I thought I post a little write-up of my timing belt change experience since there don't seem to be too many posts specific for the V6...
So, I bought a 1996(?) Bongo V6 last year. Slightly dented all around but all mechanical parts doing really well (bought it from a young mechanic. Best possible pre-owner). 200k on the clock…. and the timing belt last changed at 94k - in 2002… oooh, this would need to be addressed eventually and a couple of weeks ago I did.
Have I mentioned yet that I’m a moron? Well, this will come up a few times in the following…
Bought a new belt from the local Mazda dealer, signed up to this forum, downloaded the Factsheet, found lots of posts saying “don’t do it”, got a universal pulley holder and started.
All of the following is my personal experience with this - your mileage will vary.
- Preparatory work:
If you don’t have a workshop with a pit, find some good solid stands and jack the Bongo up, I did 90+% of the work from below (and it was often quite confined) with the Bongo jacked up on the original jack on one side and then additionally supported with a stand, should the jack fail at some point.
I didn’t remove the “bridge” with the auto selector etc. above the engine - didn’t need to, but it’s not a lot of work and might give you more light etc. - but having it there came in handy at some point (for me)
Disconnect the (+) battery terminals. Drain the coolant into a clean bucket - you can use that again if it still looks ok.
Remove the bottom plastic engine cover(s)
- Getting to the belt
Before you start with the stuff below, check if you can actually undo the crank pulley bolt (you’l likely need the pulley holder here). Even though it’s supposedly only tensioned with 150-180 Nm mine was a real pain to open. I even gave up once and put all back together until a friend suggested the rattle gun and a bit of heat which eventually did the trick.
Remove the distributor cap and distributor (good to mark the position of the distributor)
Remember/mark the direction of the aircon and alternator belts and remove them - maybe loosen the water pump pulley bolts with the belt still on if you’re not using one of those magic rattle guns.
(if you’re dumb as me you wonder how to remove the belts - and put them back on eventually since the tensioner springs are bloody hard. What I found out (eventually!! This took me a felt 2 hours! First time working on a car + being a moron is not a good combo) is that the tensioner pulley bolts make great levers (with a ratchet/wrench on them) to gently and easily undo (and redo) the belts)
Remove the tensioners - here I had an unexpected problem since the alternator belt tensioner would. not. com. off. I think it is only held by one bolt (and probably sitting on something snugly) but I couldn’t move it and damaged it a fair bit (cosmetic I hope) trying to remove it, but no luck. Unfortunately, there is one of the numerous bolts holding the timing belt cover occluded by that tensioner. I got around this by loosening the entire subassembly (what’s the proper word for it?) the alternator, tensioner and steering hydraulic pump is mounted on. That is actually quite easy, undo the connectors to the alternator, remove the alternator, then you’ll see three bolts going into the left (seen from the front of the engine, looking towards the back of the bongo) side of the engine block, one bolt into a support strut and there is a fifth bolt all the way on top, best accessed from the driver side seat (which is coincidentally on the right, correct side {we’re in japan}). I just loosened this fifth bolt a bit and completely undid the other four. Then you can swing out the “subassembly” enough for it to clear the bolt under the tensioner. I also supported the whole thing with a strap around the bridge above the engine, just in case, since I didn’t want to compromise the hydraulic lines going to the hydraulic steering pump.
This might actually be a necessary step anyway - but since I don’t have the shop manual I am not so sure this is the proper way to do it.
Remove the water pump pulley. Remove the crank pulley. Undo the bolts holding the oil-dipstick. Remove the coolant hose to the thermostat, undo the other big coolant hose there.
Remove the timing belt covers. There are loads of bolts holding these - and they are almost all different in length, so MARK THEM SO YOU KNOW WHICH ONE BELONGS WHERE (I didn’t (did I mention that I’m a moron?)).
The next steps of removing and replacing the timing belt are described quite well in the factsheet/shop manual. At this point it turned out to be quite good to have the alternator etc. subassembly swung aside a bit because otherwise I wouldn’t have been able to remove the auto-tensioner - I think. Could’ve missed something there…?
The factsheet/manual calls for a hydraulic press to compress the auto tensioner - I didn’t have one and did that in a vice (a piece of wood either end) and that worked - just. To lock the tensioner bolt I used a nail - since I didn’t have the original lock pin anymore. Worked.
Also, when putting the new belt back on it was a bit of a pain that at least one of the cams would always jump a bit off its mark when mounting the idle pulley - so I had to do this a few times until I eventually counted the number of teeth on the belt in-between the marks on the cams in the correct position (20 - might be different for you), and then made sure that that was correct before I fit the idle pulley the next time. That did help me.
… and then put it all back. Careful with the coolant. But you knew that.
The whole thing took me 4 days of 4-6h a day, including hours of testing the echo (we’re in a small valley and invariably the echo of my shouts of joy would sound like “sucker” or something like that), a few trips to the shop and hours of mulling over the next step…
I probably wouldn’t do it again a first time but now it feels like it was nothing…
The old belt looked absolutely pristine btw.
