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Engine's Cooling System Tips:  Radiator, Water Pump, Thermostat, Temperature Sensor, Coolant Recovery Bottle.
Click on the Click to Cruiseto go to its Tip:
Click to Cruise Water Pump
Click to Cruise Temperature Switches Manifold (Upper engine coolant hose)
Click to Cruise Temp Sender/switch parts (Off Page link)
Click to Cruise Fan Temperature Sensor
Click to Cruise Fan Clutch Leak
Click to Cruise Fan Clutch
Click to Cruise Easy Fan Clutch Replacement
Click to Cruise Upgraded Radiator and Fans
Click to Cruise Auxiliary Transmission fluid and Engine oil Cooler
Click to Cruise Coolant Recovery Bottle
Click to Cruise Coolant Overflow Tube to the Recovery Bottle
Click to Cruise Smell of Antifreeze -- Coolant Bottle Overflow (off page link)
Head Gasket leak -- Compression in the Cooling System
Click to Cruise Coolant Thermostat
Click to Cruise Engine Cooling - Air flow to the Radiator (off page link)
Click to Cruise Ram-Air Cooling (off page link)
Click to Cruise Engine Overheating
Click to Cruise Engine Operating Temperatures
Click to Cruise Gages and Sensor (off page link)
Click to Cruise Desert Cooler or Similar Device
Click to Cruise Radiator Cooling Tips

-- Disclaimer --
Information on this Web Site is provided by members of the "Aero Cruiser Classics" Motor home Club. All information on this site is contributed by the club members or outside sources and is believed to be reliable; however, there is no warranty or guarantee that said information or advice is correct or free of defect. It is offered on a best effort basis and is to be used at your own risk.


Subject:  Water Pump
Tip 1:  If you have and 1989 engine (and possibly others) and need to replace your water pump, ask for GMB pump part No. 120-1070. This pump replaces the original exactly and has 8 blade impeller for added efficiency instead of the original 6 blades
#212 Petrovich
Tip 2:  Industrial Engine “hi flow” water pump may be obtained through Chicago Power Systems, Inc. located at: 1533 Lathem Street, Batavia, IL 60510 
Ph. 630-406-1080.  Part No. 4493559 (ID as LH 360 Engine increased flow) This is Chrysler’s Industrial Engine Division
#102 Kinnison

Tip 3:  If you have your radiator removed for any reason, consider replacing your water pump at the same time since it is much easier to replace it with the radiator and fan shroud out of the way.
Click to CruiseReturn to the Tip List.

Subject:  Temperature Switches Manifold (Upper engine coolant hose)
Tip:  This article is in response to “Subject “HELP! Temp Sender/switch parts request ident” sent on Fri 10/23/2009 2:53 PM” by “Rick”. 

The original response by J. D. Whistler was very helpful in my research on what these devices are and what purpose they serve but I it was necessary to clarify a few points. 

The two devices in the upper coolant hose manifold are indeed thermal switches. 

The first one, forward (closest to the radiator) turns the A/C condenser fan (in front of the radiator) on and off. This is the “optional temperature switch” mentioned on Frigi-Cool wiring diagram page 5-12. Some of us have installed a manual switch on the dashboard to bypass this thermal switch so we can turn the fan on and off at will if we are in heavy traffic or overheating. In retrospect, this was completely unnecessary if the thermal switch is working properly but it does give us another gadget to play with. Also, some of our coaches were wired in such way to allow the condenser fan to keep running when you shut off the engine. Others, such as mine will shut off everything when the ignition key is removed. The original switch is most likely ARA part number 0884940 which is no longer available but there are several equivalents available on the aftermarket such as BWD TFS5 or TFS4 which have slightly different opening and closing temperatures. 

The second switch, aft (further from the radiator) turns the temmperature warning light on or off. In my case, the original switch was Stewart Warner part No. 8331. This switch may have a terminal tab or hex nut for connection. My tab broke off so I replaced the switch with BWD part No. WT330. The new switch closes at 261°F and opens at 249°F. The reason I chose these temperatures is because Chrysler Central Engineering stated in their Service Bulletin No. 029788 “On engines equipped with temperature warring light (idiot lights) the sensor should turn on the warning light at 262 deg. F.” This warning light is not the same on all coaches. In my case, and presumably all coaches with Teleflex instruments, “OIL TEMP” warning light on the dashboard is a dual purpose warning light. It means “Oil Pressure” or “Engine Temperature” depending on which device is sending the signal. On dashboards with VDO gages, you may have two individual warning lights. Should your engine reach this temperature, this switch would merely warn you by turning on the light. It will not shut off the engine. Oil pressure switch, however, will warn you and shut off the engine so it would not be damaged. 

The tab between the two switches is the common ground connection for the two switches. 

In summary, these two switches provide the convenience of turning the fan on and warning you of hot engine conditions. If ether or both are disconnected or go bad, the engine will continue to run. In other words, they do not control the engine operation. That task belongs to the engine temperature sensor located in the intake manifold on the front driver side of the engine; close to the thermostat housing. This sensor (not a switch like those discussed above) provides constant temperature reading to the computer so it can make proper adjustment for the most efficient engine operation. This sensor has two wires going to it and is Mopar part No. 5226374. This device is erroneously identified as “The sensor in the upper radiator hose closes at 220°F to turn on the (Air Conditioning) radiator fan. Chrysler replacement part No. is 5226374.” under “Fan Temperature Sensor” in our Tips. Part number is correct and it is a sensor but it does not turn the fan on and it’s not located in the radiator hose. Replacement such as BWD part No. WT394 or Delphi part No. TS10019 is available on the aftermarket 

The other coolant temperature sensor we have is also located in the intake manifold but is on the front passenger side of the engine under the A/C compressor. This sensor has one wire on its terminal and provides feed to the temperature gage. It is matched to your temperature gage and is not interchangeable between different instrument makes such as Teleflex and VDO gages. 

For additional detail see the illustration below.

 #212 Dragi Petrovich
Click to CruiseReturn to the Tip List.

Subject:  Fan Temperature Sensor
Tip:  The sensor in the upper radiator hose closes at 220°F to turn on the (Air Conditioning) radiator fan. Chrysler replacement part No. is 5226374.

Update:  Do you know what purpose thermal switches in the upper coolant hose manifold serve, what their open and close temperatures are, or who the manufacturers are?  The information that we have in our body of knowledge is not quite accurate.  -- Dragi

Answer:  I haven't looked for a while, but I went out and looked.  It appears the white wire goes to the AC fan (mine no longer has that fan) and the red goes to the temp gauge on the instrument panel.  Hope that helps.  -- Frank DeRemer 
Click to CruiseReturn to the Tip List.

Subject:  Fan Clutch Leak

Tip: Going home from the Las Vegas rally created the need for some maintenance. My fan clutch sprung a leak on the way down the Cajon Pass. Fortunately, it was down hill all the way home but when I got back, a mess had to be cleaned up. After removing the old fan clutch and cleaning up the fluid that spilled from the fan clutch all over the engine, I replaced the following parts:
Fan clutch - Hayden part No. 2797
Belts - Dynaflex by Dayco:
1 - Fan & Pwr. steering pump No. 15445
1 - Fan & Air pumps No. 15525
2 - Alternator & A/C compressor No. 15605
#212 Petrovich
Click to CruiseReturn to the Tip List.

Subject:  Fan Clutch
Tip 1:  Spare parts for our coaches may become sparse as time passes. If you need to replace the fan clutch, you can use the replacement part for the Chevrolet engine which is also a better part than the Chrysler part.
#433 Di Gilio
Tip 2:  Those of you who need a new fan clutch may consider replacing whatever you have with a GM part. Reportedly, the GM replacement part No. 15963247 is better than the original Chrysler part.
Click to CruiseReturn to the Tip List.

Subject:  Easy Fan Clutch Replacement
Tip:  If you need to replace the fan clutch without disturbing the belts, there is a simple solution. Find two machine screws 5/16 X 18 and cut off their heads to make them about 1-1/4 inches long. Remove two opposite screws from the fan clutch to water pump pulley and install the two studs you just made, finger tight. Remove the other two screws and remove the fan clutch with the fan. The two studs you installed will keep the water pump pulley in place until you replace the fan clutch. Reinstall in reverse order. Rick claims it took him longer to put away the tools then it did to replace the clutch. incidentally, the clutch replacement was Hayden part number 2706.
#101 Krafft
Click to CruiseReturn to the Tip List.

Subject:  Upgraded Radiator and Fans
  Frank DeRemer just keeps changing his rig.  In his latest modification feat, he replaced the stock radiator (shown to the right) with a larger cross-flow aluminum racing radiator that should provide better cooling ability.
...he also removed the existing fan and shroud and replaced it with two electric fans (left) common on today’s cars (others in the club say that the GM fan clutch recommended in a separate tip is a better solution than the electric fans, so Frank plans to try going back to that to test their theory)...
...he then installed an 11-inch cooler for the engine oil, and another for transmission fluid, each with an electric fan.  These are in a “floor” he added in the large space in front of and below the radiator on his 1990 Aero Cruiser.  The fans blow air downward.  We are anxiously waiting the results in the future.

Update:  The results are mixed.  I lose no HP to the engine having to pull air in, there is less fan noise, and the electric fans only come on when I go up a long, steep grade or when I sit in traffic for a long time.  However, it still goes up to 230-250 degrees on those long, steep grades.  Thus, I do want to try going back to the original fan and shroud, in addition to the electric fans, to see if that keep the temperature down even under severe stress.  I will let you know it turns out if I get around to that next experiment.
  –Frank on 11/14/07.   Visit Frank's site:
Click to CruiseReturn to the Tip List.

Subject:  Auxiliary Transmission fluid and Engine oil Cooler


Haris Hartman was sporting his new transmission fluid and engine oil cooler.


Both coolers are mounted up front against the grill to get the maximum air flow and each has a powerful fan,

Click to CruiseReturn to the Tip List.

Subject: Coolant Recovery Bottle

Tip:  Items that may last a lifetime on a car, will not on a motor home. Case in point, coolant recovery bottle. New one from the Dodge dealer had to be ordered. Chrysler part No. 5202 7784
#212 Petrovich

Update: I had the same problem and replaced it with a Large Vehicle Recovery Bottle from Kragen Auto Supply for $20.  It mounted easily in the same location.
Tom Heald
Click to CruiseReturn to the Tip List.

Subject:  Coolant Overflow Tube to the Recovery Bottle
Tip:  Lon’s coolant overflow tube was kinked and allowed hot coolant to go to the reservoir but would not allow it to come back when the engine cooled. That lead to overheating due to lack of coolant in the engine. Removing the kink took care of the problem.

If you need a new coolant reservoir, you can buy it a Dodge dealership or aftermarket in any auto parts store.
#113 Waterson
Click to CruiseReturn to the Tip List.

Subject:  Coolant Thermostat
Tip:  If you need to replace yours, make sure you replace it with a 195°F to maintain proper engine operating temperature.
Click to CruiseReturn to the Tip List.

Subject:  Engine Overheating
Tip 1:  Since many trips in southern California included driving through the desert at high temperatures, engine overheating was the top subject of discussion. Lon Waterson suggested keeping the engine speed at 3,000 RPM, clean radiator, and a good fan clutch. Pat Mogan suggested thorough cleaning of the engine block to remove rust and deposits from the cooling passages. Corrosion can build up just like in the sewer pipes and prevent efficient heat exchange with the coolant. Frank read the specification sheet from Chrysler, which listed expected engine temperature over a variety of ambient temperatures and concluded that engine temperature of 240° F on a hot day over a long grade is not uncommon.
Tip 2:  A great deal has been done and written on the subject over the years. Chrysler states that the engine can run as high as 240 F. Before you do any modifications, make sure that you have free air flow through the heat exchangers (radiator, air conditioner condenser, transmission cooler, even heater core). Your fan clutch should be operating properly, the radiator should have a free flow of coolant, and your coolant should be at least 50/50 concentrate of coolant and distilled water.

If none of that works, contact Ralph Loveland or Dragi Petrovich to see what they have done to solve their problem.
Click to CruiseReturn to the Tip List.

Subject:  Engine Operating Tempatures

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Subject:  Desert Cooler or Similar Device
Tip:  If you are using a device like Desert Cooler or the one you rigged up yourself to spray water on your radiator during hard climbs, consider using distilled water in the spray reservoir. If you use tap water, you will have hard water minerals buildup on your radiator over time which will act as an insulator and you will be defeating the purpose.
#462 Wachtell 
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Subject:  Radiator Cooling Tips
Tip: I wish I had written this document, but I have used it to my advantage as I continue to improved everything I touch on my 92 cruiser. I've read a lot in past newsletters, and heard many people argue everything about cooling systems. This is the best article on the subject and is a very good read. For those experiencing cooling issues, follow TIPs 1, 2, 3 and 9.

Do a test, run with Water only, and no thermostat on reasonably warm day and put in enough miles to determine the top and bottom tank temperatures. (A Laser temp probe works great) cooling_system_capability_in_high-performance_automobiles.htm
Click to CruiseReturn to the Tip List.

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