What's the best cleaning chemical to flush a cooling system, radiator, heater core that is effective without damaging anything?

I've got a cruddy radiator and a stopped up heater core. No leaks, so I'm wanting to get it cleaned up without making any in the process.

I've been told Red Devil Lye works well, but I have my reservations about that...

 

Now I woulda thought there would be some strong opinions on this topic?

 

The specialized flush solutions available are the best thing you can use. Obviously the very best you can do is to not use tap water and to replace the coolant annually. If the flush solution doesn't work, you will need to replace the plugged up components.

 

I used Zerex radiator flush and bought a back flush kit on my 01 5.4. I used tap water for the flush and back flush. Drained it very well and filled it with 50/50 pre mix. I flushed it into a clean bucket and I got a bunch of scale out on the back flush. The regular flush not so much.

I pulled the thermostat out to do the whole thing. I think the zerex flush helped free alot the stuff up. I would be afraid to use lye or anything with all the aluminum.

 

See, this is why this is my favorite place to ask questions like this... I didn't even think about my radiator being aluminum or having aluminum in it. That wouldn't likely be a good mix with a lye solution, would it......

 

redwood,
For what it's worth.. A few years back when I was a parts guy at a Freightliner dealership, the tech's there used Cascade automatic dishwasher soap. Those Detroits, Cats & Cummins held a lot more fluid that our trucks do but the techs would drain the coolant, refill with one whole container of Cascade and the rest was water. Run the engine until hot then drain and flush/rinse with plain water. I could not believe how clean Cascade got things. I used it on my F150 once since then, inside of the radiator came as clean as it was when new.
E.

 

Hmm....cascade...interesting.

 

I ended up using the Prestone backflush kit and some Prestone radiator super flush. Got the system clean, but there's still some build up in the heater core that prevents it from heating the cab efficiently. It does the job for the time being, though.......

 

I used something that you put in and then ran for some time as the coolant. It worked great, got a lot of Bars Leaks out of my cooling system. Can't remember what it was called, but if you find something like that it works good.

I didn't drive the amount of miles it needed regularly so I left it in for a couple of days.

Mike

 

I just bought a '98 f150 and noticed that the fluid in the reservoir was orange/ brownish, and wondered why someone would have put Dexcool in it.
But when reading this, I happened to think that maybe it's just the old original coolant that has gotten badly contaminated and has a rusty color.

I need to flush it, whichever it is. It's been several years since I flushed one and I've about forgotten how.
Do you guys buy the flush kit that you cut the hose that goes to the heater core, put in a tee, hook a garden hose up to it and flush it out the radiator with the engine running? Or is it done differently these days?

Thanks

 

That's what I used on mine. I found that the cap for the Prestone kit isn't very good, so I replaced it with a brass garden hose cap so it wouldn't blow off. Otherwise, it works really well for purging all the old junk out of the system....

 

I had the Ford manual open so I looked:

They have a flushing machine: thermostat is removed and temporary fittings are installed. There is no useful info about that ("see flush machine instructions"), except to use aluminum safe VC1 flush chemical (dealer $5 - how much?) if the vehicle has green Ford coolant. It says to flush with distilled water if orange/dexcool is installed. Installed when? At the factory? By the previous owner?

The procedure also mentions the heater core is back flushed and in a separate step. Maybe a garden hose can be coupled to it. Would that be too much pressure?

I work at an import dealer and we just drain radiator, engine, then blow air through the heater core to get water out. Heater core can hold a half gallon or more even on a small car. That is a lot of old water and enough to throw the mix off.

 

Ford Motor Company Service Dealers have the best Flushing Agent that I am aware of on the Market Place. Especially since you own a Ford Diesel Truck. The heater core is obviously gone since you say it is clogged up. You will probably have to replace it with a new one. When you flush the radiator on your truck, be sure to follow the directions in your Owner's Manual and if you don't have one available, check out a repair manual for you particular Ford Truck and follow their directions. In either case, there is no quick fix since I am assuming that the entire cooling system is in need of attention. Also, make sure that you replace the thermostat with a good quality one and check all the hoses and connections for possible leaks or weak spots. Good luck!

 

Check with the Ford parts section. Ford has a good quality Cooling Systme Flush that is sure to get your cooling system (truck's) clean to a respectable level. Also, the heater core will most likely have to be replaced since it is -according to you - clogged up. My suggestion is to also replace the thermostat with a new one. Back flushing the system might help your engine cooling system also... Good Luck.

 

I have a '98 F150 4WD with the 4.6L V8. I need to drain and flush. Where are the drains? Nothing is plugged as I have always added pre-mix or made pre-mix with distilled water and anti-freeze. I perceive the color of the coolant is slightly darker so I want to get it drained and refilled as the inhibitors are probably end of life. Never drained it before.

I read above that Ford shops use a flush machine. I hope that doesn't mean there aren't drains. Anybody done this recently?

A seemingly simple job I have done many times but at this point I have found none of: radiator cap, radiator drain, block drain, heater drain. Any clues?

--Paul Franz