Cooling problem

Tiny
JUSTSPEED
  • MEMBER
  • CHEVROLET IMPALA
I know cooling problems are brought up quite often and get kinda old. I think my problem is a little differnent in the sense that I have found no answer and it involves a converted s10.

I have an 87 s10 ext cab truck that I converted to a v8 about three years ago. Cooling has been very hard to do since then. For the most part it was no big deal because the truck was in the woods all day at idle and keeping the truck cool at idle is not a problem. Highway speeds however are different.

Basicly If I put on a manual fan and run good highway speedsit runs cool and run hot at low speeds and idle. Use electric fan and I run cool at low speeds and idle with highway speeds running hot.

I replaced the enginge 2 months ago with a mild 350 and at the same time bought all new cooling peices. New summit rad, matching summit shroud and electic fan (Summit tech support said that combo was more than needed to keep small block cool) New mildon high flow water pump, New high performance 160d stat and solid metal rad hoses. Evey cooling peice is brand new. At low speeds and at idle It maintains 180 degrees (even though the stat is 160) At highway speeds the faster I go the hotter it gets. I thought about it and tried a few things. I made cuts in the alum fan shroud and made flaps so they will open at highway speeds and allow more air to be forced through the rad. Did not help. I took the truck out the other day and it was about 50 degrees out and at 80 mph it kept at 180. Now what does that mean? I have tried to think about everything from slowing down the water pump to speeding it up. I use v-belts and the rad is a 2 core with each core being an 1 1/4. I have no room to run a manual fan plus electric. Most of the front end has been cut out to fit the 27 1/5 x 19 rad. The tranny cooler and oil cooler are both very near pushing the front grill out. So the is not much as far as room to try to run both electric and manual fans either way. Does anyone have some insight? I am really wondering now if the outside temp can tell me something. If it is cool out and the truck runs cool does that mean that when its 70 out and it runs hot at highspeeds that the water is flowing to fast to be cooled? Whats your take?

I would like to add that the temps I get are good. I have both manual and digital temp gauges. I also have a temp gun that I have used to check the temp on the rad and and such. Which is funny cause the rad is always very cool and the high temp is always at the termastat houseing.

mike
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Saturday, January 21st, 2006 AT 9:22 AM

11 Replies

Tiny
SC1 RACING
  • MEMBER
With either an elctric fan or a engine fan the shroad has to be completely sealed. With a blade fan you want half of each blade sticking out of shroad. If it is not sealed it will run hotter than suposed to.

A few more things that will make it run hot is incorrect ignition timming, and carb settings.
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Saturday, January 21st, 2006 AT 11:28 AM
Tiny
JUSTSPEED
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Good points None of those are problems. It has to be something else

I am hoping someone knows a bit more about it. It is tuned perfectly. I have no problems tuning..I just dont get it. This s10 has been a cooling nitemare

Thanks for the help

mike
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Saturday, January 21st, 2006 AT 8:44 PM
Tiny
JUSTSPEED
  • MEMBER
Come on guys! No input? I am at a loss. I can fix and or do anything but this has me at a loss. The questiion is why does it run hot when the outside temp is above 50 and run normal when the outside temp is below 50. I'm talking only at highway speeds. At idle there is never a cooling problem. The higher the speed the hotter it gets. Unless it is below 50 degrees outside.

Mike
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Saturday, January 28th, 2006 AT 10:20 AM
Tiny
ROACHED11
  • MEMBER
I used to have an s10 with the same problem. Never completely fixed it, but some things that helped. Replaced the thermostat with a big washer to let the coolant flow faster, the thermostat caused to much restriction. If your radiator is the coolest point it seems you probably could speed your water pump up and get a similar effect. The restriction would still probably be a problem though. A pop can cut to size with a hole in the center could probably fix it if a big washer is not handy Would like to know what you find out.
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Thursday, March 23rd, 2006 AT 7:51 PM
Tiny
JUSTSPEED
  • MEMBER
Good points. The rad is the coolest point. But you know I am way ahead of you on speading up the flow. The stat is a super high volume racing stat and considering I run V-belts and there were only two diff water pump pully sizes I made my own. I went from a stock 5 3/4 to a 4 inch pulley. I took the pulley from a v8 amc engine. I thought that would help. But nope never got any cooler

It is now spring time and I cant drive the truck cause it gets too hot. I have no idea what I'm going to do. Taking it to a local garage is pointless cause they take forever and they dont do very well with non-stock vehicles.

Mike
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Friday, March 24th, 2006 AT 6:41 AM
Tiny
ROACHED11
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Maybe were looking at this wrong. Was thinking about this this morning maybe were moving the fluid too fast. If the radiator is the coolest point maybe the fluid is running through it too fast not giving the fluid time to disipate the heat to the radiator. Might try slowing everything down and see what happens. Let me know what you think. If I build another s-10 would like to know how to fix this problem
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Friday, March 24th, 2006 AT 3:59 PM
Tiny
JUSTSPEED
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You have the same thought I did. But how do you slow it down? I went back to a stock pully on the water pump so it is now back to normal and nothing really changed. I have already been to the hardware store looking for a washer that would fit but have a smaller opening for the water. Could not find anything. Besides if I slowed to flow through the system would that not create other problems. Like the water pump trying to move water and it wont move. Good thought and I am willing to try. It just bothers me that the faster I go the hotter it gets.

Mike
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Saturday, March 25th, 2006 AT 9:36 AM
Tiny
ROACHED11
  • MEMBER
Not sure how else to slow it down besides the washer trick, I agree it could cause other problems, but basically isnt a water pump for a 350 like a centrifical pump? If you pinch it down a little what could it really hurt. Just had another thought. Is there a way to restrict the water coming out of the radiator? This might actually be a better option. Let Me know what you think
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Saturday, March 25th, 2006 AT 3:51 PM
Tiny
JUSTSPEED
  • MEMBER
You know after reading your post this morning I gave it some thought and decieded I could in fact slow down the water flow. Here is what I did. I took and old stat and cut the guts out so it was no more than a washer with a big hole in it. I then took a peice of sheet metal and placed the stat on it. I traced out the exact size then cut it. I mounted the sheet metal to the stat useing 3/16 rivots ( 4 of them) It sealed up perfect. Then all I had to do is figure out what size hole I want to make. All things considered I went with 1/2. I mounted it and ran some tests. At idle warmed up it was running 170. Took it on the road and same old thing. The faster I went the hotter it got. As a matter of fact it got hotter faster then with the reg stat in. So right now I am considering trying to step up the hole size to maybe 1 inch. Of course at that size I might as well run no stat or anything at all. I might try running nothing and seeing what happens. I do think you for helping me with this problem. I cant understand why with so much knowledge in these forums nobody is willing to chime in with some thoughts or even the answer to the problem. This is the most mind blowing thing ever.

I keep thinking about how the rad is cool and how that makes no sense. The water pump is of the best qaulity and is also a high volume pump. The stat I use is a super high flow. Hell I am even useing stainless rad hoses so I know there not closing. Hmmmmmmmm

I dont want to run with no stat cause warm up would be hard on the engine but I think I might just give it a try to see what happens at high speeds.

I just remembered that a friend said to me that I should try useing a four core rad rather than the 2 core I am running now. He thought that the 1 1/2 cores in mine might be flowing way to fast. I never put much thought into that seeing how The rad is made for better cooling. I dont know.

Mike
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Saturday, March 25th, 2006 AT 5:52 PM
Tiny
ROACHED11
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Indeed you may be on to something with the bigger radiator. I have also noticed there is a ton of unanswered posts in here tried to answer some of the no brainers my self the other day this one I had a personal interest in though cause of my experience with the same thing. Well let me how it works out.
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Saturday, March 25th, 2006 AT 11:22 PM
Tiny
JUSTSPEED
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Yeah your right. I'm going to have to keep trying. Something has to be right. Once again thanks for all your help.

There are so many small block s10's and blazer's out there. You would think there would be more info on this problem.

Mike
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Sunday, March 26th, 2006 AT 7:56 AM

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