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Cooling issues - and a weird question

moparedtn

moparedtn

I got your Staff Member riiiight heeeere...
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Those that have followed along as I resuscitate a former field find '68 GTX know the particulars, but in a nutshell:
'68 GTX, rebuilt '72 440 mild with purpleshaft 484 cam, headers, Edelbrock 1407. 4 speed, 3.55 gears. The car has been repaired/replaced/rewired stem to stern, mostly by me.
Six years plus into this, zero professional resto. :)
It's had more than one motor in it, this latest being bought with about 1,000 miles on it since the rebuild. Engine feels and sounds pretty darn good, just needs some fine tuning.
Got the carb pretty close, timing is in the neighborhood, dialing in on best vacuum. You can tell the engine has some grunt to it.
The car came with a 22" radiator support from the factory. It's manual brakes & steering. No a/c.
I put a new aftermarket generic 26" 3-core brass radiator in it some time ago; it has the clutch and 7-blade fan, along with a cobbled in shroud.

It all works and it's now roadworthy - but...

Last Friday evening, we took it out for its' first semi-long drive. Temps were in the low 80's.
As it went along at about 65mph, the temp climbed to a point that made me uncomfortable.
When we stopped to get some dinner, it barfed a little coolant out and the mechanical gauge wildly jumped up past 230.
(Background: the car has seen plenty of idling in the garage for extended periods, where it already got its' "seeks its' own level" out of its' system, I thought).
We ate, then headed for home. Same deal, the car getting hotter as we went and proceeding to run crappier as a result.
By the time I pulled it into the garage and grabbed a pan to throw under it, it puked bigtime, making all sorts of scary gurgling sounds as it expelled more coolant into the pan.

With previous engines, the cooling has been borderline ok (hot, but not puking hot). Now, finally with what I think is a good engine, it's apparently more than the cooling can bear.
I've decided to trash the whole cooling system - yeah, I know, but I'm this damn close to being done here.
I want overkill. I want the thing to struggle to make 180F. I want the total peace of mind that says it can't overheat - ever.

I've already decided to open up the radiator support to approximately the 26" dimensions.
Other than that, the whole mess gets replaced.
Please, PLEASE don't tell me to use what Ma designed for it - it isn't what she built, after all, not even close - and to be honest, I've already been that route.
Remember - overkill.

Oh, the oddball question?
I have removed both heater hose nipples from the water pump housing and plugged those threaded outlets. Can this be causing a cavitation or trapping of air? Should I rig a small loop between them?

Looking to finish this project off now, guys. My time is very limited and I just want it done before it becomes someone elses' problem.
Thanks! :)
 
moparedtn said:
Those that have followed along as I resuscitate a former field find '68 GTX know the particulars, but in a nutshell:
'68 GTX, rebuilt '72 440 mild with purpleshaft 484 cam, headers, Edelbrock 1407. 4 speed, 3.55 gears. The car has been repaired/replaced/rewired stem to stern, mostly by me.
Six years plus into this, zero professional resto. :)
It's had more than one motor in it, this latest being bought with about 1,000 miles on it since the rebuild. Engine feels and sounds pretty darn good, just needs some fine tuning.
Got the carb pretty close, timing is in the neighborhood, dialing in on best vacuum. You can tell the engine has some grunt to it.
The car came with a 22" radiator support from the factory. It's manual brakes & steering. No a/c.
I put a new aftermarket generic 26" 3-core brass radiator in it some time ago; it has the clutch and 7-blade fan, along with a cobbled in shroud.

It all works and it's now roadworthy - but...

Last Friday evening, we took it out for its' first semi-long drive. Temps were in the low 80's.
As it went along at about 65mph, the temp climbed to a point that made me uncomfortable.
When we stopped to get some dinner, it barfed a little coolant out and the mechanical gauge wildly jumped up past 230.
(Background: the car has seen plenty of idling in the garage for extended periods, where it already got its' "seeks its' own level" out of its' system, I thought).
We ate, then headed for home. Same deal, the car getting hotter as we went and proceeding to run crappier as a result.
By the time I pulled it into the garage and grabbed a pan to throw under it, it puked bigtime, making all sorts of scary gurgling sounds as it expelled more coolant into the pan.

With previous engines, the cooling has been borderline ok (hot, but not puking hot). Now, finally with what I think is a good engine, it's apparently more than the cooling can bear.
I've decided to trash the whole cooling system - yeah, I know, but I'm this damn close to being done here.
I want overkill. I want the thing to struggle to make 180F. I want the total peace of mind that says it can't overheat - ever.

I've already decided to open up the radiator support to approximately the 26" dimensions.
Other than that, the whole mess gets replaced.
Please, PLEASE don't tell me to use what Ma designed for it - it isn't what she built, after all, not even close - and to be honest, I've already been that route.
Remember - overkill.

Oh, the oddball question?
I have removed both heater hose nipples from the water pump housing and plugged those threaded outlets. Can this be causing a cavitation or trapping of air? Should I rig a small loop between them?

Looking to finish this project off now, guys. My time is very limited and I just want it done before it becomes someone elses' problem.
Thanks! :)
Click to expand...
I have had my heater hose outlets in the water pump , plugged for a long time. No problem ..............................MO
 
I'd change the t-stat & see if that works. A new cap would be good too. The 26" radiator with the smaller opening should still work OK. The plugged heater hose ports are no problem.
 
66Satellite47 said:
I'd change the t-stat & see if that works. A new cap would be good too. The 26" radiator with the smaller opening should still work OK. The plugged heater hose ports are no problem.
Click to expand...
Spring in the bottom hose to keep it from collapsing ? heat coming from around the radiator from the engine bay , because of rad to core support seal gone? running a hood scoop w/o being sealed to the hood-causeing reverse air flow/ (buddies truck did that !) Thermostat?
 
Banzaiii67 said:
Sounds like a stuck thermostat or a bad radiator cap not pressurized. What was coolant to water ratio?
Click to expand...
Both are/were new and they worked, verified. 50/50 on the mix.
 
66Satellite47 said:
I'd change the t-stat & see if that works. A new cap would be good too. The 26" radiator with the smaller opening should still work OK. The plugged heater hose ports are no problem.
Click to expand...
New (SuperStat 180) and new lever type Stant cap.
Thanks!
 
not so famous bob said:
Spring in the bottom hose to keep it from collapsing ? heat coming from around the radiator from the engine bay , because of rad to core support seal gone? running a hood scoop w/o being sealed to the hood-causeing reverse air flow/ (buddies truck did that !) Thermostat?
Click to expand...
I would LOVE to find one of those springs, did some time searching for one to no avail. I remember watching an episode of Engine Masters and the engine they were dyno-ing would suck the lower hose shut every time they did a pull!
True enough on seals - none presently.
No scoops on the hood, though. Stockity stock. :)
Thanks!
 
Ok guys, again I'm past trying to remedy what I had in the car. It's all removed now.
Starting from scratch - heck, even the water pump is suspect at this point.
I want suggestions on how to put together an overkill cooling system (other than buying one of those $1000 plus radiators, of course).
Milodon high flow pump and stat?
Aluminum radiator with two 1.5" cores?
Will my clutch fan and 7 blade be enough or do I go electric?
etc.
 
I know you said not to quote what Ma Mopar did, but please bear with me: My 70 Road Runner had added fuel injection and A/C to strain the system. I had Glen-Ray recore the original radiator with a 4 row (if I remember correctly). Then I installed the "stock" system back into my car. Even with 95+ degree and with the A/C running in stop and go traffic, I have never had an issue.

I have learned over the years that a cooling system is more than a radiator, water pump and thermostat. The fan shroud plays an essential part of keeping a car cool, as does the fan size, distance from the radiator, clutch, etc. You might want to check all this.

The one thing that struck me is this seems to be happening at speed, when usually there are fewer problems. Do you run a fan clutch? Maybe the fan is continuing to push air forward while air is rushing in through the radiator at speed?

Maybe something here helps. Good luck diagnosing and addressing the issue.

Hawk
 
hsorman said:
I know you said not to quote what Ma Mopar did, but please bear with me: My 70 Road Runner had added fuel injection and A/C to strain the system. I had Glen-Ray recore the original radiator with a 4 row (if I remember correctly). Then I installed the "stock" system back into my car. Even with 95+ degree and with the A/C running in stop and go traffic, I have never had an issue.

I have learned over the years that a cooling system is more than a radiator, water pump and thermostat. The fan shroud plays an essential part of keeping a car cool, as does the fan size, distance from the radiator, clutch, etc. You might want to check all this.

The one thing that struck me is this seems to be happening at speed, when usually there are fewer problems. Do you run a fan clutch? Maybe the fan is continuing to push air forward while air is rushing in through the radiator at speed?

Maybe something here helps. Good luck diagnosing and addressing the issue.

Hawk
Click to expand...
The factory mechanical fan doesn't push, it pulls. That is unless it's installed backwards......
 
If it's not cooling at 65 MPH you should be moving plenty of air through the radiator. Could be the radiator isn't transferring enough heat. Water cools better than antifreeze so you could flush the cooling system and run just water with 2 bottles of water wetter or a similar product. I saw a demo where this product was added and it dropped the cooling system temp by 15 degrees. Here is another option. http://www.evapo-rust.com/ They make a radiator flush you could try. On the flip side if you aren't cooling at idle look at the shroud and fan.
As a lower hose collapse test you could get it warmed up and watch the lower hose while an assistant brings the RPM's up to 2500.
Just a few alternatives to try, I know cooling system problems can be irritating. Good luck.
 
These guys are firing on all cylinders and what everyone is saying are good things to check. You "might" also have a cooling system plugged in the block/heads. And I HOPE I'm wrong, but you might check for an occasional big bubble in the radiator while running to make sure you didn't blow a head gasket (make the engine really hot). Like these guys have mentioned, lower hose spring, cap, thermostat, fan shroud, radiator/body seals & 50/50 mix (or better yet, water + water-wetter) and maybe give it a really good cooling system flush & check your fan clutch....maybe take a peek at your water pump (inside) to make sure the impellers aren't corroded away. Opening up the radiator core support should also help on the highway.

Now, if you are bound and determined to change the radiator....then your 2-core 1-1/2" tube radiator idea is a very, very good one. Just make sure you have a good fan shroud & seal it along the radiator core support...... and check all these other things too, maybe even remove the thermostat. I've had more than one "brand new" part be bad, so don't assume your new cap/thermostat are OK because they're new.
 
https://www.summitracing.com/parts/...86GmytEqQnW_PQLkSgIiyWeIx8ADDGPqjjBoCudnw_wcB


Spring in the lower hose is a must! at high speed romps the hose may collapse when the pumps tries to suck in more water than the hose can handle. Get stainles so it wont rust out too fast.

26" radiator a must, fan shroud a must, you need a fan that will pull in 2500 to 4000 cfm and there is a sponsor here at this site that sells good radiators for a good price ECS call them or Griffin radiators. No bypassing the heater will not have any effect. Sounds to me like others said the stat is crap. Do a total flush of the motor, I will bet you have iron chunks clogging passages. pull the side plugs on the block and flush out with cold water with higher pressure. get as much of the iron flake out of there and after its all back together get a good magnet put it on a string or wire and run it through the top tank every so often to get the rest of the loose iron out. when you get a new aluminum rad make sure it has 1" or bigger tubes 2 rows of 1" tubes are common but if you can get and fit 1-1/2" then even better.

To help your own sanity in your case you may want to get one of of those see through fittings at the stat neck so you can see if its working. Make sure you coolant mix is 60% softener water and 40% additive like royal purple or lucas or redline water wetter. it's summertime you don't need antifreeze! and remeber these additives break down in 6 months so twice a year re do the coolant like a normal service.

 
moparedtn said:
Ok guys, again I'm past trying to remedy what I had in the car. It's all removed now.
Starting from scratch - heck, even the water pump is suspect at this point.
I want suggestions on how to put together an overkill cooling system (other than buying one of those $1000 plus radiators, of course).
Milodon high flow pump and stat?
Aluminum radiator with two 1.5" cores?
Will my clutch fan and 7 blade be enough or do I go electric?
etc.
Click to expand...
put a regular stat in it, 185 and try it!
 
I have to say don't use "softener water" since water is "sofetened" with SALT, the same sodium chloride that they throw on the roads.
 
PurpleBeeper said:
I have to say don't use "softener water" since water is "sofetened" with SALT, the same sodium chloride that they throw on the roads.
Click to expand...
PB is right about softened water. I go to the store and buy distilled water, no minerals.
I had a clutch fan go bad it wasn't pulling air. It was turning but not moving a lot of air. Rev'd the engine and put hand behind the fan hardly a breeze.
 
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