.
 

Njck22

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Stop leak is the scourge of the earth. It's hard to not look down on anyone that would put that crap in their car, including GM who did it from the factory.
 

florida95fzj

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Stop leak is the scourge of the earth. It's hard to not look down on anyone that would put that crap in their car, including GM who did it from the factory.
I'm still hopeful mine is just incompatible coolants mixing. I am going to try to figure out how to be sure one way or the other.
 
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I'm still hopeful mine is just incompatible coolants mixing. I am going to try to figure out how to be sure one way or the other.
there is a video on youtube of a guy and his son doing the back flush and made some fitting out of PVC , some pump and some garden hose fittings so he could just cycle it through. Another guy here posted some pics and did just that.

I had researched it before I went down my rabbit hole so I knew of my plan a thru z in case i ended up up schitts creek.

i think if you persevere and flush the crap out of it until its light brown, the back flush and feel good, go with thermocure as the final lap . of course, your temp should be around 180 tho, if you are not at 180, that is the mark. my 0.02 and take it with a grain of salt. I am not a mechanic, just an 80 series/ snap on nut
 
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Geeze, how long do think people are leaving these flush chemicals in for? And what chemical?

The most common seems to be citric acid, and Thermocure doesn't contain any acids. You should be able to run Thermocure as long as you want without damaging any metal in your cooling system.

Also, if there's a leak that's only been sealed by corrosion or sealant, I would want to know about it.

i had mine in for like 2 weeks, started with some 20 min idle in the drive way and had to drive 2 hours with it in. no issue, was able to drain and begin the distilled flushing and getting it clear.
 

florida95fzj

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@lp2k - yep, I will keep at it. Once I get the crap out, I will feel better about changing the rad, water pump, fan clutch, thermostat, etc... Right now I have some flaky orange stuff. It does not feel like rust or anything metallic. I'm not sure if I will ever get the right temps with the old radiator if it's really plugged up with stuff that isn't going to flush out. I would change it right now if I could be sure I could perfectly flush out the heater core and engine block.
 
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yea there are some good options on amazon for a replacement rad, T rad brass for the 93-94 which is what i have, 95-97 is aluminum. i think most like the brass but i think its user preference.

Feel free to PM since we are in the same state. at some point i want to meet/establish a network with other 80 guys to build a decent resource network for info/help and use of some tools within reason
 
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My spill free funnel overflowed on my Corvette after getting the coolant too hot while filling it up the other day. It doesnt take long to fill the system and rid it of air bubbles. Put the car on ramps, turn on heat, squeeze the upper radiator hose with your hand until the engine gets warm but dont let it get to operating temp. Drive it around, make sure the heater is hot and watch your temps. Make sure your reservoir is full.
 

florida95fzj

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My spill free funnel overflowed on my Corvette after getting the coolant too hot while filling it up the other day. It doesnt take long to fill the system and rid it of air bubbles. Put the car on ramps, turn on heat, squeeze the upper radiator hose with your hand until the engine gets warm but dont let it get to operating temp. Drive it around, make sure the heater is hot and watch your temps. Make sure your reservoir is full.
Thanks. Yeah, I guess it happens and it surprised me.

I should have found the directions for this thing since it was the first time using it on a regular car. I bought it for a diesel generator years ago and that thing never really got that hot. Same for a diesel motorhome although since that took 12 gallons of antifreeze and had a 45' heater hose, I filled via vacuum first and the spill free funnel didn't really get much air out anyway. Rookie mistake. Lesson learned for the next time.
 

florida95fzj

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Looks like the previous owner did have the thermostat installed correctly.

With a flashlight, it was easy to figure out that the coolant was a mix of green and some type that was orange. No idea if it was Dexcool. I can't believe a guy that owned his own auto repair shop would mix incompatible coolant types. He had this truck it's entire life except for the first year.

I went ahead and did a better flush of the radiator again. I got another drain complete and put in about two gallons of distilled water.

Still going to be several flushes before I can feel comfortable changing the hoses, water pump, fan clutch, and radiator. I have to change the oil pump seal at that time.

IMG_8808.jpg
 

Irish Reiver

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The water pipe just above the should be sealed with a gasket (15785-66010) and not with whatever shower sealer your PO used. The water way is fairly narrow (same as the pipe) so any of that gunk that has squeezed out on the inside will be restricting coolant flow - possibly significantly. Its a $3 part and worth the effort.
 
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MoJ

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Looks like the previous owner did have the thermostat installed correctly.

With a flashlight, it was easy to figure out that the coolant was a mix of green and some type that was orange. No idea if it was Dexcool. I can't believe a guy that owned his own auto repair shop would mix incompatible coolant types. He had this truck it's entire life except for the first year.

I went ahead and did a better flush of the radiator again. I got another drain complete and put in about two gallons of distilled water.

Still going to be several flushes before I can feel comfortable changing the hoses, water pump, fan clutch, and radiator. I have to change the oil pump seal at that time.

View attachment 2771164
Yellow (Prestone) can start look orangish with age. Red can start to look brownish. Both are exaggerated when shining a flashlight through them. Put some in a clear glass before settling on a verdict.
 

florida95fzj

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The water pipe just above the should be sealed with a gasket (15785-66010) and not with whatever shower sealer your PO used.
Thanks for pointing that out. If I am lucky, he was just being too lazy to buy a gasket. Hopefully the metal surfaces are not corroded and he was fixing a leak because the gasket would not work.

Put some in a clear glass before settling on a verdict.

Will do. I need to keep track of my progress as well.
 

florida95fzj

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Pretty sure there's a gasket there. I can see the edge of it looking up close. I can only imagine it was leaking and that's why I have the sealer.

Does anyone know what that pipe is called? Looking at Partsouq and I don't see it.
 
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207 sitting in the driveway means you likely had air in the block. From my flush experience when that can happen. When you turned the truck off and circulation stopped some of the coolant in the block boiled rapidly. When you filled back up did you fill the block through the upper rad hose after the radiator was full?
 

Irish Reiver

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Does anyone know what that pipe is called? Looking at Partsouq and I don't see it.
I belive it is the heater bypass pipe. The gasket PN i gave you will be called Oil cooler gasket or similar but it is the right gasket. I wouldn't assume there is corrosion hence the sealant- probably the PO just reused the old gasket and added some sealant to be sure.
 

florida95fzj

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207 sitting in the driveway means you likely had air in the block. From my flush experience when that can happen. When you turned the truck off and circulation stopped some of the coolant in the block boiled rapidly. When you filled back up did you fill the block through the upper rad hose after the radiator was full?

I squeezed the upper hose a bit to get any air out I could. I did get to drive it last week and it was acting like it was before. Just a slow climb to 216-218F but did not go any higher. So, I am back to "normal".

I will also see what kind of craziness may have been done to bypass the rear heater. Hopefully I can get two flushes in tomorrow without getting caught by the daily thunderstorms down here. Sure wish I could fit this thing in my garage.
 

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