i have a 1968 sedan deville with a coolant leak. im having a hard time seeing if its coming from the water pump or the lower radiator hose. another weird thing i noticed is it seems like its only leaking when the car is cold. i noticed it leaking at work yesterday. i came home and lifted the car only to find no leak. i let it sit for 2 hours and still nothing. i woke up this morning and its leaking. its dripping off the block underneath the crank pulley. has anyone here replaced the waterpump on a 472? i ordered one yesterday(along with the lower hose) and im going to pick it up in a few hours. i am curious to how big of a job its gonna be.thanks for any help.
Sometimes the water pump bearing seal will leak only when it's cold. I have seen this problem before. You can verify this type of leak by using a small inspection mirror and a flashlight. Look at the underside of the shaft end of the water pump. There is a small bleed hole in the casting. If coolant is seeping out of this hole, you have found your problem. Your water pump has limited life at this point, perhaps a thousand miles, more or less.
It is not a difficult job. But take your time. You will likely spend most of your time removing the belts, fan, draining the coolant, etc. as compared to the time it takes to remove the pump itself. I believe there are 9 or 11 bolts (can't remember exactly, it has been years since I replaced one) that hold the pump to the timing chain cover.
BTW....... it looks like the lower alternator bracket uses the same bolt as the water pump. did you pull your alternator out when you did yours?did you have to yank the radiator? did you remove the fan/clutch before you yanked the water pump?
You will have to yank the fan/clutch assembly. I think the radiator is ok. You may have to remove the shroud just for elbow room. Be careful that you keep any water from running behind the timing chain cover. I did this once and thought I had blown a head gasket when I started it. The oil looked milky. Then I realized that while flushing it after the removal of the pump that water had gotten in through the timing chain. Drained the oil. New oil new filter ran for 10 minutes. Repeated this 3 times and all is well.
I don't remember having to remove the alternator. But as Sasquatch pointed out, you should remove the fan and shroud. Also, you may wish to place a piece of cardboard over the radiator so you don't accidently ding it with anything and create a leak.
i just did the waterpump. the fan was held to the original waterpump with four nuts and bolts. the new water pump is threaded so i have to stop at home depot tomorrow for 4 bolts. i noticed my original lower radiator hose had a spring in it(im assuming to prevent it from collapsing). the new hose didn't have the spring. will this be an issue? also, there is a plate that sits between the waterpump and the block. while prying off the pump i pulled that plate away from the block a bit(only about 1/8 of an inch). it happened at the top of the plate where there are two passages that go to the waterjacket. how is the plate sealed against the block? i put hi temp rtv black silicone on my finger and pressed it between the block and the plate at the two passages. do you think i will have issues with this leaking? i also used the silicone on the pump and gasket. i will be firing up the car tomorrow night when i get home and put the fan back on. the install was real easy and my only real concern is that plate leaking. im hoping the silicon i put in there will cure in the next 24 hours and prevent any problems.
Cadillac calls it the front plate, but it's really the timing chain cover. Anyway, the cover is bolted to the front of the block and some of those bolts are shared by the water pump. Between the plate and block is a gasket. Sometimes the plate will "give" a little while removing the pump. I've had this happen a few times myself. And I have done exactly as you have done and placed a little bit of silicone sealer or permatex between the the plate and block of those water passages while carefully pulling or prying a little on the cover. Although the correct procedure is to remove the plate and replace the gasket, you should get a leaktight seal using the above method. I think you will be fine.