2F Intake Manifold Leak

[KY Longhunter]

So last night I took my 1981 FJ40 for ride around neighborhood for a test drive (1st time in years). Everything was moving along OK then started smelling hot and experienced loss of power, especially when trying to shift from 2nd to 3rd slight uphill. I decided to get it home and park it asap.

Once parked, I immediately started seeing coolant drip on garage floor and steam coming out of air cleaner (and that same hot smell).

After some quick research, I've come to conclusion I have an Intake Manifold Leak. Below is Google's definition:

Symptoms of bad or failing intake manifold gaskets

• Engine misfires and decrease in power, acceleration, and fuel economy. One of the most common symptoms of an issue with intake manifold gaskets is engine performance issues. ...
• Coolant leaks. Another symptom of a faulty intake manifold gasket is coolant leaks. ...
• Engine overheating.

I also found some Mud threads on the subject:

Hesitation when accelerating, Carb, Coil or Ignition - Finally Fixed

forum.ih8mud.com

2F Manifold Woes - need advise please

forum.ih8mud.com

 

[KY Longhunter]

Where I do I begin to remedy this situation? Should I buy a new Remflex Gasket kit and redo? Do I have manifold refaced and spot face flanges?

I guess I am overwhelmed and bummed and trying to decide where to start. Any advice?

 

[Pighead]

I don't see how an intake manifold leak could lead to coolant on the floor...

 

[KY Longhunter]

I guess I need to find the leak first. I've read that I can take some Carb cleaner or something and spray around manifold while truck is running and find the exact point of leak.

Should I do this first?

 

[Pighead]

I think I would find where the coolant was coming from first. Was it simply overflow from the radiator, maybe a bad hose or hose clamp?
When cool, check the coolant level in the radiator. A coolant leak may explain all.

 

[KY Longhunter]

I think I would find where the coolant was coming from first. Was it simply overflow from the radiator, maybe a bad hose or hose clamp?
When cool, check the coolant level in the radiator. A coolant leak may explain all.

I think I could have a bad hose clamp. I recently bought new CityRacer hose clamps for this specific purpose. BTW, I've got the external 2F Oil Cooler as well.

I do NOT have the heaters hooked up right now. I ran heater hose directly from PS around the block to top of union on top of block.

 

[Pighead]

Hose clamp could be a simple solution to your problem. Much easier than an intake manifold.

 

[KY Longhunter]

Hose clamp could be a simple solution to your problem. Much easier than an intake manifold.

Could this also contribute to loss of power? BTW, besides "eyeballing" how do i check level of coolant?

 

[Pighead]

Could this also contribute to loss of power? BTW, besides "eyeballing" how do i check level of coolant?

If your engine was overheating, certainly.
Pour coolant in the radiator, see how much it takes.

 

[Steamer]

steam coming out of air cleaner (and that same hot smell).

Steam and coolant smell coming out of the air cleaner is not good at all and not from a bad manifold gasket.
If that's for sure, I would suspect a blown head gasket. Check the dipstick for signs of coolant. You may want to invest in a leak down tester.

 

[Pighead]

Steam and coolant smell coming out of the air cleaner is not good at all and not from a bad manifold gasket.
If that's for sure, I would suspect a blown head gasket. Check the dipstick for signs of coolant. You may want to invest in a leak down tester.

Let's not play the blown head gasket card so quick. Let's see if we can get him fixed with a few bucks of hose clamps instead of a few hundred in a head gasket kit...

 

[KY Longhunter]

I embarrassed to report. I was able to put 2 1/2 gallons of coolant in her. And 1 quart of Power Steering fluid.

Still running a little rough, but running!

Thanks Pighead!

 

[Pighead]

I embarrassed to report. I was able to put 2 1/2 gallons of coolant in her.

View attachment 2354019

So, a bit more than half empty. Of course, you'll have to run it for a bit and "burp" it to completely fill it.
Did this teach you a lesson? Maybe about checking fluid levels BEFORE you go for the first ride in years? And maybe inspire you to at least replace some hose clamps?
Lets hope that's all it was. Drive it more and work out that rough running, we're here for you.

 

[65swb45]

Chances are the engine got pretty hot, running that low on coolant. And being THAT hot would have changed the valve clearances to the point they weren’t closing all the way. This would explain the loss of power.

But I am 100% with @Steamer on proceeding with EXTREME caution. Steam coming out of air cleaner is BAD.

BEFORE you restart the truck:
1. Check the oil filler cap for condensation
2. Check the oil dipstick for discolored oil
3. If it were me, I would pull all the plugs and crank the engine over once to make sure no coolant come out a spark plug hole. Cheap insurance against hydrolocking and bending a connecting rod.

 

[KY Longhunter]

Ok good tips

 

[KY Longhunter]

Back to diagnosing lack of power:
1. no condensation under Oil Filler Cap
2. no milky discoloration of oil on dipstick
3. didnt get to # 3

Could it be a my dizzy needs to be re-curved since desmog?

 

[Pighead]

Could it be a my dizzy needs to be re-curved since desmog?

I'd probably startwith much simpler, cheaper stuff on a rig that hasn't driven in years. Spark plugs, valve adjustment, timing, points?
Tune it as well as can tuned as is before settling on something exotic like a recurve which you wouldn't even notice the difference on a poorly tuned engine.

 

[KY Longhunter]

I’m trying to track down an Intake Manifold Leak and making my own gaskets. Plan to use Permatex Gray Gasket maker on both sides of homemade gaskets.

Now I have a stupid question.

i removed my troll hole carb and insulator gasket and noticed the small port on bottom of carb.

What is that for?

Does it make sense to cap it with the gasket? I had a oem looking gasket with a built in rubber plug. Just seems odd to have port that gets covered by the gasket.

 

[KY Longhunter]

I re-watched Pinheads "Rebuilding an Aisan Carburetor Part 3 by Pin Head" and answered my own question. This hole is used to access a bolt that holds the fuel bowl to the carburetor base.

 

[65swb45]

I re-watched Pinheads "Rebuilding an Aisan Carburetor Part 3 by Pin Head" and answered my own question. This hole is used to access a bolt that holds the fuel bowl to the carburetor base.

It’s not an ordinary bolt; it’s hollow, and supplies a vacuum signal.

And although you didn’t ask, I will venture that the gasket on your insulator looks fine. No need for a second gasket/potential leak source, or to stack the odds of getting a new leak by using rtv where gasoline is prevalent.

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