Allison temps and Cat temps?

[LaMonte Monnell]

We just returned home from a 1600 mile trip from Florida to Tennessee and back to Florida along the East Coast.

I have a 6 speed Allison and the temps ranged from 192-208 for the whole trip once on the road for a while.

Also the 3126B Cat motor temps were about 192-193 most of the time. Just wondering if these kind of temps are good for this time of year and the traveling we did?

We have a 2001 Contessa 40' DP. Transmission oil and filters were changed last year with the Transyd oil used. Also I use Shell Rotella 15-40w oil and Cat filters.

[Steve Huber Co-Admin]

LaMonte,
Your temp readings (eng & tranny) are right in line with what our 01 Contessa ran.
Steve

[Jerry Emert]

Mine seems to run 160 - 215 on our trip from Florida to DC and back through VA mountains.  Doesn't seem to be any pattern.  Eng temp almost always 188.

[Adam Hicklin]

My C12 is 188.  When stressed by grade and heat (105 ambient) it may climb to 194 max.  Tranny is 188, 192 when stressed and that's pulling a Silverado.  Running the same oils as you.

[Gerald Farris]

LaMonte,
Your temperature readings are about as good as you can expect for a 3126 equipped rear radiator coach. You should not be worried if your engine temp starts to heat a little on a long hard climb, because you will just need to shift down to a lower gear to keep the RPMs around 2000 for optimum cooling on your coach. Do not try to compare your coach to a C 12 or C 13 equipped coach as for engine cooling is concerned. There are too many differences in the design, so it is like comparing apples and oranges.

Gerald   

[John Bagwell]

LaMonte,
I have a 3126 Cat with 6speed Allison in 2001 Monterey.  My temps run 192 engine, and 185 to 188 trans.

[Joel Weiss]

My C12 is 188.  When stressed by grade and heat (105 ambient) it may climb to 194 max.  Tranny is 188, 192 when stressed and that's pulling a Silverado.  Running the same oils as you.

Sounds as if you're describing my coach.  Except ever since I had my thermostat replaced it runs at 190-192.  Have you ever replaced yours?  I believe the newer thermostats are set for 195 degrees.

[Mike Groves]

Joel and Adam,

What are you typical highway speeds when observing these ranges?

Mike

[Adam Hicklin]

Joel,

I've never replaced the thermostat and I don't think the previous owner had either.  I did switch to Cat ELC a couple years ago and that made the engine temp more consistent.  Seemed to fluctuate more before.  The trans became more consistent with Transynd also.  Has never gone above 194 but also never below 186.  I had hoped it would run a little cooler with the Transynd.

Mike, I try to keep it between 55 and 65 depending on where I am and if I'm towing. 

[Joel Weiss]

I've never replaced the thermostat and I don't think the previous owner had either.  I did switch to Cat ELC a couple years ago and that made the engine temp more consistent.  Seemed to fluctuate more before.  The trans became more consistent with Transynd also.  Has never gone above 194 but also never below 186.  I had hoped it would run a little cooler with the Transynd.

I had my thermostats changed when I switched to ELC.  The thermostat is one of those "every 3 or 4 year" replacement items and I think moving the operating temperature range up a few degrees produced a small but measureable increase in fuel economy.  Remember that 180 is the lower recommended operational temperature for a CAT engine.

My transmission typically runs at ~190 with occasional excursions to 192 and 188.  I've seen it go to 196 in heavy, stop and go traffic, but it is a city bus transmission and I've been told by Allison technical people that it's capable of running all day at ~210 without a problem.  It is also filled with Transynd.  I do change the transmission filters regularly on a 3-4 year basis.