After 74k it looks like it's time for a new water pump. Today I smelled coolant and when looking under the hood saw evidence of coolant fluid on the underside of the hood and a few drops on other parts. I couldn't see any hose leaks and there is not much fluid loss, the overflow tank is still full. I'll have the pump tested, but I'm wondering if I should also have the optispark replaced. I don't think the optispark has been soaked with coolant and don't want to go to extra expense if it's not needed. Is it SOP to replace both when the water pump goes or is it likely the Optispark can still go a long time? Car is an LT4.

 

If you are seeing a coolant stripe on the inside of the hood, chances are the water pump is dripping on your belt, and spinning it up onto your hood (that's what it did to me).

I tried to just do the water pump, and two weeks later I was stranded 400 miles from home wishing I would have changed the opti too. Take it from a guy who's been there, change it all while you are at it.

 

Thanks Bob2.0, that's what I was afraid of.

 

Since you have a Gen II vented opti and it is still working, I wouldn't replace. The vented optis hold up alot better than their non-vented counterparts.

 

 

My dad has 130,000 some miles on his 1996 with a orginal opti. Unless you find a amazing deal on one. I might do a spark plug change and inspect the unit. But replace maybe not.

 

You can reach under the water pump and feel the weep hole to see if it is leaking there. If you don't have coolant on your fingers, pressurize the system and find your leak before replacing anything.

When my WP was leaking, I changed the opti while I was at it, I also did the hoses, belt, plugs and wires, about $700 in parts. I did that because it looked like my WP had been leaking for a while, it was winter and I had the time (and money) and I just got the car and didn't know the history. If I was confident that I caught the leak early, I wouldn't necessarily do the opti too, it isn't that big of a job to pull the WP.

 

You can take a mirror and a light to see if there is a black streak on the back of the water pump. Before replacing the opti check to see if you have any codes. (16 & 36 are death blows to the opti). On a 94-96 you can check the codes with a paper clip. If you do not kown how to do this let me know and I will post the instructions.

 

 

After hearing the horror stories about how susceptible Opti's are to moisture, on my 96 LT4, as an experiment, I power washed the front of my engine and deliberately attempted to inundate the Opti. This was probably the original Opti on a 120,000 mile engine; it had gotten a new rotor and rotor cap four years earlier. While not waterproof, the Opti proved water resistant. I drove the car for several months afterward. Subsequent teardown for a cam change revealed two things: (1) an opti is no different than any other distributor needs to have the rotor and rotor cap changed occasionally; and, (2) both vent hoses were non functional: the one bringing air from the intake coupler to the distributor had shifted and had been cut through by the serpentine belt, and the one from the distributor to the intake manifold had rotted through and fallen off.

There was evidence of water intrusion, but had the vent system been functional, proper venting, plus engine heat, would have kept the Opti dry.

My suggestion is to inspect / replace the rotor and rotor cap, seal the rotor cap to the distributor body with RTV, and, inspect and repair the vent hoses as necessary.

By the way, the funky little reverse torx head srews holding the rotor cap are 4mm, one size smaller than the reverse torx head sockets usually sold at hardware / auto parts stores; Sears sells them as a catalogue only item.

 

Thanks, I'll check for codes tomorrow. I have a code reader (had to get one; my Miata was always throwing codes). I didn't think to check since the car is running fine.