Changing your car's timing belt and water pump

I drive a '97 Mazda 626 - 4 cyl. Changing your timing belt is not a small task, and it will not be identical to your car (unless you drive a 4cyl 626, mx6 or ford probe with an FS series engine). I wrote this for my 626 community www.mazda626.net and I am copying things here (so some stuff might sound a bit off)....

Welcome my fellow auto DIYer. First, I commend you for taking on this task, I will rank this as one of the more difficult things in the realm of the 'shade tree' DIYer. The hardest thing to deal with is tight spaces, other than that the task is straitfoward for the most part

Step 1: Background Parts and Tools

First off, this is a non-interference engine design. That means that the lowest point that the valves reach is HIGHER than the highest point the piston can reach... A pretty nice idea because if your timing belt breaks for some reason, you'll avoid the cost of new valves and tearing down the head.

I did not have to replace my T-belt, my water pump died and because replacement involves removing the T-belt, I did so as a precaution.

Tools and Parts:

# New Timing Belt
# New (or reman) Water Pump
# Tensioner Spring
# Tensioner Pulley (if higher mileage)*
# Idler Pulley (If VERY high mileage) *
# VC Gasket*
# Gasket Scrapper
# Torque Wrench **
# Jack, Stands, Wood Blocks
# Black RTV sealant (I do not recommend "Ultra Black")
# Metric Allen/hex Key set (Or 1/4" - may require sanding to fit)
# Plastic Baggies and Sharpie
# Piece of Cardboard
# Feeler Gauge Set ***

*If you have the ability, wait and see if the old one is still good - I changed at 74K miles. My tensioner had play in the bearing but my idler was in great shape.
** Highly recommended.
*** Perfect time to check your valve clearance for you guys with solid lifters (98+)

The 93-97 model years used hydraulic lash adjustment (HLA) as opposed to solid lifters used in the 98-2002 design. Both work just fine, but HLA's can clog easily causing valve tap. Its just cosmetic and several frequent oil changes clear it up.

Comments

[smiley356]

Thank you for this article - it was a real life saver when I had misaligned the intake and exhaust cams during a timing belt change :-)

I've added a picture I found to be missing - it shows exactly how the I and E pip marks should match when cylinder one is at the top position.

I've also added a picture of a small tool I had to make in order to loosen the bolt on the crank - that one did cause me quite a bit of trouble. The hole in the center is approx. 30 mm to allow the 21mm top to grab the bolt while the tool holds the pulley in place. The two 8mm bolts fastening the tool to the pulley are approx. 20mm in length.

[Nimrod1109]

I have a Mazda 626 1997 I changed my water pump (before found this website) and the timing pulleys slipped (I didn't mark them) I tried to reline. The car will not start at all it makes a wierd hum noise. Could this be due to the fact the belt is not a lined or is it probably a different resin?

[mannys9130]

Seriously, this is a very important issue! If your timing belt slipped, it means the valves are not coordinated with the piston in travel. As you may be able to imagine, the piston will hit the valves, ruining both. Don't start it, and if you did, you probably screwed it up already. I wish you good luck and I hope the bill is not too expensive (though I fear it will be). The easiest way to realign would be to take the plugs out of the cylinders. Put something soft like a straight stick in a hole so it rests on the piston. Take the valve covers off. Now, using a screwdriver, slowly turn over the engine so that the piston is at the top of the cylinder. If the piston is at the top of the cylinder, PAY ATTENTION TO THE VALVES. If the valves are opened, you will damage the engine. You need the piston to be at the top with no valves opening, getting ready to open, or being open. No rockers should be moving above that cylinder! After you have the piston to the top of the compression stroke, and you know it is the correct stroke as verified by the points on a distributer or another method, you can fix the valves to be closed fully over that cylinder and then reattach the timing belt. So the piston will be at the top of the cylinder, end of it's compression stroke, and the valves are all closed with the points connected ready to fire the spark plug. This should align the belt again. Like I said, the engine is most likely messed up if you started it anyway and will require work and rebuilding of the pistons and valves. Hope it helps. I am not responsible for what you do with my advice :) *I think this is a good method, correct and all. I am sure someone will chime in to say it is flawed if it is*

[mitchell12]

I know this is a way late comment but not all cars will bend their valves and such when a timing belt slips or breaks.

I believe they are designated "interference and non interference" engines. In Certain engines like the older mazda 1.6l if your belt breaks or slips your car won't run but it won't damage anything.

[trebuchet03]

Point 1: Screw Driver trick - do it for cylinder # 1 Point 2: The FS engine is non interference. By design, the piston can never hit any valve while in any position. If you were to take apart the engine and look at the piston design, you'll find relief cuts in the top of the piston to allow valve clearance. Point 3: Add some space to your replies - it makes them much easier to read ;)

[A-Nuke1979]

I know I'm chiming in late, but...
I just replaced the timing belt and water pump on my Honda Pilot (3.5l VTEC). Anyone getting ready to save money by doing this themselves should be warned - the crankshaft pulley bolt does NOT want to come off! I discovered that Honda's use some type of metal or coating on the thick washer behind that bolt that essentially fuses itself to the crankshaft over time. I had to heat mine with a propane torch for about 10 minutes before I could get it to budge. Even then, I was using some pretty serious leverage to get enough tourque on the bolt. Bottom line= heat the bolt and washer before you start wasting your energy trying that bolt.

P.S. The special Honda tool sold to keep the pulley in place was useless to me. I just wedged the flywheel as suggested by Chilton's.

Hope this saves someone else some time/frustration/pain/cursing, etc...

[Yerboogieman]

Mazda needs to use Rotary engines in more cars.

[Swishercutter]

Very few places can properly work on the internals of the rotary engines...apex seals are the main issue I have been told. That being said I think the rotary should be used much more. Not sure why Mazda decided that the new "Renesis" Rotary they are using in the RX-8 didn't need a turbo but whatever.

[Yerboogieman]

You can turbocharge them but they are high compression engines and you risk blowing a seal. They are pretty straight forward to rip apart and put back together though.

[Swishercutter]

Exactly, very simple...except aligning the apex seals. That is where people usually have troubles.

[Yerboogieman]

No, not really. Just making sure there is enough clearance on each side and aligning the side seals, which isn't very hard.

[Tobita]

One of my cousins in Saudi Arabia owns a garage that tunes cars and he received a mazda and told the owner " OK, I'll get it done in a few weeks" he then opens the hood and looks up at the owner and says "What the hell is that? I can't do anything to that!" End of story, just goes to show, rotary engines are not very popular in saudi arabia:P

[mm23]

do you know of any website that can provide a picture of this step, or can you send me a pic. I am currently trying to replace the timing belt myself since its expensive for me as a college kid to have it fixed.

[codym]

how long does it take to replace the water pump and the 2 belts? im taking it to a garage cause i cant get it fixed and liked to know how much id be looking at spending. its 35 an hr i heard it takes about 3 hours for a skilled mechanic. please help me out thank you

[trebuchet03]

Mechanics do jobs "by the book" - there's literally a book stating how long  job takes (for billing and etc.). So if a mechanic can finish a "1 hour" job in 30 minutes - they'll charge for one hour plus materials and applicable disposal fees.

I don't actually know what the official time is... But $35/hr is cheap :p

[automd]

Yeah I agree. 35 bucks an hour is pretty cheap compared to the rates of other mechanics. I had my water pump and belts replaced and the mechanic charged me $45 an hour. It took him two and a half hours.

[deemax]

Haha I got in to look at my PS belt because it was squeaking, thought I would just simply tighten it up. When I got in there I found that my tensioner "bolt in question" that you show was completely missing..

[byardmech]

First, this is an oustanding page. I have a Mazda 626 '96 in which I am removing the head and many of the tasks you mention are ones I am encountering. Your pictures are much clearer than those in my Hanes manual. BTW is 96 4 cyl 626 also a non-inteferece model?

[byardmech]

Cool. Thanks for the reply! Still love your website!!

[heartlessangel7]

Yeah, same engine sir.

[trebuchet03]

Thanks :) All of the FS series engines are non-interference ;) Which means yes, your engine is non interference. The same goes for the 6cyl KL-DE engines with one exception. If you don't keep up on maintenance and allow carbon build up - the tolerances are high enough that carbon build up can cause piston - valve interference.

[heartlessangel7]

TY 4 the instructable. I'm banging my head against the wall with my '96 Ford Probe SE. I got the timing belt slightly misaligned and have to go try again.

[Body4Change.com]

I enjoyed your instructable. I referenced to it when I changed the waterpump on my girlfriend's 96 4 cyl. 626. Unfortunately, after changing it all out and putting it back together, discovered that it had a blown head gasket. I fixed that, but in the process, had to take out the distributor out to remove the remove the exhaust manifold heat shield. Now I have to adjust the idle speed and ignition timing. The online autozone manual and other sources online say to first disconnect the "spout connector" from the "shorting bar." I can't find them. They say that it is close the battery on the negative side and even have a diagrammed picture of it but it doesn't give me an idea of where it is exactly. They also say it has a green and yellow wire. I tried all of the connections and none have those two wires or look even somewhat similar. This seems to be a common question but nobody has a picture showing where it is at. Any help will be appreciated!

[neb6]

This was a great walk through. I really appreciate the extra mile. My brothers water pump was not bolted up to the block as the idler pulley bolt was too long. Anyway, when it came time to dial in the cam-shafts, I took the ends of a spark-plug box and inserted them under the first set of bearing caps to hold the alignment. Just being careful not to overtighten the caps. While this held the cams I pulled the #1 plug and used a long screwdriver to judge top dead center. Also pull the distributor cap to make sure the rotor bug is pointing at the #1 in the firing order. The bottom line is it is worth the performance increase to get the cams truly aligned. Thanks again. I couldn't have done it without you all. Benny aka neb6

[buhdieboy]

no irreverance intended but sulfer dioxide ( combustion gas) can cause the water to turn this color fast and thats useually a leaky headgasket at first", friends this color is always presant when some leakage ( combustion presures are high) is my plymouth has that color and my temp had is constantly swinging back and forth go figgure

[leebryuk]

Nice job. I'm never post my car stuff. Once I get going I can't stop. And I don't want to get my camera dirty. Keep up the good work.

[gwfraser]

Thank you for the information, well documented, nice work. GWfraser

[candle360]

very, very nice, but I personaly do not like newer cars, as you probably found out, because of all of the damn wiring, sensors, and shit.... its annoying, my truck's a 1965 and i dont have to worry about all those sensors, like the crank sensor, all that other crap

[home mech]

[fattball]

ok im going to try this myself tommorow 1st ill try just the alternator belt but i think my water pum is broken but we shall see

[trebuchet03]

Probably too late -- but... when the bearing (most likely to fail) inside the water pump goes bad -- it will start leaking (by design) from a weep hole on the pump. If you see water/coolant on the outside of the pump -- its time to change.