Engine overheating

[1984K20CD]

Just bought a 84 K20 has a plow on it was driving home got warmed up then started to over heat 225 plus. Pulled over temp slow goes down. Limped it home, changed thermostat to 180. It idles fine around 190 then as soon as you drive over 30 heats up pull over goes down to 190. Truck has no fan shroud I’m on the hunt for one now. Any thoughts? Looks like 2 core radiator also.
Thanks, Derek

 

[Frankenchevy]

The fan is pretty important at idle, but you’ve described that’s not where the problem is.

May be the water pump or the radiator. Water pumps aren’t too expensive.

You could try draining the radiator into a 5 gallon bucket to see how funky the coolant is. Once empty, you could do a garden hose flush on the radiator.

Might need a new radiator or your current one rebuilt. Also, if there are enough of the fins bent flat, there is a comb that can straighten those out.

 

[1984K20CD]

Thanks for the info. A guy near me has a radiator out of a 1990 suburban would that bolt in?

 

[QBuff02]

fan shroud will make a difference as it directs the air through the radiator properly. Also, check the fan clutch if it has one (which i'm assuming it does) it's probably failed or close to failing and the fan is not turning fast enough and drawing the correct amount of air through the radiator. which back to the shroud thing, if it's not pulling enough air it won't cool down correctly. pull the cap on the radiator and look at the condition of the inside if it. it could be plugged up as well. But my money is on the shroud and the fan clutch.

 

[1984K20CD]

Thank you very much.

 

[1984K20CD]

Here’s a picture of her.

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[DoubleDingo]

Definitely clean the radiator and cooling system as a whole. And get a shroud.

 

[jjester6000]

Just bought a 84 K20 has a plow on it was driving home got warmed up then started to over heat 225 plus. Pulled over temp slow goes down. Limped it home, changed thermostat to 180. It idles fine around 190 then as soon as you drive over 30 heats up pull over goes down to 190. Truck has no fan shroud I’m on the hunt for one now. Any thoughts? Looks like 2 core radiator also.
Thanks, Derek

If I were you, I would put a 165 degree thermostat in just to see if you can compensate for the issue, to me it sounds like your radiator may be plugged up (You could use laundry detergent to clean it).

Also did you consider that the plow may be blocking airflow to your radiator? It could all be an airflow issue.

 

[1984K20CD]

I will clean radiator and cooling system and see what that does. Thanks guys.

 

[Hatchet54]

Jester brings up a good point about the plow. If you are driving with it in the up position, that would be a huge change in designed air flow over the radiator. Coupled with a potential water pump/clutch etc. issue that would settle it I think.
All mentioned fixes are quick, cheap and easy. If you decide to go the new radiator route, I recommend a Champion 3 core. They are on eBay for $200 flat, have a lifetime guarantee and I made mine bolt up almost perfect. Water pump is a little more involved but they can be done in a couple of hours and for like $50.

Sweet truck!

 

[DoubleDingo]

I have a feeling the biggest culprit is the lack of a shroud. But definitely do the fixes first, as stated, they're easy. I'd shy away from a 160 thermostat unless you're planning to switch it back to a 180 or 195. During the cold months a 160 will never get warm enough to run the heater. It will blow semi-warm air after a while, but it's miserable until the engine gets warm enough to feel warm air from the vents. If you need a plow, you need a warm engine in the wintertime.

 

[gotyourgoat]

My first thought was the giant plow on the front is blocking airflow...
Maybe ditch the plow until it's cold.

 

[75gmck25]

Changing to a 160 degree thermostat will not fix an overheating problem. It will just take a little longer to warm up and overheat .

I have found it useful to look up the exact year online with Rock Auto and see what they have listed for radiators, fans, etc. GM used a couple different radiator dimensions over the years, and there are 2, 3, and 4 row versions. In most cases you can swap in a larger radiator if you get the right rubber inserts that fit into the radiator support and hold it in place. There are also at least three different fan clutches (standard, HD, and severe duty), and A/C trucks used a fan with more blades (7, IIRC). I think all the 73-87 trucks had a stock fan shroud of some type, so somebody must have removed yours.

Bruce

 

[MisterB]

Make sure you don't have an air pocket trapped in your cooling system.

Sent from my SM-N975U1 using Tapatalk

 

[legopnuematic]

As others have mentioned above, a lower thermostat temp won't fix overheating, as it gives the radiator less of a chance to radiate the heat out, since it is constantly flowing it ends up heating all of the coolant up and then overheating.