Water Leak

[Mesa Mike]

I have a water leak around the water pump. I have replaced the water pump, refilled and still leaks. I then replaced the timing chain cover and all new gaskets and still leaks. When idle in the garage to operating temp no leak. When test drive water leaks out near the bottom of the pump and splashes on the harmonic balancer. I have torn down the front of the engine several times and cannot find the problem. Engine was machined and tested before building back with new components. Block is 302 and Carb and has about 8,000 miles since rebuild. If the block was cracked on the front side could it leak out and not into the oil? I am planning to pressure test the engine in the next few days. This is driving me crazy.

[michael everson]

This may sound obvious but you need to pinpoint exactly where the leak is coming from. Check all hoses, check thermostat housing, and check the radiator. Maybe it's leaking from somewhere other than the pump and and the wind is forcing it towards your balancer. If the block was cracked, it would leak into the oil. Do you have access to a lift? That would help too.

[skullandbones]

Mike,

I have a diagnosic camera with 36 in shaft and 8 mm probe. If you want to "look for the leak", I could come over and help. I can't guarantee that you will find it that way but it might work. I found a leak underneath the upper thermostat housing on mine. It was leaving a small puddle of water on top of the WP but I couldn't really see where it came from. It turned out to be slightly bent but I had to put a straight edge on it after removing to see the problem. You can PM me.

WEK.

[Norm B]

Can you tell if the water is coming out of the drain hole in the water pump behind the pulley? I've had 2 water pumps do that on a mustang do that. Turns out I had a slight warp in the pulley that was causing the problem.

[Mustang Man]

It's not a "drain hole" but a vent for the pump shaft. Pressure can build up between the forward and rearward seals with heat, so the casting has a hole top and bottom to prevent the seal from blowing out. Some minor weepage is normal, but if it is "draining" out the hole, the shaft seal has gone bad.

As for the OP's leak. I would look at the mounting points on the pump versus the cover and ensure you're not missing a bolt. Also, on all new pumps I remove the backing plate and put some gasket makeer/sealer on the backing plate gasket and then reassemble. I never just bolt the pump on out of the box.

Triple check the pump to cover gasket, as often times the pump or timing cover comes with multiple gasket configurations and you might be using one that "looks" right, but is not sealing a specific hole in the timing cover, causing the coolant to get by and leak out.

HTH...
Mark

[frankeeski]

Mike, some of the mounting bolts for the pump go into the block where they are actually in the water passage of the block. Did you use sealant on these?

[Gumball]

Mike, some of the mounting bolts for the pump go into the block where they are actually in the water passage of the block. Did you use sealant on these?

Can you elaborate? Which bolts? All Ford small block or just certain years of front covers?

[frankeeski]

Can you elaborate? Which bolts? All Ford small block or just certain years of front covers?

I'm not standing in front of the engine right now but if memory serves, the 2 on each side next to the water passages in the front of the engine block. As far as which engines, all Ford 302 and 351 variant small blocks that I know of. I can't remember if the Ford big blocks have the same issue but a little thread sealant on those in question couldn't hurt.

[Mesa Mike]

Thanks guys for all the advice. I have tired them all. Replaced my old water pump twice, RTV the back place of the water pump(s), seal the bolts going into the water jacket, new gaskets (2) on the thermostat housing, The leak is on the front and it is not a "weep". Doesn't do much in the garage but when driving it throws out enough water to leave a drip trail behind me on the street. I am going to put some pressure in the block to see where it is coming out. I'll keep you advised. Thanks.

[Mustang Man]

Yup, best course of action right now. Get yourself a pressure tester and pump that bee-otch up and it'll let you know where it's coming from. I had to do that after replacing the pump on my DD Mustang. Turned out the lower hose clamp at the pump needed a couple of turns of the screwdriver. Didn't leak idling/cold, but down the road at temp it was leaking enough for me to see a noticable coolant level loss.

Mark

[RonnieP]

I have a 351 winsor that had a leak some what like yours. Come to find out that the intake bolt
on the left side was a little too long and I couldn't tighten the intake gasket completely.When it got hot
water would run down the front of the block.

[Mesa Mike]

Ronnie...that's a good idea. I'll try that tomorrow.

[patpur]

My car also had an intake gasket improperly installed (previous owner) the water leaked down the front of the engine in the water pump area. Had the gaskets replaced and no more leak. I hear those front two water jackets are notorious for leaking if the gasket isn't just right.

[Mesa Mike]

First of all. Thanks for all your advice. I think "dumb" tore down the front and removed the timing chain cover and "dumber" put it back on (without the lower rubber gasket). After a pressure test on the cooling system (no leak) we discovered it was not coolant it was oil. Duh! This was determined by a taste test. Not coolant, oil. All better now with new gasket set including the rubber one. I feel so dumb. After a test run (before) I would stop in the street so not the get the garage floor dirty. On black top coolant and oil is the same color. When placed on a lift it was clear where the leak was coming from. Thanks again for your help.