Just get her drivable (1 Viewer)

[RUSH55]

What’s the story with the radiator? Is the external and internal clean?

Radiator is clean inside and out.

So let’s go through the list -

Radiator (clean inside and out)
Proper radiator cap (?)
Fan
Water pump (newish, possibly still questionable?)
Coolant (fresh)
Fan drive belt (tight?)
Thermostat (no thermostat?)
Hoses (not kinked? good condition?)

This didn’t age well did it?
It’s one thing to diagnose a problem in person and see for oneself what’s going on. It’s an entirely different situation to have to try and help diagnose a problem through an online chat forum, and trust that the guy in need of the help is giving accurate information.

 

[onemanarmy]

It is an interesting diagnosis, but one that is not confirmed yet. I am going to try a different rad and see what happens. As most know, FJ55 rads are not just sitting on the shelf easy to find and easy to pay for.

My current rad has been in use for many years now, does not leak, holds pressure, is not obstructed, is clean externally, and I've dumped the -clean- coolant out 10 times over the years for other maintenance and added fresh coolant mix back in.
I put a new rad cap while throwing parts at it.
The water pump is tight, quiet, and does not drip or otherwise leak.

I took this rad out and ran a water hose into the top of it and clean water came out of the outlet, for over 5 mins, and it never overflowed.....to my 'untrained' eye, the flow through the rad seemed sufficient.

I took it to a rad shop and they said it was 'super clogged' but I don't know what exactly they did to test it, and like I said, I ran water through it and it flowed freely. So clogged a bit maybe? Not 'super'.

We'll see!

@WarDamnEagle is helping me out!

 

[samc2447]

If it was overheating as quickly as it did when you started driving, it was super clogged. As I said earlier, just because water flows through it doesn't mean it's not plugged up. Any truck with an old radiator like this should have it's radiator hot tanked and cleaned by a radiator shop since as we know these often sit around for years without being driven. There's a high likelihood a PO put tap water in at some point.

 

[J Mack]

Any truck with an old radiator like this should have it's radiator hot tanked and cleaned by a radiator shop since as we know these often sit around for years without being driven.

Also antifreeze will gel from age, most manufactures have a time limit and recommend flushing and change at a given intervals..

I’ve seen this more often in cars that sit for extended periods.

 

[onemanarmy]

Yea....water flowing through it at 20psi (and never overflowing) from a garden hose was not telling me 'super clogged'
I've changed out the coolant/water mix at least once every 2 years for other maintenance and things
There were no other signs of leaks/odd behavior
The coolant was clean and clear
Every time I took off the bottom rad hose to dump the coolant, it emptied the rad quick, and the coolant was clean....no trash or lumps
But what do I know?
If a new rad fixes it, I owe all of y'all internet points!

 

[J Mack]

I owe all of y'all internet points!

I don't need points nor am I trying to prove anyone wrong.
I'm trying to share information with the group, water entering the top of a radiator and exiting at the bottom is not a good indication of how well it will preform. An underperforming radiator will lead to head and gasket issues and I hope you didn't damage yours again when you ran it up over hot testing it.

Most everyone that has posted answers to your questions is knowledgeable and is taking the time to offer help, the reason we are still talking about it is because you keep rejecting their answers overheat your engine again then ask the same question again then get the same answer "AGAIN".... Not trying to be a Dick but if you don't like these answers take it to a shop and pay a professional, we are armchair internetpricks just offering "FREE" advice.

 

[onemanarmy]

Yep! I appreciate it!
Taking all the advice and also working with what I have on the ground here. Not once have I not 'liked' any of it....nor rejected it. Overheating (especially happening 'overnight') can mean any number of things.
A failed component, clogged this and that, inefficient system, leaks....internal and/or external, etc
When I checked compression......the #s looked suspect at the very cylinders where I was seeing buildup on the spark plugs. Head gasket? Maybe? I don't think that was a left field thought.
A 1977 radiator system is dumb simple.....water enters at the top and flows out the bottom. I took the rad out and flowed water through it, and clean water flowed freely. I'm no Einstein, but that did not raise red flags, but still took it to a rad shop, and got a diag. So I'm getting a rad to test. It just took me a while, and hopefully this is the fix. All the other work was a bit tedius, but now I know whats been done now....a win!
I never once changed/investigated an item that was not part of the pressurized cooling system.....and have changed one thing at a time to avoid introducing multiple variables at one time.
It's all been helpful and enlightening.

 

[Pighead]

2. add more JB Weld to manifold crack.,....more is better

I don't really think of JB weld as a permanent fix on a crack in the intake manifold. JB weld will burn off, and stink while it does, if it gets hot enough. A crack that close to the exhaust manifold might get hot enough. You might have a vacuum leak which causes a lean condition which leads to the overheating. You don't know that your radiator is bad or your water pump is failing but you do know that you have a bad intake manifold.

 

[onemanarmy]

Yes. Fixing the intake is on the list. The JB Weld should hold for this temporary testing phase.
I think.
I've only run it once since adding a crap ton of JB weld.
Once the rad gets here, installed and tested, I'll report back!

 

[onemanarmy]

I don't really think of JB weld as a permanent fix on a crack in the intake manifold. JB weld will burn off, and stink while it does, if it gets hot enough. A crack that close to the exhaust manifold might get hot enough. You might have a vacuum leak which causes a lean condition which leads to the overheating. You don't know that your radiator is bad or your water pump is failing but you do know that you have a bad intake manifold.

Maybe I'll slap some of the 1000* high temp JBWeld on it!

It'll fit the style of this truck

 

[PabloCruise]

Any updates?

 

[onemanarmy]

So it's got a new HG, which is good.
New exhaust guides, valves are adjusted, new spark plugs, nice water pump.....all good things
Even changed the oil!
No vacuum leaks....a plus
and you know what.....
The aftermarket aluminium radiator that I had to mod a bit to fit........fixed it!

Drove it down the freeway today and the gauge never got above 1/4 hot. She pulls good!

Lots of work yes, but I have a new baseline (and plenty more to work on)

Thanks to everyone!

 

[bobm]

Glad ya got a Win . Feels good don't it.

 

[onemanarmy]

Sounds so silly to say it out loud....but the rad looked good, wasn't leaking, and has been flushed over the years. Water/coolant looked fine/not rusty or thick. And had suspect buildup on some spark plugs AND had low-ish compression.

Whatever.

Roadtrip time!

 

[PabloCruise]

So it's got a new HG, which is good.
New exhaust guides, valves are adjusted, new spark plugs, nice water pump.....all good things
Even changed the oil!
No vacuum leaks....a plus
and you know what.....
The aftermarket aluminium radiator that I had to mod a bit to fit........fixed it!

Drove it down the freeway today and the gauge never got above 1/4 hot. She pulls good!

Lots of work yes, but I have a new baseline (and plenty more to work on)

Thanks to everyone!

So glad to hear it!

This thread is reminding me that I need to change the coolant in the Pig.