Community Forums

model a guy · 07-12-2014, 05:57 PM

I have a 1996 allegro, purchased at 40k miles, now has 60k. ran great for a year then started overheating. I have changed radiator, hoses, thermostats, waterpump and belts. washed out precooler, though it was clean, can see thru it fine. Fan is direct drive and pushes good air out rear of coach. When outside temp is 80 degrees I can't run down the freeway w/out overheating. I'm stumped, any thoughts?

onechaddude · 07-12-2014, 07:47 PM

Maybe pull your thermostat out and just make sure it's working in boiling water pot. I've seen many things brand new and fid not work right.

Chad

model a guy · 07-12-2014, 08:44 PM

thanks, I did try that and also put a new set in (second time). Has two thermostats

onechaddude · 07-12-2014, 09:16 PM

Sounds like a check to see how much water the water pump is moving. Could have some kind of blockage that is limiting the flow of water. I am no mechanic so I'm just trying to reason through this. That's about all I've got. Sorry I can't help further.

Chad

brobox · 07-12-2014, 09:20 PM

Has the radiator been sprayed with Awesome or Simple Green and hosed clean lately?

mahon1993 · 07-12-2014, 09:22 PM

Are you really overheating or do you have a bad temp sender or gauge?

jd956jd956 · 07-12-2014, 09:40 PM

Does your radiator system have a coolant filter mounted on the engine block above the alternator? I don't think that was on your extensive list of items changed out. Also, if you are on a Spartan chassis and have a hydraulic radiator fan, it shares hydraulic fluid with your power steering pump and there are two "priority valves" in-line that direct fluid to both the power steering pump and radiator fan motor. Those priority valves can wear out and as they wear out, they are designed to send more fluid to the power steering pump at the expense of the radiator fan. You can call Spartan technical assistance or your particular chassis maker and ask about them. On spartan, they are easy to change out and can be purchased on Spartans parts website for significantly less than by ordering from spartan by telephone.

Jeff on Lake Conroe
1997 American Eagle
2013 FJ Cruiser 4x4 Toad

bobguigley · 07-13-2014, 07:27 PM

could also be the fan clutch , I'd call Freightliner tech support in Gaffney to get their ideas.

model a guy · 07-19-2014, 08:13 AM

Good morning, I've been away helping my son get his hay up, been long days and haven't had time to catch up with your suggestions. The gauges are working correctly, I have checked with an IR temp gun. The fan an the coach is a direct drive, no clutch. I have washed it out several times, using simple green and other detergents, and the motor and radiator are open and clean, I checked by shining a light through. I'm thinking about adding a transmission cooler to the system, as the current one is the bottom portion of the radiator, and seems to me that the transmission is running hotter than it should (180-200). Anyone done this?

palehorse89 · 07-19-2014, 08:27 AM

Quote:

Originally Posted by model a guy

I have a 1996 allegro, purchased at 40k miles, now has 60k. ran great for a year then started overheating. I have changed radiator, hoses, thermostats, waterpump and belts. washed out precooler, though it was clean, can see thru it fine. Fan is direct drive and pushes good air out rear of coach. When outside temp is 80 degrees I can't run down the freeway w/out overheating. I'm stumped, any thoughts?

Quote:

Originally Posted by model a guy

Good morning, I've been away helping my son get his hay up, been long days and haven't had time to catch up with your suggestions. The gauges are working correctly, I have checked with an IR temp gun. The fan an the coach is a direct drive, no clutch. I have washed it out several times, using simple green and other detergents, and the motor and radiator are open and clean, I checked by shining a light through. I'm thinking about adding a transmission cooler to the system, as the current one is the bottom portion of the radiator, and seems to me that the transmission is running hotter than it should (180-200). Anyone done this?

Hi Steve, I just posted and deleted it, reread the entire thread, you first state that you replaced the radiator(reason for deleting post) then I read that you just washed it. 3 years ago, mine was 11 years old,45,000 miles, and started to have over heating issues, washed the radiator from the inside and the outside, no help. From the inside, reaching inside the fan shroud, I found the fins to be brittle and falling apart, time to replace it........After I got the charge air cooler off the front of the radiator , my jaw dropped open, the dirt and leaves and junk that was trapped in between the two was amazing, it would of never been able to be washed out, ever. New radiator installed($1600.00 total, radiator, coolant, additives) Now it just sits right at 180 deg. , 190-193 on a hard pull towing. Out west last year......195 deg tops. Washing the outside of a radiator is not the only cure, is the inside(tube passes) able to flow the proper amount of coolant from the pump, or are they plugged off.........less cooling = higher temps.
With the year of your Coach, I would lean towards a new radiator.

model a guy · 07-19-2014, 07:48 PM

Thanks for your thoughts, I assumed I would have stuff between the radiator & precooler but it wasn't bad, I washed it out good, before installing new radiator. I'm glad you solved your problem sure wish I could figger mine out. I saw else were that one owner had installed a water mister, manually operated, I've ordered one, but it's a band-aid and I still need to solve the problem.....

deandec · 07-20-2014, 11:07 AM

At what temp is it overheating.

My C8.3L mechanical normally runs between 180 degrees and 200 degrees with the standard thermostat installed. That thermostat supposedly opens at 183 degrees and is full open at 203 degrees.

The chassis manual warns against constant operation in excess of 212 degrees.

The EMS will warn at 215 coolant temp degrees of a high heat situation and will shut down at 225 degrees to protect the engine.

ivan_drago · 07-22-2014, 06:32 AM

Good day, not meaning to hijack this thread at all but I am having the same issue with my 2005 ISC 330. While traveling through Utah at night holding up a slight grade that between 40 and 50 mph the engine temp was pegged at 250. At least that's what the gauge said. I pulled over and let it rest to get it back down to 200°. Then again it exceeded the red marker on my gauge and my check engine light turned on. Never did the motor shut down.

One: space the radiator was rinsed and washdown prior to me leaving Colorado.
Two: the coolant system was serviced 10,000 miles ago by the previous owner.
Three: I have an exhaust manifold gasket leak at number four and number six cylinder as well as a possible crack between five and six on the bottom side of the manifold
Four: the coach in question is a 40 foot Monaco Knight 40 PLQ.
Five; I was traveling completely empty nothing in the coach.

A sincere thanks for any replies.

2002 Pace Arrow 37a
Workhorse/Allison
Koni/AFE

Sent from my iPhone using iRV2 - RV Forum

Gorlininc · 07-26-2014, 12:27 AM

I have a 330 ISC Cummins also. I'm
on my second 8 month trip out west. I've learned several things about keeping the engine cool. The higher the altitude, the air is thinner. Therefore cooling is reduced.
Unless I'm on a level road I keep my RPMS up. I run in 5th gear at 50 to 60 MPH.
On a long shallow uphill climb and going 40 to 45 MPH, I'm in 4th gear and 2000 RPM.
Whenever I see my temp go to 195 degrees. I slow down in order to downshift to the next lower gear. This higher rpm gives much better cooling and the engine is working less. The temp goes right back down. I keep it at 2000 rpm on hot days going up hill.