Engine radiator Koyo or Denso

You should absolutely fix, but $900 is steep from the quoter. Buy a quality rad (denso, nissens) and have it installed by a competent mechanic for $300 max.

Personally I’d be buying a koyo in full aluminum.

I went with a Koyo radiator, which is considerably better built than the factory piece, cost less than $300 with new hoses, and took maybe 2 hours, start to finish. Of course, I replaced the coolant at the same time.

just tested my new koyo hyper V at the track and that thing kept it rock solid cold, 180-203f the entire day but it was like 68 degrees out lol.

Get a Denso on Rock Auto for 130 and replace it yourself. Watch a YouTube video on how to do it and save yourself a bunch of coin.

Koyo for top quality, mishimoto for normal quality. Both will do the job well

I just bought a Koyo, goes in tomorrow and appears to be great quality

Seems like a loose ground, my s13 did this when the grounds randomly came loose. That said my s13 cluster is so damn slow to react so I run an aftermarket gauge. I have a koyo rad which came with a slot for an aftermarket sensor.

Also i would hope it's not the case, however you mentioned this after an alternator change. I had a 96 civic with a turbo setup and I had an alternator with a failed voltage regulator, all of my aftermarket gauges and temp gauge was acting like this. I would check the volts from the alternator if this is the case, it also ballooned the hell out of my battery..

I just installed this Denso 7 years ago, won't pay for that again.

I ordered a Denso radiator from RA earlier this year. Took my old radiator out of my truck before opening the new one (rookie move, I know). Well one of these fittings was bent/broken on the new one. Called every car parts store, mechanic, and radiator shop within an hour drive and no one had one. Someone finally pointed me towards a hydraulic shop and I had to have a guy there machine a new one for me. Been working without an issue. It was just crazy to me how difficult it was to find such a simple fitting.