1955 coolant in the oil while sitting for 10 years

[cmcphail]

The 292 engine in my 1955, which has not been started for about 10 years ejected a small separate lower layer of green coolant when changing the engine oil.

I am not a mechanic, but a DIYer.

To diagnose the leak, I used a boroscope to examine the pistons and there was no sign of rust and the cross-hatching was intact. I put a pressure tester on the cooling system at 10 psi and found a drop in pressure within 15 minutes.

As the first stage in removing the heads, I removed the intake manifold and tappet valley cover. I found that there was both oil and green coolant in the valley.

is it possible that the coolant in the oil is only due to a slow gravity leak from the intake manifold or thermostat dripping onto the tappet cover, passing between the bolts and the grommets on the cover and and entering the valley, making it's way to the crankcase? Would pulling the oil pan provide any confirmation?

Also, since a bad head gasket is a more common root cause for coolant in the oil, would you pull the heads anyways?

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[ICON 56]

A Lot of issues can happen when the motor is sitting for 10 years. It's common when any oils /antifreeze is sitting for that long will find it's way down from gravity. I would tighten the intake manifold to the spec's in the 55 service manual. Clean all the surfaces change all the fluids. See if you can start the car. watch for any leaks while the engine is running. Keep the RPM's low. run for 5 minutes then turn off motor. Look at the intake seals while the engine is cooling down.

 

[cmcphail]

A Lot of issues can happen when the motor is sitting for 10 years. It's common when any oils /antifreeze is sitting for that long will find it's way down from gravity. I would tighten the intake manifold to the spec's in the 55 service manual. Clean all the surfaces change all the fluids. See if you can start the car. watch for any leaks while the engine is running. Keep the RPM's low. run for 5 minutes then turn off motor. Look at the intake seals while the engine is cooling down.

Would you pull the heads or the oil pan?

 

[ICON 56]

I would start with the simple thing first, Check the oil pan if there is antifreeze in the oil pan then the next step would be the heads.

 

[Kultulz]

At which corner of the lifter valley is the leakage?

The leakage appears to be coming from the block deck or above (either head gasket and/or intake coolant crossover at the front of the engine or possibly the rear of the left cylinder head where the temp sensor is located or there is a core plug on the rear of other head.

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[cmcphail]

The majority of the coolant was observed on the valley floor just behind and around the boss where the rear valley cover bolt screws in.

 

[Tom Alpers]

If the coolant came into the oil from the heads it seems most likely you would see it on the pistons/in the cylinder. Since you didn't see it there I think the intake leaking is far more likely. I'd be inclined to RR the intake and see how that goes. When its back on fill the cooling system back up, run it briefly and again check to see if it holds pressure.

 

[Kultulz]

The majority of the coolant was observed on the valley floor just behind and around the boss where the rear valley cover bolt screws in.

If at the rear of the valley, it could be either LS CYL HEAD (coolant temp switch mtg position) or RS (core plug) leakage running down the head(s) and possibly leaking under the valley pan or or could be leaking from the intake front coolant crossover and moving towards the rear of the valley.. And then again it may be the head gasket(s).

Before removing a head(s), you might consider mounting the intake onto the heads (sans valley pan) (w/ new gasket or sealer), pressurize the system with the system pressure tester and check for any obvious external leakage. If you have a boroscope, remove all spark plugs and after/while maintaining correct system pressure view each cylinder for leakage.

Letting an engine sit for long periods is hard on it. The GREEN coolant will not protect the system after two years (corrosion), the reason it needs to be changed every two.

If you decide to remove the heads, have them pressure checked and the decks checked for warpage at a reputable machine shop. If able to do, measure the cyl block deck for true with a machinists bar and feeler gauges.

The BIRD FYB engines ran hot and FORD had many running fixes. It may have warpage.

 

[cmcphail]

If at the rear of the valley, it could be either LS CYL HEAD (coolant temp switch mtg position) or RS (core plug) leakage running down the head(s) and possibly leaking under the valley pan or or could be leaking from the intake front coolant crossover and moving towards the rear of the valley.. And then again it may be the head gasket(s).

Before removing a head(s), you might consider mounting the intake onto the heads (sans valley pan) (w/ new gasket or sealer), pressurize the system with the system pressure tester and check for any obvious external leakage. If you have a boroscope, remove all spark plugs and after/while maintaining correct system pressure view each cylinder for leakage.

Letting an engine sit for long periods is hard on it. The GREEN coolant will not protect the system after two years (corrosion), the reason it needs to be changed every two.

If you decide to remove the heads, have them pressure checked and the decks checked for warpage at a reputable machine shop. If able to do, measure the cyl block deck for true with a machinists bar and feeler gauges.

The BIRD FYB engines ran hot and FORD had many running fixes. It may have warpage.

I plan to do essentially what you're recommending as a next test. I have cleaned up the mating surfaces for the intake and the thermostat housing to facilitate a seal while waiting for the new gaskets to arrive.

If I take the heads off they will go to a machine shop.

 

[Pink T-Bird]

The 292 engine in my 1955, which has not been started for about 10 years ejected a small separate lower layer of green coolant when changing the engine oil.

I am not a mechanic, but a DIYer.

To diagnose the leak, I used a boroscope to examine the pistons and there was no sign of rust and the cross-hatching was intact. I put a pressure tester on the cooling system at 10 psi and found a drop in pressure within 15 minutes.

As the first stage in removing the heads, I removed the intake manifold and tappet valley cover. I found that there was both oil and green coolant in the valley.

I presume you know for certain the car was parked with a well running engine? Like you were the last one to drive it back then, and not someone told you it was fine when parked?
If so I’d think only 2 things are likely.
1) A gasket atrophied during storage likely in the intake to head but could be a head gasket. Can you do a compression test when you get it back together with the new intake gaskets?
2) or the bad news- as noted just because it’s still green doesn’t mean antifreeze is protecting against freezing- How cold was it during the 10 year storage? A head or the block may have cracked. A water passage may have cracked so the water went to the crankcase and not into a cylinder.

 

[cmcphail]

I presume you know for certain the car was parked with a well running engine? Like you were the last one to drive it back then, and not someone told you it was fine when parked?
If so I’d think only 2 things are likely.
1) A gasket atrophied during storage likely in the intake to head but could be a head gasket. Can you do a compression test when you get it back together with the new intake gaskets?
2) or the bad news- as noted just because it’s still green doesn’t mean antifreeze is protecting against freezing- How cold was it during the 10 year storage? A head or the block may have cracked. A water passage may have cracked so the water went to the crankcase and not into a cylinder.

The car was my Dad's. He never mentioned this issue prior to it being parked. It was rebuilt 30 over in 2005. He was having some issues with it back before it was parked, but they more related to carburetor and timing.

 

[doug7740]

I wouldn’t remove the cylinder heads just yet. Since you already removed the intake manifold to gain access to the tappet valley cover, I would reinstall the intake manifold and pressure test the cooling system.

Because of production variations in the Y-block engine series, your engine gasket set likely includes several different intake manifold gasket sets. Match the correct gaskets to your cylinder heads before installing the manifold. When installing the intake manifold, be certain not to use excessive length bolts. The intake manifold bolt holes in the head intersect the push rod passages and too long a bolt can hit the push rods. Be sure to use short bolts, about ½" of thread so you don’t hit the push rods.



It is very important that the mating surface of the intake to cylinder head is not distorted. Machine shops have the capability to resurface the manifold. The cylinder head mating surface must be clean, smooth and not pitted before the intake manifold is installed.





I do not recommend a silicon type sealant on the intake manifold. It is best to use a copper spray sealant. Spray two – three coats of the sealant on each side of the gasket letting it tack to almost dry between coats and before installation.

Before installing the manifold, ensure the gaskets are installed on the correct ports. Check them closely because they can be flipped over and miss aligned very easily. After proper gasket alignment install the manifold and torque the intake manifold bolts to 26 ft-lbs, alternating side to side and front to back as you go.

doug7740
1955 Thunderbird Blue

 

[cmcphail]

I appreciate your input.

There is some a pitting on the mating surfaces of the intake manifold, which is the most noticeable on the mating surface for the heat cross-over.

Do you know how much material the machine shop can remove from the mating surfaces?

Should I have them machine the surface for the thermostat (both the manifold and the outlet)?

I'll pick up some of the copper permatex spray.

As an aside, both the intake manifold and teapot carb are from a '56.

 

[Kultulz]

I appreciate your input.

There is some a pitting on the mating surfaces of the intake manifold, which is the most noticeable on the mating surface for the heat cross-over.

Do you know how much material the machine shop can remove from the mating surfaces?

Should I have them machine the surface for the thermostat (both the manifold and the outlet)?

I'll pick up some of the copper permatex spray.

As an aside, both the intake manifold and teapot carb are from a '56.

Have you installed the intake yet to pressure check the cooling system? If not do not worry about sealers. Buy a cheap set of gaskets, torque it down correctly, fill with water and run your checks.

You need to discover exactly where and why the system will not hold pressure. You will then know exactly how to go about a proper service repair.

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VALLEY PAN BOLT - Interfering w Intake Draw-down


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You need to pressurize the system while full of water. If the needle drops and no viable leakage, keep the tester pumped up. Look all around the cylinder heads, front cover and WP. Then you would go onto the cylinders. It may not be entering the cylinders bit leaking into the oil pan (final).

​

 

[cmcphail]

I will be looking to start my diagnosis on Wednesday when I have access to both the car and the gasket.

 

[cmcphail]

Have you installed the intake yet to pressure check the cooling system? If not do not worry about sealers. Buy a cheap set of gaskets, torque it down correctly, fill with water and run your checks.

You need to discover exactly where and why the system will not hold pressure. You will then know exactly how to go about a proper service repair.

View attachment 34152
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View attachment 34153

View attachment 34154

VALLEY PAN BOLT - Interfering w Intake Draw-down

View attachment 34156
​

You need to pressurize the system while full of water. If the needle drops and no viable leakage, keep the tester pumped up. Look all around the cylinder heads, front cover and WP. Then you would go onto the cylinders. It may not be entering the cylinders bit leaking into the oil pan (final).

​

The 292 engine in my 1955, which has not been started for about 10 years ejected a small separate lower layer of green coolant when changing the engine oil.

I am not a mechanic, but a DIYer.

To diagnose the leak, I used a boroscope to examine the pistons and there was no sign of rust and the cross-hatching was intact. I put a pressure tester on the cooling system at 10 psi and found a drop in pressure within 15 minutes.

As the first stage in removing the heads, I removed the intake manifold and tappet valley cover. I found that there was both oil and green coolant in the valley.

is it possible that the coolant in the oil is only due to a slow gravity leak from the intake manifold or thermostat dripping onto the tappet cover, passing between the bolts and the grommets on the cover and and entering the valley, making it's way to the crankcase? Would pulling the oil pan provide any confirmation?

Also, since a bad head gasket is a more common root cause for coolant in the oil, would you pull the heads anyways?
View attachment 34116

The 292 engine in my 1955, which has not been started for about 10 years ejected a small separate lower layer of green coolant when changing the engine oil.

I am not a mechanic, but a DIYer.

To diagnose the leak, I used a boroscope to examine the pistons and there was no sign of rust and the cross-hatching was intact. I put a pressure tester on the cooling system at 10 psi and found a drop in pressure within 15 minutes.

As the first stage in removing the heads, I removed the intake manifold and tappet valley cover. I found that there was both oil and green coolant in the valley.

is it possible that the coolant in the oil is only due to a slow gravity leak from the intake manifold or thermostat dripping onto the tappet cover, passing between the bolts and the grommets on the cover and and entering the valley, making it's way to the crankcase? Would pulling the oil pan provide any confirmation?

Also, since a bad head gasket is a more common root cause for coolant in the oil, would you pull theThank you to all for their responses to this thread. As per Kulutz's suggestion, I pressure tested the system as-is and found a leak from the thermostat housing. heads anyways?
View attachment 34116

Thank you to all for their responses to this thread. As per Kulutz's suggestion, I pressure tested the system as-is and found a leak from the thermostat housing.



As per Doug's suggestion, I had the intake runners and both parts of the thermostat housing area milled. After an overnight pressure test at 13 psi the pressure dropped to 12 psi, with minor leaks at the point where the upper rad hose attached to the thermostat housing and at the lower outlet of the radiator. I will replace the hoses and confirm again.

In this process I found that my radiator is likely from a Fairlane; I have made a new post to another post describing this issue to ask further questions.