1972 300sel 4.5 water pump

[Clunker]

I created a post about 2 months back about a leak in my cooling system that I could not find. I pumped air into the system and still could not find the leak. Infact, as soon as I did the test, the leak seemed to disappear. I noticed anti - freeze dripping on top of my oil pan and running under my car about 3 days ago. I deducted that it is coming from the top of the crank shaft pulley and below the water pump. The car holds excellent pressure and does not run hot. I have contorted myself into every possible position and still can't find the exact location of the leak. Every time I've lost a water pump it appeared suddenly, in the hot August sun, in the middle of nowhere. The car over heated and every drop of fluid turned to steam or fell onto the road. Is it possible that a water pump can develop a small leak? Does it mean it is going to die?

[robertbrown29]

check to see that the water pump is tight and not leaking from the seal(gasket)between it and the balancer.if your model has a crossover pipe,check to be sure that is tight.grab the fan blade(engine off)and push it back and forth.if there is more than a very small amount of play,the shaft bearings may be worn.best guess,better to know you have a new water pump on 285 than to wish you did.

[Aaron]

Clunker,

Could be a leak between the impeller housing and the main housing, or it could also be a worn shaft. It will usually make noise though if the shaft is worn. If you have any doubts, yank it apart and renew the pump. A new water pump is cheaper than a new engine!

I had the same devilish leak on my 280SE 4.5. Couldn't find it for love or money.

Just replaced the water pump a few weeks ago. Problem solved. Take Arron's advise, save your motor!

STS

PS

280SE 4.5 for sale.

Solid CA car now in Providence, RI.

See the car at

http://members.home.net/toomanynotes/

[Clunker]

There are 5 water pumps listed on fastlane. Any advice to which brand I should buy? Also what is the lowest degree I can get the thermostat in?

Clunker, I think you could get at one time a "summer" thermostat that was set at 70c. These cars are great but they run a little warm in traffic. Redline water wetter is great stuff(guage does not see over 175 even with a/c on in Fla. Make sure your fan clutch is o.k., they are expensive but worth replacing if it is marginal. Also make sure the 212 switch turns works and turns the electric fan on. I used to have a 300 3.5 and I remeber the timing would also be advanced to help cool the engine when the 212 switch grounded the wire. Replacing the water pump is made easier if you pull the radiator. You have to turn the harmonic balancer to remove two of the bottom bolts. Hope I was of some help.