Changing the L water pump

[datzenmike]

Well my water pump is dripping and although this is a pain at least it isn't the rad nor is it happening in the rainy monsoon November. I'm about to change the anti freeze for the winter so maybe just as well. Every week or so I add a few cups of water but because it does not have a coolant recovery I figured it's fine. My wife had it overheat very slightly when the fan belt broke last week and this may have speeded up the problem. Finally found a gasket at NAPA this morning after three other places last night. I've made them from cereal boxes before but for a buck I got one.

 

There's many ways to do this but I removed the grill while the rad drained, removed the hose and hose clamps from the automatic coolant lines and lower rad hose and secured them out of the way. Next the upper hose which allows the two piece fan shroud to be removed in sections. Unbolt the rad and lift out. Loosen both lower alt bracket bolts and adjustment bolt and with slack remove the fan belt. Now we can start.

 

 

Remove fan retaining bolts from the clutch fan. Remove the two right side 12mm through bolts and the three 10mm bolts around the top and left side. The pump itself is centered on two alignment dowel pins and may require some tapping to loosen it. Because it will be replaced I didn't have to be careful and used a hammer.

 

The replacement (left) is from a '78 truck and is identical. Car and truck clutch fans appear to be the same. I cleaned any gasket material from it with a wire brush and also the cavity on the timing cover below.

 

 

The cavity is clean as a whistle with no corrosion or pitting from dissimilar metals in a close contact liquid environment. This is why you should always use a good anti freeze and change every two years. Notice the dowel is missing in the two o'clock position? I noticed at the last moment.

 

It came out with the old pump so I twisted it out with vice grips and tapped it into the 'new' pump.

 

 

 

Clean the bolts and holes. Install pump with new gasket. I don't recommend a sealer, Nissan didn't use it, you won't be able to take it apart in the future, you don't need it if the two surfaces are clean and it is the mark of a mechanic that doesn't trust his own work. My finger??? Well sometimes you stick them where you shouldn't. Some learn by being told some by experience....

 

 

Check the plastic blades for damage. Damage can lead to more costly damage and vibration. Another thing is to clear out the trapped dirt on the inner side.

 

 

 

 

 

The cause of the leak. On a pump it's almost always the seal. Pumps are made with a drain hole so the water can get out and presumably you will see it and do something about it. They don't usually go all at once. If there was no drain the water would eventually get into the bearing where it could seize it which is much worse. If you have a small water loss problem you can't find get a flash light and look up from the bottom for this hole. If it has a drip or signs of dried anti freeze the seal is starting to leak.

 

I am very happy. It was a beautiful day for working on my Datsun and because I try never to throw anything away this fix cost less than two dollars for a gasket that I could have made from a cereal box. :lol:

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[izzo]

double post fail mike hahahaha

 

[datzenmike]

lolz what a tool! I guess I edited it incorrectly. Poor friggin kittehs I'm rougher on them than Kami

[izzo]

lolz what a tool! I guess I edited it

 

 

Cool write up tho man, good stuff! I have a brand new water pump in my shed but am waiting to install it till i build that L20. The one in the goon is good, ill keep it as a spare tho.

[datzenmike]

The sedan is my wife's DD until the end of the month when I store it for the rainy season. (winter) I had a spare pump but didn't know for sure the fan blades would fit, being from a truck. I would have pulled the one from the goon if I had to but it fits just fine.

[650savag]

Great write-up Mike! Thanks for the step-by-step directions and the great pics. I have one that is starting to drip a little and this will save me a lots of time and misery, I'm sure, when I start on replacing my water pump. Thanks again for all your time and effort in helping all us shade-tree, "wanna-be", Datsun mechanics! ha! Louisiana Dan