DODGE CARAVAN COOLANT PUMP

This advice is based on my experience with one 1994 Grand Caravan with 3.3L gasoline fuelled engine meeting US federal emission standards.

I presume you have a service manual, though I may include brief pointers from it to make this advice more cohesive. Some of what I cover here is in the service manual if you can find it, often not in the section you'd expect it in.

Preparation:
TOOLS
- Tool to move idler for serpentine belt (usually a long slim bar with 3/8" square on end plus short 15mm socket, and desirably a 6 to 7" firm object between bar and transmission computer to keep the belt released.
- 10mm socket and driver
- Short extension, I use a 3/8" to 1/2" adapter and a 1/2" to 3/8" adapter plugged together, perhaps two of the short extension I once had (this is Chrysler's stuff job engine installation so clearance to frame is short (and of course the service manual is inadequate)).
- Desirably a thumb-wheel device to turn the socket without the ratchet once you've loosened the bolt, speeds the job so you don't have to have two hands in the area (one to hold socket on bolt and keep it from turning when you move the ratchet), these come either as thin wheel that goes between driver and socket, or thick wheel that replaces the driver.
- Hose clamp pliers (ChannelLock types worked on the squeeze clamps, but I had to use a very large on on the large hoses and a smallish one on the small hoses, space for the handles is limited).
- Fluid handling stuff like pail and wipes.
- A face shield to keep coolant out of your eyes.
- A means of cutting the old lateral and bypass hoses to get them off, such as:
* a knife blade under the hose - dull side to the tube, or<>BR> * try to cut beside the nipple to avoid scoring it, or
* a box cutter knife with depth adjustment, to cut the outer layers of the hose
* or use a tool like.
and pry with small flat blade screwdriver to break cut hose.
- A means of cleaning the hose nipples on parts you aren't replacing.
- Hard rubber hammer to whack the pump once bolts are removed, to free it/
- If replacing bypass hose:
> A tea kettle to heat water to soften hose end.
> a freezer to harden hose to facilitate beveling inside diameter to help get it started over the nipple (actually, that didn't help much over cutting at room temperature, I did not try a large drill bit when frozen, would need to be very cold).
) > oil filter wrench and catch pan for some oil
> penetrant such as WD-40

PARTS
- in addition to the water pump you want the o-ring (may be included with pump)
- rubber lubricant is recommended but the only benefit I can see is to keep the o-ring from sticking to the metal which isn't likely, there is a shallow rectangular groove in the pump, you actually want something sticky to hold the o-ring in place so you are confident it is in the groove up where you can't see (canola oil is too thin, motor oil seems thin, you might try corn oil which is thicker than canola, but sealant will be stickier).
- however you want rubber lubricant to get the bypass hose onto the nipples if you use 5/8" hose (the bottom is hard to see and to grasp to force it, the top needs to go on a long way), perhaps vegetable oil will work (corn oil is thicker than canola oil so should lubricate better). Chrysler's hose
- you should replace the two lower hoses as you'll need to detach at least one end of each for access (one is 12" of 3/4" nominal heater hose, the large one is Goodyear 62024 or Canadian Tire 14-2681-4 or TBD)
- I recommend replacing the bypass hose which runs from the water pump back housing that appears to be integral with timing chain/gear cover to below the thermostat. It seems to be about 11/16" nominal heater hose, but I can't find that (perhaps also used on some Toyotas). Supposedly the Chrysler p/n is 4694449 but that is labelled 5/8", perhaps 6603820 is a later number. With effort you can get generic 5/8" on, but avoid stiff product like Prestone's.
- I recommend replacing the upper radiator hose (Goodyear 61172 will fit if the small diameter end is cut short).BR> (Beware that there are four different cooling systems in these vehicles, hose length apparently varies considerably:
* base
* with A/C
* HD
* "Max"
There are two different A/C systems (normal and with rear A/C), and a trailer towing option, parts catalogs may not be clear. Mitchell's parts interchange book says either option uses HD radiator. Perhaps "Max" is with both.)
- consider using worm gear hose clamps, but be careful tightening ones at the radiator which is thin meaterial, perhaps plastic. (The squeeze type limit force but are awkward to deal with in close quarters, they can be rotated by hooking a closed end wrench on one of the tabs and pulling in a direction that loosens the clamp). There's also T-bolt clamps that have a wrench hex so perhaps need less clearance (but don't overtighten those), and a design with the screw perpendicular to the hose. Tridon's clamp catalogue shows some designs, including quick-release and worm type with a wider band. They illustrate the constant-tension ones I found on my vehicle, as well as a screw type with spring to keep tension somewhat constant.
Tridon also covers the CV joint boot bands whose end folds over, and show some tools for them, additional info in another catalogue somewhere. (Princess Auto sells those clamps but not the tool, which I fortunately found in a surplus store.)
- Might as well replace the thermostat while you're in the area of the upper radiator hose.
- And... consider replacing the heater cross-tube from water pump across front of engine as it tends to rust (that's a real chase-around to get the part, Chrysler's parts catalogue says 05264155 is discontinued with no replacement, perhaps one from a later model will fit, the design was changed to better materials).
- And check heater hoses while you have cooling system drained).
- Oh, before draining using the radiator drain cock check if there is a hose on its outlet, you'll want a tight fit but soft hose such as 5/16" vacuuum line hose, as there isn't much space between the outlet and a body piece (without the hose coolant will run sideways on the body piece instead of into your bucket).

RECOGNIZE THESE FACTORS
- Diagnosis: very difficult for leaks above the water pump height, due Chrysler's engine stuff job. Consider organizing ability to pressure test the cooling system, lights to go in narrow areas, perhaps talcum powder or such to see where liquid has run, and additive that fluoresces under UV light (there are nifty portable UV lights - short) or just food colouring with plain water as temporary coolant.
* Water pump leaks often occur at the shaft seal, traditionally there is a weep hole that may have stains around it, but newer pumps have a little catch cavity that would have to overflow for stains to occur where you can see them.
* The heater return hose to the water pump may leak due deterioration from manifold heat, but the end of the attached tube may be leaking due rustout, you want to see that.
- Possible suspects include the hidden bypass hose below the thermostat housing (take the upper radiator hose off), corroded freeze plug, corroded timing chain cover, and bad o-rings in the coolant passages that go into the chain cover (the water pump cavity is in the cover, the impeller and shaft detach from it).
- Consider flushing the cooling system first
- The radiator drain cock is odd, it turns then feels like it hits a stop, but to actually open it you have to turn further.
- When you take the serpentine belt off the pulley, hold the belt up somehow to keep it out of your way and ease re-installation. I suggest removing it from the A/C pump then and holding it up and aft.
- Disregard service manual instructions to remove fender liner, the pump is beside the frame rail.
- There's probably a splash shield or two behind the bumper and under the pulley stack, to take off.
- you want to remove only the five small bolts with 10mm heads, the pulley drive, pump cover, and impeller come off (the rest stays with timing chain/gear cover).
(First take the pulley off, you have to be creative on holding it against rotating.)
- the bypass hose is very difficult to install if you try to use 5/8" nominal hose, see Tools above and:
* I recommend applying a bit of a corrosion-inhibiting penetrant such as WD-40 to the joint between the upper nipple and thermostat housing it screws into, in case you have to replace that later (there are slots in the wall of the other end of the nipple, apparently to turn it).
* remove oil filter to improve access to lower end (oil will dribble because Chrysler designers did not make filter boss of proper angle, and they attached wiring harness to lip of oil pan instead of higher up)
* I succeeded with Prestone 5/8" hose by chamfering the ID of the end of the hose, applying canola oil to the nipple, heating the lower end of the hose with water, and using bare hands to maximize grip clearance. (There isn't room for a container of water to heat the upper end, it is easier to grip but has a very long nipple with a smooth chromed area near the thermostat housing it screws into so needs more push effort, I used a hot air gun to warm it.)
* I chamfered the ID with a pocket knife, which is awkward to do smoothly, perhaps a tapered grinding stone in a drill would work on a frozen hose.
* Of course to replace the upper radiator hose and thermostat in Chrysler's odd design you'll have to move the ignition coil out of the way.
- consider replacing the front manifold heat shield at the same time as the heater return tube, as two of the bolts are common to the tube. Beware however that the left bolt is very awkward to get back in, especially after attaching hoses, you have to push the tube into place and hold it somehow. The upper bolts will hold the shield in place while you struggle with that and starting the bolt threaded in. (Very little space to radiator fan shroud. Removing the fan shroud is not feasible as the upper transmission cooler hose nipple blocks lifting upward. The shroud has two screws at top, but the right lug cannot be slid vertically, even if the shround could be slid left after removing the left clip nut to clear the right lug the nipple blocks lifting the left lug upward. Clearance to the top of the vehicle structure is also poor, there is some overhang of the shroud. There are two hooks for lugs on the lower sides, and an electrical connector. While the service manual appears to say there is some means of spacing it from radiator it looked to me to be inherent in the brackets.)

© Keith Sketchley Page version 2014.02.02

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