Auxiliary water temp gauge options?

#1

I would like to add a second water temp gauge with a warning light and retain the factory sensor and unit. I plan to put the gauge and warning light right in front of my face, so I will be less likely to keep driving after all of the coolant has exited my engine (this seems to be my personal gremlin…)

Several of you have mentioned the fitting and sensor inserted in the upper radiator hose. This seems like a good plan. Can I get a few suppliers and part #'s for this combination? Please be specific, since there are a zillion gauges and fittings out there.

Or are there better/easier options?
The warning is critical, since I cannot be trusted to check the gauges in a race or qualifying.

Thanks.

#2

Better option…A coolant pressure switch for your warning light, not a temp switch.

Temp climbs slowly. You’ll see the temp problem in time. No need for a warning light.

But if you lose coolant, with was the death of engine 5’s and 6, your temp gauge won’t warn you. The first thing that will occur when you lose coolant is that the hot water will drop away from your sensor. As long as you have coolant, your motor won’t overheat all the sudden, so it’s the loss of coolant that you need to be warned of.

There’s a number of places you can put in a coolant pressure sensor. Mine is remoted to the coolant port on the driver’s side of the block. That’s where the hose to the throttle body would go to.

#3

Ranger wrote:

[quote]Better option…A coolant pressure switch for your warning light, not a temp switch.

Temp climbs slowly. You’ll see the temp problem in time. No need for a warning light.

But if you lose coolant, with was the death of engine 5’s and 6, your temp gauge won’t warn you. The first thing that will occur when you lose coolant is that the hot water will drop away from your sensor. As long as you have coolant, your motor won’t overheat all the sudden, so it’s the loss of coolant that you need to be warned of.

There’s a number of places you can put in a coolant pressure sensor. Mine is remoted to the coolant port on the driver’s side of the block. That’s where the hose to the throttle body would go to.[/quote]

I did a quick search for these bits and couldnt come up with anything. Where did you get the sensor?

#4

Try pegasusautoracing.com. Part #1009. About $60 for the sensor and a big red warning light. I have found that the light flickers until the motor is a little warm since it is a 4 psi switch.

I am a little paranoid so I have an aftermarket temp gauge, stock gauge, low pressure warning light, and high temp warning light. Don’t get me started on oil… :laugh:

#5

This is what I used.

http://www.egauges.com/vdo_indS.asp?Sender=Pressure_Switch_4&PN=R4012-4

Since the switch has both NO and NC contacts, you can’t screw up (like I did) and order the wrong one the first time. Then I got some LEDs off of ebay that are bright enough to burn out your retinas. I put them on top of my dash so they’re aimed right at my eyeballs. Both coolant pressure and oil pressure.

A 14mm X 1.5 to 1/8NPT adapter is necessary to plumb it into the block. Doublecheck the size, that was off the top of my head. Remember, pressure switches shouldn’t be fastened right to the block. Remote them with a bit of hose.

#6

The easiest way to incorporate a pressure switch into the cooling system is to tee it into the small hose that runs from the expansion tank to the top of the radiator. A 1/8NPT" tee, a couple of 1/8NPT by 1/4" hose barbs, and a couple of clamps is all you need.

#7

Gents,
You guys are the best. I like this plan and will get the bits ordered tomorrow. A big, bright warning light and pressure sensor for August at RA (where it may be a little warm…)
Thanks for the info.
Jon

#8

I didn’t think it was legal to remove the throttle body heater.

#9

One other thought…What if the water pump fails? It seems that then the pressure would stay high and the temp would rise quickly. Perhaps a second temp gauge would be wise also.

#10

alfageorgia wrote:

No pump = no pressure.
No water = no pressure.
No fanbelt = no pressure.

A coolant pressure switch is a good thing.

#11

Ranger wrote:

[quote]alfageorgia wrote:

No pump = no pressure.
No water = no pressure.
No fanbelt = no pressure.

A coolant pressure switch is a good thing.[/quote]
That’s not right Scott. A loss of cooling system integrity will cause a loss of pressure and trigger the switch. Failure of the fan belt or the water pump won’t cause a loss of pressure and thus won’t trigger the switch. But loss of the fan belt will stop the alternator from charging and turn on the alternator warning light. So you still have a waring for that.

The most likely failures of the water pump are seal failure or bearing failure. The former, if bad enough, will trip the switch from loss of pressure. But the more likely case results in a gradual loss of coolant and simple overheating. A worst case failure for the bearings is for them to seize, which will take out the fan belt and trip the alternator warning light.

The big advantage of the pressure switch is that it will tell you immediately if you’ve had a cooling system failure (hose, radiator, expansion tank failure) way before the rise in temperature can reflect on the gage.