How to keep her cool?

Hey All,
I took the old 1010 to Denver Sunday and she did great, with one exception.
She didn’t use a drop of oil, nor ATF, but she did puke coolant a few times.
I have 33’s on her and even though her top speed is now 70mph, I kept her at 55 the whole drip. But climbing Vail Pass and The Eisenhower I had to pull over a few times seeing my lovely idiot light go red. I let her sit for 5m each time heater blowing as well and I was able to go again. Max speed 32mph up the grades.
At one point the courtesy patrol checked on me and put a thermometer in the coolant tank and it read 185, but she felt like 230 under the hood.

So....is the clutch fan stalling because of the high RPM and not pulling enough air through her? Is my gauge off. I’m definitely going to install a actual temp gauge, should I get pyrometer as well? Should I ditch the mechanical fan and put a big electric or twins on it?

she runs so well and even though she’s slow up the grade, I can’t enjoy the scenery as I’m target fixated on the indiot light.

Any and all suggestions are appreciated.

thanks all

If you still have 4.56 gears I wouldn't run it faster than 55. Too many rpms at 70mph. Also, puke coolant from where? From the overflow bottle? If so that's not too big of a deal. Water temp gauge would be important to have, normal operating water temp is 190F. Take it slower on the big grades.

ETA: last time I did a steep mountain road up hill I had to go about 20-25mph.

From my experience they never really liked long tugs up big hills. You could... Upgrade the water pump, get a coolant flush done, have the radiator dipped and cleaned, electric fans with the mechanical fan, vented hood to name a few. Lower gears too.

In my opinion it may be nearing time for a radiator if it can't keep the engine cool. You might try cleaning it out with any number of magic formulas with mixed results. Make sure there isnt any crud blocking the fins in the front of the radiator.

The fan clutch is a pretty simple device, you can usually hear it when it spools up. The hydraulic clutch is a generally reliable.

Rear cylinder coolant bypass will help. The rear pistons are undersized due to heat buildup, the $250 kit someone here sells works.

More coolant flow doesn't help so leave the thermostat in, otherwise the flow becomes turbulent which worsens the issue.
The source of the heat is the pre combustion chambers, dropping the engine speed is the key.

My 1031 overheats when running flat out and it only has 21k miles on it. Coolant is clean, overflow bottle also clean

Gripy - Yes out of the overflow tank. Ugh. 25...well it’s not much slow than 32mph.
2insane - upgraded water pump is a thought. Top down view of the rad is clean as well as the coolant.
Use the electric fans as pushers?

Swap to a 180 thermostat And a 6 blade 20 inch fan. A few of us in hot climates have done this with good results. The stock 5 blade fan just does not pull much air. Also If you have a 3 core rad upgrade to a 4 core.

ken said:

Swap to a 180 thermostat And a 6 blade 20 inch fan. A few of us in hot climates have done this with good results. The stock 5 blade fan just does not pull much air. Also If you have a 3 core rad upgrade to a 4 core.

Click to expand...

Thanks I’ll look into this was well.

Keith_J said:

Rear cylinder coolant bypass will help. The rear pistons are undersized due to heat buildup, the $250 kit someone here sells works. Awesome!!!!!!

More coolant flow doesn't help so leave the thermostat in, otherwise the flow becomes turbulent which worsens the issue.
The source of the heat is the pre combustion chambers, dropping the engine speed is the key.
Ok. That’s what I was thinking as well.

My 1031 overheats when running flat out and it only has 21k miles on it. Coolant is clean, overflow bottle also clean

Click to expand...

Same here. 29k clean as whistle.

So....after all this how do guys even move these CUCV’s with lifts and 37” hummer wheels?
I would think you have to have 12v Cummins swap and a 4L80E

I am going to the rear cylinder bypass kit as my solution to the heat issue. Then the 4L80e. Higher drag CUCVs like the 1010 and 1031 SECM dump a lot of heat into the transmission fluid through TC slip. Plus dropping the cruise engine speed to 2600 RPM will definitely help.

Keith_J said:

I am going to the rear cylinder bypass kit as my solution to the heat issue.

Click to expand...

So I did some Googling on the Interwebs and I’m not seeing any “rear cylinder bypass kit“
Or am I being a bit slow?

Thanks all

The rear cylinder bypass will only equalize the temps across the cylinders. It can't lower temps from overheating. It can only lower temps at the back of the block. Not the entire block. The temp is read from the drivers side head at the front by cylinder 1. If it is hot at number one, then it is hot throughout the block. A increase in cooling capacity will be it's only hope. If the inlet water temp from the rad is too hot you will never cool it off. The stock 5 blade fan just can't pull enough air. The original civi 6.2 came with a 7 blade fan and a 180 thermostat. Along with a 4 core rad.

Over the years I have seen several rear cylinder coolant bypass kits. Not one has claimed to reduce the operating temperature, just the rear cylinder head temperatures. In post 5 Keith j claims that they work awesome!!!!!. In post 10 he is going to install said kit. Hopefully we get an accurate review of the modification soon.

Ok. Thank you all for your input. I’ think i’ll Start with a 180 t-stat and the 7 blade fan.
Does anyone have a part number for that bad boy?

and i’ll Slow down a bit and enjoy the scenery....lol but at 32mph up the hills here in Colorado all I was watching was my idiot light.....

To be honest I would start by replacing the radiator or getting the current one rebuilt, then moving on to the modifications.

Ok. I’ll check it out, but at 29k with good maintenance records I’m not real sure the cooling system is bad.
Thats why I bought her, it was dang near like buying a new truck.
I do see a benefit of having Performance radiator build a bigger aluminum unit maybe.

thanks

I installed a new genesis radiator, Hayden 2799 clutch, derale 17120 fan, high flow 185 degree thermostat, and a kit from this thread. I have 456 gears and live in 110degree heat. It never gets above 190.

https://www.steelsoldiers.com/showthread.php?167433-CUCV-Cooling-System-Upgrade-Kit

KamikazeKunze said:

Gripy - Yes out of the overflow tank. Ugh. 25...well it’s not much slow than 32mph.
2insane - upgraded water pump is a thought. Top down view of the rad is clean as well as the coolant.
Use the electric fans as pushers?

Click to expand...

Yes you could try doing that. You can get some cheap from the junkyard.

Another vote for a new radiator. Your radiator is 30 years old. It might look good in the wide open area below the cap, but it probably has some restrictions in the tubes. Were you in 3rd gear at 32 mph doing the climb? The faster you spin the engine, the faster the fan goes, the more the water pump pumps and the more fluid the transmission pushes through the radiator to keep it cool. Try manually dropping it to 2nd next time. It might help.

Keep in mind cracked heads and weak head gaskets will cause heat build up. 29K matters not on thin steel gaskets. May I suggest a new radiator and if that don't work have the heads removed and sent to a machine shop for rebuilding and have them checked. leaking cracked heads do not need to put water in oil or oil in water. they just leak and build up heat. Good Luck. They will hold pressure when cold. The crack expands with engine heat and will begin to leak so slightly and get worse from there. Not to scare you just to make you aware. I am in the process of rebuilding an M1009 at this time and know what used 30+ year old head gaskets look like on perfect running engines. The new gaskets are much improved. Have a Great Day.