Repairing Your Imperial's Water Pump


Imperial Home Page -> Repair -> Cooling System -> Water Pump

Question from Johan (1965):

Is it necessary to pull the radiator in order to pull the water pump or will the fan and clutch come off to facilitate this? It doesn't look as if its an easy evolution (as far as water pumps go).

Unbolted the assembly has about a half of an inch to go as it hits the radiator in order to come out. Id rather take it all apart out of the car rather than in.

I had just pulled in to the auto shop at Ft. Belvoire to slip on some new shoes I had ordered then- FISSSS!! Im glad it happened there man!

Reply from Elijah:

No, but it does make the job easier. :o)

However, I've changed water pumps in a parking lot in the pouring rain without removing the radiator. It's
a little counter intuitive, but . . .

1. Unbolt the fan from the clutch.

2. Unbolt the clutch from the water pump.

3. Hold the fan in place as best you can, and remove
the clutch.

4. Once the clutch is out of the way, you'll have
room to wiggle the fan out.

5. Remove the water pump.

Reassemble in reverse. :o)

There are no doubt other methods to perform this surgery, but this is the one I've used several times. It's almost impossible to remove the fan AND clutch as an assembly, hence the need to remove them separately.

Question from Brad (1966):

I had the radiator in the LeBaron flushed and repaired. While I had everything apart I decided to get a new water pump just to save myself the trouble of having to pull everything back apart should the pump decide to go bad. I got the new pump at NAPA for $21.00. I figured that if my (Original) pump  went out, I'd be out another $10-12 for new anti-freeze anyway, I might as well get a new one and do it once.  The pump they got for me has eight blades on the impeller, not the six called for in the FSM. I guess the re-manufacturer decided this is a happy medium  replacement for the originals (6-blade impeller/AC, 10-blade impeller/non-AC).  I can go along with that, but when I test fit the pump in the housing, I spun the impeller and heard metal-on-metal scraping inside the housing. The replacement pump has the same external cover plate, but the impeller appears to be 1/2 to 3/4" larger in diameter than the original. Has anyone else run into this problem?  Does anyone have a source or PN for a correct 6-blade pump, or one that fits properly?


From Mark:

Take it back to NAPA and explain your problem. I'd even ask if they would check some of the others in stock to see if they have the proper 6-blade one there. You may also want to try a different auto parts store. When the pump on my '63 started leaving too much green fluid under the car after each fill-up, I was able to get the correct pump at Pep Boys, though it took the counter guy a couple of trips into the back to find it. (Their books showed the 10-blade was for an A/C car....) Sometimes, ya just gotta be persistent....

From Ben:

I have a 64 Crown that I did the same thing to, rodded the radiator and replaced the water pump. I bought mine from Hi-Lo O'Reilly auto parts here in Texas and it fit and works great. The manufacturer of the pump was A1 and the part # is 58-176 and I paid $19.99 (less a $4.00 core).  

From John:

I've never had any problems getting a correct water pump from a local parts store. One thing that I do is get new, never rebuilt on one of these. Not that much difference in price. I'd take the old one with you & tell them to match it up.

Question from Bruce (1978):

Digging further into the 400 ci engine on my '78 NYB to reveal the timing chain, I am having trouble getting the water pump/housing off. After removing the bolts holding the pump housing to the block, the whole thing is stuck. Is it supposed to come off with some puller? I have banged and prised (as the Brits say) and heated the housing with a small torch(but maybe not heated it enough?), but it is stuck. I've been hesitant to apply too much force or heat... Any suggestions?

BTW, I learned by doing it that the only way I could get to the crank pully was to remove the fan from the end of the water pump.


From Pete:

Did you get the pump housing bolt hidden behind one of the heater hose nipples? There are 6 bolt altogether holding that housing to the block, 3 on each side. You may have to remove the nipple to get the bolt out if an open-end wrench doesn't break it loose.

From William:

One of the thinnest and most vulnerable parts of the B/RB block casting is the upper water pump housing mounting bolt hole on the passenger side. It's raised above the rest of the casting and is kind of all by itself like a little tower with a bolt hole in it.

Plenty of quality penetrating lube might be in order too.

Question from Larry (1982):

Does anybody have thoughts about a new water pump over a rebuilt water pump? New is $34.00, rebuilt is $17.00 at Napa.

The FSM said to use correct pump since pump impeller must be compatible with the drive ratio provided by pulley system. The Napa parts person said only one pump was in the book. I did reference a 1982 Imperial.


From Steve:

For that price go with the new pump. Rebuilts are pretty dang good but the antifreeze you loose would cost you the difference in the pump

From Clint:

After selling auto parts for 18 years, Larry,I can tell you, go with the new pump. Fuel and water. The difference is not that great.

Question from Bob:

Has anyone installed an Edelbrock water pump and/or the Mopar Performance aluminum housing on their 440/413 etc?  I'd like to have at least one "improved" part on the engine, but I'd like to hear if  this is good or a wasted effort. 

Reply from Daniel:

The water pump will let you advance the distributor more or use a more aggressive advance curve without detonation--but if you run out of water, you'll know first by the knocking, and then by the loss of power due to the holes in the tops of the pistons. :^)  Okay, you probably will notice and pull the car off the road if that happens, retard the distributor and "limp" home to get more water. But it can be a pain to keep the supply topped off if it lasts much less than a full tank of gas. 

Tip from George:

EVERY TIME you open the hood of your beloved car, to check the oil etc. Grasp the fan and attempt to "rock" the shaft.  If there is any "play" the water pump bearings are probably worn, and failure is a possibility.

The first time I was shown this I ignored the warning....and had to replace the pump/fan/ radiator AND A/C (attn:Turn the car OFF..First). This is also a MUST check when you hear an unusual buzz, rumble, or "whine" from under the hood .....that X1000 RPM fan/shaft assembly can do a lot of damage, very quickly!

This "trick" will work on all front-engine rear-drive cars with mechanical fans attached to the water pump.

Tip from Graeme (354 Hemi):

I have a 354 Hemi engine and adapted the water pump to a BBC Water Pump. It  requires several modifications. You will need the BBC Water Pump & Crank Pulley (stock won't work). Your timing cover also must be modified (remove the fuel pump hump).  This conversion is recommended to Imperial owners who do not live near a water pump rebuilder (specially, foreign countries).


My 1964 Coupe has started overheating after several years of being fairly cool--on the way back from the mechanic! It was fine going out, no trouble that I could detect. The gauge doesn't work presently, so the only way I can find out is when she boils over. It overheated after about half an hour on the highway. The last thing done mechanically was closing off the valve that lets coolant flow through the heating system. I'm not convinced that it boiled over, because the coolant overflow tank had popped off and sprayed the engine.

I have noticed the following: 

--the oil level was low 

--the water pump is making a slight, occasional clicking sound 

--the engine is running a little rough 

--the overflow tank did not fill up with coolant after the engine stopped; it remained very low 

--the coolant looked oily, but I'm not sure if it was oil 

--no visible leak of coolant 

Some suggestions from friends included replacing the thermostat and radiator cap (both are about three years old, but the car has not been run much in the past two years); chemical flush of the system; recoring the radiator (which was also redone three years ago). Any other suggestions? It really did seem to be fine on the way out to the mechanic. It was about ten degrees warmer coming back, but that couldn't have been the only factor.  

Reply from Jay:

I noticed last summer that my '64 was starting to run hotter than usual. I had the same ticking or squeaking sound coming from the water pump. I replaced it and the fan clutch on the suggestion of my mechanic. Since then it has been running as cool as ever (even in our 115 degree desert heat in Palm Springs).  

The fan clutch is not easy to find. It has a silicone fluid filled thermal controlled drive mechanism (for quieter operation) and I believe it was an "Imperial only" part. I ordered one from Atlas Motor Parts but it didn't fit. I then ordered one through American Brake Supply and theirs didn't fit either. They insisted it was the correct part # but continued to search and finally produced the one that did fit. It may be that there were different fan clutches for cars with AC. Mine has AC and the first two clutches I got were too long to fit between the radiator and the engine. 

American Brake Supply is a chain. I know they are all over Southern California. I don't know about the rest of the country. I do know that they located the part in Florida. The phone # for the American Brake Supply here in Palm Springs is (760) 322-6922. They were VERY helpful.

Question from Rob (1983):

Had my first Imperial break-down Saturday. Well, it didn't strand me, but it was spitting coolant, so I left it at my girlfriend's house. Stuck in traffic, then driving it hard (up to about 90) all with a/c on, then more traffic. When I parked, it started to steam from left front corner of hood. Coolant is pouring out. I think it's the seam on the driver's side of the water pump. Would this be normal if the pump lets go? Making some clicking noises. Hopefully the pump bearing and not engine internals. Idiot light never came on and car ran fine, so hopefully I didn't overheat it. Anything I should know about doing a water pump on an '83? Any brands, etc I should avoid? Anything else I should look for?

Reply from Steve:

It sounds like the gasket blew out. They usually don't do that unless the bolts loosened-up or it was a faulty install by someone who didn't know what they were doing or didn't take the time to clean the gasket-surfaces properly. I like using a good gasket and a thin coat of tar-like Aviation Form-a-Gasket left exposed to air for a few minutes to "tack up".

Usually, when H20 pumps go, they leak out of the vent hole in the pump due to the bearings wearing out...the shaft wobbling...then H20 leaking passed the bearing seal and out of the hole.

Make sure your fan clutch is in good working order. It can lead the pump to failure. The belts shouldn't be installed too tightly. Over-tightened belts shorten the life of the bearings in the pump. Clean antifreeze is good to have in there too.

There are many different length bolts that hold a small block Mopars H20 pump on from what I can remember. The last time I changed one was about 7 years ago. A good, quality rebuilt pump will do.

This page last updated June 15, 2004.  Send us your feedback, and come join the Imperial Mailing List - Online Car Club