rpmgarage

thanks Tod...expert explanation...and well written... Changed to the correct firing order...JBWeld still holding strong on the rad and all is well...car cruises around 170-180 and climbs to 190 at long stop lights. No interstate or hilly testing yet, though.

thank you...will fix that as well.

Okay...good news updates, but one more question. I apparently punched a tiny hole in the top of the radiator tank when reinstalling the hood that I did not see. When the stat opened, which it was doing, a small spray of water was exiting the radiator, hitting the fan, and blowing away...byt the time it was running hot enough to see on the gauge, most of the water was gone...then, the water would spew out, covering the small hole that i made. Unfortunately, it could not be seen until the radiator dried competely because it was re wetting itself. We did a quick JBWeld repair at 6am...let it sit until noon. Topped it off and drove. Stat opened at about 165 on gauge, topped out about 190 in traffic, and did not overheat on a cruise up and down the strip. But, it brings up another question...I think I have the wrong firing order...although I duplicated the order that the car has been running on for years... I have the car firing order as 135624...reading the forums and an excerpt from the manual shows the firing order as 153624. The car runs like a sewing machine with the firing order as is...but obviously have two cylinders switched could mean an increase in temps...which might explain the 190 end. Then, a guy who claimed to be a "Plymouth flathead guru" told me the they changed the firing order to 135624 in the 60's and that I am running it right... So...and not everyone at once here...what is the firing order supposed to be and would the cylinder switch also exacerbate the temp issue? Thank you for all your help.

thanks everyone. i will update the post next week with what i find.

thanks to all who have commented... The car is on the stip in Pigeon Forge...I cannot perform some of the tests mentioned...nor can I flush until I get the car home. However...here is my previous experience with head gaskets: froth in the oil fill or on the dipstick (I have none); oil level overfull (mine is not); white smoke from tailpipe (none); water from tailpipe (none); water "disappearing" from/in radiator (mine seams to be exiting clearly through the overflow. i am NOT ruling it out...will take IR thermometer with me tomorrow to check for hot spots in the head and block...

Once I get it home, can i accomplish the freeze plug flush, engine in car, and get the replacements in flush and plumb? The water distibution tube will be no problem...i am getting good at pulling the radiator...

so...best advice for he morning? Fill er up with water and limp 70 miles back home? i got all day...literally... And, the $64 question...why three days of "perfect" operation, only then to have it happen with NO warning? I can pull the hood ff and put it in the wagon...come home the "back way" and stay off the interstate...pull over every time it hits 200...

opened te petcock and got immediate stream of good mosly clear water. i did not pull the water distribution tube during the replacement...i ran a small hose almost the full length of the block...no obstructions, and ran pressurized water through the tube and out the block...there was little to no crud and the outbound water was clear and had almost as much pressure as the inbound...the viewing end of the tube was excellent...looked like galvanized steel to me...no cru, or filth...

water did start moving at around 165 or 170...but did not drop...spewed out after i continued to let it run... unable to road test due to losing the parking space...

Here are the results from the last tests tonight: After the last boilover, I let the engine cool completely...waited until air temp was 80 and car was in the shade. Filled radiator to top of the neck with almost 3 gallons of water only (after the boilover and cool from earlier). Left the radiator cap off to view thermostat opening. Left driver side hood open. While the car was still "cold", i checked flow across the radiator with various sizes of paper. Fan is pulling plenty hard and held paper of various sizes in every position...incresase rpms, fan pulled even harder. You would have to shut he engine off for the paper to fall away, even at idle. At idle in these condiions, it took almost 15 miinutes for the temp gauge to get close to 175 and the water in the rad to start barely a bubble. Water in rad would slightly rise and fall to same position. Not a lot of bubbling at first. A couple of good burps led me to believe that the earlier boilovers had created an air pocket, but that the thermostat was opening. I continued to idle with the cap off...more bubbles and mild burping...but the water level did not really drop...which surprised me because I would believe it would drop as the air pockets were purged. This is where I may have made a mistake... I increased the rpms to about 1500 and held it there...cap still off...still mild burping...hood still half open. Now the time was approaching 20 minutes. The temp began rising...hitting 195 and holding...the burping increased until small amounts of water overflowed at the neck...not a jet or spray, just running over. But, it held...temp wasnt rising or falling...water level didnt really drop, but did ooze out about a cup or more. Then, the temp started climbing...as soon as it hit 200, I put the cap on...engine still running, but back at idle...small mounts then continued out the overflow tube, but the temp held just on the "over" side of 200. The car had now idled for close to 30 minutes. I shut the engine off... It immediately started hissing and sending tons of water out of the overflow tube. Plus, it sprayed out around the rad cap ( which I had apparently not tightened all the way ). But, even with all of this, and another loss of water, the temp gauge did not crest 210... so, I lost water again, but it did not BOIL over like previously where the gauge pegged. Thus, the newest question: did the purge reveal that I indeed had an air pocket? But then I went too far? Or, should it have set there an bubbled, gurgled, burped, etc, but not spewed over if the thermostat was working properly? I have driven home in my other car now and will go back again in the morning...should I do the purge again with the cap off, but stop when I see the first bubbles? Then, let the car cool again to see if the water level drops? Then drive it? This is compounded by the fact that I have a serious buyer. I cannot bring myself to sell the car without knowing the problem is solved, but I wont give it away over the issue either... To remind all again: all new hoses, new water pump, new 160 thermostat, new drive belt, complete tune up with points adjusted and verified by dwell. Did my best to flush block which was running extremely clear with no obvious sludge. Did not pull freeze plugs. Block held 2 gallons alone before putting thermostat housing back on...then 2 more gallons into radiator. Drove car for three days and over 120 miles with zero issues and cooling system working properly. Car self purged very small amount on day one then did not overflow again. I set the new water pump up just like the one I replaced...i do not know what Scruffy means by "screw on the truck side"? There is a small hose coming outbf the front of the thermo housing, just below the large upper inlet hose. There is a large hose exiting the bottom, passenger side of the pump, with a tee feeding the heater core and a larger diameter hose to the bottom of the rad, which I also thoroughly flushed. There is no heater valve, so water flows through core at all times...i just dont turn the blower on and never have a passenger, so it didnt seem to matter. These are the only hoses exiting the water pump.

The fan is stock...4 blade. The petcock is on the distributor side...I will check for flow later this evening as I am away from the car at this time. I did not pull the Welsh/freeze plugs due to seeing the cleanliness of the flush water from the block and the heater core. I have not started the car back again...it is 92 degrees right now...I plan to wait until evening before looking any further into it. There are no signs of water in the oil dipstick or any foaming on the breather tube. There was no odor of antifreeze. I cannot due a pressure test on the cylinders until I get the car home...maybe more than a week from now. As for an air pocket in the system...I filled the radiator above the water neck first, then let atmosphere adjust it with the thermo and housing off. Then I topped off the block to the brim before adding the thermo and housing. I also filled above the thermo outlet to the top of the outlet before adding the upper hose and continuing to fill the radiator. I filled the radiator just to where it was visible. I then idled the car until the thermo opened...seeing the bubbling in the neck with the cap off. I let the car cool completely...added more mixture until I could see it again...let it bubble after thermo opened again. This time, it did not drop any. There was a total of roughly 4 gallons added to the system...about 2 in the block and 2 in the rad. Drove the car in heat of the day for three days...120 miles plus...not so much as a burp and the water level did not drop. The car ran continuously for almost 1 1/2 hours at one point...all with the hood off. Temps never got above 195 mark, even upon parking and cooling. Thermo operated as gauge would rise up above 180 or so, then drop back almost to 150 or just above. It seems that any air pocket would have become apparent during that time... Now...since it boiled out so much, there might be an air pocket NOW...but I don't see there having been any air pockets before this problem. Same way with the thermostat...does it seem likely that it would operate great for 3 days from purchase...then lock closed? Maybe so...but it's a NAPA piece...so I would really not expect it. I have not ran with the heater on yet...will this evening. However, car will be sitting still for testing for two days...if I move it,I will lose my parking spot and do not have my trailer here in case of a break down. Will the heater on test help when the car is sitting still? There is a gap of about 3" between the top/upper front of the rad and the grill shell...no seal...the hood sits flush on the grill shell...no weatherstripping or welt on the front section. Sides of the grill shell bolt to sides of the rad...there are holes in the mounting bracket that air can get through...no rubber seals...But, to be honest, I don't remember any of the 30 plus pre-1950 cars that I have owned having a "sealed" radiator mounting system...definitely nothing like my Buick Roadmaster or my F350 has...

well...maybe not...apparently I can't upload pics from an iPad2? Let me know the trick if I am missing something...

here are a couple of pics...

I forgot to bring my digital thermo...will bring it back tomorrow and check all the usual spots...I will report back with the findings. I don't believe in throwing parts at the problem, but could someone recommend a quality radiator...part number, company, etc. I will not sell the car until it teaches me something... Remember...41 P12 in a 36 D2...would like a direct fit without any fab work...thanks...

Thanks to everyone for their input. Here are my responses, not in order: the radiator does not have an upper "seal" of any kind to seal to he grill surround. It does seal down the sides with the mounting tabs. The thermostat cannot be put in upside down because the housing would not seal to the block...it is installed properly and functioned as designed for three days plus of driving after doing all the above-stated work. There is a sinle row of unblocked louvers on each side of the hood. They are from the factory and are punched so as to extract heat down the sides, not deliver fresh air from the front...which they would do poorly. I started the car this morning at the Shades...idled for 40 mins plus...thermo opened and closed (verified by watching gauge and checking upper hose for pressure when thermo opened)...temp stayed below 180 the entire time...did not hiss or boil when shut off...temp climbed to about 195 while cooling... Let her cool for 30 mins...took her for a drive in heavy, slow traffic (stop and go...10mph)...she overheated within the 5 mile loop...pegged the gauge again...spit out a gallon upon parking. I believe Tod and others may be onto something...hot tanking the rad would not guarantee flow of AIR through passages...even though the water is flowing...there may be no AIR going over it...I can't perform too many more roadside tests up here... I am thinking about doing the paper test where I see if it will hold against the rad from fan vac...