Engine Water pump leak driving me crazy

[sigsterrr]

I replaced the water pump when I rebuilt the car (89 GT 5.0) and then had a cooling issue. Replaced the new pump with a high flow pump and can’t seem to get the thing to stop leaking. I’m close to setting my car on fire. I do not have the original. I noticed there are at least two gaskets between the pump and timing cover that fit, but the ports are different. Best place to get the right pump and gaskets? Could the timing cover have been replaced from a different model before I got the car? I’ve tried the black permatex, just gaskets, and only the first time I installed it (with too much permatex) when the engine was on the stand did it not leak. Picture of the proper backing plate? Gasket pictures?

 

[2000xp8]

Mustang Replacement Water Pump (79-93) 5.0L PW291 - LMR

Keep your engine cool with an OE style replacement Motorcraft PW291 water pump for your 1979-1993 Mustang 5.0L. Available at LMR.com!

lmr.com

Factory ford pumps are the most reliable.
Comes with the gasket.
High flow is pointless on other than applications that truly need more flow, which in most cases probably require a massive radiator.

 

[Blown88GT]

I didn't use the gasket that came with the pump. Get the Fel-Pro blue gasket. Then use Permatex gasket adhesive to hold the gasket in place; use no sealant. The mating surfaces must be completely cleaned of all old material; the OEM gasket bonds to the timing chain cover.

 

[Redfire Fox]

Where exactly is your leak coming from? I had a leak that was driving me crazy and took the pump off and on 4 times before I succeeded. Mine was leaking between the water pump and backing plate. There are two bottom bolts holding the backing plate to the pump. My leak was coming from between those two backing plate bolts.

 

[Mustang5L5]

Which water pump are you running?

The only two hig flow pumps I know of are the flowkooler, and the edelbrock.

There were some recent posts on another forum about the FK pump having backing plate bolts thAt the heads were too big and caused the pump to not sit flush to the timing cover

 

[2Blue2]

I have an Edelbrock HF pump on my 65, never had a problem in yeas of yuse
Recently put a Flowcooler on the 77 and it works great and was definitely runs a few degrees lower on the stock temp gauge.
Got to watch that stock back plate on install though.

 

[nickyb]

Ditto on back plate! I grinded down an open end wrench to slip in between ,so I could tighten up once installed.works like a charm.

 

[Shakerhood]

I have an Edelbrock HF pump on my 65, never had a problem in yeas of yuse
Recently put a Flowcooler on the 77 and it works great and was definitely runs a few degrees lower on the stock temp gauge.
Got to watch that stock back plate on install though.

I put an Edelbrock on my Mustang about 20 years ago, still works great.