Hot Coachmen
Q: I have a 1989 Coachmen on a Chevrolet chassis with a 454 engine. It overheated on me. Since then the heads have been planed and the engine was retimed. I installed new gaskets, a new thermostat, new hoses, new belts, new spark plugs and wires, and a new heavy-duty fan clutch. I even had a new core put in the radiator. It still ran hot. I had an original Chevrolet fan clutch installed “” which never seems to lock up “” and the coach still runs hot. Do you have any suggestions?
Douglas Frei, F296492
Yuma, Arizona
A: You didn’t mention your motorhome’s “running hot” symptoms, such as steam spewing out of the engine compartment, so I must ask the question “” “Is it really running hot?” One of the best test instruments I own is an inexpensive mechanical temperature gauge that I purchased to use on a boat that I thought was overheating (as it turned out, it wasn’t). I have since used the gauge on at least a dozen vehicles. It can be purchased at a local auto supply store “” complete with a wide array of fittings that would adapt it to practically any engine “” for around $15 or ordered from J.C. Whitney by calling (800) 726-4466 and asking for part number 88ZT7416W.
Install the mechanical temperature gauge’s sensor temporarily in place of the original on your engine and route the tube so you can see the gauge from the driver’s seat. Drive in your normal manner and note the temperature. The reading you obtain will be accurate, and you might be surprised to see a much lower reading than your OEM gauge registers. If you find this to be true and want to remedy the problem with your factory-installed temperature gauge, you will need to change the sender, clean the connections, or, at worst, replace the original gauge.
If the engine indeed is overheating, a worn water pump or one with internal damage could easily be the culprit. If you replace the water pump, use a heavy-duty, high-capacity pump at least equal to the original equipment.
Why were the heads planed? Was there evidence of warping? If so, were they magnafluxed to determine whether there was a crack? A cracked head could be indicated by the presence of water in the oil or vice versa, or by a loss of coolant after running the vehicle. Another possibility that has occurred on many 454s is a head gasket that was accidentally reversed on installation, which can block some of the coolant passageways.
If none of these remedies works, check to make certain that the radiator baffles and the shroud are in place; double-check the timing; and make certain that the new radiator core has a flow rating that is as good or better than the original. A good repair shop should be able to pinpoint your trouble without throwing more parts at it.
“” E.P.
Malfunctioning Monitors
Q: Recently a dealer’s service department replaced the LP-gas monitor and the house batteries on our 1994 Tioga (with only 16,000 original miles). Now the monitor panel glows continuously.
Prior to the dealer visit, the monitor panel would indicate fresh water, LP gas, battery charge level, or holding tank status only when the proper button was depressed. Now, however, the monitor panel (which was not replaced) glows continuously at approximately 30 percent to 40 percent of the actuated brightness level. In addition, the light-emitting diodes (LEDs) for the two holding tanks now indicate a full condition in both tanks, even though I have visually confirmed that they are empty and that the in-tank contacts have no material sticking to them to cause them to register a “full” status.
Other than a return trip of two hours, plus maintenance downtime, is there anything I can do to remedy this problem?
Carl Johnson, F288382
Zephyrhills, Florida
A: You did not mention what was wrong with the monitor in the first place that caused it to be replaced, but that’s not your problem now. It seems to me that you will have to go back to the dealer. Apparently, the technician either crossed some wires or hooked up the LP-gas monitor incorrectly, and short of you doing the work yourself, you should return it to the dealer so that the faulty wiring or installation can be corrected. I understand that a two-hour trip can be a hassle, but make a weekend out of it. Enjoy your coach for a few days in the area near the dealer after the repair has been made. If the repair isn’t done to your satisfaction, you’re close enough to have it worked on again until the problem is straightened out.
“” J.B.
Tranny Troubles
Q: I have had two transmission failures on my motorhome, which is built on a Ford chassis. The first was at 5,000 miles in July 1999. The second was in August 2001 at 28,000 miles. Both times Ford replaced the transmission under warranty.
Both transmission failures seemed to be the result of overheating after I shifted into first gear when going down steep grades. I use first gear when descending steep grades to keep the motorhome’s speed down and to protect the brakes.
The first failure happened while driving down a grade in Vermont. Last summer’s failure occurred while going down the long grade into Skagway, Alaska. We were not towing, and I have been careful about downgrades.
I have the following questions:
1. The dealer at Williams Lake, British Columbia, who replaced the transmission last August said that I have a new 12-month/12,000-mile warranty on the rebuilt transmission. Ford representatives say no. The transmission now has exceeded the original 3-year/36,000-mile warranty. Who’s right?
2. Is this transmission heavy-duty enough for our unit (loaded weight about 20,000 pounds)?
3. Mechanics tell me that Ford has had problems with this transmission for years and that this is the same unit used in some Ford pickups. Is this true?
4. At the dealer’s recommendation, I had a shift kit installed in the last rebuilt transmission, which is supposed to lower the heat buildup. Can you offer any additional information on how to beef up or alter this transmission to prevent future failure? Are you aware of other motorhome owners with a similar problem?
Stuart Alexander, F137634
Dryden, New York
A: Let me answer your questions in the order in which you asked them, and then I’ll make a comment.
1. Perhaps the Williams Lake dealer was speaking of its own warranty, not Ford’s, as that dealer did the installation. You might have to return to British Columbia to take advantage of that warranty.
2. & 3. All indications are that the transmission is more than capable of handling your load; otherwise, Ford would not continue to use it in both type A and type C motorhome chassis and heavy-duty pickups designed to haul heavy loads.
4. A shift kit, while causing the transmission to shift “harder,” can be an advantage in heavy-duty situations, so I agree with the dealer on that account. But the cure was not taken far enough. You might also want to consider a transmission cooler.
Your transmission is cooled by pumping the automatic transmission fluid (ATF) through a line in the lower reservoir of the radiator. This transfers the heat generated by the transmission to the coolant in the radiator. In normal situations, this is a very efficient method. However, when you use first gear to maintain a slower speed on steep grades, this method does not create enough cooling for the ATF.
Transmission coolers can be of two different designs “” auxiliary (used in addition to the radiator) or stand-alone. If you plan to continue using first gear for braking on steep grades, I’d go with the stand-alone “” you need all the ATF cooling you can get. Several companies manufacture transmission coolers, so check with your dealer or local auto parts store.
Now for the comment: with all due respect to the New England grades, I live on the western slope of the Continental Divide and have driven RVs and towed vehicles through several of its passes during the years. I also have driven and towed up and down many grades in the Sierra Nevada in California. On many of these roads, grades average between 6 percent and 9 percent (I’ve never seen a public highway or road exceed 9 percent), both up and down. During that time I’ve never had to use first gear to maintain a safe downhill speed (except when I lost all hydraulic brakes on an F-350 pickup truck with an 11-foot camper and flat-towing a 2-ton Jeep, but that’s another story). The rule of thumb I’ve always gone by is to use the same gear going down a hill as I must use to go up. I’ve never had to downshift from second gear to make it up a hill, and I’ve only used second gear occasionally.
In my opinion, you are overusing your transmission. Use your brakes more and your transmission less “” brake linings are much cheaper to replace than transmissions. Judicious brake usage “” applying the brakes momentarily to slow you down, releasing them to allow them to cool, then re-applying them “” even on the longest downgrades should keep you safe and your transmission operating efficiently.
“” J.B.