So I developed a coolant leak on my 85 just before I put her away for the winter. Now that I have it out of storage for the summer, it's time for me to fix the leak. I have a new water pump (< 500 miles), and this is what I have done to try and fix it. I have done two gaskets made out of Black RTV and I cut my own gaskets out of gasket material from AutoZone, and it's still leaking. The coolant runs down the front of the block from the bottom of the water pump/thermostat housing (the big cast piece that is between the water pump and the block). It is NOT a weep hole leak, as I have had one of these in the past, and I know it's not a weep hole leak. No coolant is hitting the belts nor is it being slung around the engine bay by the pulleys. What could it be? For reference, I AM missing a few of the washers that go between the bolts/nuts and the water pump. Could this be causing it?

Thanks


-Jim

 

yes, i remember reading on a recent thread that if you're missing those it won't seal right.

 

Did you make sure you put the 2 shims between the block & the water pump housing located on the right?

 

where?

 

hmm...i may have to pick up some washers tomorrow...

 

Right behind the water pump where it meets with the block. On the right hand side, first 2 long bolts before you put the water pump in you're supposed to put 2 shims. They are real thin.

 

yeah the 2 studs on the left side need two little thin washers to compensate for the water pump housing gasket.

if you dont have those, when you tighten it up, it'll pull the gasket apart and leak

 

Here's a pic of the 2 shims

 

hmm...looks like it's gonna come apart again tomorrow so I can see if these are in there. If not, can I just use a couple of washers?

 

The shims need to be a specific thickness. They need to make up for the thickness of the gasket under the other part of the pump housing.

Arran

 

If memory serves me, I believe my water pump gasket set came with them made of the same gasket material.

 

so what you're saying is that i should just make them out of the same gasket material that i'm cutting my gaskets out of.



So I did have the shims on the two studs, however they were less than 1/4 the thickness of my new gaskets. I went to the hardware store and matched some SS washers that are the same thickness as my gasket material and replaced the two spacers with those. Still leaking. I then put some SS washers under each of the nuts around my water pump. Still leaking. What can I do to stop this leak? I'm going to cut out new gaskets and some washers from the gasket material to *hopefully* fix this damn leak. I am going to put a thin coating of RTV on either side of the gasket so that *may* take up the small space where the water is leaking out. Any other suggestions?

 

I dunno man, those washers are very thin.

 

i believe you can just use some RTV and get away with it, as long as you put enough and make sure you get the bubbles out

 

those shims are the same thickness as the gasket. so substituting a washer shaped piece of that same gasket material you used will work.

 

I know that they are very thin, i have them, but they didn't stop the leak. Looks like I'm making my own washers out of gasket material.

Oh, are there any suggestions about how to tighten the nuts/bolts to increase my chances of success?

 

mazda recommends torquing these nuts/bolts to about 16-18 Ft/lbs - ie, NOT very tight. Mine buttoned up fine at this torque, so if you have to use more than this, your compensating for gasket problems-
still

Whitey your becoming the poster-boy for using the OEM gaskets

Stu Aull
80GS
Alaska

 

The gasket should be thicker than the shims. It will compress. The shims will not. Loose the gasket and...Put on the bead of RTV and original shims. Slide the housing on the bolts, but do not let it contact the RTV. Put the RTV bead on the water pump. Slide the water pump on and push the water pump and housing into the RTV gently. Just enough to get the nuts and bolts started. Let the RTV dry for several hours or, better yet, overnight before tightening the bolts down.

 

The Haynes manual recomends smearing a light coat of sealer on the water pump, and on the water pump housing, (w/gasket). Then tighten the 4 nuts on the studs (in sequence) to specified torque, before tightening the bolts.

 

I'll bet this whole issue is due to the fact that you are cutting your own gaskets. Is the material very thick? Just goop the hell out of both sides, let it dry over night, then bolt her on. That's about what I had to do when I installed the 2nd gen pump housing.

Good luck. I expect you to have her ready for the race in May... No excuses either

 

 

I have to have her ready for May....I have to move her 550 miles downstate and I don't want to tow her the entire way.

 

those gaskets are going to need a little silicon....

 

maybe the leak is coming from the lower stud threaded into the front housing? also make sure there's nothing cracked. provided the mating surfaces r clean, there's no reason they shouldn't seal.

 

That's exactly where it's leaking. The coolant drains down and falls from the lowest most point on the water pump. It only leaks when under pressure. When the car is off, then there is no leak.

I picked up some Blue RTV, scraped everything clean, rubbed everything down with alcohol, and put a huge bead of silicone on the parts. Assembled it very lightly so as to not squeeze all the RTV out (exactly as the directions said), and I'm going to let it sit until Tuesday, when I'll fill it with coolant and see if it leaks. If that doesn't work, then it's going to be cut new gaskets, put a layer of RTV on either side of them, and assemble it, let it sit for 24+ hours, and see if it'll seal. If I can't get that fixed, it may be taking it to a mechanic to see if he has any tricks up his sleeve to seal it tight. I'm at a loss right now for why it won't seal.