Any aluminum radiators that don't crack annually?

Geotrash said:

The 5.3's have a 1" thick core, I believe. And every parts house specs that radiator for the 6.2 Denali's also, but the factory Denali radiator is actually 1.3" thick.

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Learned something new today! I thought the K5Ls and 6.2s ran the same radiator.

ACDelco shows the specs as:

5.3 with KC4 & K5L - 21742/20935856 - 34 x 18.5 x 1 Core Size
6.2 with KC4 & K5L - 21648/22840115 - 34 x 18.5 x 1-1/16 Core Size

These 6.2 Denali radiators are the same number in my 6.2 Sierra pickups too. Cool beans, thanks!

swathdiver said:

Learned something new today! I thought the K5Ls and 6.2s ran the same radiator.

ACDelco shows the specs as:

5.3 with KC4 & K5L - 21742/20935856 - 34 x 18.5 x 1 Core Size
6.2 with KC4 & K5L - 21648/22840115 - 34 x 18.5 x 1-1/16 Core Size

These 6.2 Denali radiators are the same number in my 6.2 Sierra pickups too. Cool beans, thanks!

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Technically, I suppose they could. But now that I've replaced the factory radiators in both of our XL Denali's, I can say that the measured thickness of the cores in both of them was about 1.3". Go figure.

Geotrash said:

Technically, I suppose they could. But now that I've replaced the factory radiators in both of our XL Denali's, I can say that the measured thickness of the cores in both of them was about 1.3". Go figure.

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Those are ACDelco specs but there was one application showing the same part number as 1-5/16 wide. At least we know they are different! About a year ago the price doubled on my 21742 so the 21648 looks much more attractive!

I have a two year old Cold case. It stated leaking a month ago...

Once again I’m glad I never went with an all aluminum radiator. I’ve seen people complaining about the “cheap plastic end tanks” on the stock radiators year after year. My OEM 02 Denali radiator was still going strong after 19 years and 150k miles so when I decided to replace it as a maintenance item, guess what I went with.

Just get the OEM one (not aftermarket replacement, actual OEM). They last 10+ years.

91RS said:

Just get the OEM one (not aftermarket replacement, actual OEM). They last 10+ years.

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This was what I intended to do when I replaced the radiator in my 2007 a few weeks ago. However, the OEM unit was out of stock everywhere in town, so the best I could find locally (needed it quickly) was what I installed, which was a Carquest-branded unit with a 1" thick core and listed in the parts catalog as a replacement for the correct GM part number. And what I later learned was that the part number that GM has been spec'ing for the 2007 XL Denali I have isn't actually what came with it from the factory either (1.3" thick core). All of the GM parts houses list 19256745 which according to the GM parts sites replaces what came with it from the factory, but again it's a thinner core, so while it fits it does not have the same cooling capacity.

So that's the quandary. The aluminum radiators offer a 2" thick, 2-row core which as I've learned first-hand is a boon for towing heavy in the summer. And, getting either the correct radiator for the truck or finding a true OEM-quality equivalent isn't as easy as it seems. Hence why the Denso part number from Chris is key. It's the only one I've found that is actually a proper replacement for the radiator in the Denali, specifically. And because Denso makes many of the radiators for OEMs, including GM, it is an excellent quality replacement.

I used to have an Acura Legend for which many companies make aftermarket radiators that are supposed to work. But they don't. Small differences in the molding of the filler neck for example meant that the original radiator cap design wouldn't fit, necessitating a workaround that generated new problems, etc. The only solution I could find was a Denso radiator because that's who made the original.

I'm just here for the leaky aluminum radiator club. I'm pretty sure it's the core, but who knows. It's too wintery and/or muddy to mess around. I just keep adding coolant and hope something good happens.

Charlie207 said:

I'm just here for the leaky aluminum radiator club. I'm pretty sure it's the core, but who knows. It's too wintery and/or muddy to mess around. I just keep adding coolant and hope something good happens.

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Radiator core or heater core?

Rocket Man said:

Radiator core or heater core?

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I'm assuming radiator.