RUNNING HOT..after doing good stuff
 

So, my 39 Merc cools great, no issues. My passenger side waterpump was flinging coolant, so I did the following: sent the waterpumps to Skip for his well known excellent rebuilds, pulled the radiator and took to the rad shop. When removing the radiator I found there were no thermostats so I got a pair of Shewman high flow thermostats. The shop said the radiator flowed well, no repairs needed, just flushed out thoroughly. So I reinstall all of the above along with new lower hoses and filled with coolant, started her up and if allowed....it will RUN HOT! I have briefly run/driven it an was able to add some additional coolant, I do not believe there is any kind of air in the system. Just came back from brief drive, going to let things cool, and I believe I'm going to pull the stats. What do you guys think??

Shoebox

Re: RUNNING HOT..after doing good stuff
 

Did the rad shop take the tank off.
Lawrie

Re: RUNNING HOT..after doing good stuff
 

Also, what are you calling hot? 190, 200, boiling?

Re: RUNNING HOT..after doing good stuff
 

Probably not, but any chance you put the thermostats in upside-down?

Re: RUNNING HOT..after doing good stuff
 

Thanks for the questions..... no, the shop did not remove the tank. The only temp gauge is the original and previously would not go above "N"ormal. The needle gets to N fairly quick and then moves rapidly higher. The stats are 180 degree. I think this might be the excuse I need to buy a temp gun, but for now that's as precise as I can be.

Re: RUNNING HOT..after doing good stuff
 

Suggest that you check the stats to make sure that they are opening. Drill a couple of 3/16 dia holes in each stat. This will allow the air to escape as you are filling with coolant. May run hotter now that you have stats to control the temp. Should run at 185 degrees minimum. Just my thoughts!!!!!!

Re: RUNNING HOT..after doing good stuff
 

I'm thinking along the same lines as Art. Seen that more than once.

Re: RUNNING HOT..after doing good stuff
 

You DO have a fan on it don't you? LOL Really, I would think you should have the core rodded out.

Re: RUNNING HOT..after doing good stuff
 

Where did you install the stats? Up by the radiator or down by the head? From my experience, when installed up by the rad it takes a while for the heat to reach the stats to open, so the temp climbs. Unless you have holes in the stats.

Re: RUNNING HOT..after doing good stuff
 

Again thanks for all the excellent questions. I do have the stats facing correctly, the Shewman stats have 4 small holes, and they (the stats) are located up by the radiator per original. I verified operation prior to installing.

Re: RUNNING HOT..after doing good stuff
 

I believe it always prudent to change ONE thing at a time.
At this point, I'd suggest you remove the thermostats and see the subsequent result.
Do you have a hot water heater? If so, be certain the valve is all the way open. Remove the radiator cap and allow the engine to climb to operating temperature. Then, "rev" it up a bit. Shut it down, allow to cool.
You need to be certain all of the air is out of the system. I've never had a flathead that got air pockets but others have claimed they did. I suppose it's possible.

Check coolant level - should be covering top core plate. Install cap and see what happens...

Re: RUNNING HOT..after doing good stuff
 

Are you using an original temp. guage? They are not always accurate On my'48 when the guage is 3/4 of the way over, I get 160 to 165 on a laser thermometer. I'm running 160 degree stats.

Re: RUNNING HOT..after doing good stuff
 

You say you have Skips pumps.
As I recall in order for his high flow pumps to work properly he says NOT to use thermostats.

Re: RUNNING HOT..after doing good stuff
 

Believe he is using the stats GM recommends. Seems to me we are all attempting to solve a problem we don't even know exist. The original temp gauge indication is somewhat meaningless without checking the actual temperature. The question is, how do you know it is overheating if you have no idea what temperature it is running at? :)

Re: RUNNING HOT..after doing good stuff
 

If it isn't boiling over, it isn't overheating has been my experience.

Re: RUNNING HOT..after doing good stuff
 

What 'deuce roadster' said....

Re: RUNNING HOT..after doing good stuff
 

I also have a 39 Merc. On your rad does the overflow come off a bump on the top centre of the top tank. are you trying to use a 4 pd cap. that combination will not work.The overflow tub should come off the rad neck.

Re: RUNNING HOT..after doing good stuff
 

have you called Skip to see what he has to say?

and if you remove the radiator have them remove tanks and rod it out. a flow test is not a true indication of how clean the radiator tubes are.....

Re: RUNNING HOT..after doing good stuff
 

I suspect the gauge as well. With no stats and a proper cooling system the gauge should have read cold all the time unless outside temp was above 70. Should have been having trouble getting any heat from heater in cool weather.

Re: RUNNING HOT..after doing good stuff
 

I'm with Donald1950 on this one

Re: RUNNING HOT..after doing good stuff
 

After installing the rebuilt pumps did you make sure they turned complete revolutions freely. What engine the original 39?

Re: RUNNING HOT..after doing good stuff
 

As someone said earlier get a laser thermometer. With this you can pinpoint temps throughout the cooling system. If a thermostat is stuck or a radiator not flowing you will see hot or cold spots as appropriate to the condition.

Re: RUNNING HOT..after doing good stuff
 

I agree with JSeery, will purchase a laser temp gun to verify what the actual temps are. 51MERC.... Skip states to ONLY use Shewman stats if using stats, with his pumps. Regarding johnny, yes my rad is as you describe, with overflow coming off bump at center of rad top, so what are you saying regarding what cap to use??

Again, thanks all.

Re: RUNNING HOT..after doing good stuff
 

I think most of you that have responded need to go back and digest the initial post.
The car did NOT overheat prior to swapping the pumps and installing thermostats. The gauge, regardless of its accuracy never showed more than "N", normal.
So, unless the radiator shop screwed up the radiator (unlikely) the issue is either with the new pumps and / or the addition of thermostats.
This is an easy one to solve but must be taken a step at a time.

Sure, it may be nice to see how the radiator is (or is not) functioning but it still comes back to what was recently changed - THAT'S when the issue began.

I'm 99% certain, it's the pumps and / or the stats. My guess? The stats...

Re: RUNNING HOT..after doing good stuff
 

Put a house type fan against the grill and run the engine at about
speed of 35 MPH. This will give you the operating temp at normal
driving speed. The stock fan does not provide enough air through
the radiator at slow traffic speeds or long idles. G.M.

Re: RUNNING HOT..after doing good stuff
 

Kube, spot on as per usual. I pulled the stats last night and drove.....car cooled well as before doing these things, temp needle not going beyond N. I agree however that I need to find what exact temp Normal is, as I wish to run stats. Harbor Freight has an Easter Day Weekend sale, going to get a laser temp gun,....... right after church. Will report findings.

Re: RUNNING HOT..after doing good stuff
 

Another example of Fault Finding 101.
Always go back and check what you last "played with or changed" and to always simplify by only altering or changing one item at a time.
glad you solved this one.
Phil NZ

Re: RUNNING HOT..after doing good stuff
 

Perhaps you should call Skips to see if in fact he advises NOT
to use thermostats.

Re: RUNNING HOT..after doing good stuff
 

after reading all this info I understand with noo stats. the flat heads will run cooler??. Jack

Re: RUNNING HOT..after doing good stuff
 

That is true for many engines - as without thermostats, the cooling system might be over-cooling the engine . . . and it never really gets to a 180 degree operating temperature. That is NOT a good thing.

In my 42 Merc flathead (heavily modified - 284 cubes - running Skips pumps), if it is NOT hot out AND I don't run thermostats, then the engine will not get much above about 140 degrees. This is TOO cold of a temperature to run it at - causes undue wear, problems with oil and sludge, corrosion, etc.. So, I do need thermostats to keep the engine up at the correct running temperature.

I have NOT ran the special thermostats that GM and others talk about (Shewmans???), I run just a regular 180 degree thermostat. As this is a new combination, I will see how well it does this summer. If I have issues, I MIGHT try the Sherman thermostats . . . though the article that 'The Professor' did showed that he did not cool any better with these, than his regular ones.

Okay - that's my story . . . and I'm sticking to it! LOL

B&S

Re: RUNNING HOT..after doing good stuff
 

Check the timing. Retarded timing will keep the engine hot.

Lonnie

Re: RUNNING HOT..after doing good stuff
 

Without stats, my avatar roadster would NOT get above 110 degrees and ran poorly. I have 170s in there now and as soon as it gets above 150, it runs like a clock. With or without stats depends on the whole rest of the system and so you can't make a blanket statement about whether they are necessary or not.

Re: RUNNING HOT..after doing good stuff
 

Pulled Shewman's stats and engine cooled??? I wonder if you installed
them as instructed??? Don't sound right to me. I have used a number
of Shewman's stats in 90 plus weather and never had a problem. These
stats need to be installed up against the top radiator inlets. They have
preflow holes so some water flows as soon as the engine starts. G.M.

Re: RUNNING HOT..after doing good stuff
 

A laser thermometers are less than $20 on Amazon. Good to have to help track issues like this down.

Re: RUNNING HOT..after doing good stuff
 

If you have a shoebox with the original motor in it the stats are NOT up by the radiator. They are in the heads! The older motors had the stats in the hoses.......

Re: RUNNING HOT..after doing good stuff
 

Yet another example of why folks should read the thread prior to commenting.
Please, go back and read Post #1

Re: RUNNING HOT..after doing good stuff
 

When was the change made where the stats were located in the hose down by the outlet on the head? I thought that it was in 1937 when they went to the outlet at the center of the head.

Re: RUNNING HOT..after doing good stuff
 

Hi, if I have read this right my 49 should run cooler by removing the stats. ??? Jack.

Re: RUNNING HOT..after doing good stuff
 

What does this thread have to do with a '49 Ford?

Re: RUNNING HOT..after doing good stuff
 

Kube that is how these posts go sideways,next we will read no antifreeze water only. "LOL"

R