Another Coolant Leak - But Where?

[bostonbronconut]

Long-time, no problems - until now.

I just got the '77 back from the shop after they put on new coils, shocks, body mounts, and c-bushings. I took it out for a four-mile drive so I can feel the new suspension and haven't looked under the hood. It has been a few weeks since my drive and I just took a look at the distributor when I saw coolant on the front of the manifold on both sides (see photos).

I tried to get some decent photos of potential leak locations but it isn't easy getting a camera into dimly-lit areas. I'd be happy to take some more photos if requested.

I've had some concerns about white smoke in the past and have posted a video on the BONES Facebook page about it back in October - I put the same video on YouTube for your view: https://youtu.be/HT9eXSNP--4. This is the first time I've seen coolant on the manifold, which is causing me some concern.

Given the information above, how concerned should I be? Thank you for your time and help!

 

[rmk57]

First place to look would be the radiator hose to the thermostat housing, in that area. If you had cooling system pressure tester you would find it right away I bet.

 

[vintage bronco]

Check upper rad hose
thermostat housing gasket
intake gaskets

 

[chuckji]

If you go to the local Autozone or the like, they'll loan you a cooling system pressure tester. As mentioned, it'll help you quickly find the leak.

 

[bronconut73]

The by pass hose and the upper rad hose along with the thermostat housing leaking are all culprits.
If the hoses look worn go ahead and replace them as fairly easy maintenance. Same for thermostat housing unless you find it is a hose first.

SBF 's are notorious for leaking in this area then collecting in the valleys behind the waterpump making folks think their water pump is leaking when in fact it was a much simpler upper hose or t-stat housing gasket.

 

[bostonbronconut]

Thanks, guys! The weather is warming up in MA today and tomorrow so it gives me a good excuse to head to Advance or Auto Zone for the pressure tester.

I took some additional photos for the fun of it.

 

[Glass Pony]

Thanks, guys! The weather is warming up in MA today and tomorrow so it gives me a good excuse to head to Advance or Auto Zone for the pressure tester.

I took some additional photos for the fun of it.

From that first picture, I'm going to say intake gasket.

 

[Timmy390]

From that first picture, I'm going to say intake gasket.

X2 Sure looks to be intake manifold gasket.

Tim

 

[blubuckaroo]

That's an easy repair.
But seeing that you have an aluminum intake manifold, make sure you don't use a composition intake gasket. The FelPro 1250 intake gasket gets most of the complaints, but any composition gasket is an issue when the block is iron and the intake is aluminum. The expansion rate of the two metals is too different.
FelPro realized this error and made the 1250S3 gasket. It has a thin layer of stainless steel to give it strength to keep from tearing apart.
Meanwhile, Felpro and other gasket names continue selling the failed 1250 and its knock-offs.
I've personally been fooled once....

 

[doran4x]

Timing chain cover gasket. Try tightening the bolts.


Sent from my iPhone using Tapatalk

 

[matts460]

It could be the smaller bypass hose leaking. tighten the clamp when cold. When the hoses go through heat cycle the clamps loosen up and the hoses will seap when cold and then when motor warms up it will quit. In one of your pics the bottom side of clamp for the small bypass hose looks cleaned off too. Also need to retighten the intake manifold bolts after a heat cycle in the proper torque sequence. could stop the leak.

 

[bostonbronconut]

Thanks for all of the suggestions. I picked up a pressure tester and the first thing I saw was a big leak from the radiator cap and just picked up a replacement (see photos). The gasket on the old cap looks a little beat up around the sides. I'm going to slap on a new one and test the coolant system again and follow up with you guys.

 

[blubuckaroo]

How were you able to pressure test it with the cap still on it??:?

 

[chuckji]

^^

Was wondering the same thing

 

[bostonbronconut]

How were you able to pressure test it with the cap still on it??:?

Wasn't I supposed to put the pressure tester on the window washer tank?

Kidding - I put the pressure tester on the radiator reservoir/overflow tank.

 

[bostonbronconut]

So, it looks like I originally had three leak sources:
1. Worn out cap (fixed)
2. Hose connecting to the thermostat is worn and needs replacement and/or the clamp needs tightening or replacement
3. The Intake Gasket might be gone per Timmy390 and Glass Pony's suggestion. Matt460 suggested retightening the manifold bolts after a heat cycle but at first glance, it looks like I'd need to take everything off to do that anyway or at least the carburetor.

 

[bostonbronconut]

Turns out there might be more than on leak source!

1. Heater Hoses - Manifold and Firewall
2. Passenger-side Intake Manifold
3. Mystery Leak from Engine/Center

If you look at the latest photos, you'll see the manifold cleaned up and then after awhile, the heater hose leaks and puddles on the manifold. I also saw some coolant between the manifold and block. Looks like both gaskets are dunzo?

There is also a drip from the hose close to the firewall.

Lastly, there is a mystery drip that I can't find just yet but it is coming from the engine area.

Given all of this new information, what do you guys recommend (aside from replacing hoses and clamps)?

 

[bronconut73]

Piece of mind will come from pulling the intake and replacing those gaskets. Torque it back down in the proper sequence too.
Replacing the hoses, t-stat housing gasket and such will also provide piece of mind.
It's worth it.....you will feel better knowing it's done and that you cab move on to cooler eb stuff.
No matter what enjoy it....this wrench turning is fun if its not your daily driver.

 

[bostonbronconut]

Piece of mind will come from pulling the intake and replacing those gaskets. Torque it back down in the proper sequence too.
Replacing the hoses, t-stat housing gasket and such will also provide piece of mind.
It's worth it.....you will feel better knowing it's done and that you cab move on to cooler eb stuff.
No matter what enjoy it....this wrench turning is fun if its not your daily driver.

Thank you, other BroncoNut. Looks like I am going to be pulling everything off this weekend. Any recommendations on intake manifold gaskets?

 

[Skytrooper15]

Somebody posted the correct gasket to be used with an aluminum intake back above but tell me one thing,how much pressure did you pump up to get that many leaks?I had a 63 Ford with the 221 engine that had an intake leak so small like yours that I drove it for 5 years and only added anti-freeze once.But my leak wasn't aluminum to cast iron either.20 pounds should be enough pressure to test for leaks.