I installed the RealGauge about 1 1/2 years ago. Great product, works as advertised and excellent install directions. My "concern" is the engine temperature. I have redone the entire cooling system.
1. New thermostat tower and thermostat with giggle pin pointed up
2. New water pump
3. All new hoses including valley and octopus hoses
4. New expansion tank
5. New distribution outlet pipe

The system has all the air removed and of course fluid replaced a couple of times. The issue is the car runs pretty hot and with the RealGauge, the needle will sometimes sit two notches below the red. On the highway it runs around 200º. In traffic, even on a cool day, it will get up to 208º and at times getting close to 215º. Usually at this point I get nervous.

The fans are working. I think it's a visual thing, seeing the gauge that high. Most of us are used to seeing temp gauges in the middle, even when that means nothing. Are these temperatures getting too high or is it normal and I have to get used to above middle gauge readings?

 

Those are all normal temperatures for the engine. I'd get rid of the gauge since it's causing you to spend money and get nervous.

 

As stated, the temperatures are normal . . . but . . . .

1.) the RealGauge needle is adjustable. You can put it anywhere you want it.

2.) If you are reading those temperatures via the OBDII port you are actually only reading the ECM's conversion of a resistance value produced by the thermistor located in the hot side of the water pump to radiator pipe. While I am sure that your temperature sensor is within manufacturers' tolerances it could be off by many degrees after the conversion by the ECM from the Ohm value.

3.) The only way to calibrate the actual engine temperature to the RealGauge is to use an IR thermostat to measure the temp and then adjust the gauge to that value. Even my two IR thermostats were off by a couple degrees from each other.

When I replaced my cross over pipe and associated temp sensor I got one that kept the fans running all the time because the sensor was far off the mentioned tolerances. Took two more sensors before the fans shut off.

Read through this: https://www.jaguarforums.com/forum/x...rature-138312/

 

Hi Mikey, the gauge didn't make me spend the money, it was the coolant leaks and original thermostat and water pump. When I got the car and replaced the secondary tensioners, I decided since I had access, just replace all the hoses. Some were weeping and there was a crack in the cross over pipe. Thanks for the info.

 

Hi John,
I think normal is somewhere just over your thermostat temp you installed if all else is working correctly. If you are seeing a difference from prior to change did you check to see if both where the same temp?
Did you flush the radiator while you had it apart? Did you have good flow?

Nothing to do with temperature range, but might have had something to do with the leaks. Have you taken a real close look at the engine mounts. Mine were both broken, couldn't really tell unless I had foot on brake and shifting in to reverse. Found one with cracks showing and other was broken around the top and the heat shield was covering the crack so only sign was lines down the mount where it had leaked.

 

I concur. I have the RealGauge and my blue cat runs around 198-200 most days. In the Texas summers, especially in traffic, it is not unusual to hit 215 F.

In the short winter we have here, mine may run at 185 after warm-up, which is on the center mark. It is not often discussed, but a cold motor isn't the best thing either. Doesn't allow the oil to get to temp, leaves moisture in the lines, etc.

I think you're OK.

 

I concur that your system sounds normal.

 

Thanks everyone. I'll not worry about the gauge as much anymore.

 

What's the best/ hottest part of the external engine to test with an IR thermometer - I tend to use the thermostat housing but is there a better spot?

 

Those are the temps my 03 see's after doing all the same repairs you did

 

Nice Miata!

 

The exhaust manifolds would be the hottest spot but the numbers would be misleading. The ideal spot for measuring COOLANT temp is either where the temp probe is or the thermostat housing as you are doing.

The concept is that if the coolant is at an acceptable temp, the entire engine is fine. There's many areas that run hotter than coolant temp and many that run cooler.

 

Thanks - 1995 V-Spec 1.8. Most reliable car I've ever owned

 

So my UltraGauge (OBDII) shows engine temp at 95 C (203 F) and the IR thermometer reading at the thermostat housing shows 92 C (197 F) so OBDII overriding about 3% At least the OBDII is over not under reading

 

My engine is doing something similar....I replaced the thermostat (correctly)...New Tmep Sensor...a few new hoses...have not yet replaced the water pump (this weekend)...Checked the system for leaks (no leaks)....If I sit in traffic too long the engine begins to overheat and have to pull over for 10 min....then continue on and it's fine. Fans turn on as expected. When I drove to work this morning...no issues...but I checked my OBD reader and it says the engine temp was 233F...??? That's seems way too hot...but the fans were not on..??

 

233F and the fans were not on? I don't know anything but that doesn't seem right.

 

No, the temperatures are being read at two different spots via two different methods. The temp probe is immersed directly in the coolant whereas the IR thermometer is reading the outside of the thermostat housing.

Added to that neither the probe and gauge nor the thermometer features laboratory grade accuracy. I'd say that seeing only a 6* difference is pretty good.

 

Very true but I wouldn't mind betting (without any evidence) that at steady state given the heat conduction properties of the aluminium thermostat housing the temperature gradient between the coolant and the metal would be pretty minimal - either way as you say there is pretty good agreement between IR and OBDII - well within their margins of error.

 

Most likely you'll find that Jaguar put the temp range etc into JTIS, which you can get free from the site.

The aim is to run as hot as reasonably practicable as it improves mpg and reduces emissions.

 

As long as the fan relay and both fans are in proper working order along with rest of the cooling system, no matter the temp, it shouldn't be a concern unless the high speed fans come on, then I'd put the heater on full blast with the A/C button turned off. With that being said, I'd be monitoring the cooling system very close then.