Write-Up: Flushing Radiator Coolant

Albert I used to get those tabs for free from a GM tech I knew.
But I was never the type to use additives unless I knew if they were really worth it or if I only needed something for a temporary fix or to seal some system until I could get around to fixing it properly.

So I stopped using the tabs due to the discoloration on my clean plastic overflow bottle and threw the rest away.

What did I know. Never knew the chemical make-up of those tabs and even if I did I probably wouldn't have known what positive or negative effect it had to the cooling system.

Right. They buffer and adjust the pH of the coolant as well as plug leaks sort of. The sealing tabs are what causes the sludgy appearance and 'bathtub ring' in the overflow bottle. Ignore the ring.

What I was told was that GM's casting process for the blocks left porosity sometimes that could reach the water jacket. The tabs are *perfect* for sealing those without screwing up anything else. Also, they tend to make water pump seals last longer for various reasons.

Were we talking about changing from orange to pink dexcool at some point?  Mine looks pink in the reservoir, but I've seen people say the orange looks pink in the reservoir.  Pink didn't come out till mid 2000's or so, right?  I can't remember what I did on my last change, but I don't think I would have put pink in unless it was recommended as an upgrade here on the forum.

JR,
When was the last time you changed your coolant and flushed the system completely clean before putting in new coolant.?

I know you don't put many miles on your Riv per year but my feeling on that is if a solution sits too long it should be flushed periodically. So, they say every 5 years for Dex-cool anti-freeze. I would do a complete flush every 5 years at least. I don't know why, but I did a complete flush with the thermostat out as I've mentioned before and then when the Prestone Cleaner had done its job I flushed the complete system, engine block and radiator with fresh water from my garden hose.
When the system was empty, I then put in Green Anti-Freeze and distilled water. 50/50.
Prior to owning the Riv I would have never used distilled water but that was what was recommended on this forum.
I used Prestone Green anti-freeze due to stories about how Dex-Cool effected the intake gaskets. Particularly the usual spot on the passenger side rear intake to head. Very common leak spot for N/A and SC engines
Had seen that leak so many times on other 3800's that I chose to believe what was being published and would flush the system every 2 years after that. May have been for nothing other than my piece of mind. That was after I replaced the LIM gaskets just because. Wanted to catch that problem before it happened on my car.
But back then I could do the work. Bend over to remove thermostat and such as well as lay under the car and open the petcock. Seems like simple things, don't it.
Those were and are simple things, but I am no longer able to them. So, if my back was as bad as it is now I would probably just flush the system every 5 years and put a new thermostat in and fill with Dex-Cool.

Which reminds me, when it isn't so damn hot and humid I should probably attempt to do the Chevy P/U this summer as I don't know how old this fluid is. Along with the Transfer case, front end, rear end and drop the trans pan and replace the gasket and filter. I have looked at all the fluids mentioned and they are clean and have no smell of being overworked and neglected. Whoever had it before me took care of it like I would do. But I want to start from scratch so I can zero time everything and know where I stand.

This truck doesn't have a radiator cap at all, just a hose that runs to the overflow tank. It will be a challenge to flush things as I like to do.
Rick

Rickw wrote:

JR,
When was the last time you changed your coolant and flushed the system completely clean before putting in new coolant.?

I know you don't put many miles on your Riv per year but my feeling on that is if a solution sits too long it should be flushed periodically. So, they say every 5 years for Dex-cool anti-freeze. I would do a complete flush every 5 years at least. I don't know why, but I did a complete flush with the thermostat out as I've mentioned before and then when the Prestone Cleaner had done its job I flushed the complete system, engine block and radiator with fresh water from my garden hose.

How are you getting all the garden hose water out?

Jack the R wrote:

Rickw wrote:

JR,
When was the last time you changed your coolant and flushed the system completely clean before putting in new coolant.?

I know you don't put many miles on your Riv per year but my feeling on that is if a solution sits too long it should be flushed periodically. So, they say every 5 years for Dex-cool anti-freeze. I would do a complete flush every 5 years at least. I don't know why, but I did a complete flush with the thermostat out as I've mentioned before and then when the Prestone Cleaner had done its job I flushed the complete system, engine block and radiator with fresh water from my garden hose.

How are you getting all the garden hose water out?

Remove either end of the lower radiator hose and the crankcase will dump whatever is in there. Also loosen the radiator petcock and just let it all drain out on the driveway.

Rickw wrote:

JR,
When was the last time you changed your coolant and flushed the system completely clean before putting in new coolant.?

I know you don't put many miles on your Riv per year but my feeling on that is if a solution sits too long it should be flushed periodically. So, they say every 5 years for Dex-cool anti-freeze. I would do a complete flush every 5 years at least. I don't know why, but I did a complete flush with the thermostat out as I've mentioned before and then when the Prestone Cleaner had done its job I flushed the complete system, engine block and radiator with fresh water from my garden hose.
When the system was empty, I then put in Green Anti-Freeze and distilled water. 50/50.
Prior to owning the Riv I would have never used distilled water but that was what was recommended on this forum.
I used Prestone Green anti-freeze due to stories about how Dex-Cool effected the intake gaskets. Particularly the usual spot on the passenger side rear intake to head. Very common leak spot for N/A and SC engines
Had seen that leak so many times on other 3800's that I chose to believe what was being published and would flush the system every 2 years after that. May have been for nothing other than my piece of mind. That was after I replaced the LIM gaskets just because. Wanted to catch that problem before it happened on my car.
But back then I could do the work. Bend over to remove thermostat and such as well as lay under the car and open the petcock. Seems like simple things, don't it.
Those were and are simple things, but I am no longer able to them. So, if my back was as bad as it is now I would probably just flush the system every 5 years and put a new thermostat in and fill with Dex-Cool.

Which reminds me, when it isn't so damn hot and humid I should probably attempt to do the Chevy P/U this summer as I don't know how old this fluid is. Along with the Transfer case, front end, rear end and drop the trans pan and replace the gasket and filter. I have looked at all the fluids mentioned and they are clean and have no smell of being overworked and neglected. Whoever had it before me took care of it like I would do. But I want to start from scratch so I can zero time everything and know where I stand.

This truck doesn't have a radiator cap at all, just a hose that runs to the overflow tank. It will be a challenge to flush things as I like to do.
Rick

...if you can find one, you can do a good flush by installing a kit that splices standard hose fittings into the radiator hoses. See https://www.amazon.com/Prestone-AF-KIT-Flush-Fill-Kit/dp/B000CCFY5W/. If you don't like the plastic fittings you may be able to get brass ones from full line hardware or plumbing supply store, basically a couple of inline tee adapters for the 5/8" or what have you rubber hose with a 3/4" garden hose (GHT) or compatible fitting. In my experience the plastic ones work fine. Problem in the Riv is fitting them on the heater hoses, it's tight back there.

albertj wrote:

...if you can find one, you can do a good flush by installing a kit that splices standard hose fittings into the radiator hoses.  See https://www.amazon.com/Prestone-AF-KIT-Flush-Fill-Kit/dp/B000CCFY5W/.  If you don't like the plastic fittings you may be able to get brass ones from full line hardware or plumbing supply store, basically a couple of inline tee adapters for the 5/8" or what have you rubber hose with a 3/4" garden hose (GHT)  or compatible fitting. In my experience the plastic ones work fine.  Problem in the Riv is fitting them on the heater hoses, it's tight back there.

Wal-Mart has the flush kit. I've got one hanging up in my garage, it was meant for the Charger but maybe the Riv will get this one instead. I never knew what the flush kit was for when I was younger. I had to find out when it crumbled apart in my hands. It may have taken 30 or 40 years, or more, for the plastic to decay though.

Jack the R wrote:

Rickw wrote:

JR,
When was the last time you changed your coolant and flushed the system completely clean before putting in new coolant.?

I know you don't put many miles on your Riv per year but my feeling on that is if a solution sits too long it should be flushed periodically. So, they say every 5 years for Dex-cool anti-freeze. I would do a complete flush every 5 years at least. I don't know why, but I did a complete flush with the thermostat out as I've mentioned before and then when the Prestone Cleaner had done its job I flushed the complete system, engine block and radiator with fresh water from my garden hose.

How are you getting all the garden hose water out?

Drain it all either thru lower rad hose or the rad drain petcock. Get a gallon of antifreeze and mix it with distilled water, or dehumidifier condensate, 50/50. Use the mix to fill the system, top it off while burping the air from the little bung on top of the thermostat housing.

JR,
I also made sure that I had the temp control set to full hot when I flushed it out so the control valve would be open to flush the heater core as well.

Albert,
Wouldn't ever want to disagree with you but I wouldn't try installing one of those plastic Prestone flushing connectors into the heater hose on the Riviera.
Don't like the plastic deteriorating and cracking over time and I don't think it's necessary if the system is flushed the way I proposed above.

JR, with the lower radiator hose disconnected from the radiator and the petcock open you will get almost all the garden hose water out.
I never used to use distilled water on any cast iron block I ever owned anyway, until I read it on this forum. Even then, I think I just used the clean tap water we have here in this neighborhood the last time I flushed it. It will be fine. Unless of course you have small guppy's floating around in your tap water. Then use distilled.
When I lived down south if you put tap water in a glass and let it sit for a while you would have sediment in the bottom of the glass. If that's the case where you live then by all means use bottled water.
I'm lucky. We have perfectly good filtered and treated water in this area. No residue in a glass left overnight, I drink it all the time.
.

Rickw wrote:

JR,
I also made sure that I had the temp control set to full hot when I flushed it out so the control valve would be open to flush the heater core as well.

Albert,
Wouldn't ever want to disagree with you but I wouldn't try installing one of those plastic Prestone flushing connectors into the heater hose on the Riviera.
Don't like the plastic deteriorating and cracking over time and I don't think it's necessary if the system is flushed the way I proposed above.

JR, with the lower radiator hose disconnected from the radiator and the petcock open you will get almost all the garden hose water out.
I never used to use distilled water on any cast iron block I ever owned anyway, until I read it on this forum. Even then, I think I just used the clean tap water we have here in this neighborhood the last time I flushed it. It will be fine. Unless of course you have small guppy's floating around in your tap water. Then use distilled.
When I lived down south if you put tap water in a glass and let it sit for a while you would have sediment in the bottom of the glass. If that's the case where you live then by all means use bottled water.
I'm lucky. We have perfectly good filtered and treated water in this area. No residue in a glass left overnight, I drink it all the time.
.

I think you're right, Rick. What'd work is getting the equivalent brass fittings and installing them instead. The Prestone plastic would last a long time, never had one of them fail -- BUT -- when I replaced the heater hoses on my Riv I admit I did not bother splicing new flush fittings in.

As for water, I've used dehumidifier condensate with stellar results.

Albertj

I would assume that just like the 90* plastic fittings that are installed in the intake manifold, the plastic fitting that could be installed in the INLET heater hose will work.

The plastic 90* fittings are prone to failure after a long period of time. Whether it be miles or old age.

So I believe you agree if your going to go through all the labor of replacing the 2 plastic 90* fittings it's worth replacing them with the metal ones that are available and aren't expensive.

If there is no need to determine which side is the inlet side of the heater core and cut the hose to install a plastic fitting to enable flushing the heater core with minimal clearance, then i think you'd agree to just leave the heater hoses alone and flush the system a different way.

OH, By the way, I have both heater hoses (new) not NOS that I am willing to part with.

I would like a few bucks, or at least the cost of shipping. Hey Albert, what say you. Is shipping cost worth something for free.
Rick

Rickw wrote:

I would assume that just like the 90* plastic fittings that are installed in the intake manifold, the plastic fitting that could be installed in the INLET heater hose will work.

The plastic 90* fittings are prone to failure after a long period of time. Whether it be miles or old age.

So I believe you agree if your going to go through all the labor of replacing the 2 plastic 90* fittings it's worth replacing them with the metal ones that are available and aren't expensive.

If there is no need to determine which side is the inlet side of the heater core and cut the hose to install a plastic fitting to enable flushing the heater core with minimal clearance, then i think you'd agree to just leave the heater hoses alone and flush the system a different way.

OH, By the way, I have both heater hoses (new) not NOS that I am willing to part with.

I would like a few bucks, or at least the cost of shipping. Hey Albert, what say you. Is shipping cost worth something for free.
Rick

A modest charge is appropriate. No such thing as 'free.'

Did anyone ever change the heater hoses from above? I tried reaching in from the driver's side and couldn't get my arm in far enough.

Jack the R wrote:

Did anyone ever change the heater hoses from above?  I tried reaching in from the driver's side and couldn't get my arm in far enough.  

Consider using a box knife, cutting (a long-ways slit) the hose on the firewall nipple, then peeling it off.

You guys made the heater hose job harder than it had to be.  This is all you need to get the hoses off -



This came in a pack of four, and cost less than $5 at Wal-Mart.  The other probes have their uses too, but the 90 deg tip is the one for this job.  Even though the hose butts up against the firewall, you can slip this under it and work it around about half the hose.  That's enough to be able to twist the hose off by hand.

The only problem I had was with the driver's side clamp.  It was almost impossible to see, and one of the tabs kept working its way up against the other pipe.  That was some first class b.s. right there.  I had to take my needle nose pliers and work the clamp around just enough to get the regular pliers back on it.  The hose clamp pliers were way to big for that area.  In the end I randomly managed to grab onto that clamp and pull it off the nipple.  That part of the job is genuinely hard.  A cable clamp might make it easy, if you can get the head into place. It might be too big or awkward to use.

Anyway, I'm also replacing the rear tensioner.  Where does the metal elbow on the left go?

Still haven't figured out where that left metal elbow goes.  Best guess is that it's for the NA engine, but it would be strange to have the NA and SC elbows packaged together.  

Nevermind, figured out it's for the Gran Prix.

Incidentally, shop vacs are good for sucking coolant out of the engine, if you've got the water pump or the accessory tensioner off.  Just be sure to change to the wet filter first.

JR,
Can't remember if I asked you already or not; Do you need New heater hoses for your car.? If you do I have the pair I can send you.
Let me know.
Rick

I still had the pair I purchased with the radiator hoses. They're on the car now.