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Powertrain Q & A: Jan 2003

Originally Published in MotorHome Magazine

Q. We have a 1994 Coachmen 34- foot Class A motorhome built on a Ford F-53 chassis. Recently, while returning from a short outing of only about 70 miles, we noticed an odor of something very hot in the motorhome. On inspection, the only thing we could find was that the brake rotors, wheels and tires were hot to the touch. I could not hold my finger on the rotors. The tires were warm, approximately 130 F, and the rims were hot, but not as hot as the rotors.

The motorhome has only 30,000 miles and is in excellent condition. It
appears as if the brakes on all four wheels were dragging. I did not
notice any power loss during the short drive. There was no noise
originating from the brakes. The trip was made at dusk, and although it
was not raining during the drive, it had rained shortly before.
Therefore I do not believe the high temperatures were the result of hot

I have read your articles about changing the brake fluid, but I
have not done this to date and the fluid is original. Could that be the

— Bob Vigna,  Punta Gorda, Florida

A.   It’s possible, but unlikely, that old brake fluid was
the cause in this case. If corrosion caused the master-cylinder piston
to stick in its bore in a partially applied position, that would cause
the brakes to drag and get hot. However, the amount of heat given off in
normal operation is considerable, and it’s more likely that you simply
used the brakes a little harder than usual just before you got out and
noticed it. You should never touch the rotors with your hands to check
for heat because you can get severe burns. It’s also not unusual for the
tires to feel

warm or hot.

Keep an eye on brake condition and maintenance. I also suggest you
note (but don’t burn yourself) the heat coming off other motorhomes’
brakes when you’re at a rest area or a fuel stop. You’ll likely find
them equally hot. With that said, if you don’t flush the brake fluid you
will have expensive problems eventually.

Q.  I read Brian Thomson’s question about his Dodge running
hot even after doing most of the things he was told to do to solve it
(“Dodge Distemper,” September 2002).

Please tell him and any other 440 owners to go to a Dodge dealer
and place an order for the correct thermostat for the 440. It is Mopar
part no. 3512998. Apparently the parts stores have the incorrect number
for this application.

My 1978 Brave with a 440 had the same symptoms, even in Colorado on
a 70-F day. After a new radiator, engine and head work, auxiliary
electric fans, insulated fuel tanks, electric fuel pumps and water
injection, I read the MotorHome article some years ago and changed to
the Mopar thermostat.

Now, imagine my old 1978 Winnebago pulling a tandem trailer with a
full-size Ford Bronco in temperatures over 100 F and never getting out
of the normal temperature range. I can pull the steepest grades on the
hottest days here in Colorado without even a hiccup.

— Terry Blackmon,  Del Norte, Colorado

A.   The reason I didn’t recommend a thermostat was because
Thomson had stated, “Two years ago it started running hotter and
hotter,” indicating a gradual onset that is typically caused bypartial
radiator blockage. However, I never heard back from him about results.
This problem of two different thermostats for 440s hasn’t been mentioned
in MotorHome for a long time, and there are many new readers who can
benefit from this knowledge. Thanks for writing.

Q.   The heating problem Brian Thomson describes sounds very
much like what happened to a travelingcompanion a number of years ago. A
radiator shop in Las Vegas installed an automotive 440 thermo-stat in
the 440-3 engine in his motorhome, which resulted in the same symptoms
as Thomson describes. I understand that the water pump, which he also
changed, has to be the correct pump for the 440-3. Both the
passenger-auto thermostat and the water pump will bolt in, but don’t
work properly. I hope this helps.

— Al Reed,  West Region Vice President, Safari International RV Club, Huntington Beach, California

A.   Apparently there are still a lot of Dodge owners out
there, because this subject stirred more interest than most. Owners may
have trouble finding original replacement pumps. However, Edelbrock,
(310) 781-2222, edelbrock.com, sells heavy-duty Dodge pumps as part of
its Victor series.

Q.   I just read the letter from Brian Thomson and could
possibly shed some light. Dodge made two 440 engines. The regular 440
was usually only in Class C’s, and a 440-3 was used for Class A’s. Most
minor parts could be interchanged, but the thermostat and head gaskets
are different. The water holes on the 440-3 are slightly different,
causing a water restriction if not used on the right engine.

Years ago, I worked for a Chrysler/ Dodge dealership in the parts
department, and we ran into this problem quite often. Try to find a
dealer that has been around awhile and has the old catalogs, and have
the VIN when you contact him. Also, a NAPA dealer could help if the
counterperson is experienced.

— Robert Soluri,  Via the Internet

A.   Again, thanks for writing. This is useful information for Dodge owners, and hasn’t been covered here in years.

Q.   Could you tell me why the 2002 Toyota RAV4 with
automatic transmission is not approved for towing and the 2001-model
RAV4 with automatic is approved? I thought there was no change in the
model years. I would like one, but prefer to buy new. I am thinking it
may be like Honda, which can be towed, but it’s not factory approved.

— Ron Carl, Rancho Palos Verdes, California

A.   For an answer, I went to Chris Hemer, technical editor
of MotorHome, who is the author of the annual dinghy tow guide (see page
45 for the 2003 chart). Hemer states: “You are correct; there was no
significant change in model years. However, Toyota discovered later in
2001 that the RAV’s transmission was experiencing trouble when
flat-towed, so when 2002 rolled around, the company revoked its
towability status. Therefore, like some of the Honda models, it is not

Q.   In the July and October 2002 issues, people wrote in
about towing Ford vehicles and having to leave keys in the ignition when
towing the vehicle (“Key in the Ignition”). As a locksmith, I can say
that Paul Andrews’ solution (in the October issue) could cause him a
severe headache if he should accidentally turn his hardware store key in
the ignition.

All Fords of model-year 2000 and later use a special transponder
key with their anti-theft systems. A fellow locksmith recently told me
not to cut emergency lock-out keys for new Fords because if the customer
inadvertently puts that key in and turns the ignition, the whole system
could freeze up and the car won’t start at all afterward. His friend
did that, and it cost him a lot of money to repair the system.

Your suggestion about having the locking pin removed is a far better solution. Please pass on this information.

— Rodger Long, Mascoutah, Illinois

A.   If your friend had to pay a lot of money, he may have been taken to the cleaners instead of the repair shop.

According to my sources at Ford, if the nontransponder key is used,
the engine refuses to start, a theft code is set in the computer, and a
dash warning lamp flashes rapidly. The computer will then prevent the
engine from being started, even with the correct key, for a period of
time long enough to discourage a would-be thief.

The Ford scan tool can reset the computer if the key code needs to
be changed. However, if the owner just waits for about 20 minutes until
the rapid blinking ceases, it should restart with the correct key.

Q.   We purchased a 1999 Tradewinds motorhome in April of
that year; it has a Caterpillar 3126B diesel engine. On one of our first
trips, the coach would not start when we were getting ready to leave. A
mechanic who came out found nothing wrong. He had a portable scan tool
that showed no stored trouble codes. He squirted a little starting fluid
into the air intake, and the coach fired up and was fine.

After the trip, we took the coach to a Freight-liner dealer. The
mechanic looked at it, put it on the computer and said there was nothing
wrong with it. We took it to yet another Freightliner dealer and were
told the personnel couldn’t diagnose the problem and there were no
trouble codes. I have been to other service facilities and have been
told that they don’t have the computer to diagnose Caterpillars.

If I shoot a little starting fluid into the intake, the engine
always starts and runs fine. The engine has only about 16,000 miles on
it, and fuel and oil pressures were checked and are fine. I’ve had all
the filters changed, and there’s no water in the fuel system. All of the
facilities I have gone to tell me there is nothing they can do for me
since there are no trouble codes and the engine starts fine for them.

The coach is now out of warranty and no one is interested in
helping anymore. This starting problem happens any time, whether the
engine is hot or cold. The engine cranks normally, but won’t start. Any
suggestions you have would be greatly appreciated.

— Tim Fitzgerald, Sherman Oaks, California

A.   It really bothers me when service shops refuse to think
beyond trouble codes, like they had to before there were any. Now that
diesels also have computers, like their gasoline cousins, this type of
thinking, or lack thereof, seems to be common in many diesel shops too.

First, a word of caution: Caterpillar warns against the use of
starting fluids, such as ether, in this engine. Rather than glow plugs,
the engine has an electrically heated grid in the air intake.
Introducing flammable sprays into the intake tract could cause an
explosion, so you really need to get this starting problem resolved.

If the cold-start device were inoperative, it would set a trouble
code, so we’ll rule that out. Low compression makes diesels hard to
start, but since the engine has low mileage and runs well otherwise,
we’ll assume the compression is good. Low temperatures make diesels hard
to start, but the temperature rarely goes below the 40s where you live,
and you mention it also happens when the engine is warm. Therefore, the
fact that the engine starts readily when fuel is sprayed into it
indicates that there’s a fuel-delivery problem. Most likely, it is
losing its prime and getting air in the fuel system.

Diesels have zero tolerance for air in their fuel systems. The
entire fuel system should be checked for loose fittings, faulty seals at
the fuel filters, porous hoses or any component that’s not sealed
completely. I suspect that there’s an inline check valve that is
sticking open, allowing backflow when the engine is off. That’s where I
would look if no other fuel-system problems are found.

Caterpillar operates a toll-free customer help line, (800)
447-4986, that owners can call and ask for technical help, as well as
for the location of nearby dealers.

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