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cooling recommendations

J

joshkbomb

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Lafayette, CO
So lately my truck (87 blazer 350) seems to be running hotter than normal even on the cooler days. I replace the thermostat and it had no effect, so I'm thinking of using this as an excuse to upgrade my cooling system. I replaced the radiator (3 core) and water pump (stock) two years ago so they're not bad, but I can't think of anything else it would be. Except maybe the fan clutch, how stiff is it supposed to be when the engine is off and cool?

I want to get a 4 core radiator like this: http://www.partsamerica.com/productdetail.aspx?MfrCode=PCE&MfrPartNumber=433730&PartType=31&PTSet=A
Would this provide that much more cooling? I was thinking of an aluminum radiator, but they seem to be higher in cost and I'm not sure I want to spend that much or do anything other than a direct replacement.

The thing I don't know what to get (because of too many choices) is a water pump. I figure I should replace it with a high flow version, but which one? Summit, Jegs, even Autozone and Checker have several so I have no idea which other than picking the cheapest. Some help?
 
Fan clutch when cold and engine off should not turn hardly at all hen trying to spin it. If it freely spins when cold it is bad. If the engine overheats while driving down the freeway then rule out the fan clutch as you can remove the fan completely when driving at speed and it will not over heat because of the air flow across the radiator.
 
What is hot, do you have an actual read out? If yours is a fuel inj, it should run 210-225 all the time. Pump won't cause it unless it is having other issues as well.

I'm running a 4 core in mine out of a big block-ac model in front of a sb-no ac. Never gets over 205, stock pump...rad cost me $250 at car quest in arvada.
 
bent72 said:
What is hot, do you have an actual read out? If yours is a fuel inj, it should run 210-225 all the time. Pump won't cause it unless it is having other issues as well.

I'm running a 4 core in mine out of a big block-ac model in front of a sb-no ac. Never gets over 205, stock pump...rad cost me $250 at car quest in arvada.
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Well, my temp gauge is weird. Usually it reads about 170 but since I know the thermostat doesn't open until 195, I figure that's actually what it means. Assuming that, the engine has been hitting 230-240 on the hotter days. I actually had my check engine light come on a couple times until the engine cooled some. It is fuel injected.

Does this big block radiator fit without any modifications? Do you have a part number or how to describe to the guy at Car Quest what I want?

I think I'm going to try replacing the fan clutch first though because most of my problem is the stop part in stop and go traffic. It does get hot when just cruising around at 45 (which I assume is a speed the fan has nothing to do with), but not as bad as when waiting for a light to go green. Maybe I need to try and fix the temp gauge so that it reads more accurate before I spend a few hundred upgrading everything. So when trying to fix this, is the problem most likely the guage or the sensor? For that matter, where is the sensor?
 
roadnotca said:
RedLine Water Wetter will knock ~15* off the temp, if there's no functional problems.
Click to expand...
If it's only a few dollars a bottle, I'll have to try that Water Wetter stuff and see what the deal is.
 
If it is overheating in stop and go traffic. I would bet your fan clutch is bad.
When you replace it get a heavy duty one. Do you still have the stock shroud on your radiator? Gotta have one or it will not cool properly.
 
Thunder said:
If it is overheating in stop and go traffic. I would bet your fan clutch is bad.
When you replace it get a heavy duty one. Do you still have the stock shroud on your radiator? Gotta have one or it will not cool properly.
Click to expand...
I still have the shroud on.
What's the difference between a regular and heavy duty fan clutch? It doesn't seem like the kind of thing that would have ratings like that.
 
I have one off of a 93 Suburban, fan, clutch and all, Let me know if you are interested. Just have to find it in my messy garage. I'm cheap also.

I have a 4 core in mine and since I couldn't make the fan from the sub work with my shroud and my old fan from old motor was not reverse rotation, I ordered a flex a lite fan and fan spacer. I rarely ever hit the lowest mark on my guage even at over 100 degrees going uphill.
 
Fix the little things first. Check the temp guage, fan, water level, 15 psi cap that works, bla bla... if you gauge is not factory, it will be in either cylinder head.

Stupid question, is the thermostat in backwards?

After you get to this point, unless the water looks like tar, it should still run cooler. As for the radiator, I just had them look up one that fits my year, and checked that all of the dimentions were the same except the core thickness.
 
I have also heard of that water wetter, my buddy says they sell it at drag strips and people put it in before a run. I gotta get me some of that too.
 
bent72 said:
Fix the little things first. Check the temp guage, fan, water level, 15 psi cap that works, bla bla... if you gauge is not factory, it will be in either cylinder head.

Stupid question, is the thermostat in backwards?

After you get to this point, unless the water looks like tar, it should still run cooler. As for the radiator, I just had them look up one that fits my year, and checked that all of the dimentions were the same except the core thickness.
Click to expand...
I guess I have to figure out how to check the temperature guage and sender. One of them is obviously bad.
I don't know how to check for a good radiator cap, so I'll just buy another.
No, the thermostat isn't in backwards. I rember putting in correctly this time because a friend came over and distracted me to the point of forgetting to put the new one in until I had put everything back together!

I don't think my fan clutch is bad, I did some research, tested it, and it seems okay.

Even though the fluid looks good, I think I'm going to try and get the system flushed. Including pulling out the plugs at the bottom of the engine and cleaning it out.
 
No, the thermostat isn't in backwards. I rember putting in correctly this time because a friend came over and distracted me to the point of forgetting to put the new one in until I had put everything back together!
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So is there a thermostat in there or not. If you do not have a thermostat that is your problem.
 
4X4HIGH said:
So is there a thermostat in there or not. If you do not have a thermostat that is your problem.
Click to expand...
It is in there. I had to take everything apart again to put it in, which is why I remember putting it in right.
 
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