Radiator sizes

**98GPree** · 04-21-2013

I've seen a couple threads but none that really answered my specific question.

I just noticed today that the radiator in my 98 Gt has a small hairline crack on the top right. Looking around online I found a few options. 5/8", 1", and 1.25". Not sure which I have yet, does it matter which replacement I get?

I don't need anything special but figure for the price bigger is usually better. Am I safe just getting the 1"? I don't want to have to do any modifications to get one to fit.

Thanks in advance

**ericspecullaas** · 04-21-2013

it all a matter of what your engine is. when they build the car the engineers determine the best and most general use overall. but if you really want go 1.25 it will keep it cooler longer but 2 main factors are at play here. Do you have mods as in exhaust mods? and front clearance issues. like light taps on the nose and such.

**TEK310** · 04-21-2013

non-supercharged cars came with 5/8"
supercharged 97-03 came with 1"
04+ na and supercharged came with 1 1/4"

i would assume you can use the 1" core radiator with no modification required

**98GPree** · 04-21-2013

I assumed it was the 5/8". Ill probably try the 1". I have no modifications and no intention of doing any. It has 204k miles and is just what I drive to/from work 110miles a day.

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**TEK310** · 04-21-2013

my supercharged car has the 5/8" in it at the moment. previous owner didnt know the difference. it cools fine during normal driving, but under boost it heats up. so the 1" and 5/8" are interchangeable. but if you had a supercharged car, stick with the 1"

**slimguns** · 04-21-2013

I have an '03 L36 (NA) and I put the 1.25" with no issues other than it was a bit snug putting in the fan. I'm about to do a top swap and that's why I upgraded. I live in New Mexico with 100*+temps, a 180* T-stat, and a tune and it never jumps beyond my programmed temp. I think, you might as well.