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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 1979mmx350 on August 12, 2015, 10:01:54 pm
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Is this a thermostat issue? Was I supposed to dump out all the old coolant because I couldn't find a screw when I looked underneath. Air in the radiator maybe if that's even a thing? I need some suggestions.
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did the lower radiator hose have the metal coil in it? looks like a strung out spring. its meant to keep the lower hose from collapsing as the water pump sucks the coolant through it.
when i got new rad hoses in the spring i actually got the wrong one twice then the third was the correct one. and none of the 3 came with the coil so i had to reuse the one out of my bad hose
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It took me longer than it should have, but I eventually realized I never replaced the coolant that drained out of the radiator when I swapped the hoses. These need loads of this stuff and the old coolant that came out looked nasty. Only had water on hand so I'm gonna have to flush it one more time and hopefully get more of that gunk out. I was running at 200 degrees when I pulled into my drive way today, but it's usually sitting right at 190. Is this alarming in the slightest or should I be fine for the time being?
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I'm replying because I was an expert at overheating (and not knowing why) last summer.
Since you have already opened the system up and believe there is more junk in the system, take the heater hoses back off and make some sort of temporary adapter to hook a high flow water hose up to your heater core and back-flush it. The direction of coolant comes out of the intake, through the heater, and back to the port on the radiator. Run the discharge line into a white 5 gallon bucket so you can appreciate seeing all the garbage that comes out of the heater core.
Next, take your water hose and ram it into the heater port of the intake and remove the radiator cap. You will now be flushing the engine. The garbage will come out the radiator port. Keep it running until it's clear. You can flush out garbage through any port anywhere but remember it won't flush past the thermostat if it's installed.
Some other things - when you install a T-stat, drop it in FIRST, then put the gasket and water neck on top of it, not the other way around, or you'll get a T-stat lodged in the water neck. I had a really hard time getting all the air out of my system. There are crevices way back in the engine that air has to come out of when coolant runs in. I filled my engine with coolant before I dropped the T-stat in, very slowly, then installed the T-stat and filled the radiator and reservoir tank. Make sure you have a good seal on your radiator cap or buy a new one. Your system will only "suck in" coolant from the reservoir tank if the cap is good and there isn't a leak in the system. The first time you run it good and warm, expect to see a quart or more sucked in from the reservoir tank after the engine cools off and then re-fill up to the line or a little above.
NEVER use red Dex-Cool in an old school system. I made this mistake and it clogged it up like orange Jell-O. Use the classic green and a 180 stat. I am using a stock radiator in my C-10 with a 350 and the radiator was originally cooling a 4.3 V6. I NEVER get over 185, even idling in town on 100 degree days, or pulling a trailer going 65 down the highway.
Hope this helps.
Mack.
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Alright, well I followed most of your steps and flushed my radiator as best I could and then drained it one more time before filling it up with a solid coolant and tap water mix. Water still looked pretty nasty when I drained it tho. Could I be in need of a new radiator or is there really just that much crap in there. I'll see how I'm runnin after a 30 minute drive to get my back window tinted. I dropped down to 180 earlier, but I'm still sittin at 190, maybe a tad higher.
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190-200 is not overheating , even with a 180 thermostat Temps will still get above that. It's just the temperature the thermostat opens to allow the coolant to flow.
Sent from my SM-N900V using Tapatalk
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It is possible you still have that much junk in your system.
Unfortunately you need a tremendous amount of flow to really flush a radiator out, like the volume of several water hoses. But, since you're working on it and are familiar with taking the system apart, it might not hurt to take both hoses off the radiator, and feed a water hose end into the bottom pipe. Stuff the hose pipe into the bottom of the radiator and wrap it up with a bunch of plastic grocery bags and electrical tape or rags - anything to stuff it with and keep it from leaking out. The idea is to fill the radiator up from the bottom up until it flows out the top port. While water is flowing, GENTLY take a small block of wood and tap on the sides of the radiator. Since the radiator is full of water, particles will tend to break loose and float upwards and out the top hole. Once you've done this until it's ran clean, pull the hose out of the bottom and reverse the operation. Stuff the hose in the top port, or the radiator cap port, and wash downward. On mine, I held the bottom shut and filled the radiator up to the top, then quickly opened the bottom port as to let the surge of water "flush" any particles out the bottom.
I know this sounds a little redundant but it worked extremely well for me.
Your block is probably not clogged. If you've flushed the heater core and have pretty good flow, then that's not the problem either.
Your other option is to go to an auto parts store and buy some coolant flush solution. Follow the directions and add it into the radiator (not the reservoir tank) and run it for several days (several hours engine run time) and then flush, several times with clean water, then add your new coolant.
One more thing to make sure of.. Are you overheating sitting at idle or just normal driving? The fan clutch is a VERY important part of the cooling system and they do go bad..
190 degrees is not a problem. Most emissions controlled engines ran a 195 thermostat, some new vehicles even run at 210 (normal running!) I run a 180, and it tends to run on the cool side. 170 driving down the highway, and 185 is the max I ever see it, even at idle, in town, at 100 degrees outside.
Good luck and keep posting your progress.
Mack.
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Alright so ever since I swapped my hoses, I've been leaking a good bit of coolant every time i start up and give the system some pressure. It was worse, but I readjusted the clamp around the lower hose that connects to the motor but it's still leaking out slowly from there. What could be causing this? The hoses are set pretty well. The lower hose at the site of the leak is pressed in as far as I can go, but there is definitely still some space inside the hose that's molded out so it fits the connector but I can't push it in anymore. Also thanks for all the advice I'm gonna read all this stuff over til I memorize it.
190-200 is not overheating , even with a 180 thermostat Temps will still get above that. It's just the temperature the thermostat opens to allow the coolant to flow.
Sent from my SM-N900V using Tapatalk
I was at close to 240 before I realized what was goin on.
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The hose you are talking about is a 2" ID on the water pump side and a 1.5" ID on the radiator side. Go to the parts store and buy that particular hose if it's leaking. Even if the hose looks good it could still pose a problem. The water pump outlet should have a small ridge on it about 1/2" up from the bottom of the outlet pipe. Be certain the gear clamp is slightly above that ridge.
The only other place it could be leaking is the pipe outlet of the radiator where the outlet pipe is soldered into the radiator itself. In that case unless you're good at soldering, it would be best at this point to take the radiator to a shop and let them rod it out and do the repairs.
More than likely just a split hose and you can't see the split.
Mack.
EDIT - sorry I just read where you replaced the hoses already. Tell me where you see the leak, the bottom hose where it connects to the water pump or where it connects to the radiator?
It could be a water pump seal bad and it's dripping down your hose making you think it's leaking.
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The leak is definitely at the water pump side. I checked and double checked for any run off comin out of the radiator so I'm pretty dang sure.
I just got back from a car meet and a few of the guys agreed that the water pump could be the issue, but it was pretty dark so I'm definitely gonna run it and inspect it first thing in the morning.
One more thing to add. Should my engine begin heating up immediately after turning it off? I don't remember this happening just a couple days ago before taking off the old hoses, but I'm not sure if I just never noticed it.
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Yes, it's perfectly normal for the temp gauge to climb up 15 or 20 degrees after you shut the engine off.
My analog aftermarket gauge is screwed right into a port in the head between #3 and #5 cylinder. It climbs up to 200 sometimes after I shut it down. It usually reads 175 on the road.
Most factory gauges measure the temp right at the water neck on top of the intake, which would be the temp of the water coming out of the engine. Remember, your return water (after it goes through the radiator) is a lot cooler coming back into the engine.
Mack.