Filthy cooling system

[T4R2014]

Can anyone give some flush ideas?

Background: 1996 V6. The coolant is very orange with some sludge buildup visible in radiator hoses. The head gasket isn't leaking. Engine was replaced in 2015 with a JDM, radiator at the same time too. I think the shop flushed with tap water and didn't get all the sludge out from the prior failed engine. Last year the thermostat got stuck and caused overheating(I caught it the moment the gauge went up, don't worry). Mechanic replaced it and did the usual quick shop flush with the hose. Now the upper hose started leaking due to corrosion buildup so I had it with driveway covered in coolant since it isn't driven much.

I bought a bunch of distilled water. On flush number three right now and I used the $3 prestone flush and drove with it in there. Still seeing sludge in the hoses(which I will replace too).

Should I try vinegar? Clr? Remove thermostat?

Go to Dairy Queen before you mention pink milkshake here.

 

[calimobber]

Does it look clean when you use the distilled water and then get sludgy after driving? Back in the day, I used one of those adaptors to hook a garden hose to the intake hose and just let the car idle for a super long time letting it flush.

Then maybe use distilled to flush?

 

[T4R2014]

Does it look clean when you use the distilled water and then get sludgy after driving? Back in the day, I used one of those adaptors to hook a garden hose to the intake hose and just let the car idle for a super long time letting it flush.

Then maybe use distilled to flush?

It started getting clearer after flush three. Still orange. I suppose i could give that a shot. I'm mainly concerned about the sludgy, paste crap that sits at the bottom. Maybe I should drain it while it's warmer so the crap is more likely to be suspended in the water?

Maybe I should backflush the radiator as well? Spill-free funnel en route as well since bleeding without it is a waste of time.

I'm converting to Zerex Asian as well.

 

[thegipper]

When my truck got the pink milkshake (it was my brothers at the time) he flushed the cooling system with a garden hose the best he could. He replaced the radiator and everything else required to get the truck back on the road.

Fast forward to now, I still have this orange/red dried on sludge on anything that wasn't replaced (anywhere coolant flows). For instance, I had to replace one of my heater hoses last week (heater core to heater control valve) which was the original one on the truck.

Sure enough, it had a thin layer of this now hardened orange/red sludge lining it.

I flushed my original engine probably 5 times after I got it from him as preventative maintenance a couple years ago. On the 5th flush, I finally had mostly clear water coming out with a tiny tint of orange/red to it. I called it good and put new coolant back in (also used Zerex).

Moral of the story, I don't know if there is a way to ever remove that hardened sludge (if that is what you have). I used some chemical flush agent also which probably helped but never removed all of it.

Thankfully I have a new/used engine in my truck and replaced just about every coolant hose while I was doing the job.

Let me see if I can find some pictures of what I had going on.

 

[thegipper]

Does your sludge looking anything like this?

Sent from my SM-N950U using Tapatalk

 

[T4R2014]

Color is the same, but the stuff in yours looks like it chips off in flakes. Mine looks like light surface rust. It looked like that under the radiator cap at first, but now I'm starting to see the metal again.

I'm thinking once it start's you're kinda effed. I think yearly drain/fills with coolant would keep it at bay once I get it somewhat clear.

 

[thegipper]

Yup.

I think my brother didn't do a good enough job flushing out the tranny fluid which turned into the sludge. Over time, it hardens and looks like my picture.

As long as yours is still in a "sludge" state, I would try to keep flushing it out. Maybe see if you can try a different more powerful flushing agent.

 

[Wedgy]

Every time I or a shop has used some sort of flushing agent it ate a seal out somewhere else(water pump, heater core, etc.) and required another repair so I'm not a big fan or flushing agents. I would do a drain and replace with clear water until it's pretty clear then refill and drive until it's hot making sure to run the heater for a while, rear heater too if you have it-under the passenger seat. Then replace with Toyota red.
You can disconnect the heater core an flush it with a garden hose.

 

[gamefreakgc]

You want to pull the thermostat before doing a coolant flush. Reason being, you are adding "cold" water and even if you have the engine running it will cool down the thermostat, not allowing it to expand enough to allow a good flow. I'm assuming you just have the radiator open and pouring water in the top as needed.

Last time I did a coolant flush was in my 91, it took about 3 gallons of distilled water being run through before it came out clean after I pulled the thermostat. That coolant was also that rusty orange. When I flushed my brother's 95 after an overheat/head gasket failure I never got it completely clean. That brown gunk was not coming out.

 

[wcjeep]

What about a cooling system filter? They come in a variety of price points.



https://www.amazon.com/Champion-Cooling-Systems-CCHF-1-50-Coolant/dp/B01FXRJ6R2/ref=asc_df_B01FXRJ6R2/?tag=hyprod-20&linkCode=df0&hvadid=312192374842&hvpos=1o5&hvnetw=g&hvrand=14036390694515357892&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9033484&hvtargid=aud-466346483690la-570211131275&psc=1

 

[WWRD99]

I remove the theromstat and use dawn soap, put in about a cup full into the radiator and run a T splice on the return heater hose coming out of the heater core back into a bucket, once it gets hot I'll open it up and let it pour out of the heater core...I use a hose to fill and go until the soap is gone...it cleans the system to almost new...it won't take the calcite off but all oil will be gone...usually takes about 10 gallons all together but the second 5 gallon bucket is pretty much light soapy water...replace the thermostat and radiator cap and use the funnel tool to refill and purge...I'm not sure why you would use distilled water to flush the system? That won't help clean any better than tap water.

 

[m0ist]

I bought my rig with a leaking water pump. PO kept it topped off with water pretty much before every drive. Not sure for how long.

After changing everything out including the radiaior, I flushed about 40 gallons through it, then used that prestone flush stuff. I think it citric acid based.

Flushed a few times with distilled, then filled up with toyota red. About 4 months later I flushed with distilled again and filled back up with red.

 

[JRZEE2000TR4LTD]

I used CLR and water in mine. Removed the thermostat. Ran it for about 20 minutes with heat on full blast and rear heat on after it was hot than let it sit for about 3 hrs or so to cool off. Disconnected the upper and lower radiator hose and fabricated a PVC connection for the hoses for garden hose connection and ran water in backwards first then forwards. Did this numerous times until water was clear. Did the same for the heater core and the rear heat system basically treating them as separate systems. I then blew LOW PRESSURE air through each system until it was dry. If yours was really dirty I might be tempted to repeat the above. I did all this in preparation for installing a new radiator which I might also recommend if yours is old or or system is super dirty. If not then treat the radiator as a 4th system. Oh and also clean out the reservoir. Once your satisfied with the cleanliness of the systems, reinstall thermostat and reattach all the hoses. To neutralize the acid that may be left in the system, dilute about half a box of baking soda with some water and put that in the total buttoned up system and top off the system with only water and run it warmed up for a while, then drain and flush all that out as much as possible and blow it out (I open up the systems again like the first flushing) THEN refill with just distilled water and run until hot then drain. Finally, refill with coolant (hopefully red or pink) and distilled water. This is certainly a process but the system will be as clean as it's ever been.

I performed this same flush technique on my sons 99 Jeep GC which had very little heat and when I was done it was a night and day difference. The crap that came out of that system was unbelievable.

On a side note, when I had a mild pink milkshake in my other truck I ran automatic machine dishwashing LIQUID through it, because no mater how many times I drained it and flushed it I would get little remnants of Tranny fluid in my reservoir. No suds and pretty powerful on grease. My coolant passages were never cleaner and never had remnants of tranny fluid again.

 

[T4R2014]

Yup, the sludge in mine looks like that stuff. Guess I'll find someone who will let me use their garden hose for an hour this weekend. Thermostat is easy enough to pull. The radiator is a 3yo Taiwan Denso. I'd hate to toss it but once that inner surface rust starts it never fully leaves.

 

[AntleredRuin]

From what I've read on other posts about these T4R cooling systems, they do NOT like any water other than distilled.
I'm no chemist, but apparently something about the type of metal the coolant passages are made of make it more prone to rust when filled with high metal content water (like from a garden hose).

Even flushing with a hose is bad, if you don't then flush the hose water out, too.

A gallon of distilled is around 90 cents at Wal-Mart. I'd suggest getting $10 of distilled and whatever radiator flush solvent they have there (I think Prestone), remove the t-stat, and have at it.

Once you're satisfied, fill it full up with Toyota Red or Zerex.

 

[T4R2014]

From what I've read on other posts about these T4R cooling systems, they do NOT like any water other than distilled.
I'm no chemist, but apparently something about the type of metal the coolant passages are made of make it more prone to rust when filled with high metal content water (like from a garden hose).

Even flushing with a hose is bad, if you don't then flush the hose water out, too.

A gallon of distilled is around 90 cents at Wal-Mart. I'd suggest getting $10 of distilled and whatever radiator flush solvent they have there (I think Prestone), remove the t-stat, and have at it.

Once you're satisfied, fill it full up with Toyota Red or Zerex.

I was on flush three with distilled and it still looked like traveler's diarrhea(if you've traveled to south asia you know how wild that is). At which point my friend said his garden hose was frozen solid. Damn. Scrapped the thermostat removal. I said F it with distilled and filled up some containers with hot ass water from my sink. Mixed some dish detergent in there. Fedex dropped off my spill-free funnel at the same time.

8 flushes later and it has begun to come clear. I think yanking the lower hose while hot to drain it works a lot better, just be careful not to burn yourself(use you brain people). If you drain from the plug then it takes too long and the crap falls out of suspension in the water. I don't think having the tap water in there over night is much worse than the rusty sludge. I'll use my left over gallons of distilled to flush the tap stuff out as well as I can.

I don't think these 4Runners respond to tap water any worse than other vehicles. Just don't expect to use it in your 50/50 mix and not have sludge.

 

[Kanoe]

8 flushes later and it has begun to come clear.

To speed things up, I go garden hose straight off the bat.

Pull the rad hoses off and shove the garden hose in the top of the rad with the lower hose and drain plug out. Give it some time to flush.

Then I pull the thermostat and block drain and stick the hose to the engine, it takes a long time to run color free.

Then reassemble the system without the thermostat and do a distilled water run/flush. I have a thermostat that I pulled the guts out of to hold the rubber seal. Then put in the thermostat and fill with 60/40 (we get cold) Toyota red.

Seems like a lot of work but I think it's fastest and most thorough in the end. After this, simple drain and fills from the rad every 2 years seem to be adequate.

 

[m0ist]

I'm pretty sure CLR is extremely corrosive to aluminum. I would be careful and make sure you flush with many gallons of water if you decide to ultimately try it.

 

[JRZEE2000TR4LTD]

I'm pretty sure CLR is extremely corrosive to aluminum. I would be careful and make sure you flush with many gallons of water if you decide to ultimately try it.

Yes it is. I forgot one important step in my procedure. I dilute about half a box of baking soda with some water and put that in the total buttoned up system and top off the system with only water and run it warmed up for a while, then drain and flush all that out as much as possible then repeat with plain water and drain and blow it out THEN put in the final distilled water/coolant mixture

 

[T4R2014]

Well, now it's sitting with some clean distilled water in the system. Went through three flushes today. Getting new radiator hoses to install tomorrow with the pink coolant. The spill free funnel is a lifesaver. It's stupid to do cooling system work and not have it.

Can we change the thread title to "4Runner has Montezuma's revenge"?