Generation Specific > Other Car Projects (Non-Rotary)

The rest of the fleet...

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toplessFC3Sman:
Well, Kaylee hasn't been quite as trouble-free as I thought... There has been a persistent oil smell in the cabin since I got home, and finding the source of that sent me down the rabbit-hole. On the drive home I didn't notice it at all, but I had spent an hour in the car with my mask on driving it from the airport with the salesman so I may have acclimated without noticing. Then of course, I picked up the old transmission, driveshaft, and rear end from the RX-7 to bring out to MI, so any oil smell was easily dismissed as coming from them.

However, that smell lingered for at least a month, and got me worried about something else burning oil. I couldn't find any signs of external leaks hitting the exhaust or manifold from the engine, trans, driveaxle boots etc, but there did seem to be very strong air pulsations out of the oil cap - more than enough to pop the cap off if it was sitting loosely on the fill hole. The pulsations seemed to line up with the frequency of one cylinder as well. Typically, this is due to high blow-by and possibly a failed PCV. A cold compression test gave about 140 - 145 psi across the board, so there weren't any stand-out cylinders - all were low. Hot compression was about 150-155, so a bit better, but the range for this engine is 134 - 192 psi so I'm still at the low end. Even more telling is that hot compression with a bit of oil poured into the cylinders to help the rings seal was around 180 psi. Well... crap. Not terrible, still within specs, but not great either.

Anyway, to try to get to the bottom of things, I picked up a cheap bore-scope that's basically a tiny camera & lights that plug into your phone for about $25. The quality so far is about as good as other bore-scopes that I've used, and the very stiff cable allows some ability to point it in a certain direction. Anyway, for the most part the bores looked good, with notable cross-hatching on all of them. The most wear that I could see was on the thrust-side of Cyl 3, where you can see a number of vertical lines, but none of them appeared very deep - I couldn't see any shadows but again it's hard to tell. In this picture, the piston top has some MMO on it since I had been soaking the engine for about a week to see if I could free up any stuck rings.
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I also used some PB-blaster to soak the rings for a day or so, followed by an oil change to see if that'd help the rings seal any better. Changing the PCV required removing the intake manifold which was a bit of a task, with a few of the bolts requiring blindly feeling around with a combination of extensions through holes in the manifold. It was a four-hour job, with a lot of that from unfamiliarity.


Once I got down to the PCV it appeared to be working fine, and all the hoses and other connections were not blocked. There was a bit of oily residue on the inside of the manifold and ports, but that's expected with EGR and the PCV connected. The intake and cylinders got sea-foamed shortly after reassembly to try to clean things up, and the MAF and throttle were cleaned independently.


All the time she's been driving fine, and I haven't noticed any changes in performance from the driver's seat. I did a bunch of cleaning in the interior (it was already very clean, with the carpets appearing almost new and only a couple minor stains on some of the seats). For a while, you couldn't smell much over the vinegar and lemon smells, but baking soda sprinkled on the seats and left in an open container seems to be absorbing most of the smells. So far, the oil smell seems to have mostly gone away, but I haven't driven Kaylee very far since then or done much highway driving. All the cleaning and soaking of the rings seem to have helped a little - the compression pressure increased another 5 psi or so since the last warm test, so we'll see how things go on that front. Worst-case scenario, new engines for these are $500 - $700, so that'll probably be the way I'd go for minimal down-time instead of rebuilding and reinstalling the current engine.

Otherwise, two of the tires are pretty worn, and one of the ones that still had a bit of tread depth just developed a nice sidewall bubble, so it's time to get a set of 17" summer wheels & tires, with the OEM 16" wheels pulling winter duty. I got a set of 17" x 7" OEM Mazda 6 wheels for $80, and one of them was cracked so a good junkyard replacement was $50, so $130 for the new set. A few cans of paint later, and...


It's a bronze/gunmetal color that should hide dirt and brake dust pretty well. I kind-of wanted to go with a brighter gold, but couldn't find a specific color that I liked. The greens that I've been using for the RX-8 and the Saab before would clash terribly with the red paint, so those were out. The tires that came on the wheels are shot, so new tires are getting installed later this week (and I didn't bother to mask the old ones since they were getting tossed anyway).

~Groll69~:
the rims turned out well.  glad you got some improvements out of the engine. and it puts you mid way on the compression so that is a bonus.

toplessFC3Sman:
After another week, and the oil smell does not seem to be coming back. Additionally, unscrewing the oil cap and trying to pull it out while the engine is idling shows that there is now a vacuum in the crankcase too, which indicates that the blowby issue has disappeared! The compression pressure seems to be about the same, roughly 155 psi when warm, so I don't know if that's going to improve any further, but the crankcase vacuum is still very encouraging.

Additionally, the "new" used Mazda 6 wheels now have tires and are installed (although Discount Tire really screwed up the fresh paint on them - they handled the painted winter wheels for two other cars fine, but these got really beat up), the brake system is flushed, and I went through the various plastic panels and heat shields to add foam and other sound-deadening material. At this point, Kaylee is feeling like a new car!

toplessFC3Sman:
When swapping the summer wheels back on a few months ago, I noticed that one of the rear shocks was leaking badly and the rest all seemed a bit soft at the very least- it looks like they were all still OEM parts at ~122k miles. Anyway, they all got replaced with Bilstein B4 shocks - slightly stiffer than new OEM but still appropriate for stock spring rates & ride height. They were notably stiffer and more controlled than the worn out shocks that were there before, but still provide a good ride. At the same time, I greased up the bottoms of the front springs and both sides of the rears where there was a little bit of abrasion, slid some fuel injection hose over a coil, and reinstalled into new mounts. This should better protect the ends of the springs and slightly increase the ride height (maybe 1/4" in front, 1/2" in back with two hoses) so that the van is a little more level when loaded up with a cargo carrier hanging off the rear rack.

To avoid messing around with spring compressors when replacing the front struts (those things scare me a bit), I was using a jack under the lower control arm and the knuckle to gradually relieve the spring compression to disassemble it from the worn out strut (with the jack & LCA constraining the bottom end of the strut so it wouldn't fly apart when unscrewing the nut on the shock shaft), and then doing the reverse using the jack to re-compress the spring until the shock shaft pokes through the upper mount and I can get the nut onto it. On some cars (my previous Saab 9-3's for example), this can all be done without removing the driveshafts, but the Mazda5 required the the LCA and knuckle to swing down further, which pulled the inner CV joint apart internally and pulled that joint off of the intermediate shaft (I was working on the passenger side first). My guess is the MZ5 springs are softer but longer than the 9-3's, therefore the uncompressed length is significantly longer. Anyhow, I then had to remove and rebuild the passenger's side axle in addition to the struts. To avoid all this on the driver's side I pre-emptively removed the axle nut to allow it to slide in the hub splines, which worked better.

After doing all of that, the driver's side front wheel bearing got loose (I suspect I may have caused that by allowing the spline to slide in the hub, which could have pushed on the hub and un-seated part of the bearing), but this time the drive axle nut needed to be cut off the drive axle - it had completely seized up (probably contributing, if the threads were messed up then it'd get to torque before being fully tight). Once that was off, I was using one of the on-car wheel bearing pullers that you rent from auto parts stores, but the wheel bearing was so rusted in place that the puller broke one of the caliper mounting ears off of the suspension knuckle!


Cue a couple weeks of waiting for a new knuckle from Mazda since I originally ordered the wrong side (the picture was for the correct side and I was doing it on my phone...oops) and no wreckers had it within 100 miles or so, but when I finally got it everything went back together without a hitch. So, lots of extra work caused by my aversion to spring compressors....

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