Alright, I've been putting off flushing my nasty coolant, but im thinking it's about time. So here goes.

1. Is it safe to run that purple "Super Clean" through the system to remove any grease or oil that's built up over time?

2. Do I need to remove the thermostat to flush? I really don't want to, and if it makes a difference, I have access to hot hose water.

3. If I ran citric acid in it, is there anything that could be damaged by it?

Thanks.

 

I can only speak to question #2 with any sort of personal experience, and my answer is: Leave the t'stat in there.....initially. However, if you don't think you got things clean enough, you may have to take it out, as it may be restricting "stuff" from getting out of your engine. But there's no way to know this unless you open it up, so....

I'm currently cleaning-up the system in my '67 F250 (360 engine) that was left sitting out in the California desert for God knows how long. The radiator was da** near plugged, and it looked like it had mud in it when I took it out and tried cleaning it with a garden hose. Because of that I started wondering what was left in the engine, so I popped open the t'stat (more mud and crud), as well as the pipe plugs on the side of block, and ran a ton of water through it. Since then I've buttoned it up, w/a new stat, replaced all of the hoses, and have flushed it twice w/Prestone flush & kit. But I'm going to flush it again (third time) this weekend, as I'm still getting "chocolate milk" coming out of it.

But thankfully the engine runs like a champ, and the heater core puts out good heat, so I'm making progress.

But back to your question (sorry for going off script here): If you think it's clean, flush it and run it. But if you have any doubts, open it up and have a look-see.

Just my $0.02.

Good luck!

 

If there is rust scale in the system then one of these could be an idea:

 

I would disconnect the heater hoses and do that part separately. After get clear water flowing, be sure to look under the dash for any leaks.

Evap-O-Rust says it's safe around aluminum, while still removing rust from steel. Read the label. I've soaked a found framing square in it for several hours and was able to read the numbers again when done, so it doesn't really eat the metal, just the rust. Haven't had the need to do any flushing of my own, but it's an option that I'd consider.

The thermostat should open once operating temp is reached allowing for full flow, so removing it isn't required unless you are doing a static flush with the engine off. Otherwise the only flow is through the tiny bypass hole.

An in-line filter is a nice addition, but you can also open the radiator and get an idea of the quality of the coolant.

 

I did an old john deere tractor renewing parts with it too. it really works well. is pretty expensive however.

 

Not certain how oil/grease is getting in the cooling system. If you never had a headgasket failure, then I think it would not do much. CRC is something that might help. I would dump it in there and ru it for days. I would leave the thermostat out. Put a fresh one when I'm done.

Depending on the age, I would just replace the radiator after all that flushing. Probably the coolant pump too.

 

After 5 and a half hours flushing this damn thing, It looks good enough to me.

I went ahead and installed the t fitting (highly recommended and easy) and after hours running water back and forth, filling rad, running, draining, it got to a point where I liked the results enough to stop.

The amount of rust and junk I pushed out was astounding. I assume there is still some in there, however it has to be much, much better.

I wasn't able to put the full 14 quarts in there, so there's still some hose water in the block, but every time I top it up, I'll use some distilled I now have. Rad was filled fully with distilled/concentrate. (Where I live has very soft tap water, so I'm not worried about that)


I got impatient to start and didn't let it cool fully, but that is what my coolant looked like, yes it got all over me, very bitter.​​​​​​

Inside my heater core inlet when I started

Hours later, doing yet another flush

Used this setup here to alternate which side got water or compressed air, was able to blast some more junk out.



Ran this though it as well at some point.

I wouldn't be surprised if this neglected cooling system needs maintenance soon, but now it's pretty clean and I'm hoping that extends my engines life a good bit.

Maintain your cooling systems people.

 

when i flushed my system from literal black coolant initially, I used exclusively water without the benefit of a hose or compressed air (mouth to blow and poured in) gallons later, it was much cleaner, filled with green. Took a few weeks, but it went brown.

Next flushes were without hose but i had compressed air. Same procedure. Then it took a few months to get a dark green with brown scum always collecting in my overflow. I had literal mud in there!

But the final flush, which I did late 22 I think, I used prestone platinum, so its more yellow than green, but it was with a hose and compressed air. Got it very clear with distilled water ( Ibought like 5 gallons of distilled water to flush and then make 50/50 with)

That coolant is still pretty clean, but i had to dump out my overflow and clean it again this spring. IT had more mud looking buildup. But the coolant is very clean now.

 

You appear to have a 1987-1990 F series, how well do those headlights work for you? I ask specifically because the design of hte replacement uses reflectors in the housing rather than the cover to spread the light. Also, do you have an antenna mounted on your fender? on the driver side?

 

You could have drained most of the water out of the block by disconnecting the lower radiator hose from the radiator.

Only if you intentionally buy replacement headlights with clear lenses. That looks like a CB antenna on the driver’s fender.

 

But do they work? My 96's are getting faded, they were just cheap replacements of the stock variety. If the aftermarket ones with clear lenses work at least somewhat or in line with the others, Id like to try them for appearances sake.

 

Interesting place for a CB antenna, not judging just find it curious

 

​​​​​Those were the first thing I replaced, they are plenty bright, and I just use halogens.

I got them because they look much better than the dusty, yellow, dull lights it had. Very happy with them.

PO put the cb antenna there, I might relocate it.