First I would like to say I think i have read about every cooling problem post on the forum and spent many hours search online as well...

This is a 67 Barracuda Auto... eveything stock. I will tell you first not to long before it was parked it had a head job done on it because it bent a push rod. I would guess it has less than 10k miles sense. but has sat for 15 years. Last year i got the car running, the coolant was gross... it was more brown than green anymore.

So I drained the system, pulled the thermostat, filled the system with water only.. and ran it like that for a few short trips or a couple days, than drained it again. This time I added Prestone Flush and ran that same as before. I drained the system a few more times, put in a new SuperStant 180 thermostat(I noticed this had no small hole in the housing like all other thermostats I have seen I might drill a small on when I get arround to it) and I filled the system with coolant and ensured proper levels.

That summer the car got hotter than it should a few times... nothing big but was concerning... then winter came and the heater put out heat but less than expected.... well this summer gets here it goes fine until temps start getting hi 80's driving home on the freeway(70mph) from my sisters house(about 35miles) 2/3rds the way home it starts heating up, so I pull off one of the side roads(50mph) and it cools down most the way, it really only has a problem at speeds over 50. From what I have read on cooling problems this is a sign of a clogged radiator or a missing spring the in the lower hose. And sense the heater wasn't all that warm I would assume its a clogging problem. However the lower hose on the car is one of those flex types? do these have springs in them as well? I have watched to see the flow from the water pump and it looks fine.

I took the belt off and check the water pump and it is very tight, as in no play... but spins freely...Oddly it seams my pulley is slightly warped.. I will pull one off my 77. I also have also retorqued the head down to+5 over, however I have not driven it far enough to see if it heats up yet after doing this. The coolant that was new last year is now discolored some with some brownish look.....

This is what I plan to do next.
Use my prestone back flush kit (is this as good as having a professional do it?)
Drill small hole in housing of thermostat while doing the flush.
if these fail I will pull the radiator from my 77 Volare, it is a 22in for /6 + AC it is nearly brand new, and is a 3 core.

Sorry this was so wordy wanted to get everything out. any suggestions would be great!

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Mike C
http://cuda.iclownz.com
67 - Barracuda Coupe - 225 - Automatic

I believe your thinking is correct . . . 15 years is a long time for a cooling system to sit stagnant.

The small hole in the top of thermostat allows air trapped in head to escape thus eliminating potentially dangerous hot spots in the head while waiting for the 'stat to open the first time. After that, it would make no difference on cooling performance. Drill the hole.

The rad could be suffering from both internal corrosion as well as blockage from scale which has broken loose from inside the engine since you brought the car back to life. A reflush is definitely in order before the new rad goes on.
Also consider your heater core as a source of scale and trapped crud. When hooked up correctly, coolant comes from the pump, travels thru the heater valve and then attaches to the bottom of the core with the return hose attached to the top. This helps keep sediment from collecting at the bottom of the core. Ether way, if you flush the engine and replace the rad, you still might have a crud source in the heater core. Make sure its flushed thoroughly or better yet, consider replacing it as well.

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Cheers!
Al T

I was plan on doing a direct flush on this one of the frist things...

thanx )

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Mike C
http://cuda.iclownz.com
67 - Barracuda Coupe - 225 - Automatic

I spent a lot of time tracking down an overheating problem. (This was actually the reason the previous owner sold the car.)

I had the radiator re-cored. Did a flush. New Hoses. Changed the thermostat.

It ended up being a bad heater core. I discovered this when coolant started leaking on the floorboard.

I replaced the heater core and everything worked fine.

Don’t overlook the heater core.

John

When I was having problems getting my cooling system clean (three flushes, brown coolent a month later), I took the block drain plug out and hooked up the flush kit. I also had to poke a screwdriver around to knock the crud out of the way. I put the radiator cap on loosly then turned on the water. The only way the water could go is out the drain hole, and I'll tell you, I could not believe the crap that came out! I put a petcock valve in the plugs place when I was done. Makes it easier to get all the coolent out next time you need to service the cooling system. Like Al says, flush the heater core also. I disconnected the hoses and hooked up the garden hose (with a piece of heater hose so it fit the connection) and reversed flushed it. You live in Des Moines right? Need any help or want to BS, let me know!

For blocks with lots of scale and sludge in them, you can knock-out the rear freeze plug and use that access hole to help break-up and flush-out the scale.

I have knocked-out the rear freeze plugs on some old Slants and no water would come out the hole because it was completly covered up with sludge.
DD

Im over here on the east side of the state... near tri-cities.
The block coolant plug is right near the oil filter right?

Doc, whats the best way to remove a freeze plug? and also putting it back? I assume they are not reusable?

Does the Prestone black flush kit work well enough? I believe you put a T in to the heater hose....

thanx for all the info guys.

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Mike C
http://cuda.iclownz.com
67 - Barracuda Coupe - 225 - Automatic

If you have a 3 freeze plug "early" block then it is pretty easy to R&R that rear freeze plug. It is much harder to do on the later 5 plug blocks.

The freeze plugs are "press-in" 1 5/8 size so you should get a couple of new ones from the parts store first.
To get one out, just use a piece of steel rod and knock the plug into the block, try to get it to cock sideways so you can grab an edge with plyers and pull it out.

Now that you have access to the water jacket, use a long screw driver, thick wire, etc. to stur-up and flush-out all the scale and muck. When finished, I use a big socket that fits into the cup of the new freeze plug in order to hammer it in .

As for flushing the block with a cleaner, that only skims the surface of the build-up. If you have 3+ inches of muck piled-up, flush will not cut through it all so machanically cleaning it out is the way to go.
DD

Yes, its the plug buy the filter, though Doc's method will get the crud out better. I think he means just knock the freeze plug out and pound a new one in when your done. The Prestone kit is what I use when I flush out my system. When I fill the radiator, I leave the cap on the T fitting loose to let the air escape, that way no pockets in the block or head.

I agree with what has been suggested so far. I would further add that 'rodding out the radiator', by a professional, might also be necessary.

I had a similar experience with my sl/6, that was solved when I swapped in a rebuilt (and resurfaced) head.

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'66 Cuda 225/4spd
'66 Dart GT convertible 225/auto
'64 Dart GT 340/4spd

I once had an old lady that used to bring me her '73 Dodge Van with an old Turtle top on it, 318 powered, for every new squeak or rattle. She had bought it from the wife of a neighbor that had passed, and the van had been sitting for a looong time, several years, before she bought it. During the while that I worked on this van (seemed like I ws married to it, she would call me for EVERYTHING!) I replaced every single cooling system component, including freeze plugs. I remember it having the green to rusty brown in no time problem, too. Shortly after I had put in a brand new radiator and water pump, she called to say that the van was leaving a green spot in the driveway again, but in a different place under the van. I had flushed this thing out 3, maybe 4 times by now, over about 8 months or so. The back freeze plug behind the starter had rusted thru, and wasn't seeping, wasn't pouring out, kinda in between. I popped the plug out, and, I'll tell you, I have never seen so much scale and crap in a block! even with the freeze plug out, it just trickled out thru all the crud. I ended up popping all the freeze plugs out of the block that I could reach while laying on my back without pulling the engine, and then ran a screwdriver into the block thru all the freeze plug holes. I put it all back together, pulled the block drain, and ran a ton of water thru AGAIN. I then ran the engine til warmed up with a product called Iron Out in it and straight water and flushed it, repeated this 3 more times over that weekend, and then put the 50/50 back in it, and finally, no more cooling system problems. Ms. Price has since died, but that van was STILL running around last fall, 5+ years later. It sounds like a pain, but if your car sat 15 years, you may be in for this kind of a treat.

Mike C,
You can use a large flat punch, or maybe something like a smaller nut driver, to remove your freeze plug. Don't hit it dead center, but rather off to one edge. If you're lucky, it will pivot around like a door swinging open, then just grip it with pliers and pull it out. If it happens to fall into the block, don't worry, just have a long pair of needle nose pliers on hand.

Jerry

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There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

having just rebuilt my /6 and seeing the accumalation of crude in the block i would like to keep it in as clean of a state as possible. now to the question.
Has anyone ever used a zinc in their radiator and had or noticed good results? I noticed most water heators use zinc metal suspended in the tank to collect the minerals in the water. I was wondering how this would work in the radiator.

Having revived a 15 year dormant slant myself can attest to the slug and rust build up by a owner who didn't believe in anti freeze. Had to knock plug as Doc stated, but have discoverd the flushing kits not to be not up to task for even routine maintance. Took "Mircle Grown" garden applicator and plumbed into heater hose and flushed for 5 hours with "tri-sodium-phosphate (TSP) from a paint store not the common supermarket brand. This is the second vehicle I have serviced in this manner and it works for me. Matter of habbit I replace all hoses and belts at this time also.

Dave,
Are you saying you leave the water hose running 5 hours with the TSP loaded into the spray attachment? What does TSP do for the radiator?

Jerry

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.