Water pumps - how to tell one from the other?

[Darkwriter77]

Trying to eliminate suspects from a list of probable causes as to why my car is overheating so easily and why it immediately (like, the moment I start it up) gushes water out of the radiator when I have the cap off. I've so far done the following:

Total drain/flush/refill (twice, actually)
New thermostat and gasket
All hoses intact and secure, no coolant loss
Borrowed a certifiably good fan/clutch/shroud from another Fox, only to get the same results

Soooo ... I know a head gasket is POSSIBLE at this point, but because the last owner didn't seem to know WTF they were doing with a lot of other things on this car, and they replaced the water pump just before I got it, I need to find a way to verify whether or not they put the right pump on there, or if they put on a standard-rotation pump by mistake (both are listed as available for '84 models in Autozone and Checker parts listings - one's a 3 and 3/16" 6-vane, the other's a 4 and 3/8" 8-vane, both are aluminum-bodied).

So, the question: How do I tell one pump from the other without taking it off and pulling the backing plate to look at the impeller?

If it helps at all, here's the only pic I've got of the pump at the moment (ignore the shredded, misrouted belt and shroudless flex fan - both already have been replaced):

View attachment 308785

 

[Darkwriter77]

bump


Anyone?

 

[Darkwriter77]

Nobody?

 

[FrankenStang]

*resists urge to post tumbleweed smiley*

 

[theconductor]

I'm not nearly as smart as the rest of the guys on here, but could you take off the top radiator hose and see which way the water comes from? The radiator or the motor?

Anyway, just wanted you to know that someone was listening !!!!!

-kyle

 

[LiquidGT]

I don't know why I didnt think of this sooner, from what I understand the bolt pattern on standard and reverse pumps are different. You have to elongate the bolt holes on a stock pulley to use a standard pump (87-93 anyway, not 10000% sure about an '84). So check the bolt holes or see if the PO used a standard style pulley?

Compare it to one of Frankenstangs pulleys, thats the best I've got.

 

[Darkwriter77]

Hmmm...

Well, FWIW, the bolt pattern is the same between Frankenstang's Capri and the '84 because I've previously swapped the fan clutch from one to the other and vise-versa - completely identical. I'm wondering though ... would the standard-rotation pump to which you might be referring (which necessitates elongating the pulley bolt holes) be off a Panther car? (Crown Vic, Town Car, etc.)? Because according to the Autozone and Checker websites, the part numbers for all of the Mustang water pumps are totally different than those of the Panther cars, even though they look almost totally identical.

I guess I could try the pull-a-hose-and-see-which-end-spews-coolant method, but just so I know in advance, which end of what hose should be spewing (assuming that the correct pump is in there)? Like, if I pull the top radiator hose from the thermostat housing, should it be spewing coolant from the hose or from the waterneck?

Another thought: even if they were the same rotation (counter-clockwise), would it make THAT big a difference in cooling ability if they mistakenly put on the 6-vane pump instead of the 8-vane (or vise-versa)? The listings for these parts are kind of vague and conflicting - one (I think the 8-vane) is listed as a reverse-rotation pump, but the other (6-vane) doesn't say if it's reverse or standard...

 

[LiquidGT]

Those parts store sites always have conflicting data, but I saw that your pump was only made for the 84-85 cars.

I found these pics on the internet, note that the chambers are different too.

.

Standard (Panther)

 

[Darkwriter77]

Hmmmm ... yeah, definitely different, and apparently that's the difference between the 6-vane and 8-vane pumps listed for the '84. Soooooo, it's still theoretically possible, I guess, for them to have put the wrong pump on there ... although I dunno why Ford would have made a standard-rotation pump specifically for a Fox (different part # from the Panthers), if all of 'em were supposed to be serpentine-belt setups...

So, you're saying that there's a water pump specifically for the '84-'85 CFI motors?

 

[LiquidGT]

According to Advance Auto it's a two (or few?) year pump. I like their site because it lets you cross reference and see all the vehicles the part fits.

I don't know whats so special about it, lets say you have an '87 pump and its rotating the correct way, then I dont see what the problem could be with the pump.

Have you tried to make the pump rotate the other way by putting the ribbed side on the pulley, then put the fan on backwards?

 

[Darkwriter77]

According to Advance Auto it's a two (or few?) year pump. I like their site because it lets you cross reference and see all the vehicles the part fits.

I don't know whats so special about it, lets say you have an '87 pump and its rotating the correct way, then I dont see what the problem could be with the pump.

Have you tried to make the pump rotate the other way by putting the ribbed side on the pulley, then put the fan on backwards?

No, haven't tried that, but dunno how I could make that work without buying a whole separate belt of a weird length (bypassing the P/S pump and A/C compressor, I'm assuming?).

I agree, I dunno WTF would make this pump so special on the CFI models. I know that I had a helluva time finding a belt to fit the thing properly, as NOTHING listed for ANY year of Fox Mustang was the right length - wound up simply wrapping a measuring tape around all the pullies and taking several trips to/from the parts store before I found the one odd-sized belt that fit right. I assumed that it was because the pulley on the alternator looks bigger than that of a 2G, and it's an externally-regulated alt, but if the water pump has a unique pulley because it's a weird bastard-style pump of some kind, then ... I dunno.

The only other clue that leads me to believe I've got the wrong pump is that both the fan clutch and the flex fan's fan spacer were a PITA to remove because they fit so damned snug on there. I thought it was just due to corrosion inside the hole of the spacer and clutch (old parts) even though the pump was new, but maybe the water pump's shaft is a different size and, thus, the pump is different (and presumably wrong)? The same fan clutch pokes right onto the water pump shaft of Frankenstang's Capri without any resistance or snugness at all, just fits exactly; on the '84, I had to wiggle it back and forth a lot to remove it after it had been tightened down, and the flex fan spacer was so stubborn I had to use a hammer to carefully wedge a screwdriver between it and the pump pulley to be able to pry it outward on one side and then the other (no damage to pulley or pump resulted, all cooling problems were present before that).

Suppose I were to swap out the odd-sized pulley(s) with one(s) from an '86+ EFI 5.0 motor and then swap on a water pump meant for that same motor? Then I'd presumably be able to run a standard belt routing, belt size, and water pump like anyone else from '86 on up ... umm, right?

I know the CFI motors were weird, but I didn't think they were so freaky that EVERYTHING on 'em was a CFI-specific affair. I'm half tempted to just let it sit for a few months until I can afford to just swap the whole freakin' thing out for a roller motor with a carb. Damn yous, CFI motor creators!

 

[Darkwriter77]

Comparing the all-new water pumps (instead of remans) at Autozone, for the '84 I come up with part #CWP-649 which weighs 6.7 pounds and appears to have brass nipples (hehe) for the heater/bypass lines, whereas the '89 has CWP-645 and weighs 5.7 lbs with what looks like aluminum or steel nipples. The ONLY difference I can see besides the nipples is that the CWP-649 ('84 model) pump has fins on the body that extend all the way up to the end of the center of the body towards the pump shaft, whereas the newer kind has fins that only go about halfway up.

From what I can see of the pics I have of my water pump (same as the one I posted above), mine appears to have the aluminum or steel nipples, but with the pulley on there, I can't tell if the body fins go all the way up the center or not.

Does anyone know of any reason why a later-model pump would not work on an '84 5.0, regardless of whether it's CFI or carb'ed or EFI?

Only difference I know of is that the later ones use the 8-vane pump impeller, whereas the older ones use a 6-vane impeller ... but did the older 6-vane ones pump in the opposite direction or something?

 

[4montecarlo]

you can take the plate off the back of the pump to see if you have a standard or reverse pump
than compare that to your belt setup, you shoudl be able to see which direction the belt is spinning the water pump
mustang serpentine are usually reverse, and vbelts are usually standard
but i have a 87 crown vic that uses standard rotation with serpentine belt
matt

 

[seijirou]

Sounds like you have air in the system. Let it run and gush over, then when it's done gushing and the level starts dropping, start filling.

The waterpump should pump up through the waterneck, and draw in from the bottom of the radiator.

 

[Darkwriter77]

Hmmm. Well, after comparing water pumps at the parts store, the one on my motor, and one on another 302 CFI-motored Ford an ('84 Lincoln Continental), I'm pretty certain that I've got the correct pump on there. The only differences appear to be:

1. Older pumps (new aftermarket, at least) don't have extra little tabs around the outside edge to help allow you something to pry against to remove the pump;
2. Older pumps have "fins" cast on the outside body surrounding the pump shaft that extend up farther than on the newer ones;
3. The port holes on the back of the pump on the newer ones are a different shape than the older ones;
4. Pulling the rear plates off the new aftermarket pumps to look, the older ones are apparently all 6-vane and the newer ones 8-vane, but they do in fact go the same direction (counter-clockwise) ... so I dunno why they even make the 6-vane pumps because they seem pretty much identical to the newer ones, just not as efficient a design
5. Again, brass/copper bypass tubes on the older pumps, steel or aluminum on the newer pumps;

I'm 95% certain I got all of the air out of the system when I drained, flushed, and refilled - burped all the air out, ran it for awhile with the cap off, had the front-left corner raised - and it still tries to push coolant out of the radiator when it's running. Sooooo, I went by Harbor Freight yesterday and picked up a cheap compression tester that I'm going to use on there today or tomorrow to see if I have a blown headgasket. If it's not that, then ... hell, I dunno.