Monday, April 18, 2011

Truck Work - Water pump replacement

My truck had been squealing for a while. I think it is rather coincidental that I have had it for 12 years and it never squealed once, but I take it to get it inspected and it starts squealing as soon as I start it up to leave. I really think they screwed something up, but I don't have any way to prove it.

Anyway, I thought it was the belt, but everything looked fine. But I did notice a small spot that looked like some fluid was slung against the side. When I watched it running, I couldn't find anything leaking, but the fan pulley was moving forward and backward. It's not supposed to do that, and I could wiggle it, so I knew a bearing was going out. A friend mentioned that the water pump is behind that pulley, so what I saw slung out was coolant.

I kept meaning to do something about it, but wasn't too worried about it. It only squealed when starting, and it wasn't leaking much water. As long as it didn't overheat, it could wait a bit. Of course, I know better. A bearing is one of those things that gets exponentially worse. Once it fails at all, that failure makes the rest of it fail, and it cascades.

Anyway, I went to Lowe's and when I got out, I smelled radiator fluid. You know, that standard smell you get when a hose is leaking or something. I popped the hood and there was coolant all over the engine cavity. I didn't drive far, so I guess it didn't get hot enough to send up a steaming cloud. It was the last straw. I used the garden center's hose to top off the radiator and headed home, knowing I really couldn't risk driving it again unless I got it fixed. And that could be bad. I was hoping the bearing would be easy to get to and replace once I got the fan off, because it looked like the water pump was probably inside the engine block.

Luckily, I was wrong. The water pump isn't mounted to the engine like most things are. Most of the stuff, like your alternator and air conditioner compressor, are mounted on flanges and such and just attached to your engine. The water pump is much more integrated. In fact, when you replace it, you are really only replacing half of what you would normally consider a pump. Normally, you have a case with water going in one port, out another port, and the impeller somewhere in the middle. But the water pump on the truck (at least mine) is only the front half of that case. The back half is molded into the block (I think). So when you take it off, the impeller is exposed.

Anyway, here are some tips if you have to work on it.

First, there is a special tool called a fan clutch wrench. It can be used to go across the bolts on the pulley to hold it still while you loosen the nut holding the fan on. Don't bother renting it from AutoZone if you have a 1999 dodge ram. It's just a tad too small, and won't fit.

The other method my repair manual suggests is to just use a pry bar between two of the bolt heads. I originally didn't want to go this route, because jury-rigging things like that tends to be a pain in the butt, and I always end up banging my knuckles a few times before I find a good solid pry spot with the right leverage. Plus, the tool rental from AutoZone is free as long as you return it, so I figured that was the best bet. But honestly, the prying was MUCH easier than I expected. You have to stick your own bolts through the holes in the pulley, at least for me. The manual says they are there, and even talks later on about removing them, but I just had four holes. But once you get the bolts in (you don't need nuts or anything) and wedge it with, in my case, a screwdriver, the nut comes off very easily. I guess it makes sense. It is held on and tightened by the motor turning, so it really only has to be tight enough that it doesn't come unscrewed when you turn off the motor. Oh, and you're going to need a large wrench. The repair manual says 33mm, but my caliper says 36+. AutoZone didn't have even a 33, much less a 36, so I bought a big 1-1/2 inch Kobalt crescent wrench from Lowe's. I had never noticed one with a scale on it before, but this one had one and it said 36mm as well when I tightened it down on the nut..

So, I got the fan off. The only hard part really was trying to reach around the fan shroud. They really should have made that thing two piece. Either cut the whole thing in half, or at least give a removable piece on top. I almost did it myself with the sawzall, but I didn't want to make another trip to Lowe's for the mending brackets, bolts, and lock nuts I was going to use to reassemble the pieces.

Once the fan was off, it wasn't a big deal to get the bolts out of the water pump. I did have to stick a screwdriver in the output port to pull it off the block though. And when I did, a good portion of gasket was still on the block. I took the pump to AutoZone to see if they had bearing kits or anything. They said it could be rebuilt, but not with parts they sold, so I just bought a new one. It came with the pulley attached, so I didn't have to get that off. It also came with a piece that screws in and that the "by-pass" hose clamps to. The guy in the store didn't think it did, and they didn't sell that piece, so I spent 15 minutes on their counter trying to get it loose with a pipe wrench. I had decided I'd have to take it home and soak it in WD-40 overnight and was looking in the box to make sure a gasket was there and saw the pipe in the gasket bag. I should have checked that first, I suppose. It even had the o-ring that the heater pipe needs.

So, I bought Blue RTV stuff and the pump, and headed home. Before I could install it, I had to get the old gasket off. I scraped quite a bit off with a putty knife. And actually, in all honesty, I probably could have left the rest since I was going to use the Blue RTV stuff anyway. But, I decided I wanted it all off. I tried using the putty knife as a scraper, but was scraping metal as well. I tried a wire brush, but couldn't get into all of the spots or even reach the ones I could get very well. So I put a wire brush on the dremel (knock-off) I have. It worked, but was slow, and ate up the entire wire brush. I finally put a sanding "flap-disk" on it, and that did the trick. I didn't try it first because I thought it would be too aggressive. But I figured if I was careful I could keep from screwing anything up, and the gasket sealer would fill any gouges. But I was worried needlessly. I suppose the flap wheel could have screwed it up, but it seems to me you would have had to have been trying to screw it up. It did round some of the corners a little, but it's not crucial that they stay perfectly square, so I'm not worried about it.

So then it was time to install it. The only problem I had was getting that by-pass hose hooked up. You can only reach about a half inch of it, so there's nothing you can grab to push it on. And what little space you do have is taken up by the constant-tension clamp you are trying to hold open with your only free hand. The way I ended up doing it was getting my daughter to hold the clamp open while I wiggled the pump all over the place while shoving the pipe into the hose. I may have been able to do it one handed, but it would have taken longer, and I had already put the RTV on both sides of the gasket and such.

After that, it was just a matter of tightening down the bolts and putting the fan, fan shroud, and belt back on. A note about the bolts; they aren't all the same size. I normally don't worry about it. I've always been able to put anything back together once I've pulled it apart, but I took care this time anyway; I am getting older after all. There is one bolt in the top center that is different from all the rest. It has a hex head, but it also has a center socket. I think this is because it is lower than the top of the pulley on the pump; the center socket clears the pulley, but the bottom of the hex head doesn't. (I used a ratchet and socket to loosen it, then an allen wrench to get it out the rest of the way. Same thing in reverse to install it, since I couldn't get enough leverage with the allen wrench to use just that.) I used this bolt as a marker. I knew I could remember where it went, so I laid all of the bolts out starting at that one and going counter-clockwise around the pump. That way I would know where each bolt went by using that odd bolt as a reference point.

I filled the radiator and overflow container with water, started it up, and everything worked. No squealing and no water leakage. I'll take it someplace this week probably and get the radiator flushed. It's supposed to be done every 2 years, and I'm not positive I've even done it once in the 12 years I've owned it. I do know that the coolant was a very nasty brown color, and that there is apparently enough sludge on the bottom of the radiator that fluid wouldn't even come out of the valve when I opened it initially; I had to take the lower hose loose to drain it.

Oh, one more thing. The fan has a viscous clutch on it. According to the manual, the silicon in the clutch could screw up the bearing if you store it flat. So if you do like I did and disassemble one day and reassemble the next, stand the fan against something instead of laying it down.

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