water pump stiff - head blown

[Clivekillops]

How stiff is the water pump when turning by hand? Mine takes a lot of effort to turn (wet inside) and makes a rubber squeak sound.


Just purchased a Supra Combrio with the PCM 351 (Ford Windsor) owned same type 10 years ago and loved it.

first time on the water this weekend and temp ran hot - fluctuating between 160F and 180F and then briefly 200F

pulled the boat out and noticed oil in the bilge water. closer inspection and I found the left hand bank oil leaking out from the head gasket aft cylinder.

Did I cook the head and warp it?

Pulled the water pump off and it is very difficult to turn by hand and I suspect the belt was slipping because their is a shine on one side of the pulley.

I am going to have to pull the head and get it t an engineering shop to skim and reseat the valves.

I am nervous of the exhaust manifold studs, they look old and brittle.

Regards

Clive

[CJD]

I doubt it is your head gasket leaking oil. Most likely it's the valve cover gasket leaking down and running along the seam between the head and block until it reaches a low point and you noticed it there. Run a compression check on the engine before you pull the head off. You may save a lot of work that you don't need to do. Another common source of leak is the front and rear of the intake manifold. Because the heads are angled, and oil leak at the intake can run down the block to the corner too. Head gaskets normally leak compression and coolant long before they leak oil.

Open the cover on the pump and remove the rubber impeller. Then check the effort to spin the pump with no impeller...it should be very easy, but should not "spin". Look over the impeller. If it is broken, then bits of rubber blade can get lodged in the motor/thermostat and cause irregular temps. If the impeller looks brand new...the PO could have found a broken impeller and replaced it, but still left the broken pieces in the engine to cause you grief.

200 degrees is not enough to damage the engine, so long as the gage is not wrong. North of 230 degrees is where the damage comes in. At 212, adjusted for altitude, you get boil over. Once the engine boils over, the temp will spike almost instantly to 230 plus and peg the gage. Iron heads are much more tolerant of overheat than aluminum. One overheat is normally enough to ruin aluminum heads. Iron usually take an occasional overheat...but not always.

[Clivekillops]

Thank you CJD, that makes perfect sense. I will have a closer look and run a compression test.