55 Roadmaster Coolant temp worries

[bhambulldog]

After hijacking another thread (apologies to the hijacked thread starter), I've decided to start my own thread, here;

background, for those that didn't read the hijack,

My Roadmaster temp gauge goes up to the extreme high side of the normal line on the gauge. I was hoping the tune up and re-set of the timing and carburetor adjustment and new sparkplugs would cure the higher temperature. It is much easier to crank, now. And, runs much better!! It is really fun to drive it again with the engine tuned!! But, about six weeks ago, the Roadmaster heated up and lost coolant. So, I'm still keeping a close eye on the coolant and temperature. The oil drops down to the low side of normal at idle. And, jumps up to the high side of normal upon normal acceleration.

The following are taken from my hijack.. here are my previous posts, and kindly replies from Willie;

This time last year my goal was to be at the BCA with the Roadmaster. But, since then I have a new job. And, I've not been at my new job long enough to accrue paid vacation. And, the Roadmaster has been operating on the high side of the normal coolant temperature range. (I think I need to have the radiator cleaned).With the extreme heat we are having now, if I were on the road with it, I would be concerned.

Originally Posted by old-tank

James

You worry too much . The Texas Road Warriors rolled through Birmingham Alabama this afternoon (104*). My 55 with factory air on high was running 210* (I have a gauge with real numbers since the factory gauge is pegged hot at only 200*...with proper pressure cap you can run 230*+ without boil over) I finally got tired of driving with white knuckles watching a pegged gauge,

Willie

I believe I have a 7lb. p.s.i. cap. Mine doesn't boil. The only time it lost coolant past the cap was after I overfilled the radiator. What pressure cap do you use?

Originally Posted by old-tank I'm using a RC-6 which is a 13# cap as standard on 55 A/C cars. If you have the dome shaped top tank (vs the squared off one), you might be able to use that cap. It all depends on the filler neck slots for the cap (higher pressures require larger slots so that a too high pressure cap cannot be installed).

Willie

13 lbs., eh?

Wow!!

I checked yesterday. Sure enough mine is a 7lb. It is the dome top radiator. I'll get a 13lb. for it!

I drove around about an hour yesterday. I made a pretty good romp up and down a six lane expressway. And then some stop and go driving around at low speed in a residential neighborhood

It stayed on the normal line, although it creeped up to the high end of normal. It didn't burped out any coolant. After I shut the car off, I raised the hood and watched, I didn't see any coolant escape. (unless the post shutdown super-heat caused an overflow after I closed the garage door)

Alright, end of hijack. I'll start a new thread...........

:confused:

1. So, I'll replace my 7lb. cap with a 13lb. cap. If, it will fit. Mine is NOT​ an A/C job (perhaps I should change the hoses and clamps, before I raise the maximum pressure 85%)
   
2. I'm sure a cooling system flush is in order .
   
3. And, I'm thinking about adding a recovery tank. The Nissan I drive at work has a pressure cap on the recovery tank. The recovery tank cap has 1.1 cap(i guess that's 1.1lbs.? not 1.1 atmospheres?)
   
4. My roadmaster has the factory full skirted air directors in front of the radiator. Also it has the factory four blade fan. the Radiator is the factory dome topped type. Should I have it rebuilt? And, should another row of fins be added?
   
5. I am thinking of a replacement fan of six to eight blades.
   
6. the electrical system is the factory type generator and voltage regulator. I understand that adding electric cooling fans will require an upgraded charging system. (I'm not prepared to spend that amount money yet. take care of the simple things first, right?)
   
7. Willie, do I remember you telling me that you added an under body fan to cool your transmission oil? How would that work?
   

​

Any and thoughts, comments, questions, or advice are welcome and invited.

Thanks to y'all in advance!!

[old-tank]

It sounds like your cooling system is working as well or better than expected.

13# cap will not make it run any cooler, just raise the boil over temperature.

Keep the top tank only 1/2 full and there will be no puking out the overflow and no recovery tank is needed; if you have pets that can get around the car then put it on.

The stock fan for 55 A/C cars is 5 blade. I put on a 6 blade from a 55 parts car that had a Sears unit and it seems to work better, but is very noisy.

The under body tranny cooler with fan was added because the front pump in the tranny is weak and there is sometimes slippage when the tranny fluid getsreal hot; I would not have used it otherwise.

I said earlier the traveling temp at 104* air temp was 210*. If I had encountered congestion, the A/C compressor would have been turned off, I would drive in Low to keep the engine RPM up, if stopped put it in neutral and rev the engine; even then I would have probably seen 230*, lots of pinging from increased cylinder head temperature, but no boil over. If would have let it sit and idle in drive with the A/C on it probably would boil over. Most people who drive their car in summer parades do it only once.

Willie

[bhambulldog]

Thanks Willie for the reply. Reading you reply and, reading on some other sites agreeing with what you're saying, I'm more reassured now.

Any tips on where I can find a six or more blade fan? (or even a 5 blade)?

I read that a '59 Cadillac six blade fan will fit. I ordered one from a Cadillac parts site. But, they haven't contacted me....... Not even to tell that it is back ordered.

I've heard bad things about flex fans. So, I'm staying away from them.

A clutch fan would cut down on noise. But, would a clutch fan be too heavy for a waterpump not designed with a clutch fan in mind?

And, as far as water pumps; Does an A/C job have a different water pump from a nonA/C job?

What thermostat do you use? I understand thermostats control the warm up time, only. And, not running temp. But my thinking is it will eventually get to operating temp. So, there's no need to rush it to warm up. I'm leaning toward a 160degF. In my cars I always ran 180degF or cooler. This was Dad's car. And, Dad had a different idea about thermostats from me. He liked to run hotter thermostats.

I'm starting to suspect Dad put a 195degF in it when I wasn't looking. It warms up really fast

[bhambulldog]

What kind draw does fan the transmission cooler have? Can it be run on the 30amp generator that I have?

drive in Low to keep the engine RPM up, if stopped put it in neutral and rev the engine

This, I am doing when I drive it it in hot weather.

On the temp gauge; did you replace the factory gauge with a numerical gauge? Or, is there a way to have both hooked up?

Or perhaps, keep the factory as a dummy and read the numerical gauge ?

[old-tank]

What kind draw does fan the transmission cooler have? Can it be run on the 30amp generator that I have?

This, I am doing when I drive it it in hot weather.

On the temp gauge; did you replace the factory gauge with a numerical gauge? Or, is there a way to have both hooked up?

Or perhaps, keep the factory as a dummy and read the numerical gauge ?

Factory gauge is still there, numerical is under dash (kind of cheesy, but serves the purpose). You can hook both up using the same spot in the opposite head (it is at the front of the right head), but you will never get the plug out if it has the original slotted plug.

Not much current draw on the tranny cooler...about like a heater blower, but less than head lites.

I use 180* thermostats to keep sludge build up down. 195* would work, but with the stock gauge it would be pegged hot all the time.

Same waterpump for all 55's.

See

http://forums.aaca.org/f162/not-all-my-schemes-324791.html for experiment in electric fans.

Willie

[bhambulldog]

Factory gauge is still there, numerical is under dash (kind of cheesy, but serves the purpose). You can hook both up using the same spot in the opposite head (it is at the front of the right head), but you will never get the plug out if it has the original slotted plug.

Not much current draw on the tranny cooler...about like a heater blower, but less than head lites.

I use 180* thermostats to keep sludge build up down. 195* would work, but with the stock gauge it would be pegged hot all the time.

Same waterpump for all 55's.

See

http://forums.aaca.org/f162/not-all-my-schemes-324791.html for experiment in electric fans.

Willie

I was just reading the shop manual. It occurred to me, I could plug another temp bulb in the opposite head, as you say.

Temp gauge under the dash is no more cheesy than my unused fog light switch hung from the A/C control mounting holes. To put a temp gauge there would be a good excuse to pull that fog light switch loose.......

Yep, I was thinking a 195degF is in there. I was just looking through some of Dad's stash of parts and I found the empty packaging for a 195degF thermostat.

I think 180degF would be my wintertime thermostat. And, a 160degF for Summer.......

I'm going to do this a bit at a time. Tomorrow, I'll try a 13lb cap. And, check out the thermostat.

See what effects that has....... I'm going to cruise in Saturday. We'll see then.

I'll check out that link, now.

Thanks loads Willie!!

[bhambulldog]

to the coolant I've added some 'water wetter', and a 13psi Radiator cap. Yesterday i drove to two cruise in shows a round trip of about 55 miles. I didn't take the interstate highway. I went on the parallel surface highway with traffic lights. between red-lights the speed was about 40-50mph.

One or two drops of of coolant were under the over flow where I parked at the cruise in from the super heat after each engine shut down. And, the 13psi cap is a step in the right direction(thanks, Willie). With the 7psi cap it was shooting out a cupful after each shutdown.

I'm thinking of adding an over flow reservoir. If for no other reason, just to monitor how much coolant is escaping, and when.

I think it means the radiator is working good. It just needs more air flow at lower speeds. Perhaps, a multi blade fan (6 to 9 blades) to replace the 4 blade fan.

[JohnD1956]

Take a look at the sides of your radiator shroud. If you have more than a 1/4 inch gap you might try closing that.

If at all possible you may loosen the four mounting bolts and see if you can nudge the shroud loser to the radiator. Or you can go to your hardware store and buy some small diameter hot water pipe insulation. This is a black sponge foam and comes in 10' lengths. It is slit on the side so you can just pry it open and slide it on the pipe. I have thought of pulling the shroud back on my 56 and sliding this onto the front edge of the shroud and then trying to re install against the radiator. I have not done that yet because I have decided not to worry too much more about the coolant temps in my 56.

I can remember years ago that the guage never seemed to get as high as the N and now it runs just at the N or a little higher. With Willies comments about the guages reading hot at 200* I have decided that a 60 year old car is not doing anything abnormal when the guage is not even peaking into my "red" zone" on the factory guage. If anything, I will try to do the CLR flush that Shadetree had so much success with, and see where I go from there. That and use the car more often.

BTW, todays cars use 195* stats to get the heat up for more complete combustion. While my manual recommends a 160* I would tend to stay with the 180* to help vaporize the gas and provide more complete combustion. But I'd love to hear others thoughts on this.

[Joseph P. Indusi]

I have had good luck with the heavy duty thermostat sold by Bob's Automobilia, rated 160 degrees on my 1953 Special straight 8. This has a quite large opening when fully opened compared to regular parts store items. It come in a blue and yellow box, brand name escapes me now. I also installed a 6 bladed fan from a Cadillac with A/C although a 5 bladed Buick fan would also work. The car runs cool at speed and gets hotter in parades or idling in hot weather but has never overheated since these upgrades. I should also mention that I had the radiator re-cored and installed a new 7# cap.

Finally, I have heard from more than one source that the addition of 10% ethanol in our gasoline causes engines to run hotter than back in the day.

Joe, BCA 33493

[bhambulldog]

Thanks for the advice guys.

I'll try blocking the gaps around the radiator.

I agree on the ethanol. Mine did'nt run this hot on ethyl-lead gasoline.

[KAD36]

Another data point, for what its worth - my 55 had a 160 in it and on cool days it might make it halfway up between the C and N. It would just be at the start of the line that indicates "in range". With a 180 in it, it warms up right to the N and then opens (the gauge goes back down as the radiator contents dump into the engine) so at least on this gauge in the car, 180 is at the N. My radiator has a new core in it, reused the old tanks, and the 180 thermostat I put in from a local parts store was advertised as a high flow model similar to Joes post. I think the 180 is better for the engine, personally, especially if you don't drive it long distance much. Gets the moisture out and it seems to run better hotter. Sure throws the heat on a cool fall day. With a 160, sometimes I'd wonder where the heat was (have a new heater core and valve installed also so they flow well). My car has never pegged the temp gauge in the 25 years I've driven it - even before the radiator was re-cored, and with the 160 in it - the highest it would go was between the end of the "safe" line and the H. With the 180 and new core, even idling at 475 rpm in D in traffic, it has yet to go past that "safe" line between the N and H. I am guessing this is in the 190 range. The car has a 7lb cap, and the top tank is kept about half full of coolant cold, standard 4 blade fan. Have not had any overflow problems with this level of coolant, even in our heat wave.

The gauge as marked is good for general indication only and my hunch is no two gauges after this many years behave exactly alike. I'm considering putting AC in the car for next year, and am already thinking about adapting a 5 blade fan (noticed they reproduce them for Mustangs and was wondering if they would fit) or go with a generic 6 blade ones that some of the aftermarket AC people sell. At the Nationals this year, I took lots of pics of peoples AC installs (thanks Mike! ) so am toying with the idea of how to put one in the car. Then will see how hot it runs! Good to know that the H is in the 200-210 range. Thats not bad, although the numeric gauge would be required to know just how "over" 210 you really are if she pegs.

Edited July 15, 2012 by KAD36 (see edit history)

[FLYER15015]

Jim,

I just stumbled across your thread regarding "running hot", and I thought I'd add my 2 cents.

I installed a catch tank, made from a pint can and a bit of clear plastic tubing with an "S" bend at the bottom and hooked up to the radiator over flow pipe.

I also installed a 6 bladed "Hayden" stainless steel flex fan, to replace my funky lookin 4 bladed job.

She runs much cooler now, and no noticable increase of noise from the motor.

Mike in Colorado

[bhambulldog]

Ken and Mile,

Thanks for the replies.

Ken I am going for the six blade fan. Maybe even a low amp (9) fan.

Mike, I was thinking about a overflow catch as well.

Thanks again y'all.

[FLYER15015]

Jim,

FYI I used a Hayden 6 blade stainless steel flex fan # 3568 due to the skinny dim of the radiator. Hayden also makes a # 3569 which is a bit bigger in diameter. E-bay price is now about 45 dollars w/ free shipping.

I had to cut 3/8" off the back edge of each blade to clear the generator pully, but it did not seem to compromise the performance. I only have 1 7/8" between the H2O pump pully and the radiator. That's why Buick used 1" bolts!!!

My "overflow" tank is a pint can located under the fender, atop the frame rail, with a 3'8" hole drilled in the cap. It is attached to the overflow tube w/ a clamp and I swear I can hear it siphoning back into the radiator after shutdown. It has not overflowed since I installed it and the radiator is always chuck full at the top cap.

I do have a "pancake" pusher in front of the radiator, on a toggle switch, but rarely use it now.

Good luck and let us know how you make out.

Mike in Colorado

Edited July 17, 2012 by FLYER15015
spelling (see edit history)

[bhambulldog]

Well thanks for telling me about that Mike. When I saw my coolant drip out of the overflow on the garage floor, i pushed a pan under there to catch it. And I thought, I need something there all the time. ......... Makes sense that it would siphon back in on cool down, through the radiator cap's vacuum valve. I was just reading the shop manual's explanation that, without the vacuum valve on the radiator; the tank would collapse on cool down......... I was just looking at a six blade fan from Jegs. And a pancake electric fan that only draws 9 amps...........

[old-tank]

... I was just looking at a six blade fan from Jegs. And a pancake electric fan that only draws 9 amps...........

That 6-blade should help alot. Using an electric fan in addition to a mechanical fan sometimes decreases efficiency. If that 9-amp fan is a 16" Proform, don't believe it...it actually draws 15 amps and did not cool as well as the stock fan.

Willie

[bhambulldog]

hmmm.......

Thanks Willie.

Maybe, I should try one step at a time. I'll try the six blade fan first.

[old-tank]

hmmm.......

... one step at a time. ..

always a good choice:)

[Guest 54fins]

the nailheads are relatively low compression by todays standards. I would think a 160 F thermostat would be useless, better removing it if you live in a warm climate. I take mine out in the summer, not only to maximize flow but to help flush out the cooling passages. A lot of stuff hides in there! Above 80F, I don't think the 195 or the 180 make much difference, but in a cold climate (below 50 F) I believe warmer is better.

for me, I remove the thermostat for summer. I also think a higher pressure cap is logical- a boil over is bad as you loose coolant fast. I think that anyone doing AC or summer parades needs to seriously consider an electric helper fan. The Caddy club people use this stuff called "water wetter" in the summer- have not tried it myself. I'm also considering blocking the heat risers in the manifold- the carb gets plenty hot!

[bhambulldog]

the nailheads are relatively low compression by todays standards. I would think a 160 F thermostat would be useless, better removing it if you live in a warm climate. I take mine out in the summer, not only to maximize flow but to help flush out the cooling passages. A lot of stuff hides in there! Above 80F, I don't think the 195 or the 180 make much difference, but in a cold climate (below 50 F) I believe warmer is better.

for me, I remove the thermostat for summer. I also think a higher pressure cap is logical- a boil over is bad as you loose coolant fast. I think that anyone doing AC or summer parades needs to seriously consider an electric helper fan. The Caddy club people use this stuff called "water wetter" in the summer- have not tried it myself. I'm also considering blocking the heat risers in the manifold- the carb gets plenty hot!

30 years ago, I took the thermostats out of my daily drivers every summer. But, there is some thinking that the coolant going too fast through the system will not transfer the heat.... those same thinkers say that the thermostat in place provides the needed restriction.

I just have come around to the thinking I'll put one thermostat for all seasons.

I agree about the lower thermostat. Whatever the temp rate or no thermostat at all; the engine eventually will grt to operating temprature. So, why hurry the heat up when it's above 90degF ambient?

And, I used the "Water Wetter" along with the 13psi cap. With these changes, I've seen some improvement.

My next step will be to increase the air flow at idle.

[Guest 54fins]

It is possible to flow too fast in a heat exchanger. My observation in 97 to 104F is dramatically cooler temps without the thermostat, so I suspect the coolant is so agitated that you don't get laminar flow- but I have to confess it isn't very scientific!

with any speed and RPM, the cooling system is quite adequate. The temp problems only seems to be at slow speeds. Without a thermostat, I think the pump is so slow that the restriction isn't needed anyhow. Anything that ups the coolant flow and airflow at idle is probably good. I suspect airflow is the most important- if you don't move the air, you can't get rid of the heat. I think you get plenty of airflow if you are going 30 MPH or more, but sitting on hot pavement what little air does pass is too hot to do much good. The hot air gets shoved under a hot motor and cycles back into the grill if you are standing still. The bumper skirt only helps if you are moving, the only option is to move air big time at idle. old Trucks sit up higher and don't have as much trouble.

[Guest 54fins]

upon closer observation, the engine compartment is pressurized by the fan, dispelling down the cowl when you are moving. But at standstill, the pressurized air has passed through the radiator and then wants to go down and towards LOWER PRESSURE. Hmm- the grill is a nice low pressure cell when you are sitting still.

I may experiment with adding a shroud between the radiator and the cross brace for the front wheels. Even if you add a fan like old tank did, all you are doing is increasing the pressure differential between the grill and the engine. I'm going to rethink the airflow at rest

[d2_willys]

Curious, what is your oil pressure at idle? If the oil pressure is very low, the engine will run extremely hot on 100+ days. Had this problem years ago, and even with a larger radiator, shroud, and rebuilt engine, the temp gauge would go up. (The engine lower end was really loose, even though it was rebuilt, or the oil pump was bad, even though it was a new Melling pump.)

I would check the oil pressure out, and the vacuum advance.

[Airy Cat]

I have a '55 Special and it also had cooling problems. To correct it, I had the radiator recored, installed a 180* thermostat and a six bladed fan with a 1.5 inch extension in order to get the fan closer to the radiator. I then used a 50% mixture of coolant with distilled water and "Water Wetter."

Now, the car never runs hotter than 195* even in 100* weather.

Also, you might want to run premium fuel that has a higher octane rating.

[bhambulldog]

Curious, what is your oil pressure at idle? If the oil pressure is very low, the engine will run extremely hot on 100+ days. Had this problem years ago, and even with a larger radiator, shroud, and rebuilt engine, the temp gauge would go up. (The engine lower end was really loose, even though it was rebuilt, or the oil pump was bad, even though it was a new Melling pump.)

I would check the oil pressure out, and the vacuum advance.

After the timing was re-set and new plugs/wires, it is running much stronger and cooler. I'm going on the factory gauges for temp and oil. the oil pressure drops down at stop lights. But, it stays on the normal range line. When I place it in Neutral and increase RPM at stop lights, the temp doesn't climb so fast. And, of course the oil pressure stays up high. I'm thinking I'll put in some gauges with numerical reading. But, Where, to put them?.:confused:.....

I have a '55 Special and it also had cooling problems. To correct it, I had the radiator recored, installed a 180* thermostat and a six bladed fan with a 1.5 inch extension in order to get the fan closer to the radiator. I then used a 50% mixture of coolant with distilled water and "Water Wetter."

Now, the car never runs hotter than 195* even in 100* weather.

Also, you might want to run premium fuel that has a higher octane rating.

I've got these things on my list as well.

Except, I didn't think of putting the fan closer to the radiator.............

Thanks all for your suggestions!

[Guest 54fins]

I have the hood off and the thermostat out, I am pleased to report that I can't get the gage up to the N in 95F heat

This proves to me that the radiator has more than enough capacity. Hood on, I can't get down to N. All the heat is trapped under that hood.

The problem is all air flow. If hot engine air doesn't get purged, you can't cool it. At speed, it all blows down and out the back.

At very slow speeds, the fan is slow, of course, and the hot engine air is just stagnating around the radiator. I believe it is going over the top of the radiator, under the hood. Without the hood, you are pressed to get up to temp even on a hot day. I also think the thermostat is pretty restrictive. Too much flow can reduce heat transfer, but too little flow can be an issue.

My next experiment is to put in some cardboard filler over the radiator and seal it up top to bottom. There is a hole by the battery, likely to cool the battery. I propose that the cooling system is probably more oversized than undersized- if we can bring in 100F ambient air we can keep the radiator below 200F (more than cool enough) and I suspect you could even run AC without a problem. I also propose that the fan is too fast at speed, putting more drag than you need on the engine most of the time. At idle, its just circulating hot air around the radiator. The 6 blade idea probably improves the low speed airflow enough to pull in some outside air.

[oldstyle]

Outside temps where I live are in the 90's and 100's during the summer. Car still gets warm in heavy traffic but no longer reaches dangerous levels. Ive recored the radiator and still had some issues. Added a 19" 6 blade fan and that made a big difference. Also have a strong electric fan that really cools in traffic (running off a adjustable switch). Changed to a 55 or 56 shroud not sure which. It's actually shaped to fit the radiator and seems to use more of the radiator. It's much better then the 57 shroud that is just a circle.

[bhambulldog]

I thought about that hole in front of the battery. But, I believe it's more for ventilation of the battery gases, more than for cooling the battery. ......... Maybe, it would be okay to close it off. Certainly it would be an improvement to close off other gaps to direct more air into the radiator , and should make the fan more efficient.