nathanb

Hey folks,

So I've got a pretty small coolant leak going on in my 88 'Vert, it looks like. When I look under the hood, I notice that there's some coolant collected on the axle below the air pump (not below the water pump, oddly). The lower radiator hose also has some white/yellow residue spatter below the pulley for the air pump.

What does this suggest to you? Possible leak within the water pump? Or maybe a leak from the lower radiator hose? It seems like a bit of a job just to get access to the pump and the hose both, so it's a bit hard for me to tell.

Thanks!

clokker

iTrader: (2)

Given your description, I'd suspect the lower hose or possibly, the water pump housing...specifically, the bung the hose slides over.
I've seen those severely corrode, to the point where just removing the hose pulls chunks of metal away.

nathanb

Yeah, now that the engine has cooled enough that I can get my face in there without singeing my whiskers, I can see that the top part of the lower radiator hose is pretty much caked in residue.

Near as I can tell, that's the factory water pump, 28 years old. Since it appears that water pumps are not especially expensive for this car, I reckon I should go ahead and replace the pump along with the hoses, just to be safe. Thoughts? Is replacing the water pump a job that a relatively incompetent mechanic (i.e. me) could do in my garage with the tools I have on hand?

Turbonut

iTrader: (1)

If you have access to a pressure tester, just pump up the cooling system when cold
and watch for coolant. I believe that AZ has one as a loner if one is near.

clokker

iTrader: (2)

Described drily, as in a book, the replacement of the water pump is straightforward and relatively simple.
IRL, it can be a bitch because the long flimsy hardware (studs and bolts) can be reluctant to come apart, especially in the presence of extreme(ish) corrosion.

Tools required are minimal, time required depends on your engine (mostly, how stock is it?).

nathanb

@turbonut: Thanks for the suggestion. I don't much care for pressure testers, because my opinion is that even if there wasn't a leak when you started, there will be once you're done. Fortunately, I have a pretty good idea of where the coolant is coming out, I'm just trying to figure out if I can be lazy and get away with not replacing the pump.

@clokker: I figured it would be more fiddly than the manual describes. Looks like I'll have to take the belt off the air pump pulley to have even a chance of getting at it. Or is it best approached from underneath? I have a friend with a lift I can borrow if need be, but it looks like the axle might be in the way.

Engine is entirely stock. Pretty much everything under the hood is stock, from what I can tell (other than the suspension components, which I changed out last year).

Are there any hidden gotchas, like having to remember the position of the belt on the pulley or maybe other components I'll need to replace in addition to the water pump?

Turbonut

iTrader: (1)

Your choice, but have used one for many years in the shop and no problems.
Just remember to pump it up to whatever the pressure for the particular system might be an no higher. No different than having the cooling system build up pressure naturally when running.

clokker

iTrader: (2)

At this point you don't know there's a problem with the pump, so laziness may pay off, if only in the short term.

You won't even need to jack the car up, no lift necessary but you're getting ahead of yourself.
If it's just a bad lower hose, that's a different animal than replacing the water pump.
Should you deem the pump needs replacing, you'll have to remove the fan&clutch, the fan shroud, the airpump and alternator belts and the main (lower) pulley.
About the pulley...there is nothing to get out of alignment (like a timing belt) but your life gets a lot simpler if you align the timing marks before removing the main pulley. This is because the four pulley mounting bolts are not concentric- one bolt is offset- and it can be picky to find the correct alignment. If you line up the timing mark and then reinstall the same way, the pattern will automatically be correct.

See above about pulley removal but generally, no.

When running, the cooling system pressure is noticably less than the 13psi of the rad cap, it only rises to that point when air and coolant flow stop (think about it...if not true, the engine would contantly be pushing coolant to the overflow tank).

A good way to check for the leak is to get the engine fully up to temp and then shut her down and start looking. Pressure will build for the next few minutes and any leaks should be easier to spot.