For those with aftermarket temp gauges

jeffnoel

Founding Member
Aug 31, 2002
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Clovis, CA
I installed an autometer temp gauge this past winter and installed the sender were the plug is in the water jacket. Just wondering if measuring the temp there would be the same as if the sender was placed were the factory unit is up top. Just wondering because in 100+ weather and around town driving with AC on the gauge runs at about 230 never higher, jump on the freeway and it drops to 210. I'm still running the 195 thermostat.
 
I am assuming you are talking about the plug in the block on the driver side?? That is where I plan to place my sending unit.

Those temps seem kind of high. How many miles do you have and has the coolant ever been flushed?
 
Although I have a intercooler and a trans cooler now in front of my stock radiator and fan I see the same temps. I installed a switch to override the fan on at anytime but typically this does little to no good, the temps still rise. Before the install of both coolers I usual stayed between 180 and 190 never higher, that was with a 160 stat. Since pegging 230 I took the stat out and it hasn't done a thing, after that I took some anti-freeze out and added two cans of water wetter and that didnt do anything either. In your case I would put a 180 stat in and a bottle of water wetter....
 
Here is a post from a thread on this issue at Modular Depot. Seems like possibly your temps are in line with his. He also has the sending unit installed in the same plug. Keep in mind though that he has a 180 degree thermostat so he may be running a tad cooler than you.

http://www.modulardepot.com/forums/...=20&highlight=coolant temp gauge&pagenumber=3

Originally posted by IWRBB
OK, got everything installed. The block takes the smaller of the two adapters that comes with the sender, the 3/8" one.

I took it out for a drive with the digital temp reading on. The digital reading comes from the crossover tube for the heads. No A/C was used. After driving for a while, I got into stop and go traffic. The max the digital reading got to was 100C (212F), and the Autometer gauge was reading exactly 212F, just a tick past the 210 mark. At 100C, the low speed fan would kick on and drop it to 98-99C.

Then I hit the highway. After about 3-4 miles at 75 MPH in 6th, the digital temp was bouncing back and forth between 82-83C (which is 180-181F, exactly the Tstat temp) and the Autometer gauge was reading about 193, just a tick under the 195 mark. Neither looked like it'd drop anymore, so I got off the highway.

I switched on the AC at the end of the off ramp to kick on the fan (I need to hook up a switch!), and the temp starting rising and stopped at 88C. It held that all the way home on a 35 MPH road, until I pulled into the garage when it started getting up to 90C, then I shut it off.

So the reading from the block near #7 and #8 was identical to the crossover tube in stop and go traffic, but it was about 12F hotter during a steady cruise with 180F coolant in the crossover tube. I guess the driver's rear part of the engine isn't cooled very well after all. It'd be interesting to see what the Apten cooling mod would do on the same 75 MPH steady cruise.

The outside air temp was around 80F BTW.

Thanks for the help 99GrandTouring. :)
 
I added water wetter last weekend, and since it's my wife's DD I haven't driven it yet to check. As far as I know it may still be the factory thermostat. I'll change that next weekend when I have time. But will going to a 180 without changing the fan settings do any good?
 
There is a trade-off you have to consider when going with a colder thermostat. These motors are designed to operate in a specific temperature range. When you change that range you change the tolerances in the motor. You may see some performance gains with a colder thermostat but, you will also see additional wear in the motor. With a stock motor I doubt the performance gains would be worth the additional wear especially for a daily driver.
 
Another thing that may explain the high temps you are seeing is with the location of that plug. Modulars are known for cooling inefficiencies around cylinder 8 which is close to where that plug is so that may explain the high temps there.

I think the important thing here is to establish what the "norm" is for that location and just keep an eye on it from there. I think from what I have seen, the temps you are seeing are typical for that location.

Here is one of many threads on the "cooling mod" that many are doing to try and resolve the issue.

http://www.modulardepot.com/forums/showthread.php?s=&threadid=17643&highlight=coolant+temp+gauge
 
MyEarsHurt said:
I run around 210-220 in the summer, worse when I beat up on it. My temp gauge sender is located on the water neck on top of the intake.

My GT runs these numbers as well but I installed the sender unit in the driverside of the block (plug in the water jacket) down low. btw, Im in Dallas and have 4.10 gears. 5th gear on the highway brings my temp down to 190-200 but running through the gears stop and go gets the temp up to 220 (FRPP gauge).
 
hey guys, i was reading this thread and someone said that if you put in a colder t-stat that it will put more wear on your motor? how is this? is it becuase your engine wont get up to operating temps? but i thought running cooler is better?