An often discussed topic on this forum is radiator condition. I have an idea that I'll probably find out is not really anything new, but it's not something I've not heard of, so, here goes:
Several recent forum threads concerning radiator cooling ability, plus the fact that I just noticed that Harbor Freight Tools has a $35.00 no contact Infrared Thermometer on sale right now for about $26.00 is what prompts this post.
Anyway, as we all know, a Model T engine that is fully warmed up to normal operating temperature will have coolent flowing from the cylinder head thru' the upper hose into the radiator inlet at or near boiling temperature, say maybe between 200 degrees or so to 212 degrees (boiling). The upper hose will of course be much too hot to touch.
A good radiator that is cooling properly will have a lower radiator hose and pipe that is much cooler, in fact, usually cool enough to touch, at least momentarily without getting burned.
So it seems to me that with a good working radiator, the temperature difference between the upper inlet and lower outlet should be at least 40 or 50 degrees or so,...maybe more.
It also seems to me that the more inefficient a radiator is, the less temperature difference there would be between upper (inlet) and lower (outlet).
Why couldn't a table be printed up that would indicate the relative condition of the radiator by listing this temperature difference from whatever normal is in a good radiator,....I don't know what that would be, but hypothetically, say maybe 50 degrees, and list that ideal temp. difference less and less by a degree at a time, all the way down to no temp. difference at all which would indicate a totally inoperative radiator. Each degree less temp. difference would also list a corresponding approximate percentage of cooling inefficiency.
In other words, hypothetically, say a 50 deg. difference would be an excellent radiator, no temp. difference at all would be a totally ineffective radiator, and a 25 deg. difference would be a 50% effective radiator.
The idea being of course that it would be very easy to measure this temperature difference with a no contact IR thermometer which has now become a very inexpensive tool. Seems like that would take a lot of "guesswork" out of evaluating the radiator condition of a Model T with an overheating problem. As it is, it seems like we always say,......well, maybe your problem is a radiator that isn't working properly because it's partially plugged, or it's so old that the fins are loose and not effectively transfering heat away from the tubes. Well, why should we say,...."maybe it's a bad radiator", if there's a way to determine that for sure. Why spend $800.00 bucks for a new radiator just to see "IF IT MIGHT (OR MIGHT NOT) HELP" WITH AN OVERHEATING PROBLEM!
Not sure if I have explained my thinking on this properly, but if this is at all understandable, what do you think? Might be that there are those folks (like professional engine rebuilders) who do something like this already, but there is sure still a lot of "guesswork" among us backyard mechanics on the forum, about whether or not the condition of the radiator is the real, actual reason for an overheating problem,..... FWIW,.......harold
I would think some more variables would need to be considered as well to make sure every thing is spot on so not to get false readings, ie,amount of top tank coolant, fan efficiency, right speed, blade pitch etc. engine condition, a fresh rebuild runs hotter, and I'm sure there is more to take into consideration to maybe get an average.
I think the temperature drop across the radiator could be a useful part of the story but not the whole story.
Other then the radiator condition several other things will effect the temperature drop across the radiator. Some include:
The air flow through the radiator, more air flow - greater radiator temperature drop.
The water flow through the radiator, less water flow - greater radiator temperature drop.
The air temperature, lower temperature - greater radiator temperature drop.
The ability of the coolant to transfer heat, plain water - greater radiator temperature drop.
The amount of heat the engine is generating, many things will effect how much heat the engine is generating.
Maybe if the radiator could be put on a "test machine" with measured/known air and water flow, known air and water temperatures and a known heat load a radiator could be accurately evaluated by measuring the inlet and outlet temperatures. Other then that there are many variables that will limit the usefulness of an in car test.
Yeah, I think you guys are right, I guess it's just not that simple. But all I know is, immediately after a long enough drive to have the engine thoroughly warmed up, pulling into the driveway and immediately grabbing the pipe that connects the lower radiator outlet with the inlet on the side of the engine block, and noting that the pipe is just nice and warm, as opposed to the upper radiator hose that is much too hot to touch, tells me that the radiator is working just fine. I just thought for $26 bucks, an IR thermometer to measure the actual temp difference might tell me a lot more than just the "touchy feely" test.
........still think I'm gonna' go over to HF Tools and pick up one of those IR temp gizmos tho',......harold
The ir thermometer is a great tool and not just for radiator temps! You can find missing cylinders , also what people don't normally use them for. Things like checking axle bearings from one side to another or wheel bearings or even to check which side brake is dragging or not even working! anywhere you thing heat can be a indication of a problem.
I agree that temperature difference would be a great indicator of radiator performance. I know for a fact that many auto mechanics keep and use an IR thermometer to diagnose overheating.
It may not be the only tool needed for diagnosing overheating but it sure is a valuable one. I had to replace a bad radiator about 2 years ago (loose cooling fins) and now I wish I had taken readings while it was still in the car. Next chance I get I will take readings on the new radiator though, and post them. I'm guessing reading the top tank and the bottom tank would be best .... after the car has reached normal operating temp.
I sure would like to see the readings on your radiator too!
Right on, David!
I always carry an IR thermometer in the pocket of my Expedition when pulling the trailer with the T in it. Every time I stop for a rest stop or meal, I take the time to go around and check the temps of the hubs on the trailer wheels.
I also check the tread temps on all the trailer tires as well as the tread temps on the car tires.
A higher tread temp than the others tells me that the tire is low on air. A low tire not only takes more gas to pull it, but it also is more likely to blow.
I have always thought that a blowout on a trailer tire, let alone on the car's tire, is almost the most dangerous thing that can happen on the highway. The only thing that scares me more is a vehicle going the other way, drifting into my lane, and me having no way to get out of his way.
These thermal images were posted a few years ago and present some nice insights.
Note the radiator interior surfaces heat, and the color range of the upper hose.
Now....compare this view of the color range of the lower pipe, and see how much cooler. (Left side '26-'27 engine).
Now for heat!! check out the color range of the exhaust manifold.
And again, the front side of a good radiator, note the heat color range of the upper part of the radiator, and the cooler color temp range of the lower radiator as the coolant falls and looses heat by the radiator radiating heat to air.
I wonder if one of those tools could be used on a date to determine if your advances are having a positive effect?
Jim has it right, I think. You'd want to set up a test station, in an environmentally controlled shop. And take the engine out of it since there are so many variables there. Just a hot water supply tank, a basin to catch the cooled water, some thermometers, a constant speed fan, and a flow meter/valve.
Would be too many test variables to gain any knowledge to construct a test for condition of a used radiator. The thermo syphon system lets the motor heat up, then the coolant flows, in relation to the engine heat, (i.e) fast run up a hill is more load on the motor = more heat. Running slow in parade is less air flow = more heat retained.
Best way to test a radiator is to mount the thing, and run the Ford, in various conditions expected.
Am going to do that with this honeycomb. Bought at Hershey and had it cleaned and tested at shop, the repair guy said it 'looked good to him', now that is a 'test'
So will mount it to the '23 and drive it around and see if it cools the same as the one on it, which cooled well until the upper tank outlet got a big pin hole leak and spewed coolant all over the core from the inside to the outside!
Using this one as test replacement, that will test out this honeycomb.
Removing this round tube original today to take to the radiator shop and have the upper outlet soldered back, and have him check it out too. Was working good like a used T radiator should.
Cooled OK on long runs, gurgles a bit more after shut off on long run, but still no steaming or spitting of coolant. Lower pipe is cool to touch when idling, so I know its working pretty good. Of course a new radiator would do best.
Engine block is clean, motor rebuilt, timing set good, hot spark to the coils from the mag.
All these elements won't change when I replace the radiator, so its a good test for the honeycomb to see it the honeycomb is up to the task
We have discussed this topic many times on the Early Ford Club of America Forum and I do have a suggestion that may help. The topic "cooling" and "thermostats" is like water pumps to Royce <grin>. I will participate in this one.
I have done the following for that Forum:
I set my 1935 Cabriolet up in the driveway so as not to have a negative air flow at the radiator. Raise the hood and remove the radiator cap. Stick a plain kitchen thermometer in the top tank and crank her up. I check my thermometer with a 160 degree thermostat. Record the ambient temperature and we are ready. Start and get idle.
That '35 will sit there and run and run and run and run and..... In short, it has a radiator that is good and has not been to the radiator shop since 1974.
The argument "flat head V8's ran notoriously hot". Wrong, they do not run hot if the radiator is good and the distributor is correct. It will not boil. Close but no banana.
I will set up this week with my stock 1914 because I am curious what the car does run in temperature. The 1914 has a two year old Brassworks flat tube radiator in it. It will hardly "glurk" after a 40 mile an hour run, 90 degree ambient. The car does not over heat.
I am curious to see what it will do sitting up in the driveway like its Flathead sister. I am running 50/50 coolant per Brassworks. I will record the temperature every five minutes for a half hour and see what old Ken gets. I may be surprised.
Ken in Texas
I think if you were to set up a test station, with all other things being equal, you'd just want to know the heat transfer ability (i.e. it drops 220 degree by X degrees), and whether there is *significant* resistance to flow (versus a "new" radiator).
We can assume that a used/old radiator will have higher flow resistance and worse heat transfer. But the question of whether what you measure will make a difference in *your* car would take a ton of testing of old radiators that are considered "good" and those considered "bad" to generate a comparison data set.
I don't know, Harold. I don't think it's a bad idea, myself. It seems like someone had a Delta T figure for a T radiator a couple of years back. I'm thinking it was 70 deg F, but I could be wrong on that. In other words, there should be a 70 degree difference between the upper and lower tanks. Maybe it was 60? I don't remember, but it stands to reason that if the lower tank temperature is not much different from the top, that the radiator is not doing it's job. Perhaps it's not too scientific, but take some measurements on a T that has no overheating problem and then find someone who has a T that overheats and compare them. It wouldn't take much to get a feel for what the Delta T ought to be.
I hesitate to say that several of us should just report our temps because these non-contact thermometers are notoriously inaccurate. But if all we are doing is calculating a differential, we might be in the ball park, even if the actual numbers are off.
Thanks Hal. I'm obviously no engineer, but I just wondered that even if these inexpensive IR Thermometers might be somewhat inaccurate, I thought that somebody smarter than me might be able to figure out the best way to use one to at least help make a more "informed" decision as to whether or not to blow $800.00 on a new radiator, just 'cause it just "MIGHT" help with an overheating problem.
(At least my wild idea generated some good thought and discussion, right?)
That last IR photo shows how much the sheet metal of the hood radiates heat from the engine. If it were just the sun on the black paint the cowl would be just as hot but it shows much cooler.
Harold, your concern about the accuracy of an inexpensive IR thermometer is valid, but:
For the most part, what you would use the unit for, is to determine the DIFFERENCE between the readings at point A and point B. The actual temperature of each point could be several degrees off from what is displayed, but generally it's not that critical.
You could, of course, check the accuracy by boiling a pan of water on the stove, then turning off the burner and reading the temperature of the pot. Allowing for altitude, it should be pretty close to 212 degrees.
You could do the same with a bag of ice, I suppose, but we generally use these things to measure hot things, not cold.
Well...tonight is the update on the 'Honeycomb' radiator secured to replace the leaking low radiator.
Had the radiator shop clean it, and they said "looks good", well, could have been because of the fresh black paint the shop used!
Anyway, here it is 'looking good'
And after install on the '23 cutoff, filled it up, and gads! Lots of leaks from the lower tank, and only one from the upper tank! The core didn't leak at all, go figure. A steady stream from around the lower inlet casting to the tank, and so so many little weepy holes drip dripping.
But the lower tank is steel and must be a sieve now, as circling the drip spots, ran out of yellow marker ink! Don't think JB weld is a choice, unless I slather a thick layer all over the bottom of the lower tank.
Didn't have a chance to run it and see if the core cools the motor, the radiator would have been dry before the end of the driveway.....Ug.
I believe cleaning is sometimes the death knell. No doubt a good cleaning will not harm an otherwise good radiator. However, not all radiators are good. Cleaning what was once a marginal radiator can sometimes turn it into a bad one. I used the vinegar trick once and got so many leaks, it never recovered. Guess the crud was plugging all the holes.
Well, maybe the crud would have loosened out on a long drive if it hadn't loosened in the cleaning first - buying a used radiator is a crap shot, an unknown radiator should be really cheap to be worth the trouble testing it for use considering the chance for success is so low.. I know, out of about eight old T radiators, originals and honeycombs, I have brought home to my garage only two of them works and another one can be fixed, I think.. (it has been modified for hot rod use by a previous owner)
It was a blessing in disguise. It forced me to buy a new Berg's radiator. I had been fighting this thing for years with various small leaks and occasional overheating. When the cleaning rendered it almost unusable, I bought the Berg's and haven't looked back. Should have done it YEARS before.
On the 24th I said would set up a test in the drive. I think it is interesting. The run was 45 minutes and the cool down 15 minutes. Total one hour. Not one drop of coolant was lost out of that radiator. (My driveway has its own spots from me living here 40 years).
This is the setup.
I set the car so as not to have negative airflow. Although it was still most of the time, there was a very slight breeze at times during the run but the fan did the work.
As you can see, I am running a Kingston Four Ball with aluminum intake. The maximum temperature finally settled out at 191 to 193 degrees. Sort of depended on the breeze, hood open or closed and me tinkering with the fuel mixture and spark.
The coolant is 50/50 distilled water and ethyl glycol as suggested by the Brassworks. I'll try the same static test this summer when we will be blessed with 90+ days.
This car will not boil or lose coolant at 38-40 mph sustained speeds in 90+ degree days. I'll try it again near 85 degrees or so when that comes to us down here. I could have waited until this afternoon when it got up to 82 but then the wind began to blow. I need it still when I do this or it doesn't mean anything.
I believe if you get close to that chart you don't need a new radiator. You just need a 70 degree day to check it.
Ken in Texas
Where are you checking the temp? Somewhere on the block? Top tank? By chance did you do any checking of temp drop between the upper and lower tanks?
I was taking the readings with this thermometer in the top of the radiator tank.
It would reach down into the coolant by the baffle.
The only thing I had to do was keep the radiator itself from heating the gauge. That is what the sock was doing up near the filler neck.
I did adjust the spark and fuel mixture as the car warmed up. You can see the spark down and throttle minimum.
It would be interesting to see what the temp is at the bottom tank but that requires some access for the temp probe. What really matters is that the engine tends to stabilize at 191 degrees in the top tank doing nothing but idle for an extended period of time. Well below boil.
I am satisfied it would run out the six gallons in the tank if I just let it run today. That was the same scenario I found with my 1935 Cabriolet V8. That V8 has had the same radiator in it since 1974 and it wasn't new then. Radiators don't have to be new, just good.
I drive this car on tour, have put 8,000 miles on it. Rebuilt the engine 3,000 miles ago and have 2,000 miles on that brass radiator since late 2013.
I believe if a person is going to drive their car on tour, get a flat tube. Puttering around neighborhood for 30/40 miles or less at a time is not what I mean "driving".
If a Model T gets hot going to the grocery store, some things are wrong with it and/or the way it's being driven. Get with a T friend and see what you have before you spend $800 -1200 dollars for a radiator. I believe most folks that drive their cars will agree.
This is just a way that I can really check a radiator. If I bolt another radiator on that car and it performs like that brass one did today. It's good. I do have several in my shop that are NOT good even though they "look" good. I hope this helps.
Ken in Texas
Just for grins, I checked the temperature on the '18 Touring just after a 15 mile roundtrip to breakfast with a 10 minute idle while she ran inside the store for cat food and a short idle while getting my IR thermometer. Ambient temp was 61F. I got 212 to 216 on the top tank and 99 to 117 on the bottom tank and lower pipe. That's about 103 differential on average. This is a Berg's flat tube with a mix of water and green antifreeze.
WOW! I'd say your cooling system and new Berg radiator is sure doing the job! I'm guessing that that's about as big a temperature differential as we could ever expect Hal.
By the way, I guess I sorta' started this IR Thermometer "temperature differential" thing, and in case anyone wondered, the reason I haven't contributed any readings so far is because I have not yet purchased an IR thermometer! .....but I do intend to,.......harold
I was surprised that the temperature differential was that high. I tried touching the tanks and pipe to kinda 'double check' my readings. The top tank was too hot to touch and the lower one and pipe, you could have held your hand on all day. I could detect very little warmth in them at all. I would expect to see the low temperature rise as ambient temperature rises. But I think the upper one will remain about the same. That is my theory anyway. I'll try to remember to check it again when it is warmer outside. and then again when it gets hot.
I do wish someone with a marginal or poor radiator will chime in with some measurements.
Hal - That's my hope too,.....that someone, maybe several people more people, would measure their radiator "temperature differential" and share the info with all of us, because while it's been pointed out that there are many other causes for a Model T to overheat, I still think this discussion we're having on this thread would help us all to be able to "evaluate" radiator condition and enable a more intelligent decision as to whether or not to spend $800 or so on a new radiator.
Sheesh,.......just proofread this and I think that's the longest sentence I ever wrote! That's me,....always too "wordy',......harold
Sheesh,.....even "proofreading I missed,...."several people more people"! Oh well,....gotta' blame that on a couple of phone call interruptions!
I tried this today on my 1912 touring. Temperature in the garage before starting the car was 78 degrees. The Infra Red thermometer showed the radiator and engine at 78 degrees before starting.
After a 30 minute drive, including going down to the level of the San Gabriel river and back up to my top of the hill neighborhood 4 times I pulled in the garage and measured ambient again at 78 degrees, no change.
Top of the radiator tank measured 204 degrees. Bottom of the radiator measured 118 degrees. I run a gallon of Prestone and the rest water, about 2.5:1 mixture perhaps.
I don't have the Harbor Freight Infra Red thermometer or a meat probe so I had to make do with what was in the tool box.
I bought one from Amazon after reading a bunch of feed back from others who bought one. Price was just over fifty including shipping. I will use it for Babbitt so had to have one that would go to 900 degrees this one goes to 2200. Been playing with it for a week now its amazing how accurate it is on different temperatures with a lazar light pointer giving you a temperature in one second and automatic turn off in ten seconds. Like you Harold good radiators are expensive and my money is betting my 16 will have some issues before it runs at temperatures I like.
I bought 1 for 35 dollars at Harbor Freight and I love it. But I later found 1 on ebay for 9.99. From china but it was a vender I had bought a soil tester from and it came as it was supposed to. The tool looks exactly the same except for color of the case. Big A auto-parts locally has 1,case is a different color for 69.99.
So be careful what you pay for the little buggers.
I have made 2 purchases from this vendor and yes it takes a while for the items to get to you but for the money saved I can stand the wait.
The quartz clock movements work like a champ. I bought 10 so far.The items come in epacket marked as commercial samples.