Radiator hose ID
 

We’ve been trying to find rad hoses to fit my ‘69 c10. The old ones fit perfectly and the GM parts number is still on the upper. Chances are these aren’t original to this truck (engine was rebuilt in early 2000’s) so they may not be truck specific hoses. I’ve been trying to google the parts #. No luck.

The upper hose is stamped GM AY 3947120 RQ.

The lower doesn’t have any stamps still on it, but I’m hoping if we can identify the upper it will give us a clue on the lower. The bends are perfect for keeping it away from the trans cooler lines. We were close with one but the water pump end was about 1/4” to small to fit onto the water pump. And we seriously tried everything to get it on there.

Or maybe one of you amazing guys can tell just by looking at it what would work?! Go easy on me, I’m a noob.
Here are some pics for reference
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Re: Radiator hose ID
 

3947120 Inlet radiator hose 1.5" diameter is correct for 2WD '68-'72 10-30 Series and '70-'72 2WD Blazer 283-350

3918487 Outlet radiator hose 1.75" diameter is correct for '67-'72 283-350 10-30 series

Re: Radiator hose ID
 

Get a metal clothes hanger and bend it in the same fashion the radiator hose is and take it to your local parts house. I've been able to have them let me look in the back at their selection of hoses, to match it up.
Good luck

Re: Radiator hose ID
 

You're over thinking the project.. Go to your local parts house that handles Gates hoses. (not O'Reillys).. Give 'em the year, make, and model and you'll get the correct hoses.. These old trucks are still "on the Books" in the Gates catalog..

Re: Radiator hose ID
 

^^^^^^^^^^^^^^Best Advice^^^^^^^^^

But just for reference as to availability I don't endorse an of these just a reference. https://www.amazon.com/Silicone-Radi...s%2C247&sr=8-3

Also I don't know if it's made generic for both 2wd and 4wd but I have always had to trim the lower hose to fit for some reason.

Re: Radiator hose ID
 

We have tried this already and no dice. I actually have a set I still gotta return to one place. Most of the places around us are AG related so it’s all about tractors and farm equipment. That or they have part time random guys working the counter that even *I* know more about working on a truck than they do.

I was just hoping to get some guidance on what would replace these hoses because they fit perfectly and everything we’ve tried doesn’t cut it.

Re: Radiator hose ID
 

This Dayco 70935 Radiator Coolant Hose replaces Gates 20868, CARQUEST 20868, ACDelco 26027X, General Motors 343490, General Motors 3918485, General Motors 3924601, General Motors 3947120, Goodyear 60990, General Motors 6274069, NAPA 7595, AutoZone C0868, Duralast E70935, OEM parts and is perfect for replacement or a performance upgrade.

Autozone and Advance also call it Dayco E70935.

Re: Radiator hose ID
 

A quick web search for "3947120 radiator hose" yielded this hit from Classic Industries

https://www.classicindustries.com/product/3947120.html

What engine do you have? FYI, Apparently the 1967 327 uses a different inlet hose. I have not bought from these folks, but the google search yielded many more hits besides the above.

The same search with "3918487" that 1970cstblazer supplied shows many hits too, but they don't look to be as "S" shaped as your...hmm?

Re: Radiator hose ID
 

Dude, my google must be broken. The engine is an early 70’s 350. I’ve bought from Classic before and they had really great customer service.

I’m down right now with medical issues so the hubby is gonna try a different parts place on his day off next week. Fingers crossed and if it doesn’t work I’ll definitely be using those searches above!

Thanks!