Temps for engine and tranny

[Tom Fisher]

I have noticed that on a couple medium uphill pulls, I have hit 212 on both the engine and tranny. I have pulled over as soon as I could and let it cool for a few minutes. Doesn't seem to take long. I talked to a truck repair place and they stated that it could run $800.00 to $1000.00 to blow out the radiators. I looked things over myself, and it looks like trying to blow out from the engine side will be a real chore with possibly a lot of part removal necessary. The truch repair place told me that 212 was not too hot. He said the engine and tranny could both go to 232. My question, is 212 hot enough to pull over and cool down every time, or can I run higher? The tranny has Transynd in it. And does it do any good at all to try to blow out or clean out radiators from the outside?
Thank you .
Tom

[LaMonte Monnell]

I used a hose and sprayer from the access panel by the bed and washed the radiator from the inside. ran the hose thru the br window.....used extreme simple green and soaked it first...let it set then rinsed for a while.

[Jerry Emert]

I've been having the same issue.  Tranny runs around 215 or so now.  Used to get up to 225 or so and I did a lot of research.  Allison says that 250 is over heated, I have never pulled over at 225.  Had radiator/CAC cleaned at RV Shop, they said they removed the "pack" to clean it.  After the cleaning it runs at 215 at times.  Other times it's down to 188.  Engine almost always a rock solid 188.  Just had it changed over to ELC but haven't picked it up yet so we will see.  My next step will be to change the tranny filters.  Some have said that if you don't use allison filters it may run hot.  I had them changed in April but not sure if Allison or not.  After that I have no idea what to do.  The consensus here is that they should run a lot cooler.  Good luck, please let me know if you figure it out.
Jerry

[Tom Fisher]

Thank you both. I appreciate the ideas and help.

[Edward Buker]

Upping the rpm with a downshift is your best defense given it powers the fan faster and moves more fluid through the radiator and heat exchangers. Don't be concerned about using the down arrow on the shift pad to keep the rpm up while climbing.

215F and some peaks a bit higher would be well within the allowed heat tolerance for Transynd TES295 fluid. It is time/miles at temp that is the issue. So if you run 225F 2% of the time while climbing and 210F or less 98% of the time the 225F has very little influence in the life of the fluid. Fluid analysis once a year would set your minds at ease.

Transynd has far better heat tolerance then Dexron and these are the temp vs life expectancy numbers in miles for Dexron.

175 100,000
195 50,000
212 25,000
235 12,000

255 6,000
275 3,000
295 1,500
315 750
335 325
355 160
375 80
390 40
415 Less then 30 Min.

I think each coach is a little different and if yours runs 215F but that is normal for your coach then do not worry about it. Keep the radiator clean, rpm up if climbing, and if you get concerned have a fluid sample pulled at some frequency to see where it stands. More than likely it will be just fine with the kind of service our RVs see.

Later Ed

[Dave Atherton]

Ed and Jerry, just a suggestion on temp reading, ran into this many times I would suggest and get
temp probe for a.c. temp you put in your vent ( Checking a.c. Cool ) or a hand held temp gun and
When heat gauge at peck get a another reading other than gauge on dash. Remember engine is in
rear of motor home and gauges are 40 feet away. Sometimes reading at engine is different than at
dash. Next thought get a ET readout of engine will pull up heat temp history at Cat dealer. I also
found when I connect up ET for diagonostic's when party was having same as above that problem
was not heating and temp gauge was off . Last thing you could have thermostat regulator which
you should have 2 , one could be stuck half way opened. This also would bring heat up under load
Need to cler up point with a.c. Temp probe did not explain very well. You put probe into coolant
with radiator cap removed. Dave Atherton Retired Cat Mechanic

[Jerry Emert]

Thanks Dave.  After my initial panic I haven't worried about it too much.  I have been reading temps from the Aladdin.  I can't seem to see any consistency with the tranny temp.  Sometimes it's running 180 going up a hill, other times it's 215 running down a straight level highway in Florida 90+ degree weather.  I know (I think) that the tranny cooling is supposed to be tied to the engine cooling and should be close in temp.  The engine is almost always a solid 188.  Having the "pack" as they called it, cleaned did seem to bring that high temp down to 215 from 225. 
So what you are saying is that I should use an infrared at the radiator to check the temp when it's hot.  I think it pretty rapidly cools when I slow down but I would have to verify that for sure. 
Jerry

[Dave Atherton]

Jerry, still sounds like a temp misreading, take the heat gun and when temp is pegged get reading
at top of radiator and the bottom. next thing your radiator cap should be puffing stream out overfill hose
This will give so Idea of how hot you are. ( what is condition of radiator cap ? ) your engine cooling
down real fast again tell me you are not heating. Again if steam and fluid coming out bypass at top
of radiator. Last question how much fluid have you added to radiator. If answer you did not is narrowing
down your temp problem. Are you going to Branson in sept., if so I can plug in your engine with
Cat ET and ind out what's going on. Dave Atherton Retired Cat Mechanic

[Edward Buker]

Jerry.

The coolant is tied to the transmission temp. Between the radiator and the transmission, underneath the coach is a transmission cooler if your configuration in 2003 is like the 2002. It has a rubber hose in each end that passes coolant through a bundle of brass tubes closely spaced. That cylindrical unit has two hydraulic hoses coming from the transmission that the transmission fluid passes through that is flooded around the tubes that the coolant passes through. This unit does both heating and cooling. When the transmission is cool on start up the antifreeze from the engine heats it up and when the engine coolant reaches 188F it starts to cool the transmission fluid. The key is the cooling starts at 188F or whatever your antifreeze temp is. So at 215F on the transmission side the fluid is cooled to within 25 degrees F of the engine coolant temp. If you want to use an IR gun to verify you would need to do that on the inlet and outlet hydraulic hoses and the main body of this cooler. The airflow at the radiator keeps the coolant temp in check and the flow of coolant from the engine to the radiator keeps the transmission fluid temp in check. You can see that both air flow from the fan and coolant fluid flow from the engine water pump, which is better at higher RPM, is involved in managing these temps on climbs.

Later Ed

[Jerry Emert]

I just got it changed over to ELC and haven't picked it up yet.  I wanted them to get the CAT analysis of the coolant done to make sure all the cleaners were out of it like it was suggested.  Before this I never saw the temp go up when stopped.  It is always while driving and it cools really fast when I slow down.  No way I'll catch it hot while standing still.  Thanks for offer Dave but although my wife is retiring in 15 days, I still have 7 months to work.  Then we will be headed off to see the West!    I'll post again when I drive the coach home from the RV shop, its about 20 miles so I'll get a look anyway.

[Al Lewis]

Our coach has ran pretty cool for years. Now in the 100 degree texas heat the gauges tend to climb some. I am seeing 210 to 220 pm the transmission. I am still using dextron but I think it is time to change. The radiator has not been cleaned. What I notice on the transmission is the temperature climbing sharply if I am stopped at a light or traffic with the unit in drive. Shifting to neutral when stopped prevents the rise.