What thermostat should I put in my 52 F1 flathead? Should I put in a 160' or a 180'? The truck is running a little bit more hot than I would like it to. The temp gauge is at the last mark before it gets all the way on hot. Would a 160' make it run a little less hot or what should I check into. The truck runs fine other than that. I am going to try and find a tempature gauge to put in the raditator to see if it is really that hot or not. Thanks for the reply.

 

is the radiator clogged???


not an expert but in the experiences ive had a lower temperature thermostate would open too much, would be flowing way too much and wouldn't stay in the radiator long enuff too cool the antifreeze and would cause overheating.

i would be sure the radiator is clean and not with half the tubes broken and welded off. be sure the timing is right on and the exhaust isn't plugged up at all. definatly get a thermometer and put it in the radiator with it running and see how hot it really is i would do that first its inexpensive and readily available. thats where i wouldstart there.

 

I agree that before you start making drastic changes, find out what your temp really is. Lower temp thermostats only open sooner, they do not prevent overheating. If you have an issue that is causing the engine to run over 210F, whether the 'stat opens at 160 or 180 won't change that.

 

"IF" your gauge is accurate, you're running way hotter than you should, even with a 180. If you see white deposits in the radiator core, with the cap off, add some rad cleaner and let it get good and warm, neutralize, rinse etc. Then take the radiator in for a rodding-out, not just a chem clean. Get everything 100% and you'll have many years of cool running with modern antifreeze.

 

Clean engine and clean radiator, air deflectors in place around the engine, timing where it should be and it won't run hot.

As the guys have said, changing thermostats won't fix these other problems.

edit: Stock was 180 - that's what I run.

 

LOL!

And you thought if you asked a simple question "160 or 180" you'd get a simple answer didn't you.

And you already know about the free flowing through the radiator - cause we talked about it on the other thread.

Maybe if you were to ask the guys what temp thermostats are normally used they could tell you that.

Keep Wayne's 210 degrees in the back of your mind!

And remember, if you are running the engine with the truck parked it may just get a little warm.

I got your PM and the gauge will be in the mail - 3 day express - tomorrow.

In the mean time maybe you could go buy an "El Cheepo" Sunpro mechanical gauge for $15-20 at auto zone, install it, and see what the temps really are, and if you really have anything to worry about (accurate gauge) as Ross suggested.

With the voltage reducer on the electric gauge, we may just have to adjust the electric gauge a little - I had to on mine. But you need to find out if you really are hot or not first.

At least that way I think you could elliminate some of your fears about overheating.

 

clean the radiator , and flush the system , and i run 180's in mine . the only reason mine started running just a little warm was i listened to an " expert " elsewhere and didn't put sealant on my head bolts , thusly my haed gaskets started leaking after a couple years use ......... foolish me ....................

 

The radiator looks to be clean. I can see the tubes and looks like all are open on the top but I guess it may be clogged on the bottom although when the pit **** is open water come out rather fast like it is not stopped up. I don't think it is a radiator problem I'm dealing with because of that. I guess the normal temp is around 210 it should be running from what wayne said. I will get a thermometer and check what the real temp is before I pull the radiator out. Thanks for the quick information you people are great.

 

I bought new and improved waterpumps from The Hot Rod Company along with 180 degree thermostats. Keeps the temps nice and steady. I'd go this route if the previously stated resolutions dont work.

 

Not much more to add to what's all ready been said, I have the 180's in the hopped-up FH.

 

be sure to look at the rad. from the front and back where the tubes are brazed to the top and bottom tank, looking down in neck of the rad you might see open tubes but when you look at where they connect to the tanks you might find a few or more that have sprung a leak in the past and someone cut the tube and brazed it shut... after you check the temp with a new thermometer check the timing and be sure your muffler isn't all rotted out inside with a baffle blocking half of it off than i would pull the rad. and flush it out real good holding it upside down and running a hose through the bottom and let the water flow for awhile maybe take it to a radiator shop and have them flush it out... people would use pepper in a radiator and some would even use an egg to stop em from leaking and if they did there might be a 30 year old mass of nasty clogging it up that you cannot see

 

Normal running temps should be around 180 - 190, unless it's really hot out (over 90). As someone mentioned, a correct shroud, good belt on the fan, air deflectors, all make up part of the cooling system.

 

Well I just put a therometer in the radiator and it read 196' when the truck was ideling. I guess my next step will be to check and see if the therostats are opening all the way up or to change them. I did not see any water flow with the cap off. I have two brand new 160' therostats I can put in it unless you guys think I should have the radiator rotted out to see if there is a pluged spot in it first although I am getting a lot of airflow through the radiator in the front. At that temp the gauge is one mark away from being on the hot. /what should an old flatty run as far as temp? I wouldn't think it should run that hot if everything is working like it should. I did see some blackish looking stuff floting around in the spout of the radiator. I am stumped and need some answers on what to do next. If one of the therostats isn't working on one side would that make it run hot like that. I will do whatever you all suggest I do first. Thanks for the replys.

 

I took the radiator into the shop and they rotted it out and told me that it was about 40% plugged up so he cleaned it and I put it back in and have the same problem. Has new therostats in it too. The water pumps are running fine it looks like with a tight belt on them. I am used to the temp gauge being around the middle of the gauge and not on the last mark before completely on hot. I need to do something else to get it down around that area I would think. The timeing is set right I would think because it starts up to easy without any back firing. I do have a timing light but have not used it in many many years so I'm not for sure it is working properly or not either. Any other ideas that I might try. Julie is sending me another gauge so when it get here I will trade the one I got out and see if that works any better. All of this is on a flathead 8.

 

196F is not too hot, imo. That's pretty much normal operating range and seems like you have a healthy engine if you achieved that temp with a rad with 40% blockage. Just because your gauge doesn't read like you think it should doesn't mean there's anything wrong. Btw, the term for cleaning the radiator is rodded, not rotted. The shop tech removes the tanks and pushes a rod throught the core tubes to clean out the debris and deposits inside, then puts everything back together. If it was "rotted", that's a whole different can of worms. ;-)