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engine operating temperature and mileage


Guest barra

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Guest imported_barra

The temperature has been in the teens and my mpg has been running around 20. The temperature gauge reads 133 degrees. Does this low temperature affect fuel efficiency in my 1988?

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Guest imported_barra

Thank you for the advice on the thermostat and the 145 degree temperature for Lock-up. I will take the car in for servicing.

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A heads up to the service people, they should be made aware that the Reatta has special rubber gasket that goes on top of the thermostat in addition to the O-Ring seal for the thermostat housing. Most thermostats do not include this. If you ask for the gasket, they'll probably think of the o-ring. If you forget it, the car will warm up slowly. With it, the car warms up in a very short time. You live in a cold climate, you'll do better with it.

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Usually the thermostat will be marked "to radiator" (install up) or "to engine" (install down). If in doubt, the pointy end goes up and the brass plug with the set point marking goes down.

I really like the Stant SuperStat in 180F, p/n 59848 (plug), have in all of my cars.

A good thermostat will warm up quickly (get heat within two minutes) and stop very close to the set point. A cheap thermostat may cycle over 10 degrees from open to close. A good one will stay inside 2 degrees.

There was a TSB on the inner gasket, the factory had complaints about a lack of heat and slow warm ups until it was added.

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Why ? You just begin higher on the PV curve and with a hotter combustion chamber, detonation is more likely. As long as you get complete atomization and are not running a heavy weight oil, AFAIAC, the cooler the better.

Now you have to stay within the design parameters but at 180F and by clamping it there (I bring the fans in much earlier) I find that everything lasts longer. The factory expects much greater excursions - 200 to 215 is typical and 230 is "no worries" - while I keep the coolant between 180 and 189 even on a hot Florida day with the a/c on and in slow traffic.

This has always been my credo - once pulled a car trailer with a 3800 lb car onnit with a 4200 lb station wagon powered by a strong 400 over the pass at Monteagle on a July day and never broke 200F. It can be done and keeping a 3800 cool is easy

Perhaps the extra electrical load of earlier fans does affect the mpg slightly but is something I can live with. Stoplights have a much greater effect on MPG.

But the real benefit is that everything lives longer.

Bottom line is that running too cold will hurt MPG mainly because the car stays in Cold Enrichment but anything over 170F and it will be happy (would design my cars to run there if I could find a good thermostat). The only reason MPG usually drops in the winter is because cars take longer to warm up.

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Okay, her I go again. I took my 88 to Phoenix from Winnipeg, MB<CA over Christmas. I got 18-19 mpg on the first two tanks... headwind , snow and cooooold. I hit the above zero temps and got around 30 the rest of the trip until I got back to the cold temps again. BTW I never have gotten above 25 or 26 prior to that. I run a 195 here in the winter because I need the heat from the heater. I am wondering why I have such a dramatic change. It's not from just warming up.

I am wondering about the MAT. I notice it reads about 7 to 10 degrees cooler than the under the hood temp sensor that the Climate display shows. Anyone think that could cause my mixture to be too rich? You would think that even if it were off and indicated to the ECU to enrich the mixture, that the O2 sensor would correct it.

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That (ED06) ( I thought ED was something else) seems to depend a lot on headwind and tailwind. It is much wider when cold out. I am just not sure it is getting them proper reading of outside temp though the MAT since it is reading a lot lower than the other under-the-hood thermometer. I've been tempted to pull it out of the airbox and place somewhere warmer to see if it changes much. I just don't want to blow it up. I have to find the delco coil setup soon too.

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<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ekvh</div><div class="ubbcode-body">US, seen any Yeti in that snow? </div></div>

None at all.

They are all afraid of the polar bears ;-)

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