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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Iver on May 23, 2008, 08:53:15 PM

Title: Engine Temperature
Post by: Iver on May 23, 2008, 08:53:15 PM
I'm curious to know what a 8-92 turbo engine temp. should be.  While driving down the freeway at 65mph, outside temp around 80, the engine temp was a steady 195 degrees.  Mostly flat terrain with a few rolling hills.  Seems a little hot?  Not sure what would happen if I tried climbing hills.
   This is a newly rebuilt engine, first time out.
            Iver.
Title: Re: Engine Temperature
Post by: tekebird on May 23, 2008, 10:30:21 PM
180/185
Title: Re: Engine Temperature
Post by: JackConrad on May 24, 2008, 05:23:59 AM
What thermostats did they install?   Jack
Title: Re: Engine Temperature
Post by: makemineatwostroke on May 24, 2008, 06:22:29 AM
Iver,you probably have 180 or 185 degree thermostats DD will run about 10-15 degrees warmer that what the theromasts ratings that are installed in the engine . the degree temperature on a thermostat is when it starts to open and 195 is about right for a 8v92.If your cooling system is in good shape keep the rpms around  1500 to1800 and the temp will not go up over 5-10 degrees never go over 210 degree on a 8v92 but if it worries you change to 170 degree and you will run on about 185 plus give you more time for the temperature rise   be good
Title: Re: Engine Temperature
Post by: DrivingMissLazy on May 24, 2008, 06:59:36 AM
MY 8V92 run at exactly 180 degrees except when going up an incline. I had 180 degree thermostats. I have always been of the opinion that a 180 degree thermostat started opening at about or below that temperature and continued opening until the temperature stabilized at that temperature. Even at 70 MPH it stayed at 180 degrees until I started climbing fairly steep grades.

I suspect that there may be something wrong. Did you install a larger engine which would mean you needed a larger radiator or the radiator needs rodded out. Under the conditions you describe, I really feel that your temperature is abnormally high.

I have owned many vehicles and under normal operating conditions I do not recall any that operated above the thermostat opening temperature.

Richard
Title: Re: Engine Temperature
Post by: Brian Diehl on May 24, 2008, 07:03:43 AM
I put brand new 180 degree thermostats in my bus 2 summers ago.  I hot pot tested the old and new ones and they do indeed not go fully open until they are closer to that 185 degree range.  This was with my candy thermometer.  So, depending upon how accurate the front guage is you could be running perfectly on the thermostats.  You probably want to verify the front guage against the rear mechanical guage next before doing anything more.
Title: Re: Engine Temperature
Post by: makemineatwostroke on May 24, 2008, 07:09:27 AM
Richard read your DD manual sec 5 and it will tell you the different temps with different themostats , fans clutches and shutters open and closed    fwiw
Title: Re: Engine Temperature
Post by: HighTechRedneck on May 24, 2008, 07:55:48 AM
The manual for my RTS with 6V92T explains the thermostat operation in detail:

Title: Re: Engine Temperature
Post by: DrivingMissLazy on May 24, 2008, 08:28:14 AM
Thanks guys. Learn something new every day. I am somewhat surprised that my engine temperature never exceeded 180 degrees in normal driving conditions. I always turned on my misters when the temperature got over about 190-195. It seems like I would not have had to do this.

Richard
Title: Re: Engine Temperature
Post by: Lin on May 24, 2008, 08:43:59 AM
Great info, HTR.  However, that would not mean that there is no problem; only that the thermostat system is working correctly.  One could still question whether the temp should get that high under specific conditions.  I am not saying that there is a problem, but if other 8v92's run cooler in the same situation, there may be something to check.
Title: Re: Engine Temperature
Post by: prevost82 on May 24, 2008, 08:54:28 AM
My 8V92 runs at about 180 to 185 when it's below 70 and around 195 when above 75, on the flat. Pulling a long grade (6 to 8%) it will get up to 205 if it's 90 degs or below and will creep up to 210 (alarm sounds at 210) when above 90 degs.
Ron
Title: Re: Engine Temperature
Post by: luvrbus on May 24, 2008, 09:31:06 AM
I have 180s in my Eagle with a 8V92 and a Allison and in Az  I run 190 to 192 year round and never a heating problem even going from Laughlin to Kingman last week when it was 115
Title: Re: Engine Temperature
Post by: DrivingMissLazy on May 24, 2008, 06:33:24 PM
Wish I had known this when I was making my cross country trips from California to Florida and back.
Several times while traveling across Texas and New Mexico when the outside temperature was over 100 I would turn on my misters to try and maintain 180 degrees. Boy do I feel stupid now!
Course that was before the time of easy internet and long before the bus boards.

Richard
Title: Re: Engine Temperature
Post by: Iver on May 25, 2008, 01:34:21 AM
Thanks everyone for the info. 
I have to say I feel very fortunate to be able to get so much valuable information so quickly.

I'm not sure what thermostats were installed but I will find out.
The gauge on the dash read 175 deg. steady.  But when I would stop, I would go back to the engine and check the other gauge and it was 195 deg.
Should I try to replace the dash gauge? Is it possible to get an accurate read from the front?

Anyway, the rads were replaced 2years ago with the larger sized ones.
One thing I still have to do is install the plates and boots on the squirrel cage fans.  That should give a little more cooling I think.
      Thanks, Iver.
Title: Re: Engine Temperature
Post by: JackConrad on May 25, 2008, 06:21:45 AM
    Pick up one of those laser temperature guns. They are great for several test such as checking the accuracy of gauges, finding poor electrical connections and finding plugged radiator tubes. With the engine warmed up, shoot the temperature of the temperature sending unit on the engine and compare this to the gauge reading.  Jack
Title: Re: Engine Temperature
Post by: HB of CJ on May 27, 2008, 02:22:20 PM
Sounds a little bit hot.  We ran our "318" 8V71N's right at 180 degrees F and they only got to around 185 pulling a grade, which with a heavy load, meant just about all the time.  :) :) :)