!992 SL300 water pump replacement?
 

Hi,

I'm new here, but have been around cars for years. I'm looking into a 1992 SL300 that I'm told has a bad water pump. The car has just under 60k miles, and that seems a little odd. How big a job is it to replace? I saw another area of this site, but it was for a diesel. If I don't do it myself, what can I expect a mechanic top charge?

Thanks,
J

Water pump seals are a time and mileage thing. The seal has a rubber boot that will fail just as hoses do causing a leak. Are they saying the pump needs changed due to a leak or an overheating issue?

Water pumps are not difficult to change on these cars. Pull the belt, power steering pump. The pump is a large unit that also holds the thermostat. Have a look at pumps from parts sellers for an idea what to expect.

I don't recall the time to change on my 97 SL320 ( pretty much same pump as your 300 ) but expect about 3 hr.

If an overhearing issue, check the thermostat first. The bridge broke on my 97 C280 ( similar engine ) and caused a too cold at speed and kind of hot at low speed. Never pull the t stat then run this type of engine, the back of the t stat has a disc that blocks the bypass port when the t stat is open.

The owner told me it started as he saw the temp rising, then he saw the leak. His mechanic told him the pump was leaking, and now is leaking faster (he won't drive it). I'm assuming the pump is shot, and not just seals. Could there be other issues (aside from hoses)?

These motors usually don't have coolant leaks from the head gasket so water pump or hoses are a good bet.

There is a steel pipe and some hoses that attach to the water pump, any of these could be leaking.

The only way I'd buy a car like this was if the price was good enough to cover a replacement engine. These engines are pretty sturdy so unless they got it glowing hot it may survive.

And, the market for an older broken SL is so low, the price better be in the $ 2 K range.

If you really want an SL, have a look at a 94 ish 95, 96 or 97 SL320 with 97 being the optimal ( and last year ) of the 6 cyl cars. $ 5 - 6 K should get you a really nice but not perfect car. The 6 cyl cars are somewhat unloved but are completely fine.

94 gets you full EFI but expect to change the engine waring harness due to bio degradable wiring insulation,

96 gets you updated interior

97 gets you the electronic shift trans.

I got the car, and it looks like the pump is shot. Everything run/works fine, but it leaks. I'm also going to fix the top lock(s) in the window frame as they have a leak as well.

Do I need to pull the power steering and tensioner pulleys to get them out (PSP & Tensioner)? I've read a strap wrench for holding the pulley, but is there anything else needed? Is the tensioner held in with a 17mm hex bolt (I read that somewhere, but it seems like an odd fastener)?