Bob Wightman Posted November 23, 2023 Share Posted November 23, 2023 Hello Group, I am considering buying a 2006 HR Scepter with a Cummins ISL 400 with 65K miles on it. Its on consignment at a dealership, when calling for info about the coach I was told that its in great shape but its "Funning Hot". Online research before going to see (because they are closed for the holiday) says everything from: bad sensor and/or gauge, clogged or bad radiator, fan controller problem, leaking coolant somewhere, and worst....bad head gasket. I'm really interested in this coach and serious about buying it but don't want to buy a bad motor. Since this seems to be a common thread on the internet I was wondering if anybody has already been down this road and could give me some advice as to what to look for when I see the coach. Thanks in advance! Link to comment Share on other sites More sharing options...
bklaes Posted November 23, 2023 Share Posted November 23, 2023 Try the easy first... my ISL 400 dropped 35 degrees in operating temp when the (rear) radiator was hosed off using simple green and wam water. I hosed it off from the outside, and the inside through the floor hatch above the engin.e. 1 Link to comment Share on other sites More sharing options...
Tom Cherry Posted November 23, 2023 Share Posted November 23, 2023 The best advice would be to have the Motor Home inspected by an independent tech for all the items pertaining to the “House” or the “home” items. Then take the MH to a certified Cummins shop and have the engine diagnosed and get estimates. There are check lists for a combined inspection that folks have posted here. However, with the engine and mechanical issues….you need two different inspections. The “house” inspection, by s professional may take several hours….usually a minimum of $500…probably more, but is money well spent. The engine diagnostic will be at least $250 or more if they have to do detailed testing….just to give you an accurate quote. These models have a “electronic” controller for the engine. Usually, if it goes bad, it opens the valve and allows a full flow of coolant and runs cooler. It’s better to spend some money, up front, for the independent inspection and also for the engine diagnostic instead of guessing. One has to wonder why an owner is selling a “less than average condition” MH basically, “AS IS” or did they get estimates in the tens of thousands range and decided to unload it on an unsuspecting or not knowledgeable buyer. There is no one “place” to look of “gee, this is always the problem”. We have had folks with engine problems approaching $20K….not the norm, but it happens. Pardon my cynicism, but this situation is like the lyric from the Eagles’s “Hotel California”….this could be Heaven or this could be Hell . In your case, you can see flames and smoke and the “greeter” doesn’t appear to have wings. Unless you can get more solid information, discount the MH by $20K….and assume that, perhaps, it was not maintained to the standards that most of the members here do… 1 Link to comment Share on other sites More sharing options...
Frank McElroy Posted November 23, 2023 Share Posted November 23, 2023 Get a copy of the engine abuse history report. Any shop with Cummins Insite software can do this for you. In the report look at the actual history of how hot the engine has been running and the severity of overheating. This report will show engine temperature data from the time the engine was built. I wouldn't buy the coach without reviewing this report pulled from the engine ECM. 2 Link to comment Share on other sites More sharing options...
Cousin Eddie Posted November 23, 2023 Share Posted November 23, 2023 When buying my coach 7 years ago (03 Dynasty 400 ISL side radiator hydraulic fan controls) I took it to Cummins and had them plug it in to see if there was anything out of range (over revs, temperature, etc). It checked out perfectly. Once I bought it I found out that the PO had complained about it running hot (he used data from dash gauge). Bottom line: the location of the sensor installed by Monaco gave high readings but the Cummins data- read from the area around the thermostat- was perfect. I now use Bluefire to pick up the Cummins data (181 to 183 normal, maybe 193 in Colorado mountain climbs) and ignore the dash gauge. It’s a cheap first step before moving on to the steps mentioned above. 1 Link to comment Share on other sites More sharing options...
cbr046 Posted November 23, 2023 Share Posted November 23, 2023 2 hours ago, Tom Cherry said: Pardon my cynicism, but this situation is like the lyric from the Eagles’s “Hotel California”….this could be Heaven or this could be Hell . I think I'm in Hell . . . . - b Link to comment Share on other sites More sharing options...
Bob Wightman Posted November 26, 2023 Author Share Posted November 26, 2023 First, thank you to all who provided input, it was all very much appreciated. The report after seeing it and test driving it yesterday: The "running hot" was not as advertised...the motor ran cool/fine, it was the transmission that ran hot. What I noticed is that during the test drive all went well and drove and shifted great. When I got off the Interstate drive portion of the test drive and was waiting at a stop light is when I noticed the trans temp go up into almost the red line area. As soon as the light changed and we got moving it started to cool down again. When we arrived back a the dealership it was again approaching redline as we moved it slowly through the parking lot. When I parked it i left it running to see what it would do, after a few minutes at idle it started to cool down again. Having this same transmission in my 2004 Knight I shut it down and tested for codes...there weren't any. I fired it back up and tested for fluid level, it showed it was down by 2 quarts...which the dealer will add on Monday. I know the fluid also cools the transmission, so the question to the group is: Do you think two quarts low would make it run hot? The rest of the coach is in amazing condition and has lots of new goodies such as tires, batteries, AC's, refrigerator...and the list goes on. Last; I also checked the serial number on the motor and it was NOT in the serial number range (it was built before the bulletin numbers) for the wrist pin bushing potential failure (thankfully). I was able to negotiate a deal that I am happy with that included a 2 year warranty that covers engine and powertrain plus most of the big ticket "house" items so I am moving forward with closing the deal. Attached is a picture of the "New Girl" that will be joining us soon, and a picture of who she will be replacing. The Knight has been a great coach, we will miss her and hope that she gets a new loving home soon. Link to comment Share on other sites More sharing options...
jacwjames Posted November 26, 2023 Share Posted November 26, 2023 On 11/23/2023 at 8:22 AM, Cousin Eddie said: When buying my coach 7 years ago (03 Dynasty 400 ISL side radiator hydraulic fan controls) I took it to Cummins and had them plug it in to see if there was anything out of range (over revs, temperature, etc). It checked out perfectly. Once I bought it I found out that the PO had complained about it running hot (he used data from dash gauge). Bottom line: the location of the sensor installed by Monaco gave high readings but the Cummins data- read from the area around the thermostat- was perfect. I now use Bluefire to pick up the Cummins data (181 to 183 normal, maybe 193 in Colorado mountain climbs) and ignore the dash gauge. It’s a cheap first step before moving on to the steps mentioned above. I had a problem with my dash gauge showing high oil pressure. After I bought the first thing I did was take it to the Cummins shop for a service/inspection and asked them to look at the oil pressure issue. The said the the oil pressure sensor was installed in the wrong place But the oil pressure gauge was damaged so it wouldn't read correctly. But the ECM was reading from the Cummins sensor and never threw a code. A use a Silverleaf and get better information from my dash gauges, I seldom look at dash gauges. Link to comment Share on other sites More sharing options...
Chargerman Posted November 26, 2023 Share Posted November 26, 2023 (edited) Awesome looking coach. Congratulations! Two quarts low shouldn’t cause an overheating but it will be interesting to hear if adding the fluid helps at all. I would consider adding a trans cooler if you can confirm with a second gauge that indeed it is running that hot Edited November 26, 2023 by Chargerman 1 Link to comment Share on other sites More sharing options...
cbr046 Posted November 26, 2023 Share Posted November 26, 2023 One of our newest members produced a video on transmission filter & fluid replacement. I'd strongly consider it. As stated, the Allison 4000 process is almost identical. Enjoy the new coach! - bob Link to comment Share on other sites More sharing options...
jacwjames Posted November 26, 2023 Share Posted November 26, 2023 (edited) 31 minutes ago, Bob Wightman said: First, thank you to all who provided input, it was all very much appreciated. The report after seeing it and test driving it yesterday: The "running hot" was not as advertised...the motor ran cool/fine, it was the transmission that ran hot. What I noticed is that during the test drive all went well and drove and shifted great. When I got off the Interstate drive portion of the test drive and was waiting at a stop light is when I noticed the trans temp go up into almost the red line area. As soon as the light changed and we got moving it started to cool down again. When we arrived back a the dealership it was again approaching redline as we moved it slowly through the parking lot. When I parked it i left it running to see what it would do, after a few minutes at idle it started to cool down again. Having this same transmission in my 2004 Knight I shut it down and tested for codes...there weren't any. I fired it back up and tested for fluid level, it showed it was down by 2 quarts...which the dealer will add on Monday. I know the fluid also cools the transmission, so the question to the group is: Do you think two quarts low would make it run hot? The rest of the coach is in amazing condition and has lots of new goodies such as tires, batteries, AC's, refrigerator...and the list goes on. Last; I also checked the serial number on the motor and it was NOT in the serial number range (it was built before the bulletin numbers) for the wrist pin bushing potential failure (thankfully). I was able to negotiate a deal that I am happy with that included a 2 year warranty that covers engine and powertrain plus most of the big ticket "house" items so I am moving forward with closing the deal. Attached is a picture of the "New Girl" that will be joining us soon, and a picture of who she will be replacing. The Knight has been a great coach, we will miss her and hope that she gets a new loving home soon. Check your cooling stack and determine how you tranny oil is being cooled. I found one listed on RV trader which looks like the one you bought and it has a side radiator stack. See if the cooler is internal to the radiator?? Monaco, on my coach, installed a dash temp gauge with it's own sensor mounted in a block on the output hose of the transmission, wonder if it is OK. I read my tranny temp on a Silverleaf which gets it's info from the ECM. I had to have my radiator replaced in 2015, I replaced with a CG&J radiator and after that had high tranny temps. I could not find any cause other then I suspect the internal tranny cooler was not sized correctly, I contacted CG&J and they couldn't/wouldn't help and had no info on internal cooler. So I added a Derale cooler to augment the cooling which worked great, dropped the temp going to +235F when stuck in traffic to ~180F. But the Derale cooler failed. I lost 3 Gallons of tranny fluid but I got lucky and it didn't damage the tranny. I bypassed the cooler, got the fluid level to where it needed to be and ultimately drove the coach ~2500 miles home and have since did a oil analysis which passed. I have since added this cooler >>> see pictures So to your question, no I don't think 2 quarts would cause a problem and/or cause the tranny to run hot. I would get something (scangauge or bluefire) to confirm tranny temp. I would check your radiator, see if it is an OEM from Monaco, there should be a tag on the side. I decided to completely bypass the tranny cooler internal to the radiator, don't trust it. Another member with a 2002 Windsor just had his internal radiator fail and had to have the radiator and tranny replaced. The cooler I installed I believe originally installed on a rear radiator coach so it is capable of cooling a 3000 tranny, The fan I added was off the Derale and will help push air through the radiator. I took it on a test drive and highest temp I saw was ~165F even backing into my garage when I had seen +230F prior to adding the Derale. Edited November 26, 2023 by jacwjames Link to comment Share on other sites More sharing options...
Bob Wightman Posted November 26, 2023 Author Share Posted November 26, 2023 I plan to install ECM monitoring equipment as soon as I am the actual owner. I would like a permeant dash gauge panel that is always ready to go when I fire it up...suggestions on the best choice for this? Seems like ScanGuage is pretty much plug & play and fairly cheap. Don't mind spending more to get more if its useful info. I also plan to check and thoroughly clean the radiator stack as i'm sure that has never been done (I flush mine on the Knight after every trip) as the sellers are an old couple and i'm sure can't do it even if they knew how to do it. I suspect my problem will be there, however living in South Florida and towing everywhere I go having a extra transmission cooler with electric fan control would be a great idea. Link to comment Share on other sites More sharing options...
jacwjames Posted November 26, 2023 Share Posted November 26, 2023 Cooling air flows from outside to in so you should be able to visually see if you have a problem. Shining a light through will tell you quite a bit. I use a Silverleaf but it is now obsolete unless you can find a used one. It is plug and play but you have to use a different monitor, originally I used a Sony Viao laptop but it fail and I've since switched to a Microsoft Go2 tablet, which works great once you get the screen set up. I found using a mouse during the process of setting up my screen worked best. I didn't get fancy with the screen but display the important parameters and I also set up alarms for most of them i.e. if tranny gets hot I get an alarm. I also set up data logging so I can go back and see what was happening during my trip. When I installed the Derale cooler and my wife took it on the first long trip I was able to go back and check. All was good. The Scanguage is plug and play, I believe you can see 4 parameters at on time. The bluefire you get the info over Bluetooth and can use any compatible device, a lot of people just use their phone. Good luck, keep us posted. Link to comment Share on other sites More sharing options...
Bob Wightman Posted November 26, 2023 Author Share Posted November 26, 2023 I just researched all of them, my opinion is the BlueFire is the best choice and ordered one so I can use it when bringing the rig home. Link to comment Share on other sites More sharing options...
96 EVO Posted November 26, 2023 Share Posted November 26, 2023 You mentioned temp rapidly climbing at stoplight. Did you happen to notice what the idle RPM's was set at? Link to comment Share on other sites More sharing options...
Bob Wightman Posted November 26, 2023 Author Share Posted November 26, 2023 The motor was idling at approx 800 rpm Link to comment Share on other sites More sharing options...
96 EVO Posted November 26, 2023 Share Posted November 26, 2023 A hundred RPM's high. Lowering it should help. Link to comment Share on other sites More sharing options...
Bobkat11208 Posted November 26, 2023 Share Posted November 26, 2023 3 hours ago, Bob Wightman said: I just researched all of them, my opinion is the BlueFire is the best choice and ordered one so I can use it when bringing the rig home. I have the Scangauge I use for fuel primarily, but the BlueFire is intriguing! Would be interested in your input on how it works. The manual is, um, detailed. 😂 Nice rig btw. Link to comment Share on other sites More sharing options...
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