Overheating on a 170 in a 1961

[Notar61]

Hello,

I seem to be having some overheating issues. The 61 I'm working on has a new 2-row original style radiator, new water pump, new hoses, and a new 180 degree thermostat. Back at the end of May I had been driving it around a local town and it didn't seem to have any problems, temperature stayed right in the middle all day. Yesterday I was driving it at a steady 40 mph and the temperature gauge pegged out fairly quick after about 4 miles. It is warmer out now since it is going on July, but I don't understand what could make it drive so well last month and now it seems to overheat so badly? I haven't really messed with anything recently.

Based on some research I did, maybe I should check the timing? Also the fuel to air ratio on the carb? I also heard that a blown head gasket could be the culprit.

Does anyone else have any leads or maybe something I'm over looking? Thanks for any help!

-Andrew

[ew1usnr]

Hello, Andrew.


I don't understand what could make it drive so well last month and now it seems to overheat so badly?

Maybe the thermostat is stuck closed?

Is your fan belt tight?

When the radiator cap is off and the the engine is is running, can you see that the coolant is moving (circulating) in the radiator?

Thanks, Dennis.

[Notar61]

Dennis,

Thanks for the ideas.

Hopefully it's not a stuck thermostat. It's brand new. But I guess anything is possible.

The fan belt might be something though. I did put a new one on after I replaced all the cooling system parts. Maybe I didn't get it tight enough? That would make sense in that it was fine right when I put it on, but it might of slowly loosened up over time......thus making it overheat recently. I will have to check that today when I get home. Does anyone know the torque spec on the tensioner bolt?

I can also open up the radiator and verify if the coolant is moving around in there too.

Thanks again!

-Andrew

[Luva65wagon]

In addition to Dennis' great spot-on suggestions, you may want to verify your lower hose has a spring inside of it. With the motor off reach down and see if you can squeeze it to the point of collapse. Lower hoses are under suction and at a steady speed the lower hose may have got sucked closed.

I assume also the car actually did overheat with some evidence other than the temp gauge? Make sure that it isn't just a faulty sender.

Checking for flow does two thing at different points in time. When you start the car cold, cap off, there will be very little, if any flow and movement. Once the thermostat starts to open (if it opens) you will see the flow of coolant begin as you are looking down into the radiator.

Regarding a blown head gasket, this is, of course, possible, but would be the last thing to check for. Though there are testing tools for this - sniffers for combustible fumes out the radiator - there is also a potential for the water as you're running it to begin to bubble and froth like Old Faithful just running it there in the garage. If that doesn't happen, I would probably rule that out.

Also A/F mixture would be almost a non issue on a stock-ish Falcon.

[Notar61]

Roger,

I don't think my new lower radiator hose had a spring in it. If it did I may not of noticed. I can check though tonight. Do you know anywhere I can get a spring to put in there? I saw some for the V8 engines that some places sold, but not one for the six cylinder engine.

I'll do the radiator "cap off test" and let you guys know the results once I get the chance.

Hopefully its just something simple like the belt being loose or the lower radiator hose needing that spring.

-Andrew

[Luva65wagon]

You can get springs. In fact I bought a lower hose and spring (for something) once thinking the lower spring was "optional" and the hose came with a spring too...

... not sure if I still have said spring.

But check first and see. Hopefully it is simple. If all your changing was because it was overheating before, you may have simply not fixed yet what was wrong.

Keep us posted.

[Notar61]

Hello all,

Last night I checked the fan belt and it was tight.....hadn't loosened up like Dennis had thought.

I also squeezed on that lower radiator hose and it is pretty easy to smash down.....so no spring probably. My old radiator hose probably had one in it but I didn't even think to look and tossed it. Gonna have to find one of those springs now.

Roger do you happen to remember where you bought your hose and spring at? I called NAPA last night and they didn't seem to think I could get just a spring for the radiator hose.

I didn't have time last night to sit and watch the radiator with the cap off, but I plan to tonight or tomorrow.

Thanks again for everyone's ideas and suggestions!

-Andrew

[Luva65wagon]

I couldn't find (quickly) the spring for the lower on a 170, but here's the one for a 289 - and you could probably twist it in. Even if it is a little big or small, you can usually manipulate them to go in and stay put.

https://www.npdlink.com/store/products/mustang_spring_lower_radiator_hose_keeps_the-143875-382.html

There is debate on the need. Some say "YES" and some say "NO." My basic reasoning is that if the hose is soft cold, it is softer all-the-more hot. And it's not easy to see happening - while driving down the road - so for $5 it is worth doing just to rule it out. And I feel new hoses and find them inferior to those made in 196X, so why debate it. Considering your old hose had one, there's no reason not to make sure the new one does too.

Still do the other checks, even before the spring-add. These are telling of other things worth knowing.

[thumb]

[Notar61]

Roger,

Yeah I think the spring would be a good idea. Might as well at this point. I'll go ahead and get that one for the mustang and try and get it to fit.

And once I do some more tests, I will report back with what I find out.

Thanks!

-Andrew

[Notar61]

Okay. Radiator spring is ordered. I will get it installed once it gets here.

Last night I did take the radiator cap off and let the car idle. After awhile the coolant did start to move around and flow. No bubbles or anything too. I did notice that the level seemed lower than the last time I topped it off. So maybe there was a bubble and it got worked out? Seemed weird that the coolant level had dropped.

Do I need to try and burp the coolant system again?

-Andrew

[Luva65wagon]

Do I need to try and burp the coolant system again?

I'm pretty sure there was probably a few pockets of air that worked their way out. Top it up and run it a little, let it cool, check the fluid. It will probably stabilize. There is also, I suppose, a chance it did off-gas a bit (spew) when it got warm and you lost some fluid. Do you have a coolant recovery or would it have spilled onto the ground?

You'll have to rinse and repeat all of this when you pull the bottom hose off, so maybe hold-off doing any more until you have that done.

I did some more thinking on the lower spring debate. I bet (though I've not researched the debate much) that the naysayers say the "pressure in the system" should be enough to keep the hose from collapsing. Technically, I suppose, that would be true if the pressure was greater than the suction caused by the pump. But again, how would you know? Mount a video camera focused on the lower hose? Springs, I believe, we a fail-safe to make sure it doesn't happen. Why, then, are we buying hoses, or are they selling hoses, without them? I used to work in an auto parts store and all the lower hoses I sold (as best I can recall) had springs. These were all Gates hoses back then. Now, who knows where these hoses are coming from. I can take a guess...

:NERVOUS:

[Notar61]

Roger,

Thanks for all the info.

I don't have an overflow reservoir for the radiator, so if it off-gassed it would of just went onto the ground.

Guess I will try the spring and see where it gets me. Hopefully it was just some air bubbles that got caught up in the cooling system that caused the overheating. I will be sure and burp and cycle it a lot when I have to re-install the radiator hose.

Yeah the new hoses I bought were Gates brand, but no spring. Seems weird that they would just dump using the spring, but maybe it's a cost saving measure?

I did notice this little note on a website selling the Gates hose I bought.

"Re-engineered materials resist vacuum collapse. This reduces the need for internal springs in many applications."

I'm still going to use the spring for peace of mind. One less thing to worry about!

[Notar61]

Got some work done on the car this past weekend.

-Got the spring installed on the lower radiator hose.

-Felt like my back brakes where adjusted too tight. I don't think this was the problem, but I thought I should make them a little less loose.

-Found out that the diaphragm was completely disintegrated in the vacuum advance on the distributor. Replaced it with a new one.


Bad thing is I refilled the radiator and tried my best to burp the system, but it was getting too hot just idling. Maybe I need to cycle it some more.....could be air in there still since I just re-filled it.

Also I need to check the timing but I was unable to do so, because I couldn't find the notch or mark on the harmonic balancer. Or is it somewhere else? I see the thing with the lines and the numbers, but shouldn't there be another mark on something else that I line up with the correct number for timing? Anyone got a picture?

I'm going to try a new thermostat too. I've had 3 people tell me that thermostat is probably the issue......even though it seems like the coolant is flowing if I idle the car with the radiator cap off. :confused:


-Andrew

[redfalken]

There should definitely be a notch in the edge of the harmonic balancer for timing. It may have been painted over or dirty. I usually put a dab of white paint on it once found so it's easier to see under the timing light.

Or, if it's running well enough for a drive, find a steep hill and mash the throttle going up. If you hear pinging let off the gas and pull over to retard the timing a bit. Do the same test until the pinging almost goes away. It may barely ping when you really hit the gas but won't ping during normal driving.

That is usually the best way to find the timing your particular engine and the gas you are using runs best at. The manual has the timing way too retarded in my opinion but they did it for gas economy and having it a little more advanced gets more power and performance.

I've always been told that having the timing too advance can cause overheating problems too so make sure that is dialed in.

[Luva65wagon]

The thermostat may be opening, but too slowly or not completely. If uncertain - change it.

Also, many thermostat are completely closed when cold. I always drill about a 1/8" hole near the edge of it and place this at 12 oclock when I place the thermostat in the housing. This allows you to fill the radiator and have the coolant flow everywhere without hitting a wall and form an air pocket.

If you Google "Drilling hole in thermostat" you will see many pages on this. I've never read anything on-line about this (just did it now to see if there was anything out there I could point you to) and it seems there is a lot of debate about this. I learned this long before there was this thing called Internet. I'm only advocating one hole, placed near the top, to allow air to escape the block when filling. Any run-time advantage, as mentioned on threads of the Google search, are superfluous to this discussion as I feel a good thermostat, radiator, etc., etc., negate any other mods to a thermostat people may be doing. Many think no thermostat will help cooling, but it doesn't. You need some resistance to flow to allow coolant time in the radiator a allow the radiator to act as it is designed for - a heat exchanger. Too fast and it doesn't get that chance, and too slow the engine can heat the coolant more than the system can cool it.

Agree with Kenny too about the timing. Making the changes based upon driving it is ideal, though you can begin all of this at the factory setting to get you in the ballpark.

[Notar61]

Just installed a new thermostat. No luck though. Car still overheats. I can see coolant circulating in the raradiator but the temp gauge pegs out after idling for about 5 mins. Is this a sign of something way worse....maybe engine wise??? I'm at a loss at what else to try......

[ew1usnr]

Just installed a new thermostat. No luck though. Car still overheats. I can see coolant circulating in the raradiator but the temp gauge pegs out after idling for about 5 mins. Is this a sign of something way worse....maybe engine wise??? I'm at a loss at what else to try......

Could it be that the temperature gauge is bad? Unless the cooling system was dry it almost does not seem possible to peg the temperature gauge after only idling for five minutes.

Maybe you could try a ThermoCap to get an independent verification as to what the temperature in the radiator actually is.

5783

See: https://www.amazon.com/Mr-Gasket-2470R-Domestic-ThermoCap/dp/B000OF7MJS/ref=sr_1_1?ie=UTF8&qid=1469382111&sr=8-1&keywords=thermocap+2470R

[Notar61]

Dennis,

Yeah maybe it is the gauge or the sending unit. I feel like I've gone over everything else at least 2 or 3 times now.

I bought a new sending unit when I started throwing on all the other new cooling system parts. I just got it at a local parts store....looked the same as the old one. Is there something wrong with the new one maybe? Maybe its producing an incorrect reading, if it is the wrong sending unit for the car? Is that possible? Maybe I should get a sending unit from a resto-mod place....that way I know its the correct type for sure?

Guess I will try that radiator cap with the temperature gauge too.

Could the overheating be indicative of a bigger, more serious problem? My older brother seems to think the engine is on its last leg or something....but he always throws this suggestion out at the sign of any issue.

Hopefully I can get this figured out really soon. It's driving me up the walls.


thanks,
Andrew

[ew1usnr]

Yeah maybe it is the gauge or the sending unit. I bought a new sending unit when I started throwing on all the other new cooling system parts.

I am just putting out ideas:

Ground the sensor while it is cool and have it connected to the gauge. The gauge should read cool. If the gauge pegs hot there is a probably problem with the sensor, or possibly the gauge.

You could test the accuracy of the sending unit by putting it in hot water. Heat the water to about 180 degrees and use a thermometer to measure it. 180 degrees should be mid-range on your cars temperature gauge. Then ground the sensor and have it connected to the gauge and drop the sensor in the hot water. The gauge should read mid-range. If it pegs hot there is a problem.

Or, just buy another temperature sending unit to replace the one you have, and see if the new sensor pegs hot the same as the previous one. If not, the problem is solved. If it reads the same, the problem is not with the sensor.

Just look at this philosphically and keep telling yourself "This is a hobby. This is a hobby." Avoid thinking about presidential politics and do not get stressed. :)

[doghows]

Not to be a smart *** but is the thermostat in the correct way? I only bring it up because I did put mine in backwards before and she blew her top.
Just looking for the simple stuff. Good luck.

[Notar61]

Yeah I guess some sensor testing is in order. Hopefully I can get to the bottom of this.

And Dogshows, no worries on the thermostat question, but the old one was in the correct way and the new one I just installed went in the same way as well.
(Spring towards the engine, pointy end towards the radiator).

I may be grabbing at straws here, but is it possible my oil pump is dead or in the process of dying? I had a flickering oil pressure light lately, but just figured the oil pressure switch/sensor needed to be replaced. I read somewhere that if it was on the fritz it could cause the engine to overheat pretty quick. Just a thought, although I read that it is rare that they ever go out.

Thanks again everyone for all the help on this!
-Andrew

[Luva65wagon]

Andrew,

The temperature and fuel gauge both operate off a 5-volt voltage regulator on the back of the gauge cluster. Is the fuel gauge working well? If it too is misbehaving, then this regulator may need to be changed. It's a crude device at best and they will seriously alter your gauge readings if bad.

Also, there is overheating and there is high temperature gauge readings. Overheating is blowing coolant out somewhere. High temp readings can be checked for using any of the things like Dennis suggested checking for.

Of course, if the water is flowing, the thermostat has to be opening. You can often use that point, at which it opens and water begins to flow, as a "read" for what the gauge is showing. Stock gauges have no temps written on them, so if you have a 180° thermostat and you watch the gauge, when you see water just start to flow look at the needle on the gauge. If it is already pegged at that point, you can rest knowing it is not reading right. If it is reading low at that point, yet continues to climb - then you may have something totally unusual causing the overheating. These would include everything from a shot water pump, leaky head gasket, cracked block, cracked head, or the engine is on its last leg. :rolleyes: But really, as a motor gets old and sloppy, it tends to make less heat than more of it. Ring friction is at a minimum as is cam-lobe friction, which causes a lot of heat.

By now it sounds as though you have changed all the obvious things, so the question I guess I'm asking, is it a blow its lid overheating or simply an indication via temp gauge of overheating, but nothing is spewing?

[Notar61]

Roger,

Water pump is brand new and I'm not seeing any coolant leaking into the engine oil or vice versa. Who knows on the cracked head or cracked block.

When it overheats it is a steady climb. Once it hits the high end of the temperature gauge, there is no spewing or boiling over. I've had it idling with the cap off when it pegged out and it was only really hot to the touch and maybe steaming like cup of hot coffee. That's it, nothing really explosive or overflowing.

-Andrew

[Luva65wagon]

When it overheats it is a steady climb. Once it hits the high end of the temperature gauge, there is no spewing or boiling over. I've had it idling with the cap off when it pegged out and it was only really hot to the touch and maybe steaming like cup of hot coffee. That's it, nothing really explosive or overflowing.-Andrew

So this is totally a gauge reaction? Never a spewing? While running at temperature (water is now flowing) the coolant would be exactly as you say it is. Remember, also, a radiator cap raises internal system pressure and lowers the boiling point - but can also induce pressure-induced failure, like a crack might require. These will usually lower the coolant levels pretty quickly, so if the fluid is always the same, then I would focus on the gauge. The sending units are easy to find still at many auto parts stores. No need to source these from Falcon specialties vendors and pricing.

[Notar61]

Roger,

Yeah as far as I can tell the gauge is the only thing that is freaking me out. It pegs out pretty quick, but the car never does any spewing or boiling over.

So yeah maybe it is the sensor.

I'm going to buy an infrared temperature gun after work today, so hopefully that will allow me to verify the temperature when the gauge is pegging out. I might get a oil pressure tester kit too, just to verify what's going on with the flickering oil pressure light too.

I will report back with any new info I find out.

thanks again,
Andrew

[Gitanesteel]

Roger,

Yeah as far as I can tell the gauge is the only thing that is freaking me out. It pegs out pretty quick, but the car never does any spewing or boiling over.

So yeah maybe it is the sensor.

I'm going to buy an infrared temperature gun after work today, so hopefully that will allow me to verify the temperature when the gauge is pegging out. I might get a oil pressure tester kit too, just to verify what's going on with the flickering oil pressure light too.

I will report back with any new info I find out.

thanks again,
Andrew

It's definitely a possibility. My dad's 98 Contour SVT just went through a bout of the temperature gauge showing the car was overheating. But, no spewing or overflow. Turns out it was the gauge that was bad.

[Luva65wagon]

Kind-of a funny... but I've had about 4 different temp gauges and bits on my Ranchero so far. Had to change it initially when the sender was 1/4" pipe and I had a 1/8" pipe hole, but the 200 six ran very cool. Then I swapped to the V8 and it always "read hot", quick, but never spewed. I changed the sender (again) and the gauge changed, but still read hotter than I liked. Then I added an under-dash gauge and it seemed to read OK under normal driving, but showed hot (200°+) in any traffic driving condition. Then I finally decided to spend good money and get a more-than-$30-China-gauge (sprung for an Autometer gauge); and got a radiator cap gauge; and got a thermal pointer-meter; only to find all three read differently.

So I finally said to myself - if it doesn't blow steam, don't sweat it.

FYI: Mine is a .060 over bored 65 289, which until it is good and broke-in (if that ever happens at my current 100 miles a year) it will probably run a little warm. Many sites say don't bore a 289 to .060 over without a wall thickness check. I bought the block already bored, so I never did that. I have added as much as I can to aid cooling on this Ranchero, so I'm pretty confident that it is as cool as I can get it. If it ever blows up, I have a 302 I'll rebuild and throw into it. [thumb]