Monitor coolant temp, no factory gauge?

Engine, fuel system, cooling system, heating, carburetors, exhaust, transmission, wheels, and other items related to the moving the car.

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MFE
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Monitor coolant temp, no factory gauge?

Post by MFE »

What are people whose cars don't have factory temp gauges doing for monitoring coolant temp?
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TonyC
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Re: Monitor coolant temp, no factory gauge?

Post by TonyC »

Well, essentially, preventive maintenance; first, making sure the circuitry for the idiot light is in proper working order, making sure all the conventional components (water pump, fan clutch, thermostat, pressure cap, recovery tank if any) are in working order, making sure the entire cooling system is flushed to include the block itself, and stopping immediately if the light ever comes on. If the engine is properly checked, then it should never come on, except during starting.

Flushing is more involved than many people think, especially for engines this old. You need to remove the drain plugs in the block (if there are any) and flush out any rust scaling trapped in there. If nothing comes out immediately when you remove the drain plugs, then you know you have a very involved flush job ahead of you. I learned this myself very recently.

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Re: Monitor coolant temp, no factory gauge?

Post by JimA »

I put oil pressure and engine temp gauges in the ashtray on my 1978 Continental. 1.5" gauges fit; 2" don't.
IMG_1426.JPG
The screen is for a GPS/backup camera/sound system installed by the previous owner. The GPS and backup camera are handy, and they did a nice job, but I wish they had left the original sound system in it.

Gauges disappear when ashtray is closed.
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Re: Monitor coolant temp, no factory gauge?

Post by action »

Coolant on all of my vehicles is drained and refilled every 3 years or 36,000 miles. (This is the year I do a 3 year service on my fleet and two thirds are done)
Check coolant level COLD at least quarterly
When starting the vehicle make sure the warning light comes on for all systems that have a warning light.

The above applies to all my vehicles for cooling system service.

I am not concerned so much that I do not have a gauge on some or most of my vehicles. I do not have a gauge for tire pressure either. With regular maintenance of checks it is all good.

The issue always becomes for cooling systems (and other systems) when maintenance is neglected. Hobby cars are frequently neglected as to maintenance. Not draining and refilling the cooling system (automatic transmission and brake fluid) now becomes an issue where a gauge might be handy because the old fluid will degrade. Then there is reduced performance because of neglect.

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Re: Monitor coolant temp, no factory gauge?

Post by MFE »

Thanks fellas. Any idea what approximate temp triggers the warning light?
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Re: Monitor coolant temp, no factory gauge?

Post by TonyC »

An engine's normal operating temperature is usually around the 250º range, give or take. If that sounds too hot, you need to factor in other details: Antifreeze, and a proper radiator cap holding the proper range of pressure, raise water's boiling point from the usual 212º to as high as 270º, depending on the mix ratio. The common public consensus says to keep a 50/50 mix, because that is easiest for most common motorists to measure (it's also the minimum allowable mix to ensure the car doesn't freeze up or overheat). I personally recommend a 60/40 mix, with the antifreeze being the 60, which will ensure that the coolant is just fine at the regular operating temperature, and it will raise and lower the critical thresholds (boiling and freezing points, respectively) a bit more than a 50/50 mix will. But you should always ensure a minimum mix of 50/50. I also advise against doing a mix any higher than 70/30, because beyond that antifreeze will not do the job it's supposed to; it will become just as bad as straight water.

I am only guessing, based on the temp gauges I've seen on other cars, but I'm thinking that if the coolant heats up to about 260º or 270º, that may trigger the sensor for the warning light and turn it on.

---Tony
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Re: Monitor coolant temp, no factory gauge?

Post by action »

Normal operating range is not 250f
Normal is in the range of 205f to 220f depending on a lot of factors

Over heating (boiling) is in the range of 260f and higher

I am not finding a reference and the warning light likely comes on in the 240f neighborhood. But that is a guess

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Phoenix - Yeah, it's hot, however it's a dry heat
2006 Lincoln Navigator Limited 5.4l 3V
1996 Lincoln Mark VIII 2DR Coupe Diamond Anniversary 4.6l DOHC, 4R70W, 3.07
1970 Continental Mark III Triple Black 460 4v, C6, 2.80 (Used for Woodward Dream Cruise or just generally stored in Michigan)
1966 Lincoln Continental 4DR Convertible 462 4v, C6, 3.00
1966 Mercury Park Lane 4DR Breezeway 410 4v, C6, 2.80
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Re: Monitor coolant temp, no factory gauge?

Post by tomo »

A 50/50 mix of Ethylene Glycol antifreeze will protect against freezing to -34F. Increasing the % of antifreeze reduces the thermal conductivity of the solution. So the 50/50 solution is not just a convenient ratio, it is the optimum ratio.
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Re: Monitor coolant temp, no factory gauge?

Post by Dan Szwarc »

MFE wrote:Thanks fellas. Any idea what approximate temp triggers the warning light?
This is a good question. I don't believe I have ever seen this question asked or answered.

You'd think it would be in the shop manual, but I doubt it. I'll look and see.
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Re: Monitor coolant temp, no factory gauge?

Post by frasern »

I never count on a 50\50 mix without testing with a hydrometer, I have found the strength varies by brand. Any water left in the system, and expected climate will affect your final ratio, I aim for -40 in my climate, in Phoenix, that would be too strong for optimum cooling.
Also, some manufacturers are selling "pre-mixed" antifreeze, for the same price, go figure!

As for the first question, I don't object to a discrete aftermarket gauge, but it's most useful where it's easy to monitor.
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Re: Monitor coolant temp, no factory gauge?

Post by JimA »

The gauges in the ashtray work for me. I depend on the idiot light for routine warnings. The gauges were important to me to monitor oil pressure and engine temp for the rebuilt engine. Gauges in the ashtray are visible at a glance when I want them and out of sight when not needed. They're lighted when the ignition is on for daytime visibility.
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Re: Monitor coolant temp, no factory gauge?

Post by TonyC »

I looked in my '67 manual and didn't find a temp threshold, which led me to refer to my generic Reader's Digest car-care manual for a number (which Action quickly refuted).

Oh, I don't doubt that some shysters will charge the same for halfsied coolant as straight antifreeze. That's why I usually just buy the straight stuff and mix it myself. This time around, though, I may buy several gallons of halfsie-coolant plus one of straight antifreeze; that ought to bring the mixture ratio closer to ideal.

50/50 is not optimal, not with 70/30 dropping the freeze point to -85F and raising the boil point to 274F. But most people don't live or drive in Alaska or Canada's northern tundras in January, nor in Arizona in July, so 50/50 usually is acceptable.

---Tony
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Re: Monitor coolant temp, no factory gauge?

Post by action »

TonyC wrote:
But most people don't live or drive in Alaska or Canada's northern tundras in January, nor in Arizona in July, so 50/50 usually is acceptable.

---Tony
Not sure about most people in general and most drivers in AZ drive regardless of the weather.
Arizona has over 5.3 million drivers which is double that of Kansas. Summer highs rarely impact a drivers frequency. Unless the car in question does not have AC (rare) or the AC is not working.
This July is starting out a bit cooler because the weather pattern has changed a bit earlier than usual so highs are in the 105 range versus 110. Northern AZ can see below 0f temps in the winter. Flagstaff is 1500+ feet higher in elevation than Denver

The running engine coolant temps are usually double the ambient temps for an Arizona summer. So ambient temperatures do not have a lot of impact on running engine coolant temps when the engine has fully warmed up.
The heat shedding ability of an automotive cooling system in a well maintained vehicle does rather well if the ambient is 50f or 120f.
The key is to have a well maintained vehicle. This is an area many hobby car owners fall short. They do not maintain the vehicle to the necessary standard to operate it without issues.
Personally I use a 50/50 mix of coolant to water. And buy concentrate not pre-mix. Ford specifies 50/50 mix, I go with that percentage.

High ambient temp has a lot more impact on the air/fuel charge especially for engines that are electronically controlled. These engines run very lean by design as compared to a pre-1980s vehicle. But that is a topic for a different thread.

Action
Phoenix - Yeah, it's hot, however it's a dry heat
2006 Lincoln Navigator Limited 5.4l 3V
1996 Lincoln Mark VIII 2DR Coupe Diamond Anniversary 4.6l DOHC, 4R70W, 3.07
1970 Continental Mark III Triple Black 460 4v, C6, 2.80 (Used for Woodward Dream Cruise or just generally stored in Michigan)
1966 Lincoln Continental 4DR Convertible 462 4v, C6, 3.00
1966 Mercury Park Lane 4DR Breezeway 410 4v, C6, 2.80
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Re: Monitor coolant temp, no factory gauge?

Post by frasern »

No slight was intended Jim, your gauges are available when needed, with easy to read faces. Some gauges, even O.E.M., put style before function. Placement under the dash, or too far to the right, can make them difficult to see at a glance.
I also like having both a gauge and a light, kind of a failsafe. Before the mid '80s, it was one or the other.

As for ratio, 50/50 is the benchmark, a lot of people in hot areas, drive to cold areas sometimes, but if you know you will be exposed to lower temperatures, why not err in that direction. My daily driver is good to about -55C right now, but on Friday, we hit +38C ( 100F ) and everything ran fine.

I think we have even fewer registered drivers than Kansas, The whole province only has 1.2 million people, in 250,000 sq. miles! But it is the frozen tundra, after all.
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Re: Monitor coolant temp, no factory gauge?

Post by Mike »

They do say 50/50 is the optimum base point and to go to a different ratio if outside temps are much colder then that. But even beyond -35 it's not freezing coolant that's the problem it's the other fluids getting thick in that cold. I also didn't see any reference in the manual for when the light comes on or for the temperature sensor itself since its the specifications of that that would trigger it.
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