Does anyone think it is the radiator besides me?

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williaml

williaml

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Ringwood NJ
History:
I bought a 65 dart in March, when I purchased the car it had a 68 engine in it. The guy I bought it from said the 65 engine ran but overheated so I put the 68 engine in it. I took the 65 engine to be re-built. So I have a re-built engine, with new water pump a new thermostat and all new hoses. I thought it was running a little hot around town so I had the radiator cleaned up and tested. I also discovered I had put wrong temperature thermostat in the car. I changed the 195 to the correct 180 and all was fine so I thought. Drove out to Carlisle for Chrysler in Carlisle and the car in the am ran a little warm but on the way home it was almost pegged when I slowed down the needle came down a little. Drove it home 3.5 hours slowing down when needle was almost pegged. Didn't lose any coolant. Do I need a new raditr?
Bill
 
Thats kinds of odd. You would think at the higher speed the more air going though the radiator. How about the belt? Maybe slipping at higher speed.
 
I didn't hear anything squeak, very weird highway speeds hotter slow down ran cooler? 225 slant 6 any ideas?

Thanks
Bill
 
Same issue years ago with my 65 Dart. A re-cored radiator did the trick.
 
Hey this all sounds familiar. I had a thread on here last week about my Ram truck heating. Here is the thing...I had my radiator checked and tested. And I was there! A top establishment of over 60 years. 2nd generation. The test was good. So I replaced everything and I mean everything. So last Saturday my buddy opened up his shop and it turned out to be the Radiator. Mine only heated when pulling a trailer! But it made it to Carlisle and never moved. I would try the rad. If it isn't it sell the old one.
 
williaml said:
History:
I bought a 65 dart in March, when I purchased the car it had a 68 engine in it. The guy I bought it from said the 65 engine ran but overheated so I put the 68 engine in it. I took the 65 engine to be re-built. So I have a re-built engine, with new water pump a new thermostat and all new hoses. I thought it was running a little hot around town so I had the radiator cleaned up and tested. I also discovered I had put wrong temperature thermostat in the car. I changed the 195 to the correct 180 and all was fine so I thought. Drove out to Carlisle for Chrysler in Carlisle and the car in the am ran a little warm but on the way home it was almost pegged when I slowed down the needle came down a little. Drove it home 3.5 hours slowing down when needle was almost pegged. Didn't lose any coolant. Do I need a new raditr?
Bill
Click to expand...

Did you notice any pinging when it was running "hot", the reason I ask is that when an engine is really hot it will ping easily. If there was no pinging then check grounding for your temp sending system and all other wiring related to the gauge. A crusty contact can change the ohms and subsequent temp reading.
 
Good idea. Put in a solid quality temporary mechanical gauge to get a temp behavioral base line established.

Is the water cycling thru the radiator in good flow volume as the thermo opens and closes?

My first guess considering your heating during driving at speed (given that you have established a real overheating issue with a mechanical temp gauge or other methods):

The shape and arrangement of the front end of the car is causing a cushion of air to form under the bumper and in the engine compartment which stalls air flow thru the radiator at higher car speeds and negates the work being done by the rad fan.

You need an air dam under the core support to create a low pressure area in the engine compartment.

Do you have a fan shroud? This will help considerably to optimize the rad fan effort.
IF you have a cushion of air and a high pressure area in the engine compartment the fan shroud will help force air thru rad at speed.

A thermostatically controlled clutch fan is a self regulating air volume workhorse and may be a great upgrade if you dont already have one.

Have the rad professionally rodded out and cleaned. I see you had the rad professionally cleaned so that is already handled probably.

Fan shroud, thermo clutch fan, air dam under rad support, professional radiator cleaning or new radiator.


Enhancements to the various facets of a system will cumulatively yield optimal results.

My .02 :)

.
 
A few things will make them overheat at speed.

A collapsing lower radiator hose. The water pump just sucks it flat at higher engine speeds. If the engine cools right off when you idle, then look at the lower hose. Rev the engine in neutral & watch the hose. Stand clear of the fan.

Retarded timing will also make an engine run hot. A stuck mechanical advance or failed vacuum advance will raise the operating temperature at higher speeds. Retarded timing will not "ping" even when hot. A timing light should be enough to tell if things are working.

Lean running conditions will raise engine temperature. A partially clogged fuel filter, or tired fuel pump may seem fine around town. At 70 mph it can lean things down quite a bit. How do the plugs look after a highway run?

The airflow through that radiator was just fine in 1965. We drove those cars up steep grades at WOT without issue when they were nearly new. Check the basics first before you start throwing parts at it.

B.
 
thanks all. The car doesn't have a shroud around the radiator. I haven't seen one on the darts. New fuel filter,fuel pump, new bottom hose. The engine has just recently been re-built and runs fine. I will pull the plugs and see what that tells me. The running hot at higher speeds is perplexing to say the least.

Thanks to all that answered.

Bill
 
My 67 cuda with built 360 would overheat going down the interstate to the point it would start vapor lock. I bought a larger core radiator alum from Griffin and it solved the problem. Then I installed a shroud in which that brought the temps down even further.
 
You need to do a temperature check of the radiator using an infarred gun. As soon as I read this I had the DAH I should have thought of this thought so I grabbed my infarred gun and scanned my radiator. the idea made perfect sense. 45 years old and it had been checked and flushed during the restore. Results were not good and I recored it. Now scanning it the readings look good and make sense. Excellant way to check the operation of a radiator. Here's what I read:

"TEMPERATURE CHECKS
To check the opening temperature of the thermostat, aim the Raynger ST at the
thermostat housing as the engine warms up. The thermostat housing will rise in
temperature as the engine heats up. When the thermostat opens, the temperature
will level off.
If the thermostat checks out okay, make sure the cooling fan is coming on when
the coolant temperature reaches 220 to 240 degrees F. No fan would tell you
there is a problem with the fan motor, wiring harness, relay or coolant
temperature switch.
If the fan is working properly but the engine is still running hot, scan the
entire surface of the radiator to check for clogs. Temperature readings should
decrease evenly from one side to the other on a crossflow radiator, or from top
to bottom on a downflow radiator. If you find an area where there is an abrupt
temperature change, the radiator is plugged and needs to be flushed, cleaned or
replaced."
 
I did scan the engine and radiator when it was in my garage. No issues ran fine. New thermostat and the radiator I had serviced and was told it is just under the original flow. I'm not sure excatly what the numbers were around 19 gpm is what I think the tech told me. The fan is belt driven.
 
buck351 said:
You need to do a temperature check of the radiator using an infarred gun. As soon as I read this I had the DAH I should have thought of this thought so I grabbed my infarred gun and scanned my radiator. the idea made perfect sense. 45 years old and it had been checked and flushed during the restore. Results were not good and I recored it. Now scanning it the readings look good and make sense. Excellant way to check the operation of a radiator. Here's what I read:

"TEMPERATURE CHECKS
To check the opening temperature of the thermostat, aim the Raynger ST at the
thermostat housing as the engine warms up. The thermostat housing will rise in
temperature as the engine heats up. When the thermostat opens, the temperature
will level off.
If the thermostat checks out okay, make sure the cooling fan is coming on when
the coolant temperature reaches 220 to 240 degrees F. No fan would tell you
there is a problem with the fan motor, wiring harness, relay or coolant
temperature switch.
If the fan is working properly but the engine is still running hot, scan the
entire surface of the radiator to check for clogs. Temperature readings should
decrease evenly from one side to the other on a crossflow radiator, or from top
to bottom on a downflow radiator. If you find an area where there is an abrupt
temperature change, the radiator is plugged and needs to be flushed, cleaned or
replaced."
Click to expand...

He has no electric fan so this bold print wouldn't apply.
 
just curious get a sheet of paper a page from a magazine or something etc and while the car is running hold the paper in front of the radiator the fan should pull the paper up against the rad if not it could need a shroud or check to see if the fan was put on correctly where the fan mounts to the pump there should be either a stamped letters or painted words that will say engine side you can also check to see if the coolant is flowing while its cool start it up and remove the rad cap and watch the fluid you'll see it flow when the thermostat opens
goodluck
 
Oklacarcollecto said:
He has no electric fan so this bold print wouldn't apply.
Click to expand...

I also had an engine driven fan. I posted the entire quote on temperature checking. I just picked up on the scanning and it showed up my problem with the radiator. I had some serious temperature differences.
 
williaml said:
thanks all. The car doesn't have a shroud around the radiator. I haven't seen one on the darts. New fuel filter,fuel pump, new bottom hose. The engine has just recently been re-built and runs fine. I will pull the plugs and see what that tells me. The running hot at higher speeds is perplexing to say the least.

Thanks to all that answered.

Bill
Click to expand...

A lean condition can still exist with a carb problem.

A brand new hose can suck flat at high speeds.

Ask yourself what parts are common to both engines - what did you just move to the replacement engine? Carb? Distributor? Balancer?

.
 
the only thing that went from one engine to the next was the carb, and the radiator. Everything else is new.
 
Sounds like a partially blocked radiator to me. A partially blocked radiator will cause temps to rise at higher speeds because although you have more air flow accross the fins the water isn't flowing through the whole radiator & thus acts like it has too small of a radiator in it. Fine at slower speed but more rpm= more heat & a need for more capacity to cool. Have it professionally cleaned out or replace it with a known good radiator. Good luck.
 
Friend of mine years ago had a problem with LOOSE SCALE coming out of the block. It would not really plug the radiator, just get sucked into the bottom tank and up against the bottom of the core. You could take off the radiator and "fail to notice" that a little bit of loose scale fell out the bottom.

YES it would suck the hose shut, the hose had a spring in, and it damn near would rip the bottom hose outlet out of the radiator at high RPM

As for a shroud, does not mean squat on the highway. You should be able to pull the fan clear off the car on the highway.
 
UPDATE:
So today I removed the radiator and took it back to the shop that cleaned it. The first time taking it back the tech had said they meausred the flow at 10 gpm, after cleaning the volume went up to 18 gpm. Today they checked when I first brought it in at 14 gpm he did his cleaning and blew air through it and the volume increased to 22 gpm. The tech is saying something from the engine blocked the radiator. I changed the bottom hose as well, re-installed the radiator with all new antifreeze. Took it up on route 80 and it wasn't as bad but still running right at the "H" line. As soon as I got off rt 80 got it home took off the cap stuck a probe in it and registered 220 degrees. !0 minutes later my freind came over with a radtech gun shot 175 at the bottom of the radiator 215 at the top and varing temp at the thermostat 210- 220. Any ideas, this is really bugging me.

Thanks to all who read / respond.
Bill
 
Look, this is a wild shot but. This happened to me with a Furd V-6 wagon. I had the radiator cleaned, replaced ..all the things you did. It turned out the fan was the wrong one. It was running backwards.The PO had trouble and replaced it with a flex fan, it blew instead of sucked..
 
Robbie,
I thought of that so I put a piece of paper in front of the radiator and the paper stuck to the radiator so that indicates it's blowing the proper way, right?

Thanks
 
Has the block ever been flushed?

That is correct about the paper.
 
when they rebuilt the engine they say it was dipped in acid or cleaner and the engine looked brand new. Maybe a bad thermostat?
 
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