[bk2life]

way back at some post of mine in this thread i mentioned you should be able to remove your fans completely and go drive. anything above 40mph your truck should not over heat, in fact should be perfect. I have a freeway very close to me and i jump on the highway and take a 30 mile cruise to test vehicles before i give them back.
When i had a temp creeping issue on my hombre, i figured it out to be too much air circulation. Meaning, hot air was escaping and being pulled back in the rad above 60mph. there was a bubble being formed under the truck causing this.
under 60 mph no issue, above 60 it would creep up and get up to 230 before i had to slow to 60 to get the temp to cme down.
I still will bet money its your airflow.
OR, you have an internal issue with your engine. wrong head gaskets, or something more intnerla to your water jackets.
It's getting cooler outside, you shouldn't be having any getting hot issues at all

 

[Joe White]

I don’t doubt the recirculating of air. But I did test without running the fans. Engine just got hot really fast. What did you do to fix the “air bubble”

 

[Rhotpursuit]

I don’t doubt the recirculating of air. But I did test without running the fans. Engine just got hot really fast. What did you do to fix the “air bubble”

Before worrying about the bubble, I'd get a grille that Han't been hacked at the top, or come up with a way to seal that gap at the top of the core support.

I'm not an expert on radiator size, but back in the day I had a V8 Vega. I had overheating issues so I had a 4 row radiator made. Didn't help. I finally went to the Flex A Lite facility, they were in my hometown at the time, and they came out and took a look. 10 seconds into it and they told me the radiator was too big, and the Flex A Lite fiberglass fan was junk. They went back inside and came out with a 6 blade stainless steel fan. They told me to go back to 2 row radiator and life would'd be good. They were right. No more overheating issues. This was before electric fans came to life...about 1976. You might consider replacing the radiator and sealing up the gaps.

 

[Joe White]

I've looked up the grills and they come like that. It's a 93 s10. Didn't think it looked like someone cut it apart. I was thinking of sealing up the bottom and top area so they only air that can go into the radiator is from the front of the grill. I wouldn't doubt that it is recirculating on the bottom. If you stand right in front of the truck you can feel the hot air getting blown towards you. I'm guessing since the fans and engine are so close together that it just bounces off the engine and deflects it towards the front of the truck. Now if I can go find a 94+ s10 in a junkyard they might have that same plastic piece. Looks like it would be similar in size to what I need. But I know this wont fix my problem at all. I've covered it with cardboard and tape to test it, seemed to help during 100 degree days, but at this time probably would make no difference.

 

[Rhotpursuit]

I've looked up the grills and they come like that. It's a 93 s10. Didn't think it looked like someone cut it apart. I was thinking of sealing up the bottom and top area so they only air that can go into the radiator is from the front of the grill. I wouldn't doubt that it is recirculating on the bottom. If you stand right in front of the truck you can feel the hot air getting blown towards you. I'm guessing since the fans and engine are so close together that it just bounces off the engine and deflects it towards the front of the truck. Now if I can go find a 94+ s10 in a junkyard they might have that same plastic piece. Looks like it would be similar in size to what I need. But I know this wont fix my problem at all. I've covered it with cardboard and tape to test it, seemed to help during 100 degree days, but at this time probably would make no difference.

For some reason, a late model 2nd gen was stuck in my mind.

 

[bk2life]

just bounces off the engine and deflects it towards the front of the truck

try removing your hood and go for a drive. That should help out the diagnosis. No hood, plenty of places for hot air to go and not bounce back.

 

[KJF95S-10]

try removing your hood and go for a drive. That should help out the diagnosis. No hood, plenty of places for hot air to go and not bounce back.

This. You can almost rule out airflow entirely just by doing this.

 

[mmettlen]

I'm having the same problem as the OP. I've replaced the radiator with a dual-core, replaced the hoses, head gaskets, and even the heads, all since overheating began, and everything helps a little, but it still overheats. It will sit at 190 until you get up to speed, then it slowly climbs in temp and never stops. I'm going to try the hood and if that doesn't work, the water pump, as it is the only piece of cooling system I haven't changed. I was about to write a post asking for help when I saw this one. Mine is literally exactly the same situation and symptoms. The only thing I can add is I have it timed well and it starts easy and runs well. I do know what is in my engine as it came out of another car I had for years that saw much harder abuse without overheating. I did keep all the 4.3 accessories to go on the front though.

 

[Joe White]

I did change my timing, not perfectly but better, made no change to the overheating problem. Now I do feel like taking the hood off might help, but I'm worried once I get it off its not gonna be fun to get it back on.

 

[mmettlen]

Mine is a 94, and the hood is only two bolts under the plastic cowling. It's by far the easiest hood I've ever taken off or on. It definitely helps to have a second person.

 

[Joe White]

Recap/Update. I've had to take the truck on a highway drive about 210 miles each way so I learned a bit more of what it can do. Driving when it is 80-85F outside the truck will sit around 210F at 70mph once it gets under 75F outside the truck starts to cool down quite a lot, to around 190F. Since I had to drive back, I had taken off the front grill used some type of plastic board and basically made it impossible for there to be recirculation in front of the radiator, all air that goes into the front of the grill has to go into the radiator. But this made little to no difference, I was able to get the a/c leak fixed so I can run that, but it seems to make little to no difference when on either. So my only thoughts on what my problem can be is circulation or air not escaping the engine compartment properly.

For the air not escaping properly, my thought is maybe the cowl hood is forcing too much air into the engine bay, but I doubt it would cause that much of a problem.

For the recirculation issue, I'm thinking that the new radiator might be acting like a filter with particles that where in the coolant a while ago. If that's the case I would need to flush out the radiator.

It really shouldn't be an airflow issue because its on highway, and I got some not so cheap Derale High Performance fans, which I have seen used on a lot higher hp applications. I'm about ready to put the radiator in the bed of the truck, but I'd like to not do that.

 

[Rhotpursuit]

Too much radiator...not enough fan?? Mine doesn't get above 207-208 with the AC on in the desert heat.

 

[mmettlen]

I'm not trying to hijack your thread, but I thought I would share where I'm at with the same problem. This weekend I replaced the water pump, which was the last piece of the cooling system that wasn't brand new, and flushed out all the water passages with a water hose. It managed to go about 15 miles before overheating. I pulled into a parking lot and took the hood off. It ran 195 all the way home at a steady 60 mph with the radiator running, but when I slowed down at my road it started climbing again and was 210 by the time I got to my driveway. Next on the list is to cut the core support and move the radiator forward so I can change the fans over from pusher to puller.

 

[Joe White]

Too much radiator...not enough fan?? Mine doesn't get above 207-208 with the AC on in the desert heat.

I had a bigger radiator at one point, actually the one shown in my first photos. Just delayed the effect of the engine warming up since there was more coolant.

Only smaller I think there is, is the stock 4.3 radiator. I've heard people use that, but is that too small to use with a/c?

 

[Rhotpursuit]

I had a bigger radiator at one point, actually the one shown in my first photos. Just delayed the effect of the engine warming up since there was more coolant.

Only smaller I think there is, is the stock 4.3 radiator. I've heard people use that, but is that too small to use with a/c?

@Harley has one about the size of a postage stamp...well, maybe a little bigger. Mine is from a 2000 Grand Am, along with the Grand Am fans.

 

[eshaw]

I still think you have way too much radiator. It also matters on how they are constructed. There's a reason the manufacturers moved away from the multi-tube cores and went to a single larger cross section for the tube in the core. If you circulate the coolant to quickly it doesn't give it time to absorb the heat the engine is putting out. Mix is important also. I think you should start by putting a radiator in the forward position. I'd start with a 4.3 radiator.

 

[Joe White]

I still think you have way too much radiator. It also matters on how they are constructed. There's a reason the manufacturers moved away from the multi-tube cores and went to a single larger cross section for the tube in the core. If you circulate the coolant to quickly it doesn't give it time to absorb the heat the engine is putting out. Mix is important also. I think you should start by putting a radiator in the forward position. I'd start with a 4.3 radiator.

if It was the radiator I would think the one I have in it now is good. It’s either a 2in 2 core or 3 core. Don’t remember. The one I had in it was a 2.75in 4 core I believe.

Also what do you mean by putting the radiator in the forward position. I can’t put the condenser behind it. Otherwise I can’t mount the fans, and also the a/c wouldn’t work well.

 

[Rhotpursuit]

if It was the radiator I would think the one I have in it now is good. It’s either a 2in 2 core or 3 core. Don’t remember. The one I had in it was a 2.75in 4 core I believe.

Also what do you mean by putting the radiator in the forward position. I can’t put the condenser behind it. Otherwise I can’t mount the fans, and also the a/c wouldn’t work well.

Recess the radiator inside the core support. There's nothing saying it has to be all the way in. My ac condenser is in front of the radiator, but still inside the core support.

This is my condenser. Note that it is in the support, and the hood latch is unmolested.

These are pics of the fans. They attach directly to the radiator as the factory designed. As you can see, the tanks are not all of the way in the support, yet there is plenty of room between the fans and front end accessories. Those "wings" on the side of the fans allow them to snap into place on the radiator.

Here's a pic of the air inlet tube in place. A couple of the finger on the fans needed to be filed...not cut, to clear the tube. It didn't take much to clear.

 

[Joe White]

Recess the radiator inside the core support. There's nothing saying it has to be all the way in. My ac condenser is in front of the radiator, but still inside the core support.

This is my condenser. Note that it is in the support, and the hood latch is unmolested.

View attachment 367778

These are pics of the fans. They attach directly to the radiator as the factory designed. As you can see, the tanks are not all of the way in the support, yet there is plenty of room between the fans and front end accessories. Those "wings" on the side of the fans allow them to snap into place on the radiator.

View attachment 367779

View attachment 367780

Here's a pic of the air inlet tube in place. A couple of the finger on the fans needed to be filed...not cut, to clear the tube. It didn't take much to clear.

View attachment 367781

I will take some more pictures to show, but the radiator and condenser for me are is far in as they can go. I think my problem is how far forward the motor is. I’m not sure on dimensions on a 350 sbc is vs an ls. The engine is right against the firewall so it can’t go any further back

 

[Rhotpursuit]

I will take some more pictures to show, but the radiator and condenser for me are is far in as they can go. I think my problem is how far forward the motor is. I’m not sure on dimensions on a 350 sbc is vs an ls. The engine is right against the firewall so it can’t go any further back

You'll most likely need to get a thinner radiator. That thing is huge. It looks like it sticks out at least 2" more than mine. You might have to open up the sides on the core support a little more to get it in there.