Tech: At wits end with an overheating motor, long post

customcj7 · May 12, 2017

This is going to be long, but I'm beyond frustrated.

80 CJ7 with a 351w from a Skiboat.

Back in November I suffered an electrical meltdown in the best way to describe it. My electrical system was a god awful spiderweb of hacked together wires and fire hazards. It's amazing the jeep even ran to be honest.

So I decided it was time to redo all the electrical and do it right. And in that time frame I'd tune up the motor as well.

Fast forward to now, here is all that was updated:
-All new electrical harness, and wiring throughout with proper connections, relay boxes, sealed connections, the whole 9-yards. Definitely no booty fab.
-New plugs and wires
-New distributor cap only with new rotor, distributor was not removed
-New Ignitor III ingition system to replace the old points design
-New Capacitor
-New high output alternator

Now I get it all wired up and go to fire it up, and it started overheating. I burped air for a long time and then did some more digging.

Before my engine had a 195 t-stat and ran around 200 constant occasionally getting up to 210 on a hard load. But that was it. I never let it get hotter than that or I'd shut it down and let it cool.During this time of the wiring overhaul the engine sat dry.

To make this short, after an assload of trying to figure out what's wrong this is what's been changed on the cooling system. After each upgrade change, I'd try and see if that fixed the issue. These were not all done at once.

-Underdriven crank pulley changed out for an overdrive crank pulley, which explains some of my past charging issues I had as well
-New 180 T-stat correctly installed and verified twice now
-New temp sending unit, verified accurate with Ohm meter, Temp gauge was checked as well and is accurate per Autometer specs
-New Water pump, correct turning direction for my serpentine belt assembly
-New Novak aluminum radiator, replaced the old one which did have a fair bit of scaling on it.
-New fan since Novak sucks and that's another story.

So here I am with an entirely new cooling system now trying to run 210 and creeps up to 215 before I shut it down.

-I've checked the timing and I'm dead on 10 degrees BTDC per timing light and within exact specs for that motor
-Checked for a lean run on the carb, removed fuel pressure regulator and opened up the settings on the carb and she's running rich now
-Burped and tried to burp as much air as I can, I'm betting it's still this
-Firing order is correct
-No fluid in the oil, but possible head gasket leaking exhaust gasses.

So, that's where I'm at. The frustrating part is that I'm betting, if I didn't have the 195 t-stat in there before, the engine would have run even cooler than before. I thought I had a 180 and the motor was just hot like most Fords. But everything ran fine before. And now, she cranks right up and revs clean and runs smooth as silk. Sounds like a million bucks and runs great, but hot as ****.

This weekend I'm going to jack up the front end as much as I can to try and get any remaining air out. But anyone got any other suggestions? I'm beyond exhausted and my jeep hasn't looked this well put-together ever, but I can't even wheel it. Damnit.

Pics for grins and giggles.

TBItoy · May 12, 2017

are you trusting the gauge or checking with an infrared temp gun?
Same temp gauge as before?

jeeptj99 · May 12, 2017

Might be a crazy one but is the radiator blocked or air restricted?

pholmann · May 12, 2017

This may be a stupid question, but did you replace the radiator cap with the radiator?

d_daffron · May 12, 2017

I assume since you havnt said anything about it the answer is no, but you havnt changed the waterpump anytime recently, As you probably know there are two different waterpumps for a small block Ford depending on whether your belt system spins the waterpump clockwise or counterclockwise.

My best guess is:
I had an issue on my big block ford where all but two fins rusted off the waterpump from sitting without coolant in it. It always ran a little hotter than I'd like till another fin finally fell off the pump and it started overheating. Might be worth checking, would just cost some coolant and a couple gaskets, also while youre in there make sure the separator plate is still in decent shape behind the pump.

customcj7 · May 12, 2017

TBItoy said:
are you trusting the gauge or checking with an infrared temp gun?
Same temp gauge as before?

Same gauge as before. I've verified it with Autometer by checking it with grounding it out, and with an Ohm Meter. Which I would believe is accurate based on it reading 200 before and with a 195 T-stat in it prior.

I've thought about getting a Temp gun to see if I can find hotspots.

Radiator blocked or restricted, I'm not sure if I understand. The hoses are new with wire wrap so no kinks, and it's a brand new radiator. I'm trying to burp as much as I can using the bleeder funnel in the picture.

New cap with new radiator, but I haven't run it with the cap on yet as I was still trying to bleed the air. From my understanding the cap will only raise the boiling point, not keep it running cooler. I never let it get that hot so as not to damage the heads. With anti-freeze in it my boiling point should be about 220-225 without the cap. But maybe I'm missing your point. I figured if it can't run cool at idle with the fan constantly on, something is very wrong.

I've got a counter clockwise pump on my setup for the Serpentine belt setup. New pump.

pholmann · May 12, 2017

Actually the cap does keep it cooler. Sounds crazy but it keeps the hotter areas from creating steam. I would run it with the cap on it and eliminate it. When areas of your cooling system are hotter than others, it still needs that pressure to raise the boiling point. It just helps to keep the cooling system temps more even.

customcj7 · May 12, 2017

pholmann said:
Actually the cap does keep it cooler. Sounds crazy but it keeps the hotter areas from creating steam. I would run it with the cap on it and eliminate it. When areas of your cooling system are hotter than others, it still needs that pressure to raise the boiling point. It just helps to keep the cooling system temps more even.

How do you ensure you're getting all the air out? Just burp it from time to time and keep adding fluid?

redneckengineered · May 12, 2017

No one has stated the obvious problem. It's a Ford.

Sorry man, I couldn't help myself :flipoff1:

customcj7 · May 12, 2017

redneckengineered said:
No one has stated the obvious problem. It's a Ford.
Sorry man, I couldn't help myself

That took longer than I expected. You're going need to control your small block envy. I know you have to make up for your "Small" displacement with a Big block. :rolf:

BUG-E J · May 12, 2017

customcj7 said:
How do you ensure you're getting all the air out? Just burp it from time to time and keep adding fluid?

With the funnel like your using once the thermostat opens it's done. That puts the coolant level the highest point in the system so it gravity bleeds. If you have a heater core still you may have to give it a few seconds at 1500 rpm but that's it. If your getting bubbles after it opens either you have a flow problem or blown head gasket. Flow problem is a water pump issue 90% of the time assuming radiator isn't plugged.

617_Racing · May 12, 2017

customcj7 said:
Radiator blocked or restricted, I'm not sure if I understand. The hoses are new with wire wrap so no kinks, and it's a brand new radiator. I'm trying to burp as much as I can using the bleeder funnel in the picture.

I think he was implying the airflow through the radiator, not the coolant flow inside of it.

sexxy · May 12, 2017

Is water pump doing its job, moving water? May have got a defective new part?

customcj7 · May 12, 2017

617_Racing said:
I think he was implying the airflow through the radiator, not the coolant flow inside of it.

See, my brain is fried, that would make more sense. Nope, airflow is not restricted on the front. Even angled my box fans towards the front to ensure fresh cool air gets pulled by the radiator fan.

And as for the bubbles after the t-stat opens, that's kicker, I get random bubbles from time to time, and then eventually they stop which would lead me to believe I got them all.

As for the water pump, it's hard to tell with the new radiator. The cap is on the opposite side of the neck, so short of taking off a hose while running and seeing fluid pump out, I don't know how else I can tell.

matlock · May 12, 2017

Have you done the intake crossover mod?
Is your fan pulling or pushing?
Correct firing order for cam? It can be either 351 order or 302...

sexxy · May 12, 2017

customcj7 said:
As for the water pump, it's hard to tell with the new radiator. The cap is on the opposite side of the neck, so short of taking off a hose while running and seeing fluid pump out, I don't know how else I can tell.

Might be worthwhile to check. Good luck getting this figured out.

the_white_shadow · May 12, 2017

Is 215 hot for these engines?

Zjman · May 12, 2017

Does your coolant overflow jug get pressurized or over fills with coolant? Had a 302 do that and it was headgasket on exhaust side, And 215 is getting pretty warm on a old iron ford motor,
Does it cool down or heat up when ya give it steady rpm's ?

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ROKTOY829 · May 12, 2017

Re:

If you can get a hold of leak down tester, you can check the cylinders. Getting the random bubbles seems like exhaust gas is getting in. Sounds like that is what your gut is saying.

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zayne2427 · May 12, 2017

I was having issues on my LS and finally drove it down the rode a short ways with a few good blips of the throttle was able to release the last air pocket in it. After that i put the funnel back on one more time and havent had any problems since