My 66 has been run a lot lately since I rebuilt it. I have noticed lately that the tempature will stay around 190-195 no matter what. I have a 180 t-stat in, do you think this is normal or is my cooling system is not up to the task? Also, ive noticed that when I shut it down the tempature will climp up past 200 degress for about 15 minutes before cooling off, is this normal? I have a stock belt-driven fan, stock radiatior, and stock water pump.


Thanks,

FERacing66

 

Well, if it's running more than the thermostat rating, then it is overheating. Mine does the same thing. I've been looking for a bigger radiator, and I suggest you do the same. Ideally, your radiator should be big enough that the temperature cycles with the thermostat opening and closing, instead of having it open all the time.

 

If it's under 500 miles and alittle tight it will make extra heat. Just because the stat stamp # says 180* it may not open at that temp (quality control). Is it a new stat and did you place it in a pot of water on the stove with a digital thermometer to check inital and full open temp? How many row radiator, age, mileage, you do a flow test? Fan shroud, clutch fan? Extra coolers infront of radiator? Yes you will read hotter on shutdown from the heads heating up the intake sensor, this is normal. Be careful with overheating if your running a auto trans for the high heat is hard on the trans fluid and seals. I know your on the ball to even ask but is timing within specs + - 5 degrees, sorry I shouldn't of asked.

Carl....=o&o>....

 

Mine does too, I run the Mr. Gasket High Flow/High Performance thermostats. It is about time to switch it back to a 180. I may even try a 160 and see what she reads. Guys, we aren't necessarily overheating. After an overbore your engine will run a little warmer depending on how much wall thickness you had to begin with and how much overbore. Believe it or not, an aluminum intake seemd to help mine a little. I have a newer radiator in mine (Modine 3 row) and a stock replacement water pump. I wonder if a higher flow water pump (or volume ...whatever) would help and you can get them in cast iron and aluminum.

 

It probably doesn't help that I have that A/C condensor and a tranny cooler in front of my radiator.

 

Before I installed the t-stat I checked it in a pan of boiling water and it did indeed open at 180. There are a few issues that I forgot to mention, this radiator is very dirty, when I rebuilt the engine, there was lots of buildup of crap in the water jacket and the radiator. I made a note to have my radiator hot tanked and pressure tested before I installed the motor, but all my money was blown on the rebuild and I was in debt because of it so I just said the hell with it and put it in. Also I dont have a fan shroud, so there is a few things I can do before getting into major money. As far as timing, I always set it by ear so I dont know what it is, I find the specs in the book to be unsatisfacotry. There is no clutch on this fan, it runs all the time.

 

Yep Carl is right!!! Some people I have told the this over and over again....A T-stat only regulate's what the lowest temp is going to be!!Its only there for the Heater , and in the winter to warm the car up!! If your engine's recommened running temp is 195 and your running a 180* stat..that not going to keep your temp cooler..just because of a lower degree stat... And like Carl said..If its a new build..everything is tight in the engine..once everything seats..the temp should drop!!

If it doesnt after break in..then you have cooling Problems!! Years ago I built SBC that were so tight you had to use 24 V to start them the first 500 miles....And they would run for 100K with know Problem...

But those days of those Kind of Parts are Long gone!!

I hope I explained it right Via typing....I speak words better than typing!!

Russ

 

Well I would definately flush your entire cooling system, get the radiator cleaned out and flow checked and if not satisfactory, replace with a new 3 row or a 4 row. You should probably already have a 3 row. You may be able to find a used shroud in good shape or it may be next to impossible. One place I know you can get a new one from is LMC truck. There maybe shrouds off of completely different vehicle that could work with some minor modification too.

 

Im not too worried about it, some people run there FE's over 200 degrees as a preference, as long as it doseant get too out of control I wont worry about it. BTW my engine is a little tight, main and rod clearnces are just a hair above .0015, I have an old battery and it would not turn it over at all unless it was really charged up with juice from the battery charger, so it is very tight for sure.

Thanks for the input all.

 

Battery may be getting tired (highly likely).

 

Sounds like the radiator needs to be rodded out, question is do the tubes get fatter when you apply 20 psi? Electrolysis over the years (can't be helped) plus high mileage will make the tubes paper thin. Ford has deep flanges for the tank to set in, a PITA to remove the top tank. If the tubes are thin it's time to recore. Manual trans no ac 2 row, auto with or without ac 3 row. Go to a 4 row or better yet 5 row stagger. Evans make a waterless coolant that has a boil point of 260*F without pressure and causes zero corrosion. It's your money and I can spend it for what you need. With water pump speed the 67 Merc 410's had the pump spin around 7% faster than the crank, (small pump pulley / big crank pulley. Trucks had the pump underdriven around 7%. Two smalls, small and large, large and small but large and large pulley combo would hit each other. Removing the stat will make the motor overheat as the water passes thru the radiator too fast to draw off heat, slow warn up and alot more engine wear. When you go from a 180* to 160* stat to "cure or fix" you overheating problem you will add more engine wear even at full 160* temperature. I run a stainless steel flex fan, cools better at low speeds but do random crack checks as this can throw a blade. Done rambling sorry.

Carl....=o&o>....

 

Where I live, there's an old time radiator shop that would rather fix your old radiator then try to sell you a new one. Most of the other shops just want to make a case to sell you a new, crap radiator. Get yours boiled out.

Do you have a fan shroud? You need one. Do you have the thermostatic fan clutch like the original? It matters. Also, you may want to put a restrictor in your heater hose in the summertime to prevent the radiator from being bypassed. They did this with Mustangs in the 80's and 90's to help them run cooler.

70% water, 30% anti-freeze. Use distilled water, the grocery store sells it cheap.

Use synthetic oil, it prevents friction better. In my Mustang, I can read the difference on the stock temperature gauge. BTW, add a little STP oil treatment for your cam. Just a little, not the whole bottle.

The engine has the least friction when the pistons are about 210 degrees F. The coefficient of friction is lowest at that temperature.

Use a good pressure cap and a coolant de-gas system (aka overflow bottle). It burps the air out of the system.

I did all this (except I put in a 180 RobertShaw thermostat and an 'export' water pump) in my Mustang. It ran too cold and I had to change the thermostat back to a 195. Runs warmer but I need to get a good thermostat to get it to run right.

 

I don't see anything wrong here at all. You say it has been run a lot, and it runs 190º-195º. That is in line for a new rebuild, and inline for normal. The Tstat opens to allow flow of the cooling system fluid, unlike the Tstat in our homes it does not control the temp.

The increase after shut down is normal as well, no air moving through the radiator allows it to go up.

Another thing, Do you have proof that the guage is spot on? Mine usually reads around 170º but I don't worry about it.

John

 

It is a brand new mechanical gauge, it has the thermotube thing that detects coolant temp. This engine is awesome though, what a blast to drive, and the sound!! It sounds a whole bunch different then when it was stock, you tell its got an agressive cam in it, when you rev it up, it sounds..........mean. Anyhow these temps are at low speeds with me having a little fun with it, If I drive normal, it goes down to 180-185, also on the highway it wont go above 185-190. Cant wait til this summer, ill be out of school and in a job driving this beast everyday. I need new rear tires already. =(

 

And if you have any experiences like me you will work just to seemingly have money to pump gas into your truck and have hardly any money left over for anything else!

Hopefully that is not totally the case for you though.