Radiator/water pump Q for the best and brightest

I suspect from what you describe it could one of several things.

Thank you for the rapid and helpful reply!

Have you checked the radiator fins on the core be grass seed or other debris that prevent proper air air flow.

None on the outside. I will check on the inside.

Mismatched components are not likely on a 318 non A/C car.
You might want to find out if the shop installed a new or a rebuilt water pump. Most of the rebuilt pumps these days are done overseas and the quality of many of them is also crap.

I don't remember the brand, but I do remember seeing the box and it looked like a new unit. The box it came in, which had been trashed before I remembered to ask for it, was light/baby blue if memory serves.

I think that a thermostat is the most likely, many of the ones sold these days at Auto Bone and Car Crap are made in China and are very poor quality. Go on line and buy yourself a Robert Shaw heavy duty t-stat. These are made here and are the best stock type t-stat on the market. (...) I would suggest changing the T-stat first and see if that fixes your problem. (...) www.flowkoolerwaterpumps.com has the t-stats

Great, Flowkooler is the company I was thinking of using for the new t-stat! Is this the one you have? Robertshaw 370-160 Series hi flow thermostat

Check the water pump for excessive bearing play. Grab the fan and try to move the unit back and forth, if you observe or feel movement of the water pump shaft, the unit is failing.

Will do.

The other thing you might want to check is for the presence of hydrocarbons in the coolant. Most auto parts stores have a tester for this purpose. Hydrocarbons in the coolant are an indication of a cracked head or bad head gasket. If combustion gasses are being vented into the cooling system this results in aeration of the coolant (gas bubbles) which reduce coolant density and cause heating.
 
Thank you for the rapid and helpful reply!



None on the outside. I will check on the inside.




I don't remember the brand, but I do remember seeing the box and it looked like a new unit. The box it came in, which had been trashed before I remembered to ask for it, was light/baby blue if memory serves.



Great, Flowkooler is the company I was thinking of using for the new t-stat! Is this the one you have? Robertshaw 370-160 Series hi flow thermostat



Will do.

I think they make it in both a 160 and a 180, I used the 180 in a big block motor.

Dave
 
I think they make it in both a 160 and a 180, I used the 180 in a big block motor.

Thank you. That's the case for the 330 (they also make a 195), but the 370 seemingly comes only for 160. From their web page, I can't tell the difference between the two models (other than looks and price).

Edit: the company explains the difference here. I may be slow, but I still don't see why one would prefer one over the other.
 
We had a discussion about the 19" radiators in c bodies at Carlisle with @71Polara383 . I said I'd never seen one. Interesting .
 
As @saforwardlook has said many times, Chrysler Corp. sure skimped on cooling for our cars. Still, I made a call last April, when I started the process of bringing back the car to life, to stay as original as possible (well... except for that sore-thumb master cylinder, which was one of the first thing put in and, like the pump and t-stat, not an item I discussed at the time). My restorer did suggest that we might want to go bigger with the rad, but we ended up re-coring. One of the reasons was I could not find the 22-inch rad that would have fit the opening: AFAIK, the only 22" made by Chrysler Corp. in 1970 was P/N 2998969, which was for a 440 without A/C -- it should have fit in the opening on Poppy's rad support, but I was unable to find the rad. Rather than look for an after-market aluminum one, I had the 19" original re-cored.

This time around, I feel less time pressure, so I may first get the car back to working like last year, and then I can see if a more involved solution is needed. I'll start with the smaller checks, and go from there.
 
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Thank you for the response. Nope, please tell me more.

well I may be going the wrong direction here but if the heat rise is stuck closed, I think it may cause the top end of the engine to heat up but then again it should be causing a heating issue all the time.
Hopefully others can jump in here to confirm or deny my theory...
 
Another scary thought is leaking head gasket....
Have you donw a leak down test on the cooling system? example, taking a pressure tester & pressurizing the cooling system and looking for leaks in the cylinders?
 
A couple things...

First, the presence of the spring in the lower hose can be verified by a good squeeze with your hand on the lower hose. The spring needs to be long enough and the hose in good shape so it doesn't collapse at the ends too.

As mentioned, a pressure test of the system is a good idea. The cap should be checked too... although I tend to just replace them if suspect.

While opinions vary on this, I like to run a 160° thermostat. IMHO, the engine will run at whatever temperature it wants to run at. The lower temperature thermostat starts the cooling process a little earlier and in my experience, the temperature will be more consistent. In a car with marginal cooling, this may help.

A stuck exhaust valve can cause some heating issues, although they usually are more related to difficulty starting the car when hot. Easy to check, but since you didn't seem to have a problem restarting, I would be surprised if that was the issue.

The fan belt needs to be tight, I don't believe that's been mentioned.

A failing water pump would leak rather than cause a flow problem.

Since this seems to be a new problem, I would point at something failing. My bet would be the thermostat.

BTW, should this happen again, the red neck, side of the road "get you home" solution is to run the heater on full "hot" with the fan at full speed. It adds another few square inches of radiator to the system at the expense of your comfort. I'm sure more than one of us has done this... LOL!
 
Another scary thought is leaking head gasket....
Have you done a leak down test on the cooling system? example, taking a pressure tester & pressurizing the cooling system and looking for leaks in the cylinders?

Nope. I'll add that to the list. Please help me a bit more out here, as I have never had to deal with a blown head gasket. As far I understand, abnormally high temps are both a symptom and a cause of the latter.

--> What I can tell you is that I have asked my passengers, including @Imperialist67, to check for exhaust fumes every time I've cold-started this in the past 3 months. None of them ever saw any smoke coming out of the exhaust. I had asked them to check because I had a cold-starting issue (the engine would start normally but then die out unless I kept the accelerator depressed slightly for 2' or so), and they all told me that they saw absolutely nothing. FWIW, on Saturday afternoon, the car kept driving smoothly after I had overheated, cooled down, and restarted.

Note: well, it did drive smoothly till my (still original) exhaust pipe split into two, right ahead of the muffler, about 30 miles after I overheated -- but that's another story for another thread -- my return trip from Carlisle was really "interesting" this year.


--> Are you thinking about the possibility of a leaky head gasket (i) because of the dark and slightly oily appearance of the steam residue once it cooled off on the fender as shown in the second picture above, (ii) because some other specific symptom I've mentioned -- or simply (iii) because it is a possibility in general given what happened?

well I may be going the wrong direction here but if the heat rise is stuck closed, I think it may cause the top end of the engine to heat up but then again it should be causing a heating issue all the time.

As for the heat rise, I'm not next to the car right now, but I have added it to the check list.

Thank you for your continued input!
 
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A couple things...

First, the presence of the spring in the lower hose can be verified by a good squeeze with your hand on the lower hose. The spring needs to be long enough and the hose in good shape so it doesn't collapse at the ends too.

(...)

The fan belt needs to be tight, I don't believe that's been mentioned.

(...)

BTW, should this happen again, the red neck, side of the road "get you home" solution is to run the heater on full "hot" with the fan at full speed. It adds another few square inches of radiator to the system at the expense of your comfort.

Thank you for the detailed response.

I should have checked the belt tension and the lower rad hose, but I only paid attention to the top hose (to know when I could safely unscrew the rad cap). My recollection from looking at my engine bay with @71Polara383 in Carlisle, though, is that the belt did not stick out as an issue. Easy enough to check now.

In the same vein of "oops" moments, I did not think of turning on the heater and blasting the fan. It's one of those "theoretical knowledge" things that I forgot about when sitting the practical exam :rolleyes:

The cap should be checked too... although I tend to just replace them if suspect.

Last year, when looking for the cap (the old one was shot), I had a hard time finding a good one that looked OEM.

--> Suggestions?

A stuck exhaust valve can cause some heating issues, although they usually are more related to difficulty starting the car when hot. Easy to check, but since you didn't seem to have a problem restarting, I would be surprised if that was the issue.

Restarting the car when the engine is warm/hot has always been a breeze. Starts on a quarter of a click. Same on the side of the highway this time around.

A failing water pump would leak rather than cause a flow problem. Since this seems to be a new problem, I would point at something failing. My bet would be the thermostat.

Let's hope so!
 
i wonder if your muffler is plugged? that might explain your driveability issues, your overheating and your exhaust splitting. has the car been lacking power? did it have more power after the exhaust split?
 
I never had a chance to check. The muffler was hanging 1” from the road surface and I decided to have the car flatbedded to where it could be repaired.

The exhaust was the original one. I decided last year to keep it for originality even though it had to be patched in one place.
I was told today that it is paper thin in places and all of it needs to be replaced.

The order of repairs is the exhaust and the brakes (front left pulling the car left when braking), then the heat issue. Thermostat will be first. It seems that ought to allow me to check out what you’re suggesting.
 
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