Running too cool . . .

Question for the group with background.

After all of the help I received here, I have the old mustang running pretty good so I took it on a road trip this week to see how it would perform on the interstate. Overall, pretty good but with the cool weather, the car seemed to be running on the cool side.

Background. This mustang was a Florida car, and as such had an over sized radiator installed to deal with the heat, daily in town driving.

Now in NC in the spring it seems that the radiator coupled with the mechanical fan is too much, and I wonder if is causing the electric choke to reengage a bit a highway speeds as it seemed that I may have had some of the symptoms of that on my road trip. Is that plausible?

So the question:

I am planning to adjust the choke this afternoon to get it to fully open at the cooler op temp, but how can I get the car to run in a more normal range in the spring? Is there something I can do to the thermostat, fans, to correct this without sacrificing warm weather cooling?

Just what I see in your signature about your setup I am guessing its fairly likely you could be cooling the choke down at at steady cruise on a cool day. What are you using to get the heat off the headers? Tube wrapped around one or the little HELP! box? Make sure the line from the headers to the carb is as short as possible and make sure it at least has that thin insulation tube on it. Insulating the tube even more may help. Even with all that working as best they can the headers get a lot of airflow and when the ambient temps are low are not going to tend to retain much heat. Think of the factory setup, you had a massive hunk of cast iron there to get hot with that choke tube connected right to the center of it. The actual part the choke used was a cast iron bit inside the main cast iron piece so ambient cooling of the exhaust manifold did not really change the heating of the area where the tube was since it was in the exhaust flow. Headers dont have much mass to them so a little airflow cools them fairly quickly and I suspect whatever you are using to transfer the heat is not very massive either so it too can loose a lot of heat to ambient cooling. Perhaps for winter restricting the airflow would help. If your coolant temp seems to be staying normal you can just try blocking the airflow on the header side. The fan pretty much does nothing once you get to 30mph, the 'ram air' pretty much takes over from there.

Another option would be to go to an electric choke. There were only 2 or 3 diameter choke stats between most of the makes of carbs so you should be able to find one that fits your carb. If you get a Ford one it runs off something like 7v from the back of the alternator. The rest were 12v and GM ran them through the oil pressure switch so that when there was more than 5 psi of oil pressure the choke would heat.

I'm planning a swap to an electric fan for the same reason.
In the meantime a hotter thermostat might help, try a 195°.
One trick might be to bypass the heater core by connecting the water pump inlet and outlet to each other.

bucfan1234":22lgcug6 said:

I wonder if is causing the electric choke to reengage a bit a highway speeds

Click to expand...

Unlikely. As long as you have the proper voltage there you should be fine. The Holly weber electric choke take 12 VDC, if you've got that then your choke should be fine.

How are you measuring the engine temperature? The old mustang gages were not the most reliable. If you don't have a quality after market gage consider getting one. You can also get an after market radiator cap with a temperature gage in it. you can also get a candy thermomater from you food store and use it to calibrate your mustang gage by putting it in the open radiator cap hole and comparing it to the mustang gage as the engine warms while running.

If you are running cooler, I would check the thermostat. They do have a finite life span. Also if you install a new one claen the mating surfaces of the housing completely, and check the thermostat for a bleed hole, most have them, just hold it up to the light and look for some feed through, when you find it make sure that it is highest in the system. If it does not have a bleed hole I would consider buying a better quality thermostat.

How are you determining that it is running cool? Are you using the temperature gauge on the dash, or is it that the choke doesn't open fully? Don't go just by the temperature gauge, they are only a step up from an idiot light . If it is the choke not opening fully, then an adjustment may be necessary.

The thermostat is there to keep the engine at a specific temperature by restricting flow to the radiator until the engine reaches the operating temperature set by the thermostat value, then it opens fully. I know Ford's are notoriously cold-natured beasts, but they will eventually get hot. Sufficient cooling is usually the problem.

If it's a southern car, it may have a low temperature thermostat (trying to keep it cooler in a hot climate). As recommended in a previous post, go with a higher temp (195*) thermostat, but only after verifying the actual engine temperature you are running, and the choke setting.

Thanks, everyone.

Yes, using the temp gauge on the dash.

I will try these suggestions, and then look into the thermostat. Thermostat hasn't been replaced since Florida, and it is likely that it was a low temp thermo, so its seems like the logical place to start.

Before you buy stuff and change a bunch of things, just make sure the choke plate is open all the way at operating temp. When the engine is hot, loosen the ring of the choke spring and turn it just a bit to make sure it stays open. The little black cap tells you which direction is which.

You might want to use some carb cleaner to make sure the pivots are all running freely. If you think it needs lube, use graphite dry lube. Often, just polishing the sliders and such with steel wool or fine emery paper is enough. Of course you have to make sure that the choke closes when it is cold, but you can observe this directly the next morning. This may take some tweaking over a couple of days because everything changes when the engine warms up.

You could put in a higher temp thermostat as mentioned. First however, you might think about just blocking off half the radiator with a piece of cardboard . This reduces the cooling area. They do it all the time in the upper Midwest. I'm surprised that no one has said that yet. Pull it back out when it gets hot.

Now you can get ready to post: "Running too hot in summer."

JackFish":3ozbu0cm said:

In the meantime a hotter thermostat might help, try a 195°.
One trick might be to bypass the heater core by connecting the water pump inlet and outlet to each other.

Click to expand...

Remember he's talking about driving in cool weather - he might want the heater to work . I have a similar problem with my Falcon - at about 50* or less the air flowing over the engine will keep it from reaching full temp . I have to put a piece of cardboard with a small opening in the middle in front of the radiator to restrict the airflow . It won't hurt to check the thermostat - they can quit altogether , stick closed , stick open , do all sorts of things .

You sure it's got a thermostat in it? I found out the hard way last winter in my Econoline. Was always impressed that it never ran hot. Left here one Saturday morning when it was 5 degrees and froze my ass off...

That Econoline quickly got renamed "Frigidaire..."

Scot in OKC

Econoline64":205lwhv0 said:

You sure it's got a thermostat in it? I found out the hard way last winter in my Econoline. Was always impressed that it never ran hot. Left here one Saturday morning when it was 5 degrees and froze my ass off...

That Econoline quickly got renamed "Frigidaire..."

Scot in OKC

Click to expand...

8) ding ding ding, we have a winner here. chances are that the PO removed the thermostat in an attempt to eliminate overheating before they put in the larger radiator. so the first thing you want to do is check to see if you even have a thermostat, and if so what temp it is designed to open at.

I missed that little tidbit about the ELECTRIC choke so most of my post does not apply to this issue.
An electric choke should not really care much about ambient temps and airflow within reason which I would say would be anything above 0*F.

If you have or can borrow one of those IR temp guns you can pretty easily determine when the stat opens without taking anything apart. Just start it up cold and take periodic readings as it warms up. The overall block and heater hoses should heat up but the upper radiator hose and radiator should stay at ambient till the stat begins to open which for typical car applications should be 170-195. If you take readings around the stat housing it will be close to the actual internal coolant temps. If the temp in the radiator hose seems to rise with the rest of the engine then your stat is missing or stuck open.

I have been running my daily driver (80 diesel Cadillac) with the mechanical fan removed and about 90% of the radiator blocked since October. Im in MN where its hardly been above freezing and we have had plenty of well below O*F days. Even at that the engine seems to have trouble getting to stat opening temp on the cold days. Removing the fan sure helped the warm up at idle. It was a clutch fan but even free wheeling it moved enough air to keep the engine cool.

I'm running a 180* Tstat. With my cooling system in good order and with coated headers, my electric choke always resets over 40-50MPH on cool days.

But on those days, my heater barely works either.

Try a warmer Tstat, but I seriously doubt it'll fix the choke issue. You need to wrap the choke housing to insulate it some. It doesn't draw enough electricity to keep itself warm on really cold days.

Now that I think about it I dont think I have ever had an inline with an electric choke, all my electrics have been V's.

Perhaps thats an advantage to the V's is the choke is nested in the V with a little less airflow.

Hi bucfan.Another good way to check your t`stat,is to use a cooking thermometer to watch the coolant temp rise in the radiator.Remove cap,and insert the thermometer in the rad cap opening and start the engine.Then watch for the needle to start moving and see when the t`stat opens.Cooking thermometers run about $9.00 plus tax regardless of where you get one.I got mine at Ace Hardware for about$9.00 including tax.
By the way,if the coolant is at a high flow rate as soon as you start the engine,you have no t`stat installed.
Leo