My 65 Delta 88 was off the road from 1999 until 2008. I have driven it a few times and decided to flush the cooling system.

Which is better: "acid-type" flush or Prestone cooling system flush?

How long should the "flush" stay in? Most cans state to run for 15 minutes, then drain. Any problems if kept in for a few days?

 

I never used a asid or something.

I always drained it an took the radiator out and flusched it with water, cleaned an inspected the coolingvalve.

So i don't know

never had any problems, just looked now and than at the coolant
and changed it when it seems to change collor and if i saw dirt

 

I have always used the prestone way - the heavy duty cleaner. Follow directions and I think you use 2 bottles in the Olds. Drive for 4-6 hours cumulative, drain, and rinse well. Pop the block drain plugs and flush with a hose from all directions, t-stat out.

 

Just finished doing mine and did the same as Rob. The one I used said to drive at least 300 miles ( not all in one day). Seemed to do a good job. When I drained it I added the garden hose to it and really flushed it out good..... then added my prestone mixture.

 

I use distilled water, anti-freeze, and a product called No Rosion.

It has kept my aluminum radiator spotless for the past 4 years.

 

That seemed to be how far I drove mine in the 5 hours I drove.


Just do not confuse the prestone flush with the heavy duty cleaner.
Same chemicals in both (sodium citrate - a food additive ), but the concentration is higher in the cleaner, and the directions are different.

The flush says to use 1-2 bottles and run 10 minutes and drain. That will not do much. I used 3 bottles of the flush in my Ford because I could not find the cleaner. I drove for about 200 miles - worked well. That stuff was black when i drained it, and the system looked pretty clean to start with!

 

where are the block drain plugs

 

I've used the Prestone product as well. It works pretty good.

 

If you have them, they would be hex-headed plugs, one on each side of the block a couple inches above the oil pan flange. Usually they will be hidden under a load of caked on grunge...

 

This is exactly what I needed to hear.

Thanks Lady72nRob71

 

I plan on using distilled water after the flush.

 

Don't forget the coolant, too.

Glad I could help.

 

Prestone is acidic, too.
ANYTHING with an acidic base to it will accelerate any freeze plug rot you may already have.
Learned the hard way.
Lost 2 plugs on a Jeep 4.0, couple years after the flushing. They were rotted from the inside out. This always had antifreeze in it, and was in the family since it was brand new. I replaced, and painted the inside surface of the new freeze plugs. Also had to do a valve job, and head gasket. This Jeep is gonna go 300K if I have any say on it.
Jim

 

Does anyone else think that using Prestone Cleaner might cause more problems than benefits? Would it be unwise to use it for 300 - 600 miles when the weather is in the 90's?

 

You are taking your chances any time you use any flush chemicals in your engine. They are corrosive and will dislodge all the crap that has built up over the years. If you have neglected your car for years they will certainly find all the weak spots for you.

I can't remember the brand we use at work for flushing out cooling systems but it has a flushing agent and a neutralizer that you run through the system after the flush. I personally don't trust flushing it out with a hose since you can never be sure you flushed out all the coolant passageways and any leftover flushing agent can cause problems later on..

 

Anytime I do a coolant flush I just open all the drain plugs, let it drain, cram a garden hose in the radiator and douche thoroughly. When all the crap stops coming out fire it up and run it a few minutes. Put the plugs back in, top it off with coolant and you're good to go. I've never had any problems on any of the vehicles I've flushed this way. It's definitely not as good as using a chemical agent to get rid of every last bit of crud, but it works pretty well and it's cheap (I'm dutch). I would recommend hooking the garden hose up to one of the heater hoses as well and douching the heater box. All kinds of fun stuff comes out when you do that.

 

Many years ago I was told not to use Prestone to flush my block, this was by a radiator shop that was owned by a long time friend. I removed the plugs, flushed w/water and refilled with distilled water and anti freeze.

 

Anyone have ideas on a neutralizing agent?

 

Don't forget to throw your Heater ON "Full Blast" too -- gets the entire system opened up + flowing out crud! I'd never leave those flushing agents in too long...20-30 Mins top after adding & running is plenty! I always add a tube of "Aluma-Seal" after those flushes too; JUST IN CASE and to ensure you plug up any pin holes/leaks in the system. (GM's been doing this at the Factory for years on our cars when they're brand new!) Good luck. (Don't use any of these new "LONG Life" Orange Coolants in the older cars either...they don't mix w/ the older systems...)