I was all set to roll to a meet tomorrow morning; I went to buy gas, and when I got back to the garage I detected a distinct whiff of antifreeze.

Careful looking around showed it to be coming from the area of the water pump, but with everything assembled, I could not tell if I was dealing wit ha bad pump seal, or a bad gasket, or "X", so I pulled the fan, shroud, outer pulleys... and I'm still not sure what the deal is.

Background;

Engine was rebuilt a year ago, and there are only a few hundred miles on the build; no more than a thousand. Water pump was brand new (not a reman) Gates cast-iron pump installed with the new build. Car sat for abouthte last 5 weeks.

Problem; everything is so clean that I can't judge with certainty if the leakage was from the seal weep hole (meaning the pump is bad, even though new) or from the pump to pump body gasket seal (which was sealed with RTV on both faces of hte felt gasket, and then torqued to FSM spec of 13-20 ft/lb).

Pump shaft feels normal-new, tight, no wobble or end play. Alt and air pump belts were at proper tightness.

I'm leaning toward the gasket having not sealed properly, except for one troubling thing; the drop of anti-freeze on TOP of that lower fastening bolt. I'm having trouble explaining to myself how it got up there, as that is above the seal line, though only slightly.

Look at these pix and give me your opinions:

a) Bad pump
b) Failed gasket.

 

I think its coming from the weep hole. If you look closely you can see a tell tale trace where the coolant ran down to the head of the bolt. Its not obvious, but it is there.

and btw, you take excellant pics.

 

It doesn't have that look of "drooling" out of the weep hole. The gasket might have gotten a crease in it, I've seen it happen. Sometimes they're not cut precisely enough to fit the bolt pattern. You tighten it down, it folds up a little, and creates a tiny space for coolant to leak out. I'd pull it back off and check it for creases.

And a problem I run into sometimes - I'm extremely impatient and will often go for a drive before the RTV fully dries

Edit: Oh yeah, and did you torque the bolts in the correct order?

 

In this pic you can see if you look very closely the trail the coolant left.

 

Shows up better on DD's full size pic. It's the nest to the last one.

 

OK, so one vote each way so far, lol.

Bonus question; RTV without a paper gasket? I've never done it (always used both - and never had a problem before!), but it seems like Permatex markets stuff just for that purpose.

I'm going back to the garage and see if there's any AF inside the weep hole, and look inside the pulley for signs of moisture.

 

It would show up more except for the fact that you, being the perceptive nose you are, caught it early.

 

Use permatex "the right stuff" if you dont use the gasket, the stuff works!

 

The inside of the water pump pulley is clean, dry, and has no odor of antifreeze about it.

I ran a toothpick wrapped in a strip of paper towel up into the weep hole, and it came out dry.

Kinda leans toward the gasket, rather than the pump seal, yes?

I'm going to pull the air pump off, see if anything more becomes visible. Either way, I'm going have to drain the block and pull the pump housing; I just need to know if I need a pump.

 

apparently you are not seeing what I see in the pic.

In my view, it doesent matter which one is leaking unless you are willing to take a chance and keep the pump. Saving the $30.00 to $70.00 by keeping the pump will seem insignificant if you have to pull it all back off when the weep hole continues to leak, and I think it will.

Its one of those situations that bug me. If you replace it there is no way to know that it was needed, if you don't then you kick yourself for wasting the time and effort on having to do the job twice.

 

I never use a paper gasket. just a good sandpaper to roughen the water pump mating surface and a copper or gray silicone. and never had a problem with the heavy water pumps also.

 

option #2 is that its leaking thru the lower bolt hole. you can see they didn't machine the washers mating surface flat all the way around, part of it is as cast.

 

It's coming from the weep hole. I say don't worry about it. New waterpumps do this sometimes. Most likely from sitting.

It will either self-seal or get worse. For peace of mind you could get another waterpump and if/when the leak gets worse, and you feel like it, swap them. Otherwise don't worry about it. It's not like it will become a stream of green any time soon. Run the engine more often and it should self-seal.

 

This is actually the argument that was running around in my head (along with some of Jeff's comment, below.)

I was hoping to get everything solved to make a meet the next morning (today, now) but the more I looked at it, the less comfortable I got about trying to half-*** it.

Now that the pump's off and in my hand and it's daylight out, I can see just the faintest hint of a mineral deposit/erosion of the clearcoat from the weep hole down and to the left toward that bolt, and also above it continuing left. The hot AF leaking on my polished front cover likewise eroded the clearcoat.

It's very faint, and I don't know if it is enough to account for the amount of AF that was leaking onto the front cover and getting blown by the fan onto the thermal reactor (which is why the smell was so noticeable).

Bottom line is: with antifreeze approaching $20 a gallon, and "Right Stuff" sealant at around $15 a can, plus the hassle of possibly having to do the work over again, a $45 new water pump from Bosch makes good economic sense as well as eliminating any doubt about the current pump.

I ordered a pump this AM and will have it sometime later today.

I've never had a problem with sealing, nor with more thanthe most minial short-term weeping new pumps either, which is why this just left me square on the fence. It didn't make sense that it would be leaking as much as it clearly was, judging from the AF trail on the front cover & the mineral buildup on the front of the TR. Once the engine cooled, I was down about 3/16" in the overflow bottle too... and that's been rock-steady since I finished 'burping' the last rebuild back around June. So, something changed just recently.

I looked at that, too. That hole doesn't lead to the water chamber; it actually goes straight thru the pump housing and is open on the back.

If the gasket sealant had failed between the water chamber and the bolt hole, it would exit out the bolt hole to the front, whether or not it washer sat 'flat.' So that was a candidate.

Examining the remains of the gasket, there's no clear indication that it had lost seal. Naturally, the coolant trapped in the pump housing spilling out when I pulled the pump obliterated much evidence. There were no wrinkles or cuts in the gasket that I could see.

I've seen that happen before, and it's usually only a few drops now and then; sitting too long exposed to fluids is not good for seals. But this seemed to have suddenly appeared or gotten worse, based on the water loss from the overflow bottle once the engine cooled. If it hadn't been for the amount of loss, I would have driven it to the meet today (at a Mazda dealership) and re-checked, but it's about a 35 mile freeway run and I decided not to chance it.

The engine was last run about three weeks ago (just for a warm-up), and the car has been driven at least monthly since completion in June. It sat for a max of six weeks just before this re-start.

So, this pump will go into "spares" tagged as 'poss. bad - unknown,' and I'll drop in the new pump when it arrives today.

 

I would say the water pump weep hole as well. watson has a well-annotated pic in his post. Hope replacing the pump and the gasket do it for you, your car needs to be driven

 

I have always wanted to take one apart to see what kind of seal is in there and determine how difficult it would be to replace, along with the bearings.

Would be neat to be able to refurbish one for two or three dollars rather than the $30.00 + for a replacement.

and you wouldn't have to worry about what kind of impeller would be there when you open the box.

That does it , it is on my to do list!

 

But... It'd get DIRTY!!!

 

are you that Frugal?
I thought Fc owners were cheap..lol!
I just paid 80 bucks for a water pump.
Then I find out Rock Auto has them for 35.
It would have to be shipped though,so same day I get the pump is a lot better than waiting 10 days to get.
It is on.

 

DD
FWIW, when I replaced my Wpump (and the pump body too) I used a dab of plain ol' axle grease on BOTH sides of the gasket. The Old Timers swear it makes the gasket seal better, and the side benefit of: when the pump comes off, the gasket just slips off too. No scrapping crushed, baked paper bits.
3 years - no leaks. Just a thin bead with your finger-tip...

Stu Aull
80 GS
Alaska

 

$45 for a new (not reman) Bosch pump. I was supposed to have it last night, but apparently their driver went home early. Now supposed to have it by 11:30a.

 

the seal is NLA from Mazda, other than that, it looks really simple.

 

Finally got the pump after lunch; thanks so much Pep Boys.

I decided to install it without the gasket, using Permatex "The Right Stuff" Grey gasket maker.

Pressurized can makes doing a nice clean bead about as hard as putting Cheese Whiz on a stalk of celery. I was very careful to get full surround of all bolt holes.

Slid it home, torqued it in place - - 20 ft/lbs still feels light but that's the spec - - & got a good even ooze-out all the way around. Per Locktite, there's no delay required in 'returning to service,' which is a big improvement over the older silicones.

Long story short, got everything bolted back up, wiped down, adjusted, filled, burped, and was out for a test drive just about sundown.

Leak free. Yay.