[staleg]

My engine is in need for a cooling system flush. Chevy small block, 1st gen 1992 model
If I remove the water pump, and opnes up the low located plugs on each side of the block, can it be a good idea to simply flush the block by using a garden hose in each of the water pump channel holes at the front of the block?
I do have a high pressure washer as well, but that might be to much?

 

[bigmac73]

I remember prestone used to.sell a home flushing kit to include fittings and a cleaner . U might try looking for that.
I would just recirc a bottle of CLR or citric acid or vinegar throught the system and then drain

 

[75gmck25]

The old flush kits installed a garden hose T in one of the heater hoses. I think you just opened the radiator cap and let the engine run with fresh water coming in from the garden hose. However, unless you also took out the thermostat you probably didn’t have flow through the entire system.

Opening up the block drains and removing the thermostat to help flow usually works fine for the flushing action, but unless you break up the corrosion you might have a lot of rusty gunk left over. I’ve never tried using CLR, but I think it should help.

 

[wave1957]

Using just water will not be an efficient clean of the system, you need first to run a product that will remove gunk or corrosion. I would not know what to recommend in Europe.

 

[39 master]

Back when...used Cascade dish washer soap to clean the cooling system. Add the Cascade, run the engine until up to temp and thermostat opens. After a while of running to clean the system shut it down, let it cool and drain the system. Add water and run again to flush. Might have to do this several times until the water comes out clear. Once it comes clear, drain the system again and add anti-freeze.

 

[57Nomad]

Make sure to flush out all garden hose water with distilled water. Tap water has chlorine, fluorine, and other minerals not especially good for cooling system. Maybe a flush that they use for boats would also do the job.

 

[johnsongrass1]

How much are you trying to clean?
The easy way is pull the block drains and stick a garden hose on low pressure into the radiator and run it for 15 minutes.
Another way is pull the block drains and reinstall them, add 2 gallons apple cider vinegar and run it 15 minutes, let it sit for 24 hours and flush like above.

Any of the system cooling stuff on the shelf is some sort of mild acid. Apple Cider is acidic and much less expensive and won't harm you or pets.

Another way is Muratic acid and water. This will strip it all! but beware it can also be hard on aluminum parts. Flush well after.

 

[curtis73]

I pull the drains and the thermostat then pull the heater core hose off the manifold. Stuff the hose in the heater hose so it backflushes the core and feeds backwards into the engine. Put it back together minus the stat and fill with water and a bottle of flush stuff and run it for a while. Sometimes an hour, sometimes a couple days, whatever. Drain and flush again.

I don't worry about distilled water anymore. Tap water has junk in it that can increase electrolysis, but distilled water has far more solubility and can dissolve things faster. The general consensus is that tap water erodes metal stuff faster and distilled water dissolves gaskets faster, but I've not seen compelling evidence that one is specifically better than the other.

 

[2old2fast]

I am a very low maintenance type ! I think we waste a lot of time & money on unnecessary tasks . Example , I have a 1984 GMC 3500 crew dually , it's my camper truck , it has 135k miles , original everything , water pump was replaced 8or10 years ago , that's the only time its been " flushed " . 50/50 tap water & green on sale antifreeze is all that's ever been in it . The only " maintenance " addition is installing an anode when I think of it . That's 37 years , no leaks , no problems , how many even keep a vehicle that long ?

 

[WABOOM]

You can still buy the Prestone garden hose kit at Walmart.

 

[cozwurth]

I lost an engine to one of those stupid prestone flushing tees. Cap broke, all coolant dumped out on the highway, gauge never moved. Car started slowing down, then started knocking, then died. Done deal, blown head gaskets minimum. Never tore it down, just pulled it and replaced it. Your mileage may vary...

For flushing, I have seen people use CLR to flush a heater core before. CLR/water mix in a 5 gal bucket, drill pump and a couple of pieces of heater hose. Suction out of the bucket, through core, then back into bucket. Ran the pump in both directions. I guess it would work in a running engine, but I think I'd remove the thermostat.

 

[eric32]

Here is one method that I have seen on youtube and it seems to work well and I can't say I have done it but I have saved the video in case I have to do it in my future. Some of the other methods above seems to be pretty good as well.