This one: https://smile.amazon.com/TYC-1140-Aluminum-Replacement-Radiator/dp/B000IYPNC8 - direct-fit replacement.
EDIT: Amazon is showing that as a no-fit for 1990. I didn't think the 1.6 was different but make sure before you buy!
Also get a new cap. Use your judgement on the hoses but since you'll be in there, especially the one down low, may as well replace if it isn't in great shape.
This is the one I got and like most things it's no longer that price, but with that said I've put in two of these and no issues. Our club president recommended this one so I went with it as he does a LOT of Miata work and is a encyclopedia when it comes to the NAs and NBs.
Still worth $138 IMHO, that plus some coolant and maybe a hose if they look cracked.
This is the one you want: https://smile.amazon.com/gp/product/B000IYPNC8
I have installed two of these with good results. Direct fit. Just pull your radiator, transfer the mounting hardware and fans to the new. Install everything and replace any lost coolant. Replace hoses as needed, of course. "Burp" the system and you should be good for many more miles.
Note: the unit is AT compatible but if you have a manual, you can ignore or remove the AT cooling line connectors. It's a separate chamber in the radiator.
Stock is fine if yo u don't plan to turbo or track the car. This one from amazon works great for most people.
If you do think you'll ever turbo or track it go for one of the mishimoto all aluminum ones. They're more expensive and seem to have a few quality control issues here and there but they come with a lifetime warranty and offer better cooling over the stock replacement.
Stock is absolutely fine unless you add forced induction and/or race it on a track.
I have purchased the TYC radiator on Amazon twice and both have been quick, easy, and problem free. Be sure to also order a new radiator cap, it won't come with one and you shouldn't reuse your old one.
Pull out your old one, swap over the mounting bits and bushings, transfer the fan(s), and install. Fill with coolant to replace what you lost, and "burp" it. Some people suggest replacing the upper and lower hoses while you're at it. They're not expensive.
The one you'll get will have the AT line connections at the bottom, which you can ignore. They are not connected to your coolant system. It's no concern if one or both of the little rubber caps fall off.
I went with this radiator on Amazon and it hasn't let me down in the year and a half it's been in. If you're going for the upgraded setup (a pretty good idea considering the turbo) then I would look at mishimoto or similar, but I haven't done extensive research.
It does look like a good deal. Properly maintained by an engineer owner? Wow. All it needs is a radiator to replace that brown one which is certainly approaching failure (under $100 DIY with the TYC radiator from Amazon) and you should be all set!
That price is reasonable, especially for a B-package. It's not quite bone stock (aftermarket lip) but looks good in the photos. Mazda decal intact, so possibly original paint. White paint on those early NAs is known to start falling off. This one seems not to have that problem yet. That original radiator is very much due for replacement, if the guys at miata.net know anything (they do) - brown like that indicates failure is coming. You do not want to overheat a Miata engine. $75 on Amazon, get the TYC sold and fulfilled by Amazon.
I'm not sure what's going on with the top along the upper edge of the window. Are those clips? Basic vinyl tops with plastic window can be found for under $200, so that's no deal breaker. Also note missing driver's side mirror.
SNC is a concern on these engines. With it running, look at the crankshaft pulley to see if there's any wobble. If there is, I'd pass. If it looks OK, your next concern is when (or if) the timing belt was done. At 91k, you're hoping it hasn't been done. Interval is 100k, so it'll be due. If it made it this long, chances are the crank bolt is OK and you can make sure the SNC is properly addressed. There's a ton of info about this at miata.net. (Also a checklist that you should print and bring with you if you're serious about buying the car.) In a nutshell, if the crank is OK now, and no main seal leak, leave it alone and do the TB without touching that bolt. If the main seal is leaking, buy a new crank bolt and Woodruff key from Mazda to replace. Torque to 97-104 ft-lbs with medium Locktite.
Go drive it, look for rust. But it's a worthy candidate, I'd say.
My logic was exactly the same. I have every reason to think the old piece I swapped over the weekend was 25 years old and still working (not leaking, keeping the car at 11:30 during a DC summer), so why chance it? The Amazon special that everyone suggests is built for an automatic, so it has slightly greater capacity than the manual OEM, which is cool.
Buy OEM for the hoses and thermostat. I just bought the cooling hose kit for my NA6 from rosenthal Mazda online for ~$90-100.
This seems to be the standard low cost radiator most people use. I just bought one myself a few weeks ago. It is ~$75. http://www.amazon.com/TYC-1140-Aluminum-Replacement-Radiator/dp/B000IYPNC8
Note that a LOT of owners wait until closer to 100k for TB and water pump replacement if there are no issues. Owner's manual for CA says 105k, everywhere else is 60k. Same exact belt. But doing it at 60k won't hurt anything. Read here: https://www.miata.net/garage/timingbelt.html
For radiator get the $78 TYC radiator on Amazon. It is direct fit--even for your 1993 according to multiple forum posts I've read. Amazon will disagree but you can ignore that. Here's one recent comment about this--see #24. Transfer the rubber/metal mounting bits and fans from old to new and bolt it right in. If it comes with auto trans cooler connectors on the bottom (I'm assuming you have a manual) just leave them alone. Replace your coolant hoses if needed. Reuse the spring clamps if you have them. Total cost including a little antifreeze should be around $100.
I am preparing to do a timing belt/water pump replacement myself. All my research says to get a Gates belt. I've seen total kits on Rock Auto before but for something you'll have in the car for 60-100k miles why not spend a bit more and get things with good reviews? Get the seals separately if you can't find a kit that has a Gates belt. Most people replace the water pump when they do the TB. I'm hoping to find a water pump with a cast impeller rather than stamped and spot-welded.
EDIT: FlyinMiata has a good reputation and they have a kit: https://www.flyinmiata.com/na6-big-nose-timing-belt-kit.html - worth consideration.
I agree it looks promising and the price is OKish although the remaining visible damage from the (literal!) fender bender wouldn't be cheap to fix. Rust is always the #1 concern to watch for. Seller claims none but you should confirm this yourself, especially considering your location. Look for damage behind the fender and under the hood. I'd watch for bent suspension components.
On the plus side black NA paint is single stage and oh-so-restoration friendly. Seller is correct with statements about the "Black and Tan" 1992 Miata. BBS center caps are missing, and somewhat hard/costly to obtain if you want them. Glass rear window indicates a replaced top, probably a good thing. Bonus if it includes the original boot cover because the tan ones are going up in price on eBay. I got one for $100 in June but they were all $130+ last I checked.
Ultimately this resource is the gold standard for Miata inspection: http://www.miata.net/faq/usedmx5.html
Bring tools. Be careful if you pull and inspect spark plugs; do not tighten more than 11-17 ft-lbs (132-204 in-lbs). Not noted in that guide is the radiator color. Black is OK. Olive is showing age. Brown is time to replace ASAP. Miata engines do not like to overheat, so a well-sorted cooling system is critical. But replacement TYC on Amazon is affordable and easy direct swap.
Good luck! Post back with an update if you look at it or buy it.
This is probably the radiator you want to get. Haven't heard anything bad about it.
Since Miatas have their batteries in the trunk, they use this interesting "sealed" type of battery that prevents battery fumes from getting into the passenger compartment. There are tubes that connect to the battery to exhaust the gases.
I think this WestCo is a common replacement
TYC 1140 Compatible with MAZDA... https://www.amazon.com/dp/B000IYPNC8?ref=ppx_pop_mob_ap_share
It was 85 after tax when I bought it in 2020, price has gone up quite a bit
The original radiator was still working fine, but it was getting long in the tooth as the plastic had changed to that ugly green color indicating potential failure. I watched this NA radiator replacement video to get an idea of the size and scope of the job and then went at it. The replacement is a TYC 1140 Radiator.
The first photo is the old radiator drained with the top hose and overflow tube removed. I'd meant to take a "before" picture and forgot, so this is the 1st in progress pic.
In the second photo you'll see that I took the protective skid pan off so that I could get to the two mounting brackets for the factory installed AC piping. This step can be skipped for those who don't have factory AC.
Third is with the old radiator removed and forth is the side by side prior to transferring the fans and mounting hardware. Fifth is with the fans moved and the additional cooling pipes removed from the bottom as they aren't required on my car. The trick to getting the fans to fit was to loosely insert the bolts and tighten them in rotation - it is a snug fit.
And the sixth photo shows a mistake. I installed the lower mounting pins on the front side rather than the back - doh! An easy fix. Those are rainbow sandals if anyone is curious. The seventh shows the correct orientation of the mounting posts.
Last two are the final installation and hookup. Filled with a 50/50 mixture of antifreeze, ran it for a while checking for leaks. Stopped the engine, topped off the radiator as fluid is now filling the engine block and hoses. Ran it a while more and all looks good.
I also noticed that it is time to replace some belts and check the timing belt, but that's a project that I'll hire out.
Radiator for an NA is $96 usd.
TYC - 1140 90-97 Mz Mita 1.6L L4 A/Mt 1R Pa Rad https://www.amazon.com/dp/B000IYPNC8/ref=cm_sw_r_cp_api_glt_fabc_AJ4G3H1FM25R1Z7BY49Y
Keep an eye on it for sure. When it is brown like that, it is brittle. Info here - see p 13. The photos on that page are of my car. Here's the higher res version - if you are seeing crazing marks like that, beware. Sometimes you'll see cracking before failure. I did: https://i.imgur.com/wqe46km.jpg
This TYC radiator is a direct-fit replacment: https://smile.amazon.com/gp/product/B000IYPNC8 (you can just ignore or remove the AT connections - that chamber is unused on a manual car.
It's a fairly easy DIY job. Just transfer over the fan(s) and rubber bushings. You also have to budget for coolant because you'll likely lose a little even if you try to save it. And check your hoses while you're at it.
The $80 TYC brand radiator available on Amazon is a direct fit replacement. It has connections for AT cooler which you can simply ignore if installing on a manual transmission car. Drain coolant, pull old, swap over the mounts and bushings and whatnot, install new, replace coolant, burp it, top it off, done. A lot of people replace upper and lower hoses too, that's up to you. Definitely get a new radiator cap also.
That one in the video is really brown. Look it over carefully. See info about this in the guide: https://www.miata.net/garage/garagebuying.html
I suggest the TYC brand radiator on Amazon
https://www.amazon.com/dp/B000IYPNC8/ref=cm_sw_r_cp_apa_fabc_deiSFb37K03ND
it's a direct oem replacement. works fine if you're making stock power
Got any links? This was the cheapest I could find.
While you have everything taken apart you should replace all of the rubber seals you can. I bought this kit on ebay when I did mine. Rosenthal Mazda also has a kit of OEM parts if you don't trust ebay quality. I also replaced the radiator because it was turning green. You had might as well change your accessory belts too.