Mountain driving and engine temperature - Page 2

NV245 · 08-08-2013, 11:26 AM

Before you purchase a linking device, better check your coach for the proper connector. My 2008 does not have an OBDII connection, it has 2 round connectors, one under the dash, one at the rear under the "hood". The Freightliner display gives the temperature info the same as a readout box would.

I-RV · 08-08-2013, 02:27 PM

Quote:

Originally Posted by NV245

Before you purchase a linking device, better check your coach for the proper connector. My 2008 does not have an OBDII connection, it has 2 round connectors, one under the dash, one at the rear under the "hood". The Freightliner display gives the temperature info the same as a readout box would.

I have a Berkshire 390BH-40. Can anyone explain what and where the OBD2 connectors is? Thank's

NV245 · 08-08-2013, 04:05 PM

OBDII refers to On Board Diagnostics, second generation, where the Environmental Protection Agency (EPA) required automotive manufacturers to provide emission control checks to be run for proving emission devices are working. It also required a universal connector so that aftermarket scanners could connect to the powertrain controller, making it possible for one scan tool to be used for diagnosis/monitoring. Apparently, the legislation did not include heavy truck (Freightliner Custom Chassis) so Freightliner/Cummins probably does not have an OBDII connector. I don't know how the Mercedes connector is configured.

kingwood390bh · 08-09-2013, 06:11 PM

Well, I got back from my 4000 plus mile trip out west. My rapid temperature rise came climbing Big Bear in California. Lots of switch backs and steep climbs. I had the Allison 3000 in normal drive and the overdrive was kicking in. I was alarmed at the rate of rise (and fall) of my temp guage. My take away from the experience was that I should gear down and slow down while on extended climbs. I never pushed the unit to the point of overheating. Just by backing off the throttle and slowing down brought the guage back down in seconds. The book is very specific that you should "never" shut the engine down.
My guardrail damage came from too tight a right turn on a very tight switchback. I didn't even notice when I hit it. My wife was following and watched in horror. I was sooooo close to missing that darn thing!!
Will

tmmar · 08-09-2013, 06:37 PM

There is a computer port in the back of the coach where the radiator is located. It is a round port that is brown in color ( I believe). Not sure if it OBDII or not but that is where Freightliner connected to when they did some maintenance on my coach.

NV245 · 08-09-2013, 07:07 PM

You may want to set your Freightliner info center to engine temp. After rereading your original post, I wonder if your thermostat is opening too early and showing the 1/4 temperature on "light" load, and actually getting to operating temp under load. If the Freightliner info center shows below 190 degrees, you may want to consider a thermostat change.

RKC02 · 08-09-2013, 10:31 PM

As far as I know, diesel pushers (Freightliner at least), do not use an OBDII connector. Ours is called a Deutsch diagnostic plug and is either 9 pin (J1939 - newer models-approx 2004 and up) or 6 pin (J1708/J1587 for pre 2004). I don't know of one but maybe there is an adapter from OBDII to Deutsch.(?). There are diagnostic devices/readers but they are expensive.
** I got this info from the Silverleafelectronics.com site

csichoice · 08-16-2013, 05:40 PM

I was having the same problem with my 2011 390BH. We traveled from Colorado to California and on the steep hills leaving Nevada our temp climbed and set off the alarm for extreme engine temp. We pulled over and it came right down to normal. I figured out that every time I pulled a hill I could not go over 2,000 RPM if I did the temp would start to rise. I made it back with no problems and then a few weeks ago it started doing it again when pulling hills I could not rev the engine over 2,000 RPM or it would get real hot fast. I took the motor home into Cummins and they told me it was a fan of some sort and I would have to take it over to Freightliner to have the fan replaced since they were not an authorized Freightliner repair shop.

They said the fan would come on at high RPMs but then cut out occasionally> I will let you know what the fan is called once I pick my motor home up next week from Freightliner.

ernest917 · 08-16-2013, 05:55 PM

Just curious - did you manually downshift to a much lower gear OR did you just let the transmission do it ???

I'm asking because I just returned from a month in the mts of MT, WY, UT and CO..... I manually downshifted before I started the climb and then downshifted to one gear lower than I used to climb when I started the descent.... I'm talking 8, 9 and 10% grades.... I never overheated a single time.... Took my time and kept my speed around 40-45 climbing and 20-25 coming down....

Obviously that's all a moot point if you have a defective fan....

csichoice · 08-16-2013, 06:09 PM

I just let the transmission do the work. Freightliner said the fan was only working at half speed when it did work. they said it would not effect the motor home as much when traveling at highway speeds on flat land since I would have a lot of air going through the engine area but on climbs you are going much slower with less air and that is when the fan comes into play.

kingwood390bh · 08-18-2013, 11:59 PM

Is the fan on the back side of the radiator? That may be my issue because I never heard any fan engage.

csichoice · 08-19-2013, 11:51 AM

I am not sure were the fan is located. I will have more information for you once I pick my motor home up from Freightliner this week.

klucas · 08-19-2013, 12:22 PM

Quote:

Originally Posted by kingwood390bh

Is the fan on the back side of the radiator? That may be my issue because I never heard any fan engage.

Yes. It is behind the radiator if you are looking at it from the rear. I can hear mine spin up as I am going over mountains and temp comes up. It will spike then quickly cool off and you can hear the fan slow back down.

JohnF · 08-19-2013, 12:32 PM

There appears to be two fans in this 2011 GMC Sierra. Can I assume one is for the radiator and the other for the transmission cooler as you are describing?

speedmerchant · 08-23-2013, 07:41 AM

Quote:

Originally Posted by JohnF

There appears to be two fans in this 2011 GMC Sierra. Can I assume one is for the radiator and the other for the transmission cooler as you are describing?

Typically the second fan is for when the a/c is on. When you turn on the a/c it should automatically engage one of the fans to keep some air movement through the condensor. It likely is on a mutlifunction circuit which would allow it to turn on under other circumstances as well. They could both possibly turn on with the a/c as well. There are many variations in which manufacturers utilze dual fans and their purposes for activating.

You may also like: