'01 5SFE Repeated water pump failure

[bill buttermore]

Why would two new water pumps fail within 6 months/5000 miles?

Car is a 2001 Solara with a 5SFE four-cylinder engine. Six months ago the engine was completely rebuilt using a new Aisin water pump, oil pump, timing belt pulleys, timing belt, and tensioner spring. The belt tension seemed normal - not too tight or loose. But the new pump was leaking within 1500 miles. The pump was replaced with a new after-market pump (not Toyota). The new pump failed after another two months.

Is there any reason that any of you can think of, other than two defective pumps, that would cause two new water pumps to fail?

Thanks for any help.

[Frodo65]

Originally Posted by bill buttermore

Why would two new water pumps fail within 6 months/5000 miles?

Car is a 2001 Solara with a 5SFE four-cylinder engine. Six months ago the engine was completely rebuilt using a new Aisin water pump, oil pump, timing belt pulleys, timing belt, and tensioner spring. The belt tension seemed normal - not too tight or loose. But the new pump was leaking within 1500 miles. The pump was replaced with a new after-market pump (not Toyota). The new pump failed after another two months.

Is there any reason that any of you can think of, other than two defective pumps, that would cause two new water pumps to fail?

Thanks for any help.

• Issues with coolant, as in incorrect formulation or 'gritty' contamination, causing seal failure.
• Alignment issue with belt, creating excessive pressure on bearing, leading to seal failure.
• Excessive belt tension - from a tensioner incorrectly installed or 'bad'

What do you mean by 'completely rebuilt'? Like engine tear-down? Any chance that the replacement pulleys are not aligning correctly? If block was 'boiled' for a rebuild, any chance of contamination?

[bill buttermore]

Thanks for the reply, Frodo.

Originally Posted by Frodo65

• Issues with coolant, as in incorrect formulation or 'gritty' contamination, causing seal failure.
• Alignment issue with belt, creating excessive pressure on bearing, leading to seal failure.
• Excessive belt tension - from a tensioner incorrectly installed or 'bad'

What do you mean by 'completely rebuilt'? Like engine tear-down? Any chance that the replacement pulleys are not aligning correctly? If block was 'boiled' for a rebuild, any chance of contamination?

The cylinder head was completely rebuilt by Midwest Cylinder Head in Nevada, Ia. New engine parts include: pistons, rings, pins, oil pump, water pump, timing belt, tensioner pulley, idler pulley, crankshaft seals, cylinder head gasket, valve stem seals, valve cover gasket, oil pan gasket, camshaft seal, and all associated gaskets. Recently replaced by the previous owner: radiator, accessory drive belts, and radiator hoses.

Previous owner had cooling system drained and filled with fresh coolant when the radiator and hoses were replaced. When I rebuilt the engine I drained and filled the cooling system with fresh coolant. I did not observe any grit at all in the coolant I drained prior to the rebuild.

The cylinder head was professionally cleaned. Cooling passages in the block were flushed, and the cylinders and deck were carefully cleaned following honing. The block was not tanked, but there was no evidence of any crud or sludge buildup in the coolant passages. Coolant was completely replaced with new "mixes with any type/color."

No apparent alignment issues with belt and pulley, plus timing pulleys were new.

Tensioner pulley and spring were replaced when engine was overhauled. I did not measure the tension of the timing belt, but I have done several 5SFE rebuilds and the tension did not seem to be any different than any of the others I have done.

Edit: I suppose the heater core could have been a repository for contaminants. (?) I don't know if the previous owner flushed the heater core. I don't recall that I did. When the next pump is installed, I will recommend a complete cooling system flush.

[73sport]

I was going to say that some shops (after major overhauls) fill the system with water for the first fire off and leave it in for a couple hundred miles to check for leaks and what not.

This if fine if they add a lubricrant to the water to keep the seal alive. But pure water will trash a seal and burn it up. Is there any chance they did this? As it could lead to a latent failure down the road for the seal. . .

So my question is this: HOW excactly did the pump fail?

Were the bearings good but leaking coolant? Or were the bearings shot and binding up, maybe even squealing??

What was the failure mode? Not having the block tanked after honing leaves a huge grey area for particals to circulate. I mean that stuff will lay there like the cast iron itself!

Me, even after the shop is done with them I brew up the hottest batch of water and detergent and go over it again (not an option when the whole job is farmed out tho). Anyway, any machining process leaves tons of grit.

[carsrus]

Originally Posted by 73sport

But pure water will trash a seal and burn it up.

Ive never heard of this.

Ive ran straight water before and never had any issues.

[73sport]

Originally Posted by carsrus

Ive never heard of this.

Ive ran straight water before and never had any issues.

It doesn't take much to keep it alive. But pure water doesn't offer much lube to keep the seal from "catching" on the spinning shaft.

I'm just trying to throw out possibilites. . .

[bill buttermore]

Thanks for the ideas, guys. As I best remember, the only machine work done on the block was honing with a fine 3-stone hone saturated in kerosene. I lightly honed the cylinders and carefully cleaned the cylinders and the deck afterwards. I use soap and water and WD-40. I check for cleanliness by using a white lintless paper (coffee filter) dragged across the surfaces and checking for any particles. None of the kerosene (presumably with grit) made it into any of the coolant passages. I have rebuilt scores of engines including cars that I and my neighbors are currently driving and this is the first time I have encountered recurring water pump failure.

Re failure mode: The current owners said that the pump I installed with the rebuild failed by leaking coolant at a pretty good rate. I can't say whether the bearing failed or squealed as I was not there when it happened, but I may be able to find out from the current owners.

After the rebuild, the cooling system was filled with 50/50 coolant. I drove the car for about 300 miles to make sure everything was working right before delivering it to the new owners.

They would have had to at least drain and refill coolant to change the pump, but probably did not flush the system.

Of the possible causes of failure, I think that cooling system contamination seems like the most likely. I can't imagine contamination came from the block or head, though, as I handled those during the rebuild as I have handled others for years with no problems. I will recommend a complete cooling system flush (reverse flush) including the heater core when the pump is replaced again and hope that will resolve the problem.

Thanks again for the help.

[73sport]

This is a longshot but I'll toss it out there.

Any chance you live in a real cold place and at some point in time the anti-freeze froze? Specifically behind the water pump and cracked the block thus letting water into the bearing area?

I know its slim, but I don't think the alignment thing or some of the other ideas hold much merrit.

The simple thing is you had to defective pumps.

[bill buttermore]

Originally Posted by 73sport

This is a longshot but I'll toss it out there.

Any chance you live in a real cold place and at some point in time the anti-freeze froze? Specifically behind the water pump and cracked the block thus letting water into the bearing area?

I know its slim, but I don't think the alignment thing or some of the other ideas hold much merrit.

The simple thing is you had to defective pumps.

Thanks for the reply.

It got down to -17F here a couple of weeks ago, but that shouldn't be cold enough for 50/50 to freeze. And, I think the first pump failed before it got really cold. Maybe you are right and it is just two bad pumps. I will recommend that the new owners buy a OEM pump for $130, and do a good flush of the entire cooling system. With any luck at all, that should be the last time they need to worry about that pump.

[pronkie1]

On our 2000 Camry with a four cylinder in it,the water pump was leaking and Ventura Toyota replaced under warranty at just under 60k..While they did that they also did the timing belt.....Around 123k miles, the pump went out and caused the timing belt to slip ,hence a valve job was done by a local shop near our house...Car never seemed right as it sounded like a bunch rocks while at idle...After running the car this way for a year and hallf,took the car to Ventura Toyota and was informed that the sisicior gear was out of alignment and water pump was bad....So the car has 148k on it now and went through three water pumps and now on its fourth one......Just letting you know what we gone through with this car......

[JohnGD]

That's interesting, because Aisin is a Toyota OEM pump.

Originally Posted by bill buttermore

Thanks for the reply.

It got down to -17F here a couple of weeks ago, but that shouldn't be cold enough for 50/50 to freeze. And, I think the first pump failed before it got really cold. Maybe you are right and it is just two bad pumps. I will recommend that the new owners buy a OEM pump for $130, and do a good flush of the entire cooling system. With any luck at all, that should be the last time they need to worry about that pump.

[bill buttermore]

Originally Posted by JohnGD

That's interesting, because Aisin is a Toyota OEM pump.

Right, the current owners replaced the OEM pump I installed with an aftermarket pump. It also failed within a couple of months. I don't know of anything better to recommend at this point than a good reverse flush and a pump from the Toyota dealer, which will probably be another Aisin.

Thanks for the reply, John.