47-55.1 Having cooling issues

[AD51]

Hi to all, I haven't posted here in forever but I know there is a world of knowledge on here. I am having issues with not being able to run cool enough. I have a 51 on S10 chassis with 350 TPI motor and 700r tranny. I have the universal aluminum radiator that fits our trucks it has the 2 rows of 1 inch flumes in it. I have a puller fan on the motor with shroud and an electric fan (running all the time) on the front pushing air too. I'm running a 160 thermostat. I do have air conditioning condenser and a trans cooler mounted ahead of the radiator. I can stay in range (200-210) if I'm running down the open road but any slow down or even hills seem to make it heat up. Any help anybody can send my way would be greatly appreciated.

[MiraclePieCo]

The first thought that comes to mind is COOLANT VOLUME. The 19x22 aluminum radiator that everyone universally uses for these S10 conversions is barely adequate even under ideal conditions; put a condenser and trans cooler in the way and it really gets marginal. On my S10 conversion I had to relocate my trans cooler under the truck, and I also added an air deflector to route ambient air into the radiator. Then I bought the biggest, most expensive SPAL fan I could get. All that helped, but it still got warm climbing steep grades on hot days. My current panel truck has a stock-style radiator; it holds a FULL GALLON more coolant than my S10-AD truck with the 19x22 radiator. For maximum cooling, there's no substitute for volume.

Pics of your system would help. Have you modified your latch plate assembly or the lower splash pan below the radiator? Those things are integral to the air flow system on an AD truck.

[AD51]

Originally Posted by MiraclePieCo

The first thought that comes to mind is COOLANT VOLUME. The 19x22 aluminum radiator that everyone universally uses for these S10 conversions is barely adequate even under ideal conditions; put a condenser and trans cooler in the way and it really gets marginal. On my S10 conversion I had to relocate my trans cooler under the truck, and I also added an air deflector to route ambient air into the radiator. Then I bought the biggest, most expensive SPAL fan I could get. All that helped, but it still got warm climbing steep grades on hot days. My current panel truck has a stock-style radiator; it holds a FULL GALLON more coolant than my S10-AD truck with the 19x22 radiator. For maximum cooling, there's no substitute for volume.


Pics of your system would help. Have you modified your latch plate assembly or the lower splash pan below the radiator? Those things are integral to the air flow system on an AD truck.

Thanks for your reply, I also made a air deflector and mounted it underneath but my truck is so low I’m not sure how much it’s helping, I’m gonna move my trans cooler like you mentioned, I do not have the lower splash pan on there, with my setup it seems like it wouldn’t fit on there. I’ve been concerned that the radiator might not be sufficient but it holds a lot of coolant probably at least a full gallon. Thanks for help, gonna keep on chasing this thing down.
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[AD51]

Originally Posted by AD51

Thanks for your reply, I also made a air deflector and mounted it underneath but my truck is so low I’m not sure how much it’s helping, I’m gonna move my trans cooler like you mentioned, I do not have the lower splash pan on there, with my setup it seems like it wouldn’t fit on there. I’ve been concerned that the radiator might not be sufficient but it holds a lot of coolant probably at least a full gallon. Thanks for help, gonna keep on chasing this thing down.
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[mr48chev]

Is the last photo the way you go down the road or does it have the latch plate in place?
They have to have the panel above the grill in front of the radiator to direct the air though the radiator rather than over it.

Still if it is only going up to 220 or so and not puking coolant it is't actually getting hot for what engine you have in it. You have understand what temp that engine normally runs at in the vehicle it came in every day and not get caught up in the "I'm driving an old truck and oh crap the temp can't go that high or it will die" thing that is prevalent. It's not a 216 with a 2 pound cap anymore so 216 stuff doesn't apply anymore and if you check the application for the engine you have there is a solid chance that it's normal thermostat is 195 to begin with. Still as Miriicalpieco said the more coolant volume you have the better off you are.

[AD51]

Originally Posted by mr48chev

Is the last photo the way you go down the road or does it have the latch plate in place?
They have to have the panel above the grill in front of the radiator to direct the air though the radiator rather than over it.

Still if it is only going up to 220 or so and not puking coolant it is't actually getting hot for what engine you have in it. You have understand what temp that engine normally runs at in the vehicle it came in every day and not get caught up in the "I'm driving an old truck and oh crap the temp can't go that high or it will die" thing that is prevalent. It's not a 216 with a 2 pound cap anymore so 216 stuff doesn't apply anymore and if you check the application for the engine you have there is a solid chance that it's normal thermostat is 195 to begin with. Still as Miriicalpieco said the more coolant volume you have the better off you are.

I just removed the cover for the pic, it is always on in place. I have seen it get to 230 and puke out some coolant, I’ve never let it run any longer to see if it would keep climbing from there.
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[joedoh]

from what I see here:

you have the radiator blocked for airflow except through the shroud, the aluminum part of your shroud is too close to the rad.

your shroud is completely enclosing the fan which will block airflow. a fan should be just inside the shroud to partially (no more than half the fan blade width) out of the shroud. the only way a tunnel fan works is if there are no air gaps at the fan tips. any gaps, you have an air mixer.

your electric pusher is not open enough, you are blocking airflow going in and it will go around.

this is also why you need the lower air director, because air will choose the path of least resistance and its probably going around. use abs plastic and you can get a nice lower deflector that is air tight and routes all the air through the rad. look for places the air can get around at the top and sides, if it can it will.

[AD51]

Originally Posted by joedoh

from what I see here:

you have the radiator blocked for airflow except through the shroud, the aluminum part of your shroud is too close to the rad.

your shroud is completely enclosing the fan which will block airflow. a fan should be just inside the shroud to partially (no more than half the fan blade width) out of the shroud. the only way a tunnel fan works is if there are no air gaps at the fan tips. any gaps, you have an air mixer.

your electric pusher is not open enough, you are blocking airflow going in and it will go around.

this is also why you need the lower air director, because air will choose the path of least resistance and its probably going around. use abs plastic and you can get a nice lower deflector that is air tight and routes all the air through the rad. look for places the air can get around at the top and sides, if it can it will.

I removed the shroud to see if there would be any difference, made no difference at all. I run cool enough when I’m moving down the road it’s just when I’m in traffic or pulling hills etc. I’m starting to wonder if this radiator just isn’t doing the job. Thanks for input
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[joedoh]

Originally Posted by AD51

I removed the shroud to see if there would be any difference, made no difference at all.

well, thats what I said, the shroud you have both on the rad and around the fan blades isnt providing any benefit at all, so either having it in place the way it is now or removing it completely isnt going to change anything.

you need the fan on the engine to pull air through when you are going slow or sitting still, thats what they are for. with the big electric in front blocking airflow and the shroud on the mechanical fan making it an air beater instead of a puller, you arent going to notice any difference sitting still.

get a fan shroud that covers no less than half the fan blade and no more than all the fan blade. thats when you will see a difference.

if you are using a speedway 19x22, its a 3 core and plenty of cooling for a 350 check out skymangs sticky s10 swap thread, he uses it exclusively. you could also check your base timing it could be advanced and heating you up.

[AD51]

Originally Posted by joedoh

well, thats what I said, the shroud you have both on the rad and around the fan blades isnt providing any benefit at all, so either having it in place the way it is now or removing it completely isnt going to change anything.

you need the fan on the engine to pull air through when you are going slow or sitting still, thats what they are for. with the big electric in front blocking airflow and the shroud on the mechanical fan making it an air beater instead of a puller, you arent going to notice any difference sitting still.

get a fan shroud that covers no less than half the fan blade and no more than all the fan blade. thats when you will see a difference.

if you are using a speedway 19x22, its a 3 core and plenty of cooling for a 350 check out skymangs sticky s10 swap thread, he uses it exclusively. you could also check your base timing it could be advanced and heating you up.

Awesome, thanks I will try this, I’ll post my successes and failures.
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[mr48chev]

I'm with Joe on the shroud, there looks to be 3/4 to 1 inch of clearance between the flat on the shroud and the radiator and that isn't letting air flow.

The style of that pusher fan looks like it might block as much air as it lets though.

If the truck is just sitting in the shop with the engine off and you turn that electric fan on how much air does it actually move with the hood closed? If you hold up a T shirt or something a couple of feet from the grill will it pull it towards the grill? Then if you open the hood will it pull it better? It may be a multi faceted effort to increase low speed air flow on it.

Even with 120 louvers in my hood I fought air flow on my 48 with the 250 because I have a nearly flat "racing' flex fan on it that doesn't pull enough air to write home about. The same 2-1/2 ton truck radiator that would keep the 350 that was in it before right at 180/183 didn't work that well in slow traffic with the little fan. As soon as I hit 25/30 mph the gauge dropped right back down.

[MiraclePieCo]

The missing lower splash pan allows a significant percentage of air flow that comes through the grill to divert UNDER the truck rather than through the radiator.
On my S10/AD I built a deflector from a truck mudflap to close that gap and force air upward into the rad.

[AD51]

Originally Posted by MiraclePieCo

The missing lower splash pan allows a significant percentage of air flow that comes through the grill to divert UNDER the truck rather than through the radiator.
On my S10/AD I built a deflector from a truck mudflap to close that gap and force air upward into the rad.

Great ideas and information, I’m going to try all that until I hit the right thing. I’m running a small flex fan also, probably the reason I’m not moving enough air.
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[AD51]

Originally Posted by MiraclePieCo

The missing lower splash pan allows a significant percentage of air flow that comes through the grill to divert UNDER the truck rather than through the radiator.
On my S10/AD I built a deflector from a truck mudflap to close that gap and force air upward into the rad.

That is an awesome idea for your splash pan. I will certainly do one of this.
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[youngrodder]

One other suggestion is to look at replacing your raditaror hoses if you are using the corrigated steel flex hoses. While they are convient they are also corrigated on the inside and can cause quite the turbulance with your antifreeze flow. I too had cooling issues and I went with a 2 speed fan from Cooling components http://coolingcomponentsinc.us.com/portal/. They come with a shroud and are thin (2 3/4"). They have a brushless motor. They are not cheap but quality never is.....I also upgraded to a 4 core radiator and added a air deflector like others have stated. The combination listed above helped me out a ton. I also agree to get rid of any fans in front as they ipead air flow.

Good luck, you'll get it.

Marc

[dsraven]

maybe think about changing the stat to a higher temp. all that low temp stat does is create flow sooner so if the engine is running hot the stat is open all the time anyway.
air flow across the rad is dependent on a couple of things, fan capacity, the ability of the fan to access air and not "cavitate" and "outflow" capacity. if you have a couple of fans blowing air across the ard but then have the outlet dampered down with a big shroud that fits tight to the engine then the outflow is possibly dampered down so the air can't get away. sure, the fans are turning, but where is the air escaping to? since you have electric fans it is the shrouding between the fan and the rad that is important so the fan can access the entire surface of the rad, downstream from that a shroud is a damper and cab be restrictive. add to that the low rider effect and a closed hood. where is the air able to escape? when running down the road the engine runs cooler. maybe because there is a ram effect for the fans but also maybe because there is the ability for the hot air under the hood to be drawn out of the area under the truck? have you tried removing the hood to see if that helps low speed engine temps?

[dsraven]

think of your shop vac. if you plug the intake the vac motor speeds up, that is because it is cavitating and there is no air movement so no work to be done really. the same theory applies to the engine fan, sure, it is running fast, but maybe thats because there is basically no load. the push fan should precharge the pull fan so there really should be lots of airflow capacity assuming there is no intake restrictions. you just need to figure out how to get that much flow capacity out the other end of the ventilation flow path.

[joedoh]

one thing I didnt think of,

if its 19x22 side tank, you should be running an expansion tank on it, which has a 13-16lb expansion cap (usually comes with the rad) and a tank with a line from the BOTTOM to the vent on the rad under the cap. an expansion system burps the excess coolant (and air) out of the cap into the tank when running, then as it cools down draws just coolant (why the tube runs to the bottom of the expansion tank and not to the top) back in. after a few cycles of this the air in the system is gone.

If you plug the vent tube, the air cant escape and the cap cant draw coolant back in, air in the system is usually the reason for climbing temps, a pressurized system will have a higher boiling point but any air will be steam, which measures at a higher temp than coolant.

also, modern chevy V8s are made to have the heater lines flowing water constantly. I dont know what kind of heater you are running but if it uses a coolant line shutoff valve, it can trap air in the valve and the lack of flow through the valve can cause a higher reading on the gauge.

the coolant hose youngrodder talks about can be a problem too, mostly I have seen those sucking shut at speed.

[AD51]

Originally Posted by youngrodder

One other suggestion is to look at replacing your raditaror hoses if you are using the corrigated steel flex hoses. While they are convient they are also corrigated on the inside and can cause quite the turbulance with your antifreeze flow. I too had cooling issues and I went with a 2 speed fan from Cooling components http://coolingcomponentsinc.us.com/portal/. They come with a shroud and are thin (2 3/4"). They have a brushless motor. They are not cheap but quality never is.....I also upgraded to a 4 core radiator and added a air deflector like others have stated. The combination listed above helped me out a ton. I also agree to get rid of any fans in front as they ipead air flow.

Good luck, you'll get it.

Marc

Are you running A/C and trans cooler?
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[AD51]

Originally Posted by youngrodder

One other suggestion is to look at replacing your raditaror hoses if you are using the corrigated steel flex hoses. While they are convient they are also corrigated on the inside and can cause quite the turbulance with your antifreeze flow. I too had cooling issues and I went with a 2 speed fan from Cooling components http://coolingcomponentsinc.us.com/portal/. They come with a shroud and are thin (2 3/4"). They have a brushless motor. They are not cheap but quality never is.....I also upgraded to a 4 core radiator and added a air deflector like others have stated. The combination listed above helped me out a ton. I also agree to get rid of any fans in front as they ipead air flow.

Good luck, you'll get it.

Marc

Are you running A/C and trans cooler?
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[_Ogre]

Originally Posted by AD51

I just removed the cover for the pic, it is always on in place. I have seen it get to 230 and puke out some coolant, I’ve never let it run any longer to see if it would keep climbing from there.

230* is nothing, with 50/50 coolant mix you should not boil over
if your puking a little fluid it is thermal expansion only, leave it at that level, if you fill again you will puke again
50/50 coolant is good to 265*

i'd definitely go with a 185* thermostat and 16lb radiator cap

i had a 56 chevy bus with 396 truck motor that ran 250* plus in hot weather all the time
ran that way for years

[youngrodder]

Originally Posted by AD51

Are you running A/C and trans cooler?
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Yes to both questions...but my trans cooler is mounted on the frame rail. It is not in front of the radiator.

Marc

[mr48chev]

I'd agree that you need the coolant recovery tank as suggested earlier. The cross flows are designed to use one on most all rigs now.

The right antifreeze mix while raising the boiling point of the coolant won't help an engine run cooler.

I'm not sure on the heater hose has to be having coolant flowing all the time on later small blocks thing as though I have read it from guys posting on the net I have never seen it
I looked and can't find any definitive answer and if someone knows where a viable one is please post the link.
I did find that in the Camaros these engines came in they normally run between 210 and 220 as their normal operating temp. That is where they work efficiently.

The 160 thermostat thing just means that 160 is the minimum temp the engine run at once the thermostat is open. it has nothing to do with what the actual temp that the engine is going to operate at after it is fully warmed up and working. If you look at the vehicle model that the engine came out of most likely it had a 195 thermostat in it so getting upset and peeing on your shoes because the engine runs over 195 degrees is rather silly. Do some research and see what the normal operating temp for that exact engine is in the exact vehicle that it was built for originally.

[AD51]

Originally Posted by mr48chev

I'd agree that you need the coolant recovery tank as suggested earlier. The cross flows are designed to use one on most all rigs now.

The right antifreeze mix while raising the boiling point of the coolant won't help an engine run cooler.

I'm not sure on the heater hose has to be having coolant flowing all the time on later small blocks thing as though I have read it from guys posting on the net I have never seen it
I looked and can't find any definitive answer and if someone knows where a viable one is please post the link.
I did find that in the Camaros these engines came in they normally run between 210 and 220 as their normal operating temp. That is where they work efficiently.

The 160 thermostat thing just means that 160 is the minimum temp the engine run at once the thermostat is open. it has nothing to do with what the actual temp that the engine is going to operate at after it is fully warmed up and working. If you look at the vehicle model that the engine came out of most likely it had a 195 thermostat in it so getting upset and peeing on your shoes because the engine runs over 195 degrees is rather silly. Do some research and see what the normal operating temp for that exact engine is in the exact vehicle that it was built for originally.

The block and heads are 5.7 from an 86 G20 van, the TPI setup is from a mass air system era camaro, I’m not far away from where I need to be just need a little more air flow when I’m not moving to keep it within the range it should be. If it would top out at 220* and not go any higher under any circumstance I would be comfortable with it, just always been afraid of an overheated engine.
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[AD51]

Well I’ve done everything imaginable and I still cannot get this thing to run cool, I have followed all the advise given here and still can’t get success. I have all the air flow passages closed up to direct all air through the radiator, I have it shrouded with an electric puller, coolant is 50 50 mix, cap is 16lb, thermostat is 160*, water pump is new, radiator is new aluminum has the two 1” flues , I have checked my timing and set it with a light exactly where it needs to be, I have flushed the system twice, it will run 220* as long as I’m moving down the road but any slow moving or grade pulling it goes up. If anyone can help with any ideas I’d appreciate it.
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