What to look for on a '94 Miata?

"BaconSandwich is tasty." (baconsandwich) 03/14/2018 at 12:02 • Filed to: None

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On Saturday a friend and I are going to take a look at a 1994 Mazda Miata (for him, not for me). Are there any particular problem areas to look out for?

I remember hearing something about the Woodruff key on the crank being an issue in early Miatas, but I’m not sure that still applies to a ‘94. That, and it’d be potentially somewhat difficult to check for it.

Jake - Has Bad Luck So You Don't Have To > BaconSandwich is tasty. 03/14/2018 at 12:18

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94 doesn’t have woodruff issues. Check for rust in the rocker panels, see if you can lift up the carpet behind the seats on the package shelf (held in with plastic snaps) and look for rust under there. Rust under the battery in the trunk can be an issue sometimes. See if there’s oil leaking from the CAS (sensor on the back of the intake cam).

DasWauto > BaconSandwich is tasty. 03/14/2018 at 12:19

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My expertise on Miatas is minimal but the crank issue is limited to 1.6l engines so if you’re looking at a 1.8l that’s not a concern.

AestheticsInMotion > BaconSandwich is tasty. 03/14/2018 at 12:21

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Lifter tick is pretty common. Make sure headlights go up and down. Soft top should operate smoothly and seal properly. Check wheels. There are various factory options, here’s where you can find the best (lightest).

https://www.miata.net/faq/wheel_weights.html

Look for mold and mildew under and behind the seats. Check the battery tray in the trunk. Is the tie-down there? Rev to redline. Any rattles in the exhaust?

HPoz - I like Honda Fits and I cannot lie > BaconSandwich is tasty. 03/14/2018 at 12:22

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Rust is the main killer of NAs as far as I know

Jarrett - [BRZ Boi] > BaconSandwich is tasty. 03/14/2018 at 12:24

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Rust is the biggest issue on these cars from what I’ve read.

Only the 90-91s had the short-nose crank issue, if I recall.

Also, check the transmission. If it has PNRDL on it, the car isn’t worth more than $1000 bucks, regardless of condition. (I’m only half joking. The autos are worthless in terms of resale value, but I don’t judge!)

ITA97, now with more Jag @ opposite-lock.com > BaconSandwich is tasty. 03/14/2018 at 12:38

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The woodruff key issues was only a problem on early 1.6 miatas from 1990 and early 1991 model years. Pull back the boot on the clutch slave cylinder and expect there to be fluid leaking (super common problem and super cheap and easy to rebuild/replace, but worth knocking some off in negotiations). Expect there to be an oil leak on cam angle sensor on the back of the head. Any miata/spec miata shop will have that o-ring on the shelf. Looks for signs of arching on the coil packs while you’re poking around back there.

Look at how fresh the radiator is (color of the plastic, the plastic tanks turns brown/green with age). The plastics tanks get brittle and will crack at the radiator filler neck eventually on every single NA/NB miata. OEM type replacement radiators are about $100, and there are tons of aftermarket aluminum options. Look at the condition of the heater hoses, as they’ll be the first hoses in the cooling system to go. They’re a non-interference engine, so a timing belt failure isn’t fatal, but the job will still cost money to do every 60k-100k. They’re hydraulic lifters, so a bit of lifter tick is a good indicator to start running a bit thicker oil in an old engine. Spark plug access is so easy on miata that there isn’t a reason to not do a quick compression test on a prospective purchase.

The condition of the top is a big factor in the value of a miata. Figure $1000 for a new top installed and done right. Look for signs of carpet getting wet in the footwells and/or the trunk. That is sign of a cracked rain rail (which will mean a new top) or a previous owner who cheapened out on a top replacement and didn’t also replace the rain rail at the same time. If the car comes with a factory hard top, it is probably worth buying for the top alone. Those are worth $1500+ these days.

They’re really bullet proof little cars, and there is phenomenal parts support for them.

Wrong Wheel Drive (41%) > BaconSandwich is tasty. 03/14/2018 at 12:48

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Rust is the only issue worth caring about. Everything mechanical is super easy to deal with. As others have said, definitely make sure to check the top as that is an expensive fix. Lifter tick is completely normal and expected. Being a 1.6, it will be slow but thats also expected lol. Otherwise everything is just your normal used car stuff. Just be sure to check the front frame rails (although this generally only affects NBs), the rocker panels (even a small bit of rust on the outside indicates a major problem underneath), and easy to spot places like the rear quarters. Rusty/dented fenders and doors are fine since those can easily be a bolt on fix with a clean part. Anything else involves welding.

While the car is noninterference meaning the timing belt is not a big deal, the water pump most certainly should be replaced every 100k or less. So if there is no history on that, plan to be doing a timing belt job because of the pump. These engines WILL NOT survive any sort of overheating so it is not worth the risk. Cooling system health in general is paramount and probably the number one preventative maintenance item to remember. Everything is easy/cheap to replace but must be replaced ASAP if there is no history.

nerd_racing > BaconSandwich is tasty. 03/14/2018 at 13:17

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Rust specifically on the rocker panels, especially in front of the rear wheels near where the soft top drains.

ITA97, now with more Jag @ opposite-lock.com > BaconSandwich is tasty. 03/14/2018 at 14:00

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I also forgot to mention the rubber shift boots that seal the transmission at the the gear shift, and the gear shift at the body. They only last a few years at a time, so expect them to be torn. The clue is a center console that gets hots with driving. The inner and outer boots are about $70 for a set and also super simple to replace, but are worth knocking a bit off the price of the car for. Same boots for every NA/NB miata.

Nick Has an Exocet > Jarrett - [BRZ Boi] 03/14/2018 at 15:57

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Early 91's. I have a later 91 without the crank issue.

Agree on the autos not being worth much.

Nick Has an Exocet > BaconSandwich is tasty. 03/14/2018 at 16:00

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The only thing I will add to what others have said is that maintenance records are key if they have them. They can be worth an extra $500 over a similar car to know if the timing belt, water pump, clutch, etc have been done and when.

Check for oil leaks. If there is oil coming from the cam angle sensor, that’s fairly easy to fix and is a $1 o-ring.

Also inspect any suspension rubber (bushings). It’s of the age where those are hard and need to be replaced. You may hear clunking in their suspension if it needs bushings badly. They’re not hard but they are time consuming to do and somewhat pricey.

daender > BaconSandwich is tasty. 03/14/2018 at 19:32

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The crank key issue normally pertains to early NAs but it can happen to the 1.8s if the person doing the timing belt screws up the install...just like the once-local Mazda dealership did to my ‘02. It took about 2 years and a few thousand miles but no one else touched it since then!

Anyway, it’s always rust. Check under the front fenders before the doors, as the cowl draining exits around there. If it gets clogged, debris and mosture will build up and rot it from the inside. Ditto goes for the rear quarter panels ahead of the rear wheels. The softtop drain exits around there and is also another location for clogging that leads to rust.

Check for a LSD. The best solution besides pulling an axle is to launch it with one wheel on a loose surface (grass, sand, dirt, etc.) and one wheel on pavement. If you go nowhere, then it’s probably an open diff. Powered windows and cruise control were part of a package that included a LSD.

Also, check the radiator color (black = best) for condition and make sure the top is in good order with no leaks or tears!

wkiernan > BaconSandwich is tasty. 03/15/2018 at 08:36

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I’d like to add a couple of things to the previous comments. If, I mean when, you replace one side of the clutch hydraulics, replace the other at the same time. The master and slave cylinders are cheap. The first time I replaced my slave cylinder I didn’t do the master cylinder and a week later it also failed and I ended up with almost double the labor time, had to bleed it twice! Also if you’re going to replace the two shifter boots, go ahead and spend an additional $20 and also replace the bushing at the bottom of the shift lever. An easy fix and your shifter will feel ever so much better, you will love it.