Engine Temperature going down mountains

[Ron & Dee]

Should the thermostat maintain the engine temperature at normal while going down mountains?

I have noticed, especially while going down the mountains in the Rocky Mountains NP, that the temperature falls way below normal temperature and never recovers to normal until I get to the bottom.

Thanks,

Ron

[Ron & Dee]

Should the thermostat maintain the engine temperature at normal while going down mountains?

I have noticed, especially while going down the mountains in the Rocky Mountains NP, that the temperature falls way below normal temperature and never recovers to normal until I get to the bottom.

Thanks,

Ron

[abarkl]

My 2001 does the same...but it wouldn't if I fired it up today in Phoenix at 105F outside!

[Fred and Bonnie]

Ron, if you haven't done so, download the 2006 version of the Workhorse owners' guide. On pages 49-50 is a description of the Engine Operating Temperatures. My experiences have been as described. I use a Davis Instrument Car Chip that records various parameters, one of which is Engine Coolant Temperature. Traveling eastbound on I-70 going from Grand Junction CO to Cheyenne WY the temp rose to 225º climbing and a low of 190º on descend. The instrument panel temperature gauge did not indicate any readily noticeable changes. Based on my experiences I would say your thermostat is not functioning properly.

Fred

[DriVer]

You would have to pull the T-Stat and look at it to see if it's seized. The boiling water in the pan routine works best to rule out problems with the stat. You can see it operate in the pan as the water begins to boil.

It's very difficult to point to the thermostat and say it's bad unless you can physically look at it. There are indicators early on if the engine doesn't achieve operational temperature for an extended period of time however a stuck open condition occurs infrequently.

A stuck closed T-stat will present an over heat condition almost immediately but in my experience it's very rare that you will see this type of condition.

As you have a 2002 motorhome perhaps a good cleaning and flush would be advised and finishing off a new radiator cap would be appropriate.

[Ron & Dee]

I'm very paranoid when it comes to engine temperature.

The first question I had for the service department right after we bought the MH was, why the temperature indicator was at the half way point and not three quaters like my old MH. Also, why the incicator seemed like it was stuck and never change much.

I was told not to worry about it, that the position of the indicator showed the normal operating temperature and the WH factory has pretty much locked down the indicator at the half way point.

The drop in temperature going down mountains in the lower gears has been this way since we bought the MH three years ago.

Without taking the thermostat out and inspecting it's condition and operation, I'm assuming it is operating as it did three years ago since there are no noticable changes.

How long does it take, on average or approximate time, for the MH to get to operating temperature from a cold start?

Thanks,

Ron

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ron & Dee:
How long does it take, on average or approximate time, for the MH to get to operating temperature from a cold start? </div></BLOCKQUOTE>Ron, That number is on a sliding scale. If you let the motorhome sit and idle it'll take 15 to 20 minutes to achieve operational temperature. If you jump in the seat, start the MH and drive away the MH should achieve operational temperature in practically half the time.

This is typically included in a new vehicle owner's manual. The text normally states do not idle your vehicle for extended periods of time (over 1 minute) because you will begin to use fuel unnecessarily. It is much better to get in the vehicle and simply drive away and allow the systems to do their magic rather that sit idling.

Now this is only a guideline for a non-RV motor vehicle. Motorhomes on the other hand need time to pull in slideouts and suck up jacks. This process is most often better accomplished with the vehicle running rather than pull a heavy load off the automotive battery after it might have been sitting for a week on a campsite.

By the time we start the engine and are out of the campground, we probably are very close to having the MH up at its operational temperature. If you're getting on the Interstate and by the time you achieve your cruising speed the engine should have long achieved its operational temperature range.

[John-D]

Q:Why is the temp indicator at the half way point and not the 3/4 like it was in the old MH.

A: The old MH ran hot, Mid point on the gage is normal

Q: Why does it appear to be stuck there

A: That indicates the thermostat and the rest of the cooling system is operating properly, if it starts climbing (or dropping) you may have a problem


Q: (Mine this time) How close to the service manager's answers did I get?

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by John-D:
Q: (Mine this time) How close to the service manager's answers did I get? </div></BLOCKQUOTE>Those are accurate descriptions. To answer your question, it's all good!

[eandy]

Hi guys,
Think we've been here before but probably good to cover again with Summer coming.
Driver, my mini-van manual also says to start and go but everything I've learned over years says to let the engine warn before driving. Not allowing the different alloys of the block, piston rings etc to warm causes premature wearing of parts. Great for after market parts and service, bad for engine life.

Also, an old commercial pilot tipped me to using only distilled water for coolant mix eliminates rust in block and thermostat.

[Full-Timers]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by eandy: Driver, my mini-van manual also says to start and go but everything I've learned over years says to let the engine warn before driving. </div></BLOCKQUOTE>The rules probably changed when the government got involved. Letting the engine idle until warm waist gas and un-necessarily pollutes the environment.

I do as DriVer does. Start the engine, bring in the slides, raise the levelers, and do my final walkaround. Otherwise, I don't let the engine warm up. I start it and drive off. I would never pull a 6% grade until warmed up though.

[John-D]

On my rig (Power Gear jacks) bringing up the jacks takes "Flea power" (Not much) as the springs do the work, all the battery has to do is open the valves.

Slides get their power from the house batteries and the PD-9180 makes sure the chassis battery is well fed when I'm parked. (With some help from the BCC)

You need to let an engine "Warm" just long enough to get oil to all the working parts. This is about as long as it takes you to buckle your seat belt.

If you don't believe in wearing seat belts this will be a long, long time

[Ron & Dee]

So far there are only two of us with engine temperature going south during mountain downgrade?


Ron

[eandy]

Ron, to answer your question, my needle sticks just above middle always. I've installed a pyrometer with the probe about 2" from no.7 plug and the gauge ranges from 125 at idle to 175-285 depending on all the usual variables so I'm not at all sure about the dash temp gauge. Only will get alarmed if either gauge goes way high.