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Temps
PC folks, I Need your advice.
Here is what i have:
Trip from Little Rock to just outside Dallas. About 1 hour in the drive i was passing a slow truck and saw a flash from the check engine light. Light was on for a few seconds and went out.
I checked my gauges and saw the oil temp running just below 200.
Oil temp usually runs around 195.The water temp was guesstimated at around 210.Water temp is generally 195 to around just below 200.
I watched the gauges and the temps would cycle back close to normal then run up. It did this for the remainder of the drive. It did not exceed those numbers.
I checked my coolant and it is good. All the way to the top with a tiny bubble in sight gauge.
I checked the fan. It free spins with power off.
I guessed the low temp relay may be bad. I replaced the 78 relay with my spare. I only had one in my kit so the 78 got dibs. I’ll pick up more at Prevost tomorrow & do the 79 & 99.
The 6 amp CB was in. I reset it just in case.
I had Pam put the key in the first click as i spun the fan, the fan clicked and stopped when she did so. This makes me think it was possibly the relay.
Q: am i doing this backward? & is the clutch replacement a hard DIY job?
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12 Replies
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Were you climbing a hill? Was it hot out? Running A/C?
The “oil temp” on our coach is actually the transmission temp; or so I’m told and verified when I’ve used the transmission retarder hard going down a steep mountain and the temp went real high. Verify what your “oil temp” actually is.
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Since all our gauges have variations and since the markings only can give us approximate values my question would be relative to if the temp readings you saw were above the range you have normally seen,
I would also question if you were going up a hill, if so how long was the hill, and if after this incident all gauge temps were within the range you consider normal.
Dick is correct and the oil temp gauge for your vintage is the transmission temp. If you have a retarder you can expect to see temps affected by use of the retarder and brakes. If you have a Jake however the transmission should generally track engine temps.
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The temps you list will not set off a light. It may have been something else.
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If your dash air was on and the key gets turned on it could lock the fan in high. With a cold engine, you should be able to spin the fan with the key on.
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If the yellow check engine light flashes, and the cruise control drops out, and the DDEC code shows 043, swap in a new coolant level sensor at the expansion tank.
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Little thread creep, Dan what did you find out when you were in Springfield about your temp issue? Just curious.
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American Fleet ohmed out the electric for the fan clutch, found it functioning ok. So I got a new fan clutch in from Prevost and they installed it. So now my dash coolant gauge cycles between about 200 and 205. Never ran that cool the past ten years (say 20 months of actual usage). Don’t know if this makes any sense, but it seems that the low speed cut in was not doing it, and only the high speed was working because I was cycling between about 205 and 210. Also had them swap in two new thermostats and drain, flush, and fill with Shell Rotella Ultra Extended Life Coolant, the yellow stuff. Life is good, spending less on therapy and preparation H.
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More info: we were actually on a slight downhill grade when the light came on. Jake was on but not engaged. Like I stated earlier, just a brief illumination of the check engine. The temps are the difference. The water usually runs around 195-200. Even when we were running down out of the Ozarks on hwy 65, those were my temps.
Today we we drive to Fort Worth. We’ll be out of the bus for 2 weeks. I’m taking her into Marathon for a separate appointment. Since Prevost is right up the road, I’ll go talk to them.
My job today is to document what the temps and conditions are and pass them to Prevost. If things are normal, I’ll chalk it up to replacing the relay.
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Dan, my 94 mirrored yours exactly, new fan clutch was on my to do list before she got crumpled.
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Try to pull the code and see what it is.
(Copied bc it’s easier)
A. Turn the ignition key to the start position, but do not start the coach.
B. Immediately to the right of the ignition key is the red engine override switch. Press it once and release.
C. This will begin the DDEC diagnostic. A code is interpreted by a series of flashes. The red stop engine light will show you active codes. The yellow check engine light will show you historical codes. All codes have two digits. So, after you follow the steps above you see the red light flash two times quickly followed by a brief pause and the five quick flashes again that would be equal to code 25. The diagnostic tool will progress through all active codes (red) first and then show all historical codes (yellow). This can be very valuable at helping to narrow the possibilities of what is going on when you are stranded.Jeff and Lindsay
91 Marathon XL -
Dropped the bus off at Marathon today. On the way The bus cycled from 195 to 205 on the water. The oil (trans) temps stayed below 200 but ran from 185 on up to 200. Cycles were not as extreme as yesterday but they were still there. Marathon will check it out for me to see if it is the relays or clutch or thermostat. They can check the DDEC codes.
After i dropped off at Marathon we took the toad up to Prevost. I talked to a mechanic about my temps. He said it sounded like the thermostats. Said the low side thermostat could be bad and causing the high side to kick in thus the cycles. I’ll see what Marathon comes up with and go from there.
I will replace the clutch no matter what. I have no records showing it being changed.
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The bus is at Marathon. We decided to go ahead & be thorough. We are having both thermostats replaced, the temp sensor and the fan clutch assembly. I cannot find any service record on the coolant system in the records the previous owner, Bill Robinson, gave us. So i have an opportunity to reset the clock and get it all done.
We are also doing the following:
a) new windshield seals (windshields were replaced in July but the new seals did not arrive)
b) having the new thermal coating applied on the roof
c) new fabric put on the jack knife couch
d) new rope/mood lighting
e) flush & clean grey & black holding tanks
We are staying in a cabin until the bus is done. Our plans of travel have been placed on hold. For now we stay in Texas as Pams Father is going back into cancer treatments. We’ll stay put and be here for him & my mother inlaw. Really grateful we retired and can do this. When my stepfather was ill we were still stationed in DC and could not be there for him & mom as much as we wanted. This time we have the chance to be of service.
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