The symptom was smoke out the breather cap. That sounds like blowby, not an overheating issue. Especially since the OG temp gauge never gets above halfway.
I was installing mechanical temp gauges to rule the stock gauge not reading correctly and figured I might as well install new thermostats. Would blowby possibly cause the geyser when I tried burping the coolant system?
X38 is correct, smoke from the breather has nothing to do with overheating. Your engine has some blow by which is perfectly normal for an 8BA with any amount of miles on it. You will also have some coming out of your road draft tube that comes from the top of the intake and discharges below the engine. For the coolant system, fill it to just below the neck and drive it. It may puke a little bit out of the overflow when it heats up but it will stop. Without a coolant recovery bottle, which I assume yours doesn’t have, the level will stabilize at some point below the fill neck. Forget the “burping” procedure, that will happen on your first drive. The cooling system in that Flathead is not comparable to modern cooling systems that must be bled at multiple points to get the air out.
Do you think it's worth removing the thermostats and testing the to ensure they're opening up at the correct temp? Or does the fact that it geyserd when it got hot imply the were opening?
Reading that you are in Denver made me think that altitude is against you with the rad cap off. The 212F boiling .point is a sea level or zero altitude. Water at 5000 ft boils at 203 F. The rad cap needs to be on to hold pressure to keep the coolant from boiling. That is why all the warning with opening a rad cap on a hot engine. The coolant can instantly boil and flash steam when the pressure is released. At a minimum the engine needs a good working radiator cap given the altitude. There is a lot of good advice here. https://mountainhouse.com/blogs/backpacking-hiking/effects-of-altitude-on-water-boiling-time There are a lot of for and against coolants in a flathead engine. I live in Canada and we have to mix antifreeze to a 50/50 ratio at a minimum to keep it from freezing. The boiling point is higher with Prestone 50/50. I have never lost a heater core or a radiator running Prestone for 50 plus years including 20 year old trucks.
If you don't drill a hole in the thermostat, air is trapped below the thermostat so the heated water is not in contact with the stat. DRILL THE HOLE.
Alright I think I've got my marching orders. You guys are awesome, thanks so much for your advice it is much aplareciated.
Make sure that you drill the hole in the proper place You want a small amount of coolant to bypass the thermostat air can get out this way https://www.jalopyjournal.com/forum/threads/thermostats-in-flathead-ford.1226816/ Go to post 16 This is a good read about thermostats in a flathead Hunt for the Denver Timing Association...DTA They have a great bunch of 'oldtimers' I'll PM you a contact number Good luck
What you experienced is actually normal. I don't know how many times I have dumped coolant out on a fresh fill. The problem isn't air trapped in the radiator, it is air trapped in the block. An easy way to get most of the air out cold, is to remove the temperature sending unit and fill until coolant comes out that hole. With a flathead you would need to do this on both heads. Replace the sending unit and/or plug, fill the radiator, replace the cap and get the engine up to temperature. Once it is up to temperature, you can check the coolant level and finish filling the radiator.
I used to have a 1973 ford F-100 back in the 80's. I recall the manual said to have the heater turned on also to bleed the hole system. I would think it applies to all engines.
Interesting enough, maybe that pressurizing is a head gasket issue? Not entering the combustion chamber but combustion gases in the coolant?
I guess if these tips don't work will have to start looking into other possibilities. I hope it's as simple as drilling a hole in the thermostat and running it with the cap on. It was running fine before
I just tested the thermostats they take quite a while to open up, I put them in when the water was at 180 degrees. They opened after about two minutes and by that time the water was at about 200 degrees. That coincides with what happened when I was trying to burp it. The car got to about 200 ish and then I am guessing they opened up, all that pressure came through the radiator and geyser'd out the top. I am going to get some new thermostats and send these back. I'm a newb but that seems like a long time to wait for them to open up.
Whatever the rating on a thermostat, 180, 195, etc, the rating determines when the thermostat first STARTS to open up. A 180 thermostat starts to open at 180 degrees, but fully opens at a higher temp, typically about 20 degrees higher than the rating such as the 200 you experienced. They don't instantly open all the way at 180. This might be a helpful link https://knowhow.napaonline.com/temperature-control-engine-thermostat-testing-tips-and-tricks/
lol yea just got off the phone with speedway and they said the same thing. So if it doesn't open until 200, isn't that kind of hot? I feel like a 160 would be better since it'll be fully opened at 180 and likely keep the temperature at around 180/190.
All thermostats have a a temperature range at which the begin to open and fully open. Also, are you aware there is a recirculation hole at the top of your water pumps that allows water from your engine to recirculate before the thermostats open? Despite what the video shows, there's really no need to drill small holes in 8BA thermostats. Read about it here: https://www.fordbarn.com/forum/showthread.php?t=278985&highlight=water+pump+hole+8ba+pumps You are wasting your $$ if you buy new thermostats. Your 180's should work fine.
Well seeing how hot it got with the 180s scared the hell outta me to be honest. Maybe it was because I didn't throw the rad cap on but I'm gonna try the bypass holes in a 160 like the shoebox central video and see how it goes. If it runs at 180 then I'm just gonna keep them, if it's too cool I'll try the 180s.
If you live in a cool climate, run the 180's. Remember, the thermostats don't control how hot the coolant ultimately gets. They only control the temperature at which the coolant in the engine begins to flow out to the top tank of the radiator. You are going to see very little difference between the 160's and the 180's.
I will add a caveat to that... I've tested different brands of thermostats side-by-side to check opening temps, as well as opened areas and opening speed. The best I found at the time were "Stewart" brand, which I found to open quickly, consistently, and with a large annular area opening. A few bucks more for a quality thermostat is money well spent.
most of the previous posts have given you good information. Always check thermostats in a jug or pot (kitchen bench) before using. Before installing thermostats, I fill everything up through thermostat housing to level where coolant starts to come out of thermostat housing. I do this “ SLOWLY “ so that water can dribble down allowing time for air to displace. Can alternate between housing and radiator. Then install thermostats and hoses, and continue filling slowly through radiator cap. When everything is full, I will run for a minute, at idle, cap off or loose, ( air would like to go somewhere quickly) turn it off, top up coolant and repeat process until no more coolant can be added. ps, I have never drilled the thermostats out, - although I have often thrown the thermostats out of vehicles years ago as I believed that faulty thermostats caused more overheating issues than any other or all other problems combined. I think that your geysering is probably due to trapped air and coolant trying to form steam……… Others are welcome to disagree with me…….. (now, if only I could figure out the issue with my wife’s ot HID xenon headlight bulbs……).
Nope. This whole thread revolves around the belief that smoke from the breather was due to overheating. The OP then did some work on the coolant system and ran the engine with the radiator cap off which resulted in the coolant flowing rapidly out. This caused him to “freak out” and go down the rabbit hole of over analyzing a problem that seemingly doesn’t exist. Now there is a whole thread about thermostats operating or not, drilling holes, burping, and all kinds of other nonsense. He needs to learn that if you run a car without the radiator cap, sometimes the coolant will rapidly flow out, that’s just how it is. In the end, this guy is just trying to learn but he is quickly finding out that the simplest of things turns into a two page thread of opinions when placed on a public forum.
Thanks Clem, I appreciate your thorough a concise response. I was contemplating filling the block with coolant through the heads before installing the thermostats so it's nice to see other people are doing this. I am new to all of this, most I ever did was change the oil and brake pads on my f150 but I am eager and excited to learn as much as I can. You have all been extremely helpful and patient with me and I really appreciate it.
LOL I have learned my lesson and yes, I tend to over analyze things. I am an analyst by trade and I tend to over think things. I'm working on it! I hope you all enjoy your weekend!
Hey guys! So.. quick update and set back lol I installed the new thermostats and drilled the holes, filled the heads with coolant before installing the water outlets, let it sit for a day to seal up good. This morning I went and connected the hoses and filled the radiator with coolant and the damn radiator is leaking fluid everywhere LOL so... I took out the radiator and took it to my local radiator shop to see about getting it re-cored but they are asking about $800. I don't want to throw down that kind of money atm so was wondering if anyone had any recommendations for a good aluminum replacement. I am looking at one on speedway that's about $350 its a direct fit, 3 row. How many rows should I be considering for a flat head application? Thanks
Check into Champion radiators, I've used them in about 3 hot rods, including flatheads. For today's aluminum radiator suppliers, I think they are good quality. My flatheads run very cool, current one struggles to get up to 160*, they cool very well. I paint the outer edge of the fins, look like an original, hide the shiny aluminum. Just my experience, good company to deal with.
Great thanks for the heads up will, do you think 3 rows is enough? What PSI cap should I be using on a flathead? Current one has 7lb.
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