No Thermostat ?

[712edf]

While we are on the subject of cooling (and summer will get here soon), is anyone familar with those wetter water products that go into the radiator? I have seen them mentioned on some forums, but never really researched them.

BTW I never leave home w/o my thermostat, its just that sometimes its in the glove box awaiting September. But that's just me (& maybe some others in tejas).

Thanks

Bucky

[Blisters]

MaineSS:

There was a very well-documented and researched article in MVPA's "Army Motors" magazine a few issues back which I believe described the use of waterless (anhydrous) engine coolant as tried in an older military engine. The conclusion was that it did not cool as well as hydrous coolant, and the engine continuously ran too hot. This is just from my poor memory, but I am sure I remember the basics correctly.

Gordon and Kevin:

If I may add, modern engines (OBD1 and OBD2, as of approximately 1995) will set trouble codes if the engine runs too cool. This is due to (as was already noted) the fact that a too-cool engine will run dirtier. As those of us under the control of the air pollution authorities know, a clean-running engine is much more desirable than an over-polluting one, as you will not pass smog check and not be able to drive your vehicle until it's fixed.

SO:

Anyone like to put in their two cent's worth on a problem I face?

A flat-head 6 for a 1941 Dodge truck with an over-sized military radiator which runs hot with a thermostat installed. Engine was blasted, baked, blasted and flushed before complete rebuild, all core plugs removed, new water pump and new reproduction distributor tube. Will heat up quickly and go over 250 degrees at idle in winter. The only thing I could think of was to try drilling a 1/8" hole in the t-stat flange to aid in bleeding air from the system at initial fill (which I have not done yet, seems that if this was necessary it would already have that). I am using 50-50 distilled water and Prestone regular "green" coolant. New fan belt, good fan, no fan shroud. Engine seems tuned properly, runs great. I would like to use a t-stat as it is a necessary part of the cooling system, but cannot when idling in the summer in parades.

How common is the fan shroud? It was missing when I got the truck, and I rarely see them on others.

Thanks for any ideas.
-Ken J

[Charles Talbert]

I would get a fan shroud in place before proceeding, air flow (or lack there of) is a critical factor, and will be a vital component for parades in summer conditions. You might look into a more viscious fan to pull more air flow volume and the use of a smaller diameter fan pulley so it turns the fan faster also.

You didn't mention the possible condition of the radiator. I can add that aluminum radiators are way better at transferring heat, we use custom built replacements on almost all our rebuilt trucks, we have noticed a vast difference. Since we have been forced into installing all electronic Cummins engines as of Jan 2010, (emissions regs) that require frontal charge air coolers, we now use 10 blade viscious drive fans with a full shroud, and 1.35 ratio fan drive to force more air flow. It works great and I love the responsiveness of the newer engines, but we now have to pay more attention to some issues that made little difference before.

As mentioned, electronically controlled engines do shoot a fault code if the temp gets outside a given range. This is a crucial part of the engines compliance with emissions guidelines. Too cool, too much bad stuff going out the exhaust, to hot leads to internal engine damage. The Cummins we are dealing with shoots a fault if normal operating temp doesn't happen quickly, shoots a fault on the warning lamp if the operating temp rises above 215*, an automatic shutdown is approaching if it exceeds 230*. Pretty ridgid guidelines must be adhered too if the engine is to operate within EPA guidelines. As a result running hotter than they used too is the rule. A full open thermostat in the Cummins doesn't occur until 205*

[gmharris]

I drove my pickup in the 126 degree heat of Death Valley with the air conditioning on. No problem. The temperature gauge didn't even move above normal. A properly designed and operating cooling system will have plenty of reserve.

If the thermostat is working properly, it will not cause the engine to overheat. Taking it out can only harm the engine over the long haul. Even during the summer, a missing thermostat will cause the engine to warm up slowly, if at all.

I thought the temperature gauge in my car had gone out. The temperature never read above cold and this was in the Summer in the California desert.

One day I drove up the nearby Cajon pass on a hot day. The temperature gauge needle began to move. Then I realized that the thermostat was bad. I replaced the thermostat and the temperature gauge read normal

About using distilled water, is there any real evidence (other than anecdotal) that it reduces corrosion? If so, why don't vehicles come from the factory with distilled water? I doubt that the cost would be significant.

I know that some industrial systems use specially treated water in their closed systems to reduce corrosion. I wonder if this could be used for vehicles?

[712edf]

Obviously my no-thermostat trick is NOT for most. I mainly do it on carbureted gas engines that are well past 100k in mileage & no longer have much in the way of functional smog stuff, if they ever did. They don't do emissions tests here (yet). This is strickly for the old beaters that I drive, the newest that I ever done this to being a 91 Ford Probe 4cyl & 93 Jeep 4.0 (yes those are FI, worked just fine).....But mainly my 70's 318 trucks. I don't do it to "fix" any overheating problem, I'd just assume to run them cool. And I have never had any issue with doing this, they all ran fine for years this way. I'd put the t-stat back in around Sept along with fresh antifreeze mixture.

To the originator of this thread, yes you need a thermostat. As do 99.9% of the vehicles driven do.

Bucky

[QuantumJo]

To the originator of this thread, yes you need a thermostat. As do 99.9% of the vehicles driven do.

I never asked if I need a thermostat. I know that it's there to keep the engine at proper operating temperature and should be kept in place... I can't remember ever running with out one.

Not having any personal experience driving in a warmer climate I had to consider, that there may be an advantage to running with out one. As of yet I haven't read anything that supports that.

[712edf]

I never asked if I need a thermostat. I know that it's there to keep the engine at proper operating temperature and should be kept in place... I can't remember ever running with out one.

Not having any personal experience driving in a warmer climate I had to consider, that there may be an advantage to running with out one. As of yet I haven't read anything that supports that.

I'm sorry. I believe my original statement about t-stats was in another thread started by another member (DB69) asking about what thermostat & radiator cap to use. I wasn't refering to you, being the originator of this thread. I lost track of where I was.

From the feedback apparently I am the only one who benefits from pulling out my thermostat during the summer months. I will continue to be the odd man out, as it works for me.

Bucky

[Gsmith]

MaineSS:

There was a very well-documented and researched article in MVPA's "Army Motors" magazine a few issues back which I believe described the use of waterless (anhydrous) engine coolant as tried in an older military engine. The conclusion was that it did not cool as well as hydrous coolant, and the engine continuously ran too hot. This is just from my poor memory, but I am sure I remember the basics correctly.

Gordon and Kevin:

If I may add, modern engines (OBD1 and OBD2, as of approximately 1995) will set trouble codes if the engine runs too cool. This is due to (as was already noted) the fact that a too-cool engine will run dirtier. As those of us under the control of the air pollution authorities know, a clean-running engine is much more desirable than an over-polluting one, as you will not pass smog check and not be able to drive your vehicle until it's fixed.

SO:

Anyone like to put in their two cent's worth on a problem I face?

A flat-head 6 for a 1941 Dodge truck with an over-sized military radiator which runs hot with a thermostat installed. Engine was blasted, baked, blasted and flushed before complete rebuild, all core plugs removed, new water pump and new reproduction distributor tube. Will heat up quickly and go over 250 degrees at idle in winter. The only thing I could think of was to try drilling a 1/8" hole in the t-stat flange to aid in bleeding air from the system at initial fill (which I have not done yet, seems that if this was necessary it would already have that). I am using 50-50 distilled water and Prestone regular "green" coolant. New fan belt, good fan, no fan shroud. Engine seems tuned properly, runs great. I would like to use a t-stat as it is a necessary part of the cooling system, but cannot when idling in the summer in parades.

How common is the fan shroud? It was missing when I got the truck, and I rarely see them on others.

Thanks for any ideas.
-Ken J

My M37 and M43 pull bunches of air across the radiator, so as Charles said start with a shroud, and yeah what's the radiator condition?

[maineSS]

Some might be wondering about my assertion that coolant velocity is never going to be a problem- if so, why would engines run too cool when the T-stat is out?

The reason is that cooling is controlled by flow volume more than flow speed in engines. Have you ever seen a water pump rated in "feet per second"? I haven't. The cooling system is designed to flow a certain volume (gal/min) of coolant to a radiator to exchange a certain amount of heat (Btu/min) to a certain volume of air (cu ft/min). The system is several times larger than it needs to be to account for weather conditions and fouling. If everything is running as planned, it should defintely overcool your engine.

To keep engine temp in the proper range, you need to run a restrictor plate or a T-stat. Race cars typically use restrictors because they run in fairly constant conditions, and a plate with a hole in it has no moving parts to fail. Road vehicles need thermostats to regulate coolant flow to constantly changing conditions.

There are many ways cooling systems can run hot. They're generally traceble to insufficient flow of air or coolant. The two major exceptions are cracks in the head or water jacket that let exhaust into the coolant, or insulating scale buildup. If you have a clean, properly sized cooling system, and the engine still overheats, exhaust leaks are high on the list of suspects. They usually take some time to open up, so if you overheat during road driving, it could be your problem. Scale insulation is usually evident by looking at passages- if it looks like the inside of a hotwater heater, you've got an acid cleanout ahead- not a lot of fun. Curiously enough, subjecting water to an intense magnetic field not only prevents scale, but removes what's already been deposited! It's being used to treat boiler water on an increasing scale, but I don't know if it works with glycol solutions. I also haven't seen how long it takes to descale, but I assume it would be as long as it took to deposit initially. Scale builds up most heavily on the hottest parts- the top inch of the cylinder bores, and on the backside of the head areas exposed to combustion.

Ensuring sufficient airflow thru the rad AND engine compartment is usually the biggest cooling problem- especially with engine swaps. When air is pulled thru the rad, it has to go somewhere- and that somwhere is the engine compartment. If a big ol' V8 is occupying a 4cyl engine compartment, there's not a lot of room left for airflow. When that V8 heats up, so will the air around it, increasing its pressure relative to the outside. Outside air will now go around the car, instead of the rad, and temps will climb bigtime. This is also a problem that usually occurs after some run time.

The MVPA article is something I'd like to see. Participants in the cross-country "Great American Race" have used Evans coolant with no cooling problems whatever. They typically are running Ford flatheads, which are famous for overheating. Evans coolant temps will be hotter than typically accepted temps, but the temps that matter are actual surface temps inside the engine. Using coolant temps to measure these are similar to measuring the temperature of your bathwater to see if you have a fever. Did the MVPA people measure oil or exhaust gas temps? They would give a better indication. The gold standard would be a cylinder head thermocouple.

With respect to using distilled water in coolant- Prestone uses it in premix solutions, and I have seen it recommended in both today's and Yesterday's coolant literature.

[Andyp]

hard water

I get the whole t-stat thing and have run without in emerg once,then have since always carried a new spare.
My question is if I have extremely hard water in my area, how would i pressure clean or completely flush the system?
I don't mind buying the good stuff but is it a matter of drain\fill\run\drain\fill\run ?or is there a better way.
fyi = the local rad shops would be using the same crap water that I have.
hhmm?

[maineSS]

There's no "flushing" treatment available for hard water scaling I know of- just the Muriatic acid solution poured into a sealed up block/head and allowed to sit, then drained out. That's followed with a neutralizing alkaline solution, then clean water. A very messy, time consuming job best avoided by not using hard mineral water to begin with.

If the rad shops in your area persist in using hard water, you might ask if they'll descale your cooling system for free using the acid method after it scales up. If the answer is "No", don't let them add anything to your cooling system- this is one case where an ounce of prevention is worth a ton of cure.

If you're not overheating now, just use distilled water for your coolant. If you are overheating, rule everything else out first- the acid treatment is a giant PITA.

[Blisters]

My truck has an original "honeycomb"-type large capacity radiator; I have removed the top and bottom tanks, rodded and flushed the core, and re-assembled. Clean engine block, clean radiator, new water pump, fresh 50/50 coolant/distilled water charge, new water distribution tube, new old stock t-stat, then a second new old stock t-stat.

Since both t-stats tested good in a pan of water brought up to boiling point (valves began to open at 160 degrees or so, fully opened at the marked 180 degrees), I am going to have to go with "find a shroud".

I had hoped that maybe I had missed some trick to the installation of these t-stats, but as they're simple and only go in one way I had not much hope for that.

As to an aluminum-cored radiator, I will avoid that for as long as possible. I agree they conduct heat better than brass, but I prefer the correct appearance of the honeycomb model. Since the model truck I have was used throughout the world in WWII in all climates, I believe the lack of a fan shroud is probably the culprit.

I have a crappy one here, but I will work at finding a good one as applied to the 1/2 ton WWII WC-series trucks.

Thanks to all of you for your kind input!

-Ken J

[gmharris]

I just purchased a 48 PW. It 's in pretty sad shape as it's been sitting out in the open for 15-20 years.

The cooling system was empty, but I found large chunks of rusted metal in the lower radiator hose, so I expect the system is not in the best condition.

Anyway, it too does not have a shroud on the radiator. I flushed the system and filled it with water and rust inhibitor. To my surprise, it shows no signs of overheating when I drive it.

Looking at the huge radiator and fan, I suspect there is plenty of cooling capacity, even without a shroud.

I had an overheating problem on one of my cars. Seems I went through the same process as you. Eventually, I figured out that the belt was slipping.

Make sure your belt is tight enough, and not glazed or worn. You should not be able to make the fan slip on the belt when you grab the fan blade (engine not running :).

Vintage Power Wagon has used shrouds.

On the other hand, my Dodge D200 with a 383 engine will not cool correctly without a shroud.

[Charles Talbert]

Just to recap all this

I would still recommend getting a shroud in place, especially important for parade driving, but shouldn't be an issue with an otherwise good system when driving on the road at say 40 MPH. After having a chance to read through all the post here, I sort of have a feeling something else that you have not put your finger on as yet may be an issue, ever just have that feeling? We've had a few I'm still scratching my head on, sometimes you do everything humanly possible it seems with virtually the same outcome. Outward things you see and know are good, some inward issues may never be completely figured out. Many times we have just felt all but certain that overheating issues were at hand only to find after checking that conditions weren't as severe as they appeared. You can purchase a hand held infrared thermometer at most auto parts stores, this is a reasonably priced, very valuable tool in diagnosing issues like this. You can get a temp on any surface within seconds. You can get actual surface temps along the water jacket area, radiator top and bottom tank, etc. An example of testing like this is as follows, if the engine temp read on the thermometer coresponds closely with that on the gauge, you can be fairly certain that no gauge issues are going on. If temps at the bottom radiator tank are not much cooler than those taken at the top tank, then that's a very good sign that coolant flow is restricted within the core or air flow restriction is in play. Air flow restriction issues you can see by examining the core surface, feel the lack thereof on the back side, etc. Ruling out what you can see leaves only internal core issues, so you know which way to go. If there is a significant difference between top and bottom tank temps, it's a safe bet that internal core flow and air flow are OK. At this point you would need to concentrate on possibilities within the engine, blockages restricting coolant flow, thermostat, hoses, sediment in the lower areas of the block, someone may have loaded it up with stop-leak at some point, or an internal coating of scale that Maine SS covered in his post.

I'll mention this as I've found it in many engines, you may have already covered it in your case. When the drain cock on the block is opened, no fluid appears, removal of the valve shows a blockage within the port. Digging around in the port usually reveals a soft gummy substance, sediment from years of service. Dig out all you can, sometimes we resort to a drill bit being carefully inserted to ream out the junk. We follow that up by placing the steam jenny nozzle directly over the port and steaming it until water starts flowing from the radiator hoses. Let it drain completely, and repeat this several times until it runs clear. I have seen this procedure prove to be a life saver several times.

[gmharris]

Yep, Charles, some very good points. Especially, the infrared thermometer and not trusting the dash temperature gauge.

Harbor Freight has some fairly cheap infrared thermometers which seem to do the job. An infrared thermometer can be used for other things such as diagnosing a dragging brake shoe or a cylinder that's not firing.

Also, don't always assume that just because something has been done, that it was done right.

I had an overheating problem on one of my cars I could not solve. A "rebuilt" radiator had been installed, so I didn't suspect the radiator. After much frustration, I installed a new radiator and that solved the problem.

One of my Power Wagons has the same problem with a gummed up block drain that you mentioned. I will go back and try to do a better job of cleaning it out.

I wonder if chemically cleaning the block of rust and sediment will get rid of the gum?

Thanks Charles, for letting us benefit from your experience with Power Wagons.