Engine Coolant leak by water pump

91GTstroked

Active Member
Jun 14, 2007
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Hey guys,

Merry Christmas! Well I went to check on the 90 coupe this morning at the storage unit. It appears I have a small coolant leak.

I can see some running down the sides of the timing chain cover where it mates to the water pump. But I put my hand under the thermostat housing and had some there.

I recently bought this car and was told the water pump and thermostat were replaced in 2018. It has a edlebrock water pump.

Not much I can do do about it during the winter while it's in storage. I didn't have any leaks during the summer.

Is it possible some bolts are loose? I might try to tighten some down while the temps are in the 30's.

For now the leak is some minor drips.
 
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91GTstroked

Active Member
Jun 14, 2007
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T stat housings are famous for leaking.
i wouldn't try tightening anything, broken bolts and stripped threads are a pain. Just put a catch pan under it and wait till warmer weather to fix.
That's probably the best idea. I'll wait until spring.

Thank you!
 
Nov 30, 2019
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Toronto
Your water pump may be “leaking” from the weep hole? I’d let it run a little bit and try to see where the leak is, all water pumps generally have a weep or bleed hole, but I also know thermostat housings are notorious for leaks too.
 
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91GTstroked

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Jun 14, 2007
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Your water pump may be “leaking” from the weep hole? I’d let it run a little bit and try to see where the leak is, all water pumps generally have a weep or bleed hole, but I also know thermostat housings are notorious for leaks too.
Thanks. It appears the weep hole is on the bottom of the wp. Coolant seems to be on the sides of the wp where it mates up to the timing cover.

I'll have to wait to fix it in the spring. If my guess is right,. I'll be replacing the timing cover, gaskets, and probably the thermostat housing gasket. But I'll try snuggling bolts first.
 
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Nov 30, 2019
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Toronto
Thanks. It appears the weep hole is on the bottom of the wp. Coolant seems to be on the sides of the wp where it mates up to the timing cover.

I'll have to wait to fix it in the spring. If my guess is right,. I'll be replacing the timing cover, gaskets, and probably the thermostat housing gasket. But I'll try snuggling bolts first.
I think you’ll just have a bad gasket seal. Did you notice any coolant in the oil ??
 
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Mustang5L5

A little massaging and it went right in
Mod Dude
Feb 18, 2001
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Leaky timing covers are a common issue. When you bolt on a water pump/timing cover, there are 4 sealing surfaces you need to seal on each side into the block. Miss one tiny little spot and a leak will develop.
 

7991LXnSHO

Mustang Master
Sep 1, 2010
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A coolant system pressure tester is likely to help. It will pressurize the system without being hot and make finding that leak a lot quicker. The kits are not bad to buy on amazon, and I have seen them in the borrow tools at Advance auto. I like to use the tool to chase down hose clamp and pin hole leaks, but this will be another slick use.
 
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91GTstroked

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A coolant system pressure tester is likely to help. It will pressurize the system without being hot and make finding that leak a lot quicker. The kits are not bad to buy on amazon, and I have seen them in the borrow tools at Advance auto. I like to use the tool to chase down hose clamp and pin hole leaks, but this will be another slick use.
I'll definitely be buying one, thanks.
 

revhead347

I have face herpes.
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Jun 14, 2004
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I'll definitely be buying one, thanks.
The coolant pressure tester is a free Rental tool at Autozone I believe. Might be Advance; one of those stores. If it's the thermostat housing, replace it while you are at it, as the factory ones are aluminium and famous for warping. Usually they warp, because the thermostat drops down during installation, and the installer cranks down on the bolts bending it. Don't go for looks on that part, get a cast iron replacement for it. I just looked it up on Advance, and it was $10.99 with the gasket, part number "Carquest #84884." Or you can ask the parts guy for a "water outlet." The cast iron ones never leak. I guarantee that's money well spent.

Kurt
 

91GTstroked

Active Member
Jun 14, 2007
92
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The coolant pressure tester is a free Rental tool at Autozone I believe. Might be Advance; one of those stores. If it's the thermostat housing, replace it while you are at it, as the factory ones are aluminium and famous for warping. Usually they warp, because the thermostat drops down during installation, and the installer cranks down on the bolts bending it. Don't go for looks on that part, get a cast iron replacement for it. I just looked it up on Advance, and it was $10.99 with the gasket, part number "Carquest #84884." Or you can ask the parts guy for a "water outlet." The cast iron ones never leak. I guarantee that's money well spent.

Kurt
Thank you. The one on my car now appears to be cast iron. But I have a coolant sensor installed on it. If I did replace the housing, I'd have to tap a hole or find one already drilled out.
 

revhead347

I have face herpes.
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Jun 14, 2004
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Thank you. The one on my car now appears to be cast iron. But I have a coolant sensor installed on it. If I did replace the housing, I'd have to tap a hole or find one already drilled out.
If it has the bung for an extra sensor, then that's already the cast iron one from the parts store. Like I said, those almost never warp.

Kurt
 
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91GTstroked

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Hey guys,

I tried a pressure tester today. Car is still in storage. It held pressure for the few minutes I left it hooked up.

I did see one drip of coolant come out the water pump weep hole. Other than that nothing.

The timing cover and wp gaskets look damp though. I may just need to start it up here in spring and see what happens.

The water pump is a edlebrock and was replaced in 2018, so I've been told. It looks pretty new.

Thoughts?