Coolant Leaking After Timing Belt/water Pump Changed

[eds92sc]

Does anyone have any idea why I would be leaking coolant after I had my timing belt and water pump replaced? I see coolant dripping down to the ground with the engine running and the heater on hot. It seems to be dripping between the engine block and transmission area. I first noticed the problem when my heat stopped working. I then realized I was low on coolant, and after topping it off with my engine running and heat on high, I got my heater to work again. Then I realized I had a slow leak from the rear of the engine block.

I've been searching this forum, and I saw another member (older LS400) had the same problem after the same parts replaced. When my mechanic replaced the water pump, was there a chance he might have loosened the water pipe leading from the water pump to the heater core as he was prying out the old water pump? Could that have caused this leak? I'd like to give the shop an idea when I bring it back, so they don't just try to pass this off as a new problem. I didn't have any leaks prior to the work getting done.

If it ends up being a water pump problem, or water bypass pipe issue, do they have to remove the timing belt for access, or can they take something else off for access to the pipe? It seems like either way, it's going to be a big job.

[jzz30]

sometimes the valve for the heater leaks.

[eds92sc]

sometimes the valve for the heater leaks.

Do you think the valve for the heater would leak right after the water pump change as a coincidence? Or do you think it was caused by the work done? Mele Kalikimaka

[jzz30]

it could be coincedence but do you have any pics of the problem? i dont see how changing timing belt in the front of the engine causes a coolant leak at the rear of the engine...

[Air Force Rascal]

Does anyone have any idea why I would be leaking coolant after I had my timing belt and water pump replaced? I see coolant dripping down to the ground with the engine running and the heater on hot. It seems to be dripping between the engine block and transmission area. I first noticed the problem when my heat stopped working. I then realized I was low on coolant, and after topping it off with my engine running and heat on high, I got my heater to work again. Then I realized I had a slow leak from the rear of the engine block.

I've been searching this forum, and I saw another member (older LS400) had the same problem after the same parts replaced. When my mechanic replaced the water pump, was there a chance he might have loosened the water pipe leading from the water pump to the heater core as he was prying out the old water pump? Could that have caused this leak? I'd like to give the shop an idea when I bring it back, so they don't just try to pass this off as a new problem. I didn't have any leaks prior to the work getting done.

If it ends up being a water pump problem, or water bypass pipe issue, do they have to remove the timing belt for access, or can they take something else off for access to the pipe? It seems like either way, it's going to be a big job.

What type of gasket was used..? Silicone or the gasket that comes with the water pump..? The best gasket to use on a water pump is the paper type that comes with it. Silicone can worm it's way out around and leave air gaps that can leak. If the water leak is coming straight down from the water pump past the crankshaft..check the small water line that runs into the block next to the thermastat opening...I had a water leak after replacing my water pump and I swore it was coming from hte water pump..but turned out to be just the connection of the small water line next to the therastat..was not tight enough.

Good luck.

[Steelwheels]

While changing the water pump, you are suppose to open the two drains on the bottom of the engine. It is possible one of those might not have been shut all the way. Still, if the hoses are intact on top of your engine and it is not one of the two drains, it may be coming from your water pump gasket. You should be able to see if it from the water pump by checking the bottom of the timing belt cover.

Good Luck with the leak.

[eds92sc]

While changing the water pump, you are suppose to open the two drains on the bottom of the engine. It is possible one of those might not have been shut all the way. Still, if the hoses are intact on top of your engine and it is not one of the two drains, it may be coming from your water pump gasket. You should be able to see if it from the water pump by checking the bottom of the timing belt cover.

Good Luck with the leak.

Thanks for all the replies from everyone. I just got back from vacation, and didn't use the computer to go online while on vacation. I'm not sure if the leak is coming from the water pump. I looked all around the pump with the engine running and don't see anything coming from the pump (looking down with the hood opened. It does look like the shop mechanic used sealant to seal the pump to the eng block. Are you sure there are two drains on the bottom of this motor. I hope it is like you said, that is, he forgot to tighten the drains. Otherwise, I'm not sure what it could be.

[caspergsx]

if your using a factory pump they use FIPG to seal it up ,, there is not a gasket ! unless your useing a aftermarket one ,, i bet it is the heater valve in the rear !

[eds92sc]

if your using a factory pump they use FIPG to seal it up ,, there is not a gasket ! unless your useing a aftermarket one ,, i bet it is the heater valve in the rear !

What do you think would be leaking on the heater valve? The o-ring on the tube going from the valve to the pump??

[eds92sc]

Well, I got the car back from the shop. They found coolant leaking between the eng block and the tranny. They dropped the tranny, and found coolant leaking from the "seal plate". They replaced the gasket and it hasnt leaked since. Does anyone know what this seal plate is? I drove the car home and found the check eng light and the trac light on. I took the car back, and they found a bad o2 sensor, and was able to reset the trac light. I hope everything else is ok after this. I already dumped over two grand into this car (between the busted timing belt and the exploded idler pulleys and the coolant leak). The car still drives really nice though.

[jzz30]

i believe the seal plate allows coolant flow from one side of the head to the other.