85 C10 Fan help

[Joshua Keith]

Hello all!

I have an 85 K10 crate 350 engine that’s running hot. The truck is running around 220 at both idle and highway speeds. Thermostat is new, fluid is full and has a stock radiator. There are 2 issues I see.

1. It has a 3 inch body lift raising the radiator and shroud above the level of the fan.

2. It has a flex fan and no clutch.

Can anyone point me in a direction of a good clutch/fan setup? I see 5 blade fans withy the oddly spaced blades or could I go with an evenly spaced 6 blade? Any 2¢ about the subject would be greatly appreciated! Thank you!

 

[Arkansas_V8]

I have always ran electric fans. Never had an issue. If that is an option for you.

 

[Snoots]

If you're gonna stay stock, a 7 blade fan with a Hayden Thermostatic clutch. If you want to go electric, there are some GREAT threads here on fan choices, set up (with shrouds) and wiring.

 

[chengny]

Hello all!

I have an 85 K10 crate 350 engine that’s running hot. The truck is running around 220 at both idle and highway speeds. Thermostat is new, fluid is full and has a stock radiator. There are 2 issues I see.

1. It has a 3 inch body lift raising the radiator and shroud above the level of the fan.

2. It has a flex fan and no clutch.

Can anyone point me in a direction of a good clutch/fan setup? I see 5 blade fans withy the oddly spaced blades or could I go with an evenly spaced 6 blade? Any 2¢ about the subject would be greatly appreciated! Thank you!

Maintaining proper clearances between the fan blades and the shroud is critical to the efficiency of the cooling system. That includes how far the fan blades are set into the shroud.

 

[Matt69olds]

While it’s hard to beat the airflow of a mechanical fan, I would suggest electric fans for you. If the body lift prevents the fan from drawing air directly thru the radiator core, the best fan and clutch will be a compromise at best in this situation.

don’t get cheap on fans!! Try to adapt a late model factory fan from a big well optioned car. The cheap parts store fans have seriously inflated airflow ratings. Make sure you use quality wiring and relays.

 

[Joshua Keith]

Well, I think I found an issue here. I tested my temp gauge for accuracy just to be sure it wasn’t just the gauge being off before I put money into an electrical fan and new radiator. Has anyone else had issues with an inaccurate gauge? Could something else be making the gauge inaccurate? Thank you all.

You must be registered for see images attach

You must be registered for see images attach

 

[Matt69olds]

I seem to recall reading somewhere that certain sending units need to go with specific gauges. Get another sending unit, just for comparison. Do all square body temp gauges read up to 260?

 

[Joshua Keith]

I’ve been doing some research and have ran across that too. Looks like they all run up to 260. I’ve tried 2 different sending units. It would really help if someone out there knew what sending unit they had in their truck! thanks

 

[roundhouse]

I was koi’s fixing to ask of you had verified the temps with a laser thermometer

And ask if it was over heating while sitting still or if it happens while driving at highway speed

Overheating while sitting still is an airflow issue
Fan or shroud or the air is leaking past the rad instead of going thru it

Overheating at highway speed is a water flow problem
Stat not opening , water pump not moving enough water

Lower hose collapsing etc

 

[82sbshortbed]

I think I used to have a spacer for my fan in my 75 GMC back in high school that pushed my fan deeper in the shroud and closer to the radiator. I don't know if they still make those or not.

 

[thompson335]

if you are maintaining the same temp at idle and speed it is not fans or shroud. It is more likely something that is not affected by air flow more like gauge thermostat, blockage, ect

 

[Joshua Keith]

Thanks guys. I posted some pics ^^ up top and found out my gauge is inaccurate for some reason. Still not sure if it’s a bad gauge or if I have the wrong sending unit..Possible bad ground? I have. I have no idea..

 

[chengny]

Thanks guys. I posted some pics ^^ up top and found out my gauge is inaccurate for some reason. Still not sure if it’s a bad gauge or if I have the wrong sending unit..Possible bad ground? I have. I have no idea..

The gauge and sender have to be compatible. The OEM 1513321 "nail head" style senders are getting wicked hard to find. The after market replacements don't have the same resistance curves as the original senders.

Read these threads - a couple of very knowledgeable guys cleared things up :

https://www.gmsquarebody.com/threads/new-temperature-gauge-reading-low.22367/

http://67-72chevytrucks.com/vboard/showthread.php?t=661104

BTW - what's up with the installed sender in the image you posted? Is that the one that originally came in the truck?

You must be registered for see images attach

 

[Joshua Keith]

Awesome! Looks like I’ll try to get ahold of one. No, I bought another sending unit for 8$ to see if maybe it was bad. Both are same part numbers. Figured it’d be easier to test one already out of the block instead of getting coolant everywhere.

 

[Snoots]

I''m not disputing the fact that you could have a sender (or gauge) that is inaccurate but you will not get the proper reading from the metal like the method you are using.