RAD4Runner

There are bells and whistles for petty things on the vehicles (There is even a beeper inside a Prius to alert driver that he is backing up -DUH!).
However, there is no audible alert that engine is overheating - that could lead to major engine damage. Worse, when the going gets tough, we are too busy watching things around us and may forget to watch the already pathetic temp gauge. Hence, this thread.

I'D LIKE:
1) Indication of actual temperature, not a needle that jumps to red when it's too late.
2) Audible alarm because oftentimes, it is when we are too busy watching out for traffic and conditions around us that overheat happens.

POTENTIAL PRODUCTS TO USE:

1. Engine Watchdog from Australia here. Max operating Temp:127 degrees Celsius or 255 Fahrenheit., AU$ 149 including shipping. Already featured on youtube here.
2. Thermomart Guardian-Watchdog from Canada here. Temperature Range 0 - 300 C (-22 ~ 572 °F) CAN$45 plus shipping? Not sure if thermocouple wire is included.

Both seem plug and play, but one from Australia (2 from Canada) has extra relay outputs that can be used for, say an extra cooling fan. or a louder beeper.

Need more research and will update as we go.

ewong

Thats neat!

I'm old skool.
I would run a mechanical temp gauge (270 degree sweep) and a temp sensor switch wired to an AutoMeter warning light......

Charchee

That's what RAD4Runner and I were discussing on another thread a little while ago. The circuits I build usually include a temp switch or sending unit, a 5 pin relay, a little indicator light of some sort and a generic buzzer. $25 or less most of the time. I've done a bunch of them but usually on air systems. Coolant temp wont be any more difficult.

I haven't seen a lot out there on building one of these rigs into a truck so I'd like to get a little feedback on a couple things so I can hunt up some cheap but good quality parts to use in a mod like this.

What temp do we want the alarm to sound at?
Where are you guys plumbing in your add on coolant temp gauge sending units?

RAD4Runner

Would be great to brainstorm it here.

A fixed-setting temp switch like Ewong mentions above is good IF whe already know what temp setting to get. However, right now we still do not know what's a good trigger point.

Advantage of the digital display ones I mentioned above is that we can watch actual temp readings under various conditions (in my case driving up the Tejon Pass, up to the Palm Springs Tram station, or up Mineral King Road in the summer), then decide on max temp setting at which we want the audible alarm to go off.

I stress audible because when traffic or road conditions get challenging, we may not immediately notice the temp gauge creep up, especially since the stock temp gauge does not indicate actual temp, not does it operate smoothly.

Charchee

I want one of these. http://www.truckpillars.com/page0/page0.html
I'd put me a coolant temp and oil pressure gauge in there and while I was doing my plumbing, I'd run a maybe 250 degree sending unit to a buzzer with a switch so I could kill it if it malfunctioned and I'd be thrilled. Still not sure on the temp for the buzzer. I can't remember what psi rating is on our radiator caps. If it's 13 like I'm thinking, a 250 degree sender would sound the alarm 1 degree before boiling.

osv

great thread... an audible temp warning would have saved my last engine, after a chunk of aluminum trailer wheel went into the radiator on the freeway, and it didn't notice it.

Terrys87

iTrader: (1)

This is a great idea. Usually when the idiot light goes off things are a little late at that time. Especially during daylight driving or when you are distracted with heavy traffic.

scope103

The Engine Watchdog uses a washer-type temp. sensor, hooked under any convenient bolt. It's good not to try to open the cooling system (and risk something breaking off inside), but the temperature of the cast-iron will significantly lag the coolant temperature. By the time the outside of the engine gets hot enough to trigger an alarm, I suspect the inside of the engine would not fare well.

This example https://www.aliexpress.com/item/DC-9...605715559.html doesn't have an audible alarm, but uses an automotive sensor plumbed into the coolant, so it will react much quicker. (Also, less than 10% of the price of Engine Watchdog.) The sensor claims to be 10mm, which as discussed recently on this forum is close-but-no-cigar to the 1/8" BSPT we want. I wouldn't be surprised, though, if the resistance curve of the two sensors was the same, so you could throw the 10mm sensor away and just hook up to your existing sensor. (Calibration is an issue once you display the temperature to 0.1°)

Another issue for temperature monitoring is hinted at by osv. Once he took a chunk through the radiator, he probably lost coolant so fast that it uncovered the stock temp sensors. There was no longer any coolant to measure, so by the time any sensor at that location got hot enough to call for help, the inside (rings, valve seats, etc.) of the engine was probably gone.

So detecting what you WANT to know is not always a matter of watching the temperature of the block.

RAD4Runner

Thanks, guys!
Good points, scope103.
Yes, coolant not reaching the temp sensor explains why when my head gasket was failing, my temp gage was reading cooler while driving in 3-digit San Bernardino County, CA. On the drive down the mountain, I finally got the idiot light and engine stalled.
Chefyota's pic below shows a port way in the back. I wonder if that's part of the water jacket where a good coolant temp sender could be mounted.


A washer-type (Thermocouple) sensor would at least be non-invasive and we can somehow calibrate it against actual coolant temp then set a limit temp.

millball

That port in the back has a valve for draining the coolant from the block.

Since it is at the lower limit of the water jacket, some coolant should remain there even after a catastrophic cooling system breach.

Might well be a good place for a temp monitoring sensor.

It certainly won't show as hot as the head, near the water outlet, but allowance could be made for that.

scope103

The problem with high-tech engine monitoring is that engines aren't supposed to overheat. It's not something that you need to regularly monitor (like fuel level or speed). Temperature is only an issue when something "breaks." Like the loss of coolant. Thermostat doesn't open. Fan stops. Head gasket leaks combustion product into water jacket. Radiator clogs.

And each of these has a very different effect. If you monitor the temperature at the exit from the radiator, that would tell you when the fan quits, or a plastic bag is stuck on the radiator. Measure the temperature on the entrance to the radiator will tell you if the thermostat doesn't open. Temperature right in the head might tip you off to a head gasket failure. Do you equip your truck with 6 or 7 temperature gauges? (And then how about the electrical system?) Toyota has figured out that measuring the temperature in the water bypass "should" tell you about "most" temperature related problems.

I'm a big fan of gauges, but interpretation of the readings is 90% of the diagnosis.

ewong

I have a 22-RE engine

The water outlet from a 22RTE (turbo) has a boss on it to locate a temp probe just on top of the thermostat

I run an Autometer MECHANICAL (tube) type temp gauge.
I had a 270 sweep electrical Autometer gauge at one point, but I think the sender failed?

Its fascinating in the winter, watching the thermostat open and close until the temp stabilizes.

millball

It doesn't really matter where you monitor the engine temps when all you're looking for is early warning of an unspecified, but potentially engine ruining event.

You just wanna know immediately when the engine temp goes outside ordinary operating perameters.

A coolant temp sensor that relies on contact with the circulating coolant, obviously has serious limitations.

Any secondary input that does'nt rely on flowing coolant can only be helpful.

The failure mode diagnosis can wait. The important thing is that the failure was found fast, before any damage was made worse by prolonged excessive temps.

Charchee

I like where this is going. So, where and what are we going to measure that will give us our shutdown warning? It doesn't have to be just one thing. We can throw in oil pressure / temp, block temp, coolant temp etc. All can be triggers for our indicators. Only thing with measuring against temperature with a washer type sender is that a failure in any part of the engine will give high readings long before the temperature spikes at the location of your sensor. Say for instance that you had an issue with the head on the passenger side of a V6 and your sensor was stuck to the driver's side of the block. I'm not sure oil temp wouldn't be a good way to go. With two relays in line, you could set it up to sound the alarm when both coolant and oil were above your specified temperature.

We can literally do anything we want with this idea. Just really need to know what to measure. Here is one thing to consider. What would be a measurable symptom that would occur just before a head gasket failure? Is it coolant temp?, head temp?, block temp? All are going to get hot. Which one is going to get first? That would be a place to measure so lets get some thoughts on that.
Oil pressure is going to give you a dash light. I would think we could easily add that to our audible alarm circuit as well. Does anybody know I good place to tap in for oil pressure / temperature? Anybody already have a sender they are using for this or know the diameter and thread pitch of the hole?

wyoming9

iTrader: (1)

What about a coolant flow sensor something like what is used to shut off output when coolers fail.

Could be plumbed in quite easy and wired to a light or back up alarm mounted behind the drivers seat to ensure one can hear it over the 8 Track player

To me looking at the gauges is about like breathing most times I just do it

ewong

Right now I have a T off of the OEM OIl Pressure sender location (below the oil filter)
I run a mechanical pressure gauge and the OEM idiot light (which, since I have an SR5 cluster now, is disconnected, there is not enough room to connect the OEM pressure sender in my current configuration)

I run a mechanical oil temp sensor in the -10AN line that goes to the remote oil filter...