James Mackintosh 14 years ago

How To: Replace Your Water Pump In A Few Easy Steps

Remind me later

So recently, it came to my attention that my water pump on my '88 Saab 900 SPG was going bad. It wasn't exactly a difficult diagnosis.  The car was leaking coolant like a sieve, it was trying it's damnedest to overheat at every given opportunity, and the pump itself was making an awful grinding noise, much like an innocent clunker's crankcase being filled with sodium silicate mixture.

Now, like any sane person, I went and got an estimate on getting someone who knew what the hell they were doing to replace the water pump, from my friendly neighborhood eccentric Saab mechanic.  He quoted me two hours labor ($160) plus the pump ($129) and coolant ($35.)  Total cost: about $325, give or take.  Me being a notorious cheapskate, as well as being somewhat mechanically inclined, decided I'd look into what's involved in replacing it yourself.  This turned into a two-day long project that drained every ounce of energy from my mortal coil.  So we'll present the meaning before the lesson here:  there are upsides to DIY labor.  And boy, are there downsides.

My first step in my waterpump replacement journey was to the The Saab Site's 900 FAQ's Page, perhaps the be-all-end-all resource for hopeless 900 lovers such as myself.  If you have a Saab question, chances are The Saab Site's FAQs pages have the answer.  If they don't, perhaps God does.  Anyway, the FAQ's presented what seemed like an easy 5-step process for water pump removal on the updated Saab "H" engine.

coolant expansion tank

History lesson - the "H" was a revision of the "B" engine that originally powered the 900's predecessor, the 99.  One of the major changes to the "H" engine, which centered around simplification and weight reduction, was a change from a jackshaft-driven water pump (ugh) to a pulley-driven water pump powered by the crank.

Here's what The Saab Site had to say about how to remove your water pump.

"Step 1: Remove the belt off the AC compressor.  Remove or loosen the 4 10mm bolts in the water pump pulley. Step 2: Remove the alternator belts.  You will want to remove the 18mm nut on the back of the alternator adjusting screw and remove the adjusting screw to pull the alternator over to the compressor bracket to facilitate removal of the belts. Step 3: Now that you have the belts and pulley off, remove the 6 12mm bolts from the water pump and push down on it from the top to remove.  There are guys that say removing the compressor makes this job easier and they would be correct.  I just use a razor blade and a mirror with a light.  I remove the old gasket that way.  Be careful if you decide to use a wiz wheel as you can groove the timing cover when trying to clean the gasket. Step 4: I use copper gasket spray to make the water pump gasket seal to the water pump and timing cover. Step 5: Refit in reverse order."


See? That doesn't sound so hard.  Admit it.  You'd be tempted to save the $160 in labor and do it yourself too!  After contemplating for a bit, and listening to  my water pump grind itself to death, I decided I was going to do it myself.  Here's my step-by-step guide to replacing the water pump.  I find it to be a bit more accurate.

Step 1: Acquire Parts. I sourced a brand new OEM water pump from CarQuest (I know, right?) for $61, including gasket.  I also picked up a small tube of Loc-Tite 518 Anaerobic Gasket Maker (great stuff) for about $5, and a gallon of Mercedes-Benz coolant for $22.  Total parts outlay: $88.  Sounds a bit better than $325 when you're a broke cheapskate like me.

Step 2: Stare At The Engine For a Few Minutes.  Sometimes staring at something helps you to figure it out.  Sometimes it doesn't.

Step 3: Remove A/C Compressor From Bracket. The A/C compressor sits on the top of the engine at the back, directly above the water pump.  It's a huge heavy thing held to the bracket by four bolts.  Of course, being a Saab, two of the nuts that secure these bolts are nearly inaccessible.  Also, the front right bolt won't come out of the bracket without removing the entire intake manifold, as when you push it out of the bracket the head runs into intake runner number four.  Adorable.  Spend a good while trying to figure out how to get that bolt out, then realize that you can simply slide the compressor off the bracket with three of them loose and the nut off.  Problem solved.

EVIL A/C Compressor.  Evil.

Step 4: Drop a Bolt. And watch it disappear into the black hole that is a Saab 900 engine bay.  This was not a one-time occurence.  Bolts, nuts, washers - they'd all disappear, never to be seen again.  Very irritating.

Step 5: Remove Some Belts. Actually, remove all the belts.  Remove the wide single belt that runs around the A/C compressor, idler pulley, and crank pulley.  Also remove the twin drive belts that run around the alternator, water pump pulley, and outter ring of the crank pulley.

Step 6: Remove Water Pump Pulley - held on by 4 10mm bolts.

Step 7: Drop 2 of Those Bolts - of course!  Then jack up the right front corner of the car, and search underneath with a flashlight for 20 minutes to find the part of the wiring loom they got stuck in.

Step 8: Remove Water Pump - actually the easiest part of this whole job!  6 12mm bolts (drop one!) and a little downward force, and that sucker is out.  Upon observation, there's a large amount of shaft play in the pump and the gasket is completely shot.  Take a look at this:

Shot water pump gasket

Step 9: Remove Gasket On Block - sounds simple, right?  Well, except that since the water pump faces the firewall, and it's under the massive A/C compressor bracket, you can't actually see the gasket mating surface on the block.  So you're forced to hold a mirror against the firewall, with a shop light above it to provide light while you slowly scrape gasket off of the block with a straight razor.  Of course, since you're guiding your hand by the mirror, everything's backwards.  Fun.

Step 10: Seal Gasket to Pump: using Loctite 518 Anaerobic sealant, which is some truly nasty stuff.  Wipe off the excess.  Spend 10 minutes removing the rest of it from your hands with Gojo to get it off.  After all, it's gasket maker.

Step 11: Replace Pump. The core of the job is usually the easiest part.  This is the case here.  It literally just slides in and you tighten down the 6 bolts.  If only the rest was this easy...

Step 12: Wonder How All Those Belts And Pulleys Go Back On. This is the part where you wonder out loud why you didn't label parts or take pictures with a digital camera to remember how these things go back together.  Why is hindsight always 20/20?  You'd be confused, too.  Look at this mess.

Saab 900 accessory drive belts

Step 13: Replace Belts.  Well, try to anyway.  Note that the belt off the idler pulley is stuck on something on the bottom side of the car.  Jack up the front corner again to investigate.  Become completely befuddled when you notice it's stuck between a bolt head and a bushing.  Tug at belt in 6 different directions for 20 or 30 minutes before realizing the bushing is part of the shift linkage.  Shift the gearbox into neutral, free the belt, feel stupid.

Step 14: How the F*(& Does This Belt Go Back On? By this point, it's going on half past ten at night.  Ponder aloud how the belt is supposed to go back on the pulleys since there's not nearly enough flex in it, and it's about an inch short of stretching around the idler pulley.

Step 15: Remove A/C Compressor From Bracket.  AGAIN. Realize that the belt needs to go on the A/C compressor pulley before you bolt the compressor down.

awful compressor bracket bolts.  awful.

Step 16: Drop Another Bolt. Of course.

Step 17: Get Everything Bolted Back Together, Top Off Coolant Tank With Water, Start Car. Observe awful whining noise coming from the belt area that sounds like a cat being sucked through a Dyson.  Turn car off.  Yell expletives in an angry tone.  Give up for the night, hitch a ride back to your apartment and feel dejected at failing to accomplish a seemingly "easy" task in almost 12 hours of labor.  Why fill the coolant tank with water?  Well, you don't know if it's going to leak or not when you fire it up.  Mercedes-Benz coolant is $22 a gallon.  Do you want to risk spraying it all over the ground?

Step 18: Start Again The Next Day.  At 9am.  When You Have Work At 3. There's nothing like needing your car to work so you can get to your job so you don't get fired to motivate you to finish fixing it, and quickly.  Works every time.

Step 19: Diagnose Problems. As it turns out, I'd screwed up two separate things with the belts.  For one thing, I put that static idler pulley on backwards. I know, I should get an award.  Also, the twin drive belts that go around the alternator/water pump/crank pulley had skipped a row on the bottom, so the outer belt was on the inner groove on the crank pulley, and the inner belt was... wedged in between the block and the pulley.  This mean pulling the compressor again, pulling all the pulleys again, and reassembling everything again. Hey, it's more experience, right?

Step 20: Drain Water. We actually started this the night before, but were too tired for it to really work.  For one thing, I had no trouble finding the coolant drain plug on the block, but we searched for a good 20 minutes under the car and couldn't find the radiator drain plug.  Sneaky little bastard.

there's the drain plug!

Step 21: Fill With Coolant, Run and Check things. Mix the Benz coolant and water 50/50, slowly pour in, check for leaks, and you're good to go.

See?  That' wasn't so hard.  And to imagine they wanted to charge me two hours of labor!  What a rip off. No, but seriously: result.  No more waterfall of spewing coolant when the car's running!

pump7 So while it might've taken a bit longer than originally estimated, I feel like I'm better off.  Every time you do stuff like this, you learn more about your car - and you save money.  The problem is, the more you do the more you're comfortable doing - it becomes addictive.  In other words, look out for more DIY articles.