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Water Pump

Nearly two weeks ago, my engine overheated. I pulled off to the side of the road immediately to avoid damage to the motor. Opening the hood, I knew it was bad – there was no steam rising from the engine. I carefully removed the “radiator cap” (which is located on the coolant bottle, and not on the radiator), and the system was bone dry.

I called a friend to ask them to bring water. It poured out the bottom as fast as I poured it in. Not a good sign. It was getting dark and stormy, and all I could see was the water was comming out from below. I suspected the lower radiator hose had ruptured. I couldn’t move the car on my own, and it was turning into a dark and stormy night, so instead of having the car towed home, I decided to have it towed to Pep Boys, the only repair shop that was open. They also have a convenient arrangment with towing companies.

Why does the name Pep Boys remind me of hyperactive juviniles?

They diagnosed the problem as a failed water pump, and handed me an estimate for over $1000. That was too much for me. I was figuring on replacing a lower radiator hose and getting on with my evening, but they had other plans.

The water pump is driven by the (cam) timing belt. I’d replaced the two of them at 105,000 miles – the factory recommended service interval for the belt. So I’d done the job already, and was familiar with what it took to get it done. I bought a water pump, timing belt, and a timing belt tensioner pulley, and left the car overnight, as I couldn’t arrange for a tow truck anymore that night.

The next morning, another friend gave me a ride back to Pep Boys, and I arranged to have the car towed home. Disassembly went fairly fast, aided by a pneumatic ratchet wrench. By lunch time, the car was at “parade rest” (see photo above).

Reassembly is always more difficult. With this job, the challenge is to get the cam timing correct. The belt tensioner is also a bit of a pain. The belt tensioner is a hydraulic device, that pushes on that new pulley I bought. It has to be compressed and pinned. The pin is relatively small, though, and the tensioner tends to destroy the pin. I’ve used allen wrenches, and drill bits, and both will be destroyed in the process, bent or broken.

As the tensioner takes up the slack on the belt, it tends to move, disturbing the carefull alignment. You have to anticipate how the belt will move when tensioned, and compensate. And if you get it wrong, the computer will see the misalignment between the cam position sensor and the crank position sensor, and fail to allow the engine to start. This is probably a good thing, but it’s frustrating to diagnose. I got lucky this time.

Reassembly went fine, although I did have to reinstall the timing belt and tensioner twice to get things to line up the way they are supposed to. Then came time to add water, and it poured out as fast as it went in. Did I just replace the water pump for nothing?

This time I could see the water gushing from the side of the engine. Near the Thermostat housing where the lower radiator hose connects. I felt around, and it seemed like I had attached the lower radiator hose OK. It’s really hard to see that area. From the front, it’s blocked by the alternator. From underneath, it’s blocked by the oil filter. From up top and rear, it’s blocked by the exhaust manifold. So I removed the alternator for better access, put back the lower radiator hose, and filled with water.

No leaks! Evidently, I failed to get the lower radiator hose on correctly. Maintenance induced error. I put everything back together a final time, filled with water, and still no leaks. Good. Drove around with water in the cooling system for a few days just to make sure, then drained and filled with coolant (it seems a little rediculous to talk about antifreeze in Florida, but it lubricates things like the water pump, and keeps things from rusting, so it is necessary).

It’s been just over a week, and the car has worked fine. No overheating. No coolant leaks.  Success!