1990 Newell w/ 8v92ta . Cooling issues

[marcg007]

Hi all, im happy to have found u all!!! An i have a few questions about a detroit 8v92ta. Production date sometime mid/late 1989, Silver. Shes in a 1990 newell 40ft coach #223. auto 4sp Allison, an i think....think its an h-700 series trans. 145k miles.

Im hoping to find detroit or newell people who know this motor an can point me in the right direction as she is doing the infamous overheating. Its unfortunate as the detroit fellow i was to have check her prior to purchase had a stroke 4 days prior to my fly in. He is doing well ive been told. i could not find a detriot tech in such a short time. One who could come on-site or nearby an i settled for one nearby to help me change fluids and fluid filters. 40 weight cx-ii in the motor, trans filters an fluid, an gen filters an fluid etc. He would not have been my choice as he was a general diesel tech an knew some on detroits but i did what i could. We also did the belts, alternator rebuild. battery check , brake an air line inspection. Did not do a coolant flush yet, but replaced the radiator cap. coolant level was good as the eyesight showed level throughout multiple checks, coolant was a decent green an not brown from rust etc in anyway.

145,000 miles on motor. From a cold start( 65f out at the time)she fired right up, no pulsing, no excessive smoke at all. no excessive oil leaks. after warm up oil press ran 45psi at around 1700 rpm, an 12 or so psi at a 550rpm or so idle. Level road from a stop when pushed the boost bounced off 22psi as shifted through the gears, cresting 1900 rpm. like i said when pushed checking her out...

Ive asked a few about the motor an the ones i did ask know some but not direct details on detroits. so here goes.


She ran different throughout 2 trips, will go into that later. I drove it from central fl to keywest an back early march. Then just up the east coast from florida to massachusetts an experienced some cooling issues along the way. she ran the key west trip good, but about 200f. but i learned the 2nd trip up the coast that she couldve ran better . the tech stated the air filter looked good so i did not replace right away.

so onto the situations; the 2nd trip back north. Mainly when running over 7psi of boost the cooling seemed it could not keep up. temps would start to rise over 210-220. one time it spiked to 240 going thru the blue ridge mtns on the 2nd trip. I Also pulled over a bunch of times an let her cool. At an idle or fast idle she would cool to 180(which is center of vdo gauge) . an later on even at a toll both temps would drop back down. If i stayed 7-8 psi max she rode 200ish, boost 8-10 an she would warm to 210, boost 12,15 an she would def go way over. drop back to 7-8psi boost during that climb or where ever an she would hold or start to lower temp for the most part.

after the the bluridge mtns an major hills moving I-81n night started to fall, temps were about 65 out then, it then dropped 50, then 45, then about 40f after 2am. About 12am Once the temps where 50ish she started to run better. an I remember reading how important the air filter is to this motor. as it uses the intake air not only for combustion but to force the hot gasses out the exhaust. Pulled off at a stop, removed the air filter in a few minutes. she ran so much better. less pedal more boost an response, temps stayed 180 the rest of the night even maintaing 12-15psi throughout the right times. i noticed an immediate response an huge improvement in power an temps.

4am i stopped pa ny border, slept 4 hours an was back on road for the last 450miles. she ran like it was a new motor for me, after an hour or so, an outside temps were rising, i noticed she started to run warmer an warmer. I reduced my max boost as i went along, by noon she wanted to keep getting warmer again if i didnt run past 6psi by 1pm. temps outside 65 or so by then.



Hope i didnt loose anyone, i am a technician by nature an i notice details.



THE FIX: so i am asking for recommendations. i hope i didnt ruin any seals or damage further. she never ran past 240 which i know is bad, an heard anything over 210f even bad in the first place.

but it was the situation , baby her within reason an risk some damage an do a rebuild near home. i didnt have log books prior, an after filter replacements an fluids i questioned prior maintenance. i already came to terms that if problems arrise i may need to do a rebuild anyway.

1) pay the money towards a tow, then do repairs when i get back. Or 2) run her an pay attention as best i could an risk damage an do rebuild if it gets bad.

I am also aware that running no filter is problem waiting to happen. i also am aware that later when outside temps got higher my cold air intake was reduced as turbo intake is middle of engine cab pulling in warmer air. there was only the filter connector attached to the turbo.

Would a coolant flush an clean by detroit be recommended. or is there a known good flush i could do? . i also read that detroit have test strips to tell contaminates , oils, nitrates, ph & ppms etc. any experience with that. if so i will do that when i call an find out monday. ( i do own a PH an PPM meter)

Do water pumps loose performance or either work or fail??

Likelyhood of coolant temp sensor failure? or just try remove an clean an or ohm out before replacement. or is my temp reading off an oil temperature sensor?

Any other real important points of interest? turbo after coolers?? I am getting what i think is good air movement across radiator. The radiator is clean an not oily on the outside. Could it be internal radiator buildup preventing proper heat transfer from coolant to radiator fin?. engine coolant port build up likelyhood?

again i am medical equipment technician. i am familair with small motors, i have rebuilt carbs, 2 stroke 4 strokes small motors. rebuilt water pumps, worked on genesets, hydraulic pump repairs. pressing bearings pulling bearings. 120v an 12v systems. r22 r 134 hvac systems. I use a multimeter an ohm out sensors an solenoids etc on weekly a basis. reading error code troubleshooting. thou my diesel knowledge is on yanmar motor gensets. i know some vw tdi's info, basic biodiesel knowledge an the important of atomization of fuel vs temps etc. i have some volvo diesel marine troubleshooting. Just no detriot yet, keyword yet!!!

thanks in advance an i hope my erratic post didnt deter anyone. thanks in advance an thank you. Any Newell techs worth while in New England, or NY.

marc