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post #1 of (permalink) Old 05-21-2002, 08:28 PM
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Overheating problem

My 88 1/2ton suburban has quite the overheating problem. It's no wonder really.. it has a leaking radiator full of "barsleak" compound, and I think a bad thermostat. Anyways.. the engine gets up around 210, and I need to have the heat on constantly to help with the cooling process. So my question is this.. If I were to purchase a new radiator, and flush the cooling system out, and checkout the thermostat would everything be ok?? Also.. any tips on how to flush this thing out? And one more thing.. whats the operating temp on my engine? It's a stock 350 fourbolt main small block. Everything stock. Thanks!
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post #2 of (permalink) Old 05-21-2002, 08:49 PM
 
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Re: Overheating problem

Hmm, well, I would think that replacing everything would make it fine again. But, don't hook that new radiator up, then flush. You will just fill the new clean rad. up with barsleak, which is a no no. Pull off the old radiater and upper and lower lines and pull the old thermostat and you can prob. pour some radiater flush down the thermostat housing and pour water through it or stick a garden hose in there for an hour or two. Once it's all clean, put the new therm. in, new upper and lower hoses, and the new radiator and fill it with the proper 50/50 mix and be off, with no heater on[img]images/icons/smile.gif[/img].

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post #3 of (permalink) Old 05-21-2002, 10:10 PM
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Re: Overheating problem

couple of things to add on to willyswanter stuff,
i saw what the "stop a leak" qick fix stuff does to a motor, and never in my life will i ever put that crap in mine, it clogs up the whole system and looks like fine grit mud in there,
other thing if it still overheats after you replace the thermostat and the rad. next thing to do would be to check if the water pump is pumping like its supposed to, not sure how to check that exactly, i just take the cap off the rad. (when its cold and shot off of course) and crank it, if it spits out some and or you can see the coolant flow its good enough by me. the last thing i can think of, (if those previous are fine) is that you might have a cracked head, the motor will overheat and it will keep getting worse over time, and tricks that worked previously will become usless with time (higher revs, heater running, perfect mixtures, water only......) had it in a civic once, hated the basterd, but than again a civic is a far cry from a chevy buhhahaha.
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post #4 of (permalink) Old 05-21-2002, 10:13 PM
 
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Re: Overheating problem

Is there any water in the oil at all? This would show that you may have a cracked head or leaky head gasket. And yeah, I've seen what the stop leak stuff does too, and thats why I don't use it and why I think you should get every bit of that stuff you can out of there before putting the new stuff on.

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post #5 of (permalink) Old 05-22-2002, 09:10 PM
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Re: Overheating problem

There isn't any water in the oil which from the small amount of knowledge I do have is a good thing. I plan on flushing the whole thing to all he*l to get any sort of corrosive debris, or radiator sealent inside my cooling system out. Any tips on how to exactly flush it? I see the two main big hoses.. one at the top of the radiator and one at the bottom (on different sides of course), then there are two more.. one which appears to be going to a smaller radiator (perhaps for the tranny) and another hose that comes out of the main radiator and goes into the firewall. I imagine that is for the heater. Any input would be appreciated!
post #6 of (permalink) Old 05-25-2002, 09:41 PM
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Re: Overheating problem

those two smaller hoses youre talking about should both be going into the fire wall, kinda close to eachother, there supply and return for your heater, tranny doesn't use coolant for cooling, it just runs tranny fluid through its own radiator.
as for the flushing part, stick garden hose into the radiator hose (going into the motor) and seal with had or other device, hold until drinkable LOOKING water comes out the other end.
post #7 of (permalink) Old 05-26-2002, 10:03 PM
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Re: Overheating problem

Well, first flush the heater core with a garden hose. Make sure you blow it in the in so you don't hurt the heater core (flushing backwards might flake something loose and you end up replacing a heater core which isn't a lot of fun on a truck with AC).

Oh yeah, when you get done, bypass the heater core so you're not pumping anything through it when you do the radiator.

Since you're already buying a radiator I'd get new upper and lower hoses and new heater hoses. Get a new thermostat too, they aren't worth reusing since they only cost $5.

For flushing a block, that's a tricky one. I've always just drained the radiator and block by removing the lower radiator hose and then filled it up with pure water. The I'd run it until it got to operating temperature and then drain it. I'd continue doing this until I quit getting sediment and flakes. However, I know a guy that flushes radiators with a garden hose and runs the truck and lets everything dump on the ground. It makes sense that it works but I'd be paranoid about it feeding back through the garden hose even with the newfangled one-way valves they have in the faucets now. I imagine his way works better at getting junk out.

I don't trust those radiator flushes you buy at the store.
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post #8 of (permalink) Old 05-27-2002, 11:07 AM
 
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Re: Overheating problem

<font face="Comic Sans MS"><blockquote><font class="small">In reply to:</font><hr>

It makes sense that it works but I'd be paranoid about it feeding back through the garden hose even with the newfangled one-way valves they have in the faucets now

<hr></blockquote>

It's physically impossible for the coolant to backflow through the garden hose if you have the hose on the intake side of the water pump and you have the hose turned on. In fact I'm betting it'd be physically impossible for backfeeding even if you had the hose on the output side of the water pump. This is because the water pressure is greater than the pressure resulting from the water pump, thus until you shut that garden hose off no coolant water could possibly backfeed into the hose and therefore the house. So all you need to do is stop engine and then pull out hose and let it run on the ground to further dilute the coolant that's there to harmless levels... And then shut it off at the house a short time later... [img]images/icons/crazy.gif[/img]

</font>
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post #9 of (permalink) Old 05-27-2002, 11:28 AM
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Re: Overheating problem

Perhaps for city slickers that don't have a well. It's nothing to see a well drop to around 8-12lbs. Most radiator caps are good for 14lbs and a water pump can do 20 without a problem.

Since you're an "enginmanear" that has probably already had fluids and statics, you should know that coolant readily mixes in something such as a garden hose full of water. Now lets say that you turn off the hose with just a miniscule amount of antifreeze in it and you put the garden sprayer back on the end. It sits in the sun for an hour. Pressure builds to around 80 psi and you turn on the garden hose. All that water that was in the hose goes in to the house because most houses only have 40-70psi.

This is the reason why under federal codes you now have to use outdoor faucets with one way check valves in them. They're easy to spot because they're the only ones with the little plastic cover on them.

Granted, it takes something like half a pint of pure antifreeze to do you any harm. However, it still makes me nervous since the part that kills you is your innards rotting away.


As far as "diluting" the antifreeze to harmless levels, that's nuts. It's still the same amount of ethylene glycol wandering around in your driveway. The only difference is that you made it look like it wasn't there. And since antifreeze doesn't evaporate that won't work either. It's like those shady-tree mechanics I see that "dilute" oil with gasoline or kerosene and dump it on the ground thinking they're not actually polluting anything.
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post #10 of (permalink) Old 05-27-2002, 11:50 AM
 
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Re: Overheating problem

<font face="Comic Sans MS">I'll grant you that. I hadn't considered well water or constraints with those having never had a well...

For city water I stick with my original statement.

As to the pressure building in the hose, then yes that could happen. But that is why I made it a point to state at or near the end to leave the hose run for a little bit to chase even the last potential little bit out. End of problem...

<blockquote><font class="small">In reply to:</font><hr>

As far as "diluting" the antifreeze to harmless levels, that's nuts. It's still the same amount of ethylene glycol wandering around in your driveway. The only difference is that you made it look like it wasn't there. And since antifreeze doesn't evaporate that won't work either. It's like those shady-tree mechanics I see that "dilute" oil with gasoline or kerosene and dump it on the ground thinking they're not actually polluting anything.

<hr></blockquote>

Diluted antifreeze is a hell of a lot better than concentrated sitting around. If an animal drinks diluted it will probably cause no major harm due to the fact that there is less antifreeze per volume. If they drink the entire puddle either way they're still going to have trouble. But diluting antifreeze *does* help since an animal or whatever will only consume a certain volume. A cat for example usually drinks considerably less than a cup of water when it wants a drink. Would you rather have that cat drink a cup of highly diluted ethylene glycol or a cup of 50% ethylene glycol/water mix? If you have to choose one or the other I'd sure as hell rather that cat drink from the highly diluted stuff. Once again this is because that the certain volume the animal drinks will be far less harmful it it's highly diluted than a similar volume of concentrated.
Get the drift on that one?

I do not advocate dumping oil or gasoline or any such thing. There is a convenient place to take that. But what're you going to put your used coolant in when you flush your engine? A 55 gallon drum? Who has those just lying around? I sure don't. Some cities even say you should dilute coolant and let it run to sewer where it can be taken care of. An environmental engineer/technician over there even stated that I do believe... Not for gasoline, oil, etc, but for ethylene glycol.

<blockquote><font class="small">In reply to:</font><hr>

Perhaps for city slickers that don't have a well. It's nothing to see a well drop to around 8-12lbs. Most radiator caps are good for 14lbs and a water pump can do 20 without a problem.

<hr></blockquote>
If you are on the suction side of the water pump you will never see 20psi. You will see negative gage pressure or an absolute pressure of less than approximately 14.7psiAbsolute. It has to be this way. If you're seeing pressure on the suction side of a pump then something is definitely *not* right... You *do* know a pump has two "sides" right? The low pressure side (where it draws material to be pumped in by creating a low pressure area) and a high pressure area (the side where the material is being pumped to). You can't physically put the hose in the pressure side of the water pump anyhow since it's bolted to the block... And since a part of the system is open you can't build pressure in the engine anyhow. Any excess pressure goes out the lower radiator hose or lower port in the radiator. This is because you have the lower radiator hose off in order to feed water into the low pressure side of the water pump.

Now go back and re-read what I typed in my previous message and this one once again before once again introducing your foot to your mouth...</font>
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