cold radiator?

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Raider L

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I'm not going to look through 156 pages of posts to see if anyone has a post on a radiator problem. If anyone knows of one just move this one to there!
I installed a 3 core all aluminum radiator recently and now my water temp. gauge won't show but a dab over 180 F. It's hot down here in Louisiana and driving around on the streets I know are hot as hell and the water temp. is only 180 degrees? I've heard that these custom radiators will run 20-30 degrees cooler, but...really? It really is running that much cooler than my 3-core factory brass/copper radiator that used to run 190 degrees in summer and a little hotter on really hot days? Well, that's not good because if that's the case it's not letting the engine heat up to operating temp. And it's not letting the oil heat up to operating temp. either. You know when the oil is cold it robs horsepower due to the thickness of the oil. And besides the oil is supposed to operate thinner, not thick.
If this is the case, that it's running that cool, it will be a real problem this winter. I'll have to break out the cardboard to block off the radiator to get it warmed up to operating temp. I mean I like my engine running cool, don't get me wrong, but I would like to see it between 180 and 190.
 

Craig 85

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My last truck was a '79 K15 with a smogged down 350. A prior owner had replaced the radiator with a 2 row aluminum/plastic version. Due to required smog testing, I ran a stock 195 thermostat. On average that truck ran 185. I could never get it to run close to the 195.

Maybe just change your thermostat?
 

SirRobyn0

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I'm not going to look through 156 pages of posts to see if anyone has a post on a radiator problem. If anyone knows of one just move this one to there!
I installed a 3 core all aluminum radiator recently and now my water temp. gauge won't show but a dab over 180 F. It's hot down here in Louisiana and driving around on the streets I know are hot as hell and the water temp. is only 180 degrees? I've heard that these custom radiators will run 20-30 degrees cooler, but...really? It really is running that much cooler than my 3-core factory brass/copper radiator that used to run 190 degrees in summer and a little hotter on really hot days? Well, that's not good because if that's the case it's not letting the engine heat up to operating temp. And it's not letting the oil heat up to operating temp. either. You know when the oil is cold it robs horsepower due to the thickness of the oil. And besides the oil is supposed to operate thinner, not thick.
If this is the case, that it's running that cool, it will be a real problem this winter. I'll have to break out the cardboard to block off the radiator to get it warmed up to operating temp. I mean I like my engine running cool, don't get me wrong, but I would like to see it between 180 and 190.

You do realize your talking about 10F difference, that's not much. Did you change the thermostat? What is the thermostat rated for? The thermostat is the main thing to regulate the temp. If it's new and is a 195 stat try blocking off part of the radiator with cardboard and go for a drive and see if it heats up, or better yet see what the radiator and upper hose and lower hose temps are with a heat gun. knowing the hose temps would make this easy to know if it's the rad or not, but again the thermostat is the temperature regulating device.
 

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What viscosity of petroleum jelly are you running in that thing? The correlation from oil temp to water temp isn’t necessarily a direct one. I’d go by oil pressure and oil temp if you’re worried about oil viscosity/temp, not coolant temp.
 

Raider L

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Craig85
When my original radiator finally bit the dust I already knew where there was another one just like it on line but I got to thinking, "Maybe I can find one, a newer one that's not so expensive." even though $150 something was cheap, I just wanted to look anyway. Now get this; I looked everyday and night for over a month and couldn't find a three core aluminum with plastic radiator for my truck! Oh, I could find 3-core rad's. but they weren't the right size. After quickly exhausting all the truck one's like my truck, '74 C10 I went to 1973 and worked my way forward to 1991. That was due to those rads. changed to a completely different system as most Chevy engines went to reversed flow systems. So I said, "Okay, I'll move to other trucks.", like all the "K" trucks from '73 forward including all 10's, 20's, 30's of every engine size. That produced no results that fit my truck's size and the same thing about the 3-cores, not my size. I was not going to stop. I thought, "What would have a 350 in it and would have been a brass/copper radiator?" Well heck, of course, Cadillac's! And big GM cars like La Sabre's, Bonneville's, even 442''s with big blocks in them. Pontiac's, Oldsmobile's, etc.. Anything big block because I soon found that the 350 engineed cars had these weeny 1" wide "single core" radiators. I knew from driving around during hot Summers down here with the street temp at 130 degrees there wasn't any way my engine was going to stay cool in stop and go traffic.
To make a long story a little shorter, I went through all the vans as well 10's, 20's, and 30's, they all had been replaced with single core 1" wide alum. with plastic rads. ALL of them!! Even the later cars like '85 big cars rads. had been replaced with single core rads. I couldn't believe it. Then finally late one night I found one that was my size off a '91 Cadillac Coup Deville with a big block in it. But when I pulled up the picture of it I saw something that caused my blood to run cold! I didn't have the heater return tube, the one just below the filler port! So I gave up and just bought one of those after market all aluminum ones. It was $156 dollars. So I got that one. I don't know how many pages of notes I have on my search. If anyone is looking for a alum. plastic rad. let me know I'll tell you what's available, ha, ha.
 

Ricko1966

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Your oil temp ideal would be 200. + or minus 10. Bring the engine up to temp,oil doesn't heat up as quick as the coolant, so check oil temp 15 minutes after the engines at temp. If it's too cold step up the thermostat.If your real worried about it get a oil cooler that uses engine coolant like a sandwich cooler at the oil filter, it will bring your oil up to temp quicker and maintain oil temp a more consistent summer and winter.I didn't read on that cooler just the first one I saw, but you get the idea coolant heats and/or cools the oil.
 
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82sbshortbed

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I'd drive it like that. 180 thermostat in mine and if it stayed there I'd be happy. 185 190 is what it runs down the road.
 

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It shouldnt care if its winter or summer. The thermostat regulates the same year round. Our winters dont get cold enough very often to be that dramatic of a change.
It will get hotter in the summer yes because thats how heat works. There is no cold in physics..only an absence of heat. In other words the engine should have no problem regulating keeping heat in the winter because it will just close off but in the summer you cant exceed the capacity of the cooling system....it will only drop temps so much.
 

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Craig85
When my original radiator finally bit the dust I already knew where there was another one just like it on line but I got to thinking, "Maybe I can find one, a newer one that's not so expensive." even though $150 something was cheap, I just wanted to look anyway. Now get this; I looked everyday and night for over a month and couldn't find a three core aluminum with plastic radiator for my truck! Oh, I could find 3-core rad's. but they weren't the right size. After quickly exhausting all the truck one's like my truck, '74 C10 I went to 1973 and worked my way forward to 1991. That was due to those rads. changed to a completely different system as most Chevy engines went to reversed flow systems. So I said, "Okay, I'll move to other trucks.", like all the "K" trucks from '73 forward including all 10's, 20's, 30's of every engine size. That produced no results that fit my truck's size and the same thing about the 3-cores, not my size. I was not going to stop. I thought, "What would have a 350 in it and would have been a brass/copper radiator?" Well heck, of course, Cadillac's! And big GM cars like La Sabre's, Bonneville's, even 442''s with big blocks in them. Pontiac's, Oldsmobile's, etc.. Anything big block because I soon found that the 350 engineed cars had these weeny 1" wide "single core" radiators. I knew from driving around during hot Summers down here with the street temp at 130 degrees there wasn't any way my engine was going to stay cool in stop and go traffic.
To make a long story a little shorter, I went through all the vans as well 10's, 20's, and 30's, they all had been replaced with single core 1" wide alum. with plastic rads. ALL of them!! Even the later cars like '85 big cars rads. had been replaced with single core rads. I couldn't believe it. Then finally late one night I found one that was my size off a '91 Cadillac Coup Deville with a big block in it. But when I pulled up the picture of it I saw something that caused my blood to run cold! I didn't have the heater return tube, the one just below the filler port! So I gave up and just bought one of those after market all aluminum ones. It was $156 dollars. So I got that one. I don't know how many pages of notes I have on my search. If anyone is looking for a alum. plastic rad. let me know I'll tell you what's available, ha, ha.

I'm really confused by this? What were you trying to achieve? You wanted a small size radiator that was also a 4-core? A 74 C-10 would have had the shorter height core right? You wanted the benefit of the bigger radiator but without going to the larger size? My 1980 K25 with a 350 w/AC came from the factory with the tall 4-core. The 1997 K2500 Suburban I bought with the 454/4L80E had a 4-core radiator that is the same height but 4 inches wider than that radiator. It is aluminum w/plastic tanks and had the trans and engine oil coolers in the radiator.

Why wouldn't you have just upgraded to a big block radiator and changed your upper mounts to fit the taller height radiator?

To your main question on this thread... you probably have a 180 thermostat in it to make up for the small original radiator. I'd switch it to a 195 if you want it to run warmer now. 180 is plenty though and shouldn't hurt anything. Like others have said, even with the colder coolant temps, the engine oil is probably still getting up around 200-220. Especially with no cooler. If you want your engine oil to last longer and run more consistent in a certain viscosity, put an in-radiator engine oil cooler on it. Your engine oil will come up to temp faster and stay more consistent.
 

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Craig85
When my original radiator finally bit the dust I already knew where there was another one just like it on line but I got to thinking, "Maybe I can find one, a newer one that's not so expensive." even though $150 something was cheap, I just wanted to look anyway. Now get this; I looked everyday and night for over a month and couldn't find a three core aluminum with plastic radiator for my truck! Oh, I could find 3-core rad's. but they weren't the right size. After quickly exhausting all the truck one's like my truck, '74 C10 I went to 1973 and worked my way forward to 1991. That was due to those rads. changed to a completely different system as most Chevy engines went to reversed flow systems. So I said, "Okay, I'll move to other trucks.", like all the "K" trucks from '73 forward including all 10's, 20's, 30's of every engine size. That produced no results that fit my truck's size and the same thing about the 3-cores, not my size. I was not going to stop. I thought, "What would have a 350 in it and would have been a brass/copper radiator?" Well heck, of course, Cadillac's! And big GM cars like La Sabre's, Bonneville's, even 442''s with big blocks in them. Pontiac's, Oldsmobile's, etc.. Anything big block because I soon found that the 350 engineed cars had these weeny 1" wide "single core" radiators. I knew from driving around during hot Summers down here with the street temp at 130 degrees there wasn't any way my engine was going to stay cool in stop and go traffic.
To make a long story a little shorter, I went through all the vans as well 10's, 20's, and 30's, they all had been replaced with single core 1" wide alum. with plastic rads. ALL of them!! Even the later cars like '85 big cars rads. had been replaced with single core rads. I couldn't believe it. Then finally late one night I found one that was my size off a '91 Cadillac Coup Deville with a big block in it. But when I pulled up the picture of it I saw something that caused my blood to run cold! I didn't have the heater return tube, the one just below the filler port! So I gave up and just bought one of those after market all aluminum ones. It was $156 dollars. So I got that one. I don't know how many pages of notes I have on my search. If anyone is looking for a alum. plastic rad. let me know I'll tell you what's available, ha, ha.

There's a **** ton of misinformation in this post. Where does one start?
 

Bextreme04

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There's a **** ton of misinformation in this post. Where does one start?

Agreed, I'm so confused....

I guess whatever he did to get here, he has an aftermarket all aluminum one now :shrug:

Just put in the correct thermostat for the temp you want and move on. Also, if you have it hooked up to use the factory heater core connections, it will bypass the thermostat and you will be running cooler with a more efficient radiator. You can move that stuff around if you want, but I would recommend making sure you know what you are doing first.

Also, upgrading to electric fans can be a decent way to allow the engine to warm up faster while still allowing it to stay cool when you need it. YMMV... make sure you know what you are doing ahead of time
 

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OP, pump the brakes for a minute.
What thermostat do you have and how do you know the temp gauge is right?
Secondly, if you have a working thermostat, it does have a thermostat, correct? Then it should make no difference in ambient temperature.
Last, you live in Louisiana, it doesn’t get cold and there’s pretty much no chance you can’t get the engine up to operating temp even in “winter” down there.
 

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It shouldnt care if its winter or summer. The thermostat regulates the same year round. Our winters dont get cold enough very often to be that dramatic of a change.
It will get hotter in the summer yes because thats how heat works. There is no cold in physics..only an absence of heat. In other words the engine should have no problem regulating keeping heat in the winter because it will just close off but in the summer you cant exceed the capacity of the cooling system....it will only drop temps so much.

If it's cold enough it will never heat up enough to keep the thermostat open. One time I was driving home around 02:00, the outside temp was in the low 30s high 20s. My jeep had a 180 in it and the heater wasn't working well at all. Thinking it was low on coolant, I pulled over in the first town, and the radiator was full. So I kept driving. The temp gauge would get to 180 and then drop again, climb to 180 and drop. Just kept cycling like this. I put in a 195 and it didn't have that issue. In the summertime the temp gauge is about 210 with a 195 in it, in the wintertime it is around the 195 mark and the heater will roast you out. My jeep always has a 195 in it now.

But in my older vehicles, when I drive in the higher elevations in the winter I always put in a 195 now, and will change it a 160 in the summer. But summer here sees many triple digit days, so there's that.
 

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If it's cold enough it will never heat up enough to keep the thermostat open. One time I was driving home around 02:00, the outside temp was in the low 30s high 20s. My jeep had a 180 in it and the heater wasn't working well at all. Thinking it was low on coolant, I pulled over in the first town, and the radiator was full. So I kept driving. The temp gauge would get to 180 and then drop again, climb to 180 and drop. Just kept cycling like this. I put in a 195 and it didn't have that issue. In the summertime the temp gauge is about 210 with a 195 in it, in the wintertime it is around the 195 mark and the heater will roast you out. My jeep always has a 195 in it now.

But in my older vehicles, when I drive in the higher elevations in the winter I always put in a 195 now, and will change it a 160 in the summer. But summer here sees many triple digit days, so there's that.


Thats fair and true. I never run anything other than a 195. I certainly cant speak on the physics like I understand it all out. I was assuming since he was in Louisianian he never saw below 30deg for more than a few hours. But totally see your point however ive never had a c10 heater not work because it wasnt 195deg or 180 for that matter...mine usually starts heating up the cab around 160deg.
I did have a problem in an XJ 4.0 that did the same cycling phenomenon so I know it happens in that community. I went with a two stage thermostat and had no more issues on mine. I actually have one around here somewhere for an F2t mazda turbo engine if anyone wants it,LOL
 
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