Skip to main content ↑ ↓
Topic: 98 Magna with Detroit Diesel 40E Overheating (Read 1646 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

98 Magna with Detroit Diesel 40E Overheating

Yahoo Message Number: 63502
We purchased a '98 Magna (w/330HP Detroit Diesel 40E) in early August near Phoenix, and have been unable to leave the area due to high engine temperatures. Just driving around town we're seeing 225 on the gauge after about 15 minutes of driving.
We had the cooling system flushed, the thermostat has been changed and even the temperature sender (w/matching gauge) have been replaced. Freightliner assured us that everything was okay with the engine and that "there must be a wiring issue between the gauge and the sender" since their infra-red temperature gun was showing temps 20 degrees lower at the engine than the gauge.
So we hooked up the car, and pointed the rig up the mountains towards Payson. After about 40 minutes of driving, maybe 10-12 minutes up the first 6% grade we heard an engine temperature warning message, followed within seconds by the Engine Protection Module kicking-in and shutting us down.
Since then, we've verified that the hydraulic fan is working properly (the PTO driven hydraulic pump is delivering proper pressures). We've also verified that the fan is spinning at 2800+ RPM at around 2000 engine RPM.
We now have the rig at Divine Coach Care where they want to remove the radiator and send it out to be cleaned and "rodded". I looked inside the radiator with the tech and it didn't look too bad to me. They're giving me no assurances that this will fix the problem and are quoting $2000+ for the work (much more if the radiator "needs" a new core!). When we had the rig at Freightliner they said the change in coolant temperature between the top and bottom of the radiator was 25 degrees, which indicated it was doing its job.
It has been hot around here, however the engine temps have been just as high whether I've been driving in 85 degree heat or 115. Air temp was about 90 the day we tried to climb to Payson and we were letting the transmission do the shifting. A/C was on during the first part of the drive, though we shut it off once we saw the engine temp start climbing. We were towing a car, though we don't yet have the coach loaded with much in the way of personal gear.

Anyone have any thoughts on the matter?

Scott & Susan Ueland

1998 Country Coach Magna #5587
w/Detroit Diesel Series 40E

Re: '98 Magna with Detroit Diesel 40E Overheating

Reply #1 –
Yahoo Message Number: 63508
Has anyone checked to be sure you have coolant circulation. If the circulation pump on the motor has failed it may not be circulating the water like it should. What temp thermostat was put in, was it the right one?

Mikee

Re: '98 Magna with Detroit Diesel 40E Overheating

Reply #2 –
Yahoo Message Number: 63509
Take it to a Detroit dealer and have them read the DDEC.

Re: '98 Magna with Detroit Diesel 40E Overheating

Reply #3 –
Yahoo Message Number: 63510
You have checked everything I would have checked, so any guess I make will be just a guess.
I had an old BMW 7 series that was bad about getting air bubbles in the cooling system, gave the same results you are seeing. One of the mechanics suggested burping the hoses at the highest point in the water system, and that fixed it.
"Burping the system" sounds real easy if you say it fast, but that may be a major chore in a diesel RV.
I considered putting a petcock in the high point of the system to vent when needed, but since I only drained the system every two years or so, just dealt with it.
Sounds like the engine module agrees with the dash gauge. I would not expect a "wiring issue" (and folks here will correct me if I do not understand the system) as wiring issues are usually shorts or open. If you DO have a wiring issue, look for part of the loom in common with both the gauge and module. Sorry if that seems simplistic, but that's all I "got".
Jack Nichols, 2003 Intrigue, Cummins 400, 11527

Re: '98 Magna with Detroit Diesel 40E Overheating

Reply #4 –
Yahoo Message Number: 63594
Hi Friend, Just my two cents. Have the coach put on the Dyno at the Detriot dealer, The techs there will find the problem, Been there and done it! Leave this to the Pros! Ken 99 Allure 30356 heading to Yuma Az. in a week. Retired Cat Tech. Hope the 2000$ is not wasted.