MTFCA Forum

(I apologize in advance for the length of this post, but I thought I ought to include as much detail as possible so others may help me figure out where I may have gone wrong.)

I’ve had my ‘25 Express Wagon less than 3 months, and about a month after I got it, it started leaving a small puddle of coolant (the 50/50 water/antifreeze that it came to me with) on the floor after each drive. It wasn’t much, just enough to make a mess in the floor. I added probably less than a quart over the next month of driving. It never overheated, just occasional steam out of the vent hole in the radiator cap when idling too long or driven too slowly.

The culprit on the leak seemed to be one of the radiator hoses, all of which seemed to be stiff, and all of the clamps were covered in corrosion. When I went to drain the radiator to change the hoses I got only a slight drip out of the petcock, and had to shove a piece of safety wire up into the petcock which initiated a gush of rusty red followed quickly by relatively clean antifreeze. Upon removal of the hoses I found a couple of tablespoons of rusty red sandy material in the radiator outlet, and a smaller amount in the engine block after removing the inlet elbow.

I wiped and flushed the rusty material as best I could, then installed the new hoses and clamps, and filled the system with 2-1/2 gallons of distilled water. At the end of about a week, maybe 30-40 miles total, I attempted to drain the radiator, and found the petcock plugged again. The safety wire produced the same rusty initial gush followed by relatively clear water. I let about a quart drain, and added a quart of Thermocure, which I ran for about another 30-40 miles over a week.

Today when I went to drain the radiator, the petcock was plugged again, but this time just a little sediment followed by relatively clear water. I completely drained the radiator and refilled with softened well water, drove a couple of miles, then drained that (more sediment in the petcock), then stuck the hose in the radiator and ran the engine with the petcock open and the filler neck overflowing from the hose.

I then let all of the well water drain, filled the system with 2-1/2 gallons of distilled water and ran that for a few miles. This time the petcock ran clear so I let it completely drain and refilled the system with 50/50 antifreeze/distilled water. Less than a mile into the first run with the antifreeze, I came to a stop and was immediately enveloped with steam from the exhaust! I stopped and checked the coolant level and it was fine (and the radiator cap was warm, but still cool enough to handle), so I drove it the short distance home and proceeded to write this thread.

I hope it’s just a blown head gasket, but it seems odd to me that it waited until I added the antifreeze to do it. There had not been any steam in the exhaust until then.

It sounds like a head gasket leak, unless you somehow got water into the exhaust system while working on the radiator or washing the vehicle. Sometimes, anti-freeze or coolant additives will leak out of a system that has been holding water due to dirt and sediment plugging off small leaks. A significant head gasket leak will cause a miss, and may allow coolant to get into the crankcase. Exhaust steam from an engine with an antifreeze freeze coolant leak into a combustion chamber usually has a rather strong odor, something like the odor of Coca-Cola spilled on a hot surface.

Steam in the exhaust; highly desirable.

It's worth noting that a slight head gasket leak into the water jacket can make the coolant very nasty in a hurry. Perhaps your engine had a slight or intermittent head gasket leak that fouled the coolant and accelerated corrosion. That, rather than long neglect, might explain the condition of the system as far as the rust and crud. As a first step, I would drain and store the antifreeze solution safely, then refill the system with tap water and check the oil for any indication of coolant. If the oil shows indications of water/anti-freeze, I'd drain it off and leave the drain plug out and place a pan under the drain. You could try retorquing the head bolts, but that isn't likely to solve the problem, and it risks twisting off one or more head bolts.

Miles, Steam in the muffler/exhaust system indicates a very abnormal amount of coolant has found it way into the exhaust. It may be a head gasket failure as other have mentioned but considering all the rust you have been getting out of your radiator drain petcock, this indicates the innards of your block is probably very rusty and one of the water jackets may have rusted through into one of the inlet or exhaust ports. Water can be sucked into the cylinder on the inlet stroke and expelled out the exhaust valve and port on the exhaust stroke. It happened to me once and the block had to be junked.

If its a slight water jacket leak,"waterglass" may be a "fix". Its a coating treatment that works its way into the leak & seals it up. Search for evidence of head gasket leaks first. Have you pulled plugs looking for the offending cyl? Check oil for grey milk shake. Should narrow it down.

There’s little doubt that billowing white smoke is anti freeze and of course it’s getting into the exhaust. I don’t recall if straight water will smoke but I don’t think It does which is probably why you didn’t see smoke earlier. While it’s going to mean pulling the head I (as usual) am going to suggest doing a wet and dry compression test before doing the head job. Not that you’ll be looking for the leak point (though it might show that) but just to get a really good idea of the condition of the engine.

Having someone with Model T experience look at your vehicle before taking anything apart would be a good idea. There is probably a MTFCA chapter in your area.

A plain water leak into a combustion chamber or two will produce lots of steam, especially in damp or cool weather. A leak large enough to produce a lot of steam will usually also cause one or more cylinders to miss. In some cases, coolant from a slow leak can accumulate in the exhaust pipe and muffler, and only after driving long enough to get the system hot will the steam appear. An in-person look at the vehicle by someone with old car experience can be very helpful, as can an in-person discussion with the operator who experienced the symptoms.

I haven’t noticed any loss of coolant since I replaced the hoses several weeks ago, and both the coolant and oil have looked normal. I have not checked the oil since yesterday’s steam episode. I’ll run it one more time as is just to make sure I wasn’t dreaming, then drain the coolant and replace with water to see if that makes any difference. By the volume of steam I was seeing though, there’s not much doubt in my mind that the best case scenario is a blown head gasket, maybe worse.

It does not take much coolant in a cylinder to create a lot of steam.
Without pressure in the cooling system, depending on how large the leak, the coolant loss may be small.
Sure sounds like a head gasket leak opened up from the flushing. Or [hopefully not] a crack in a port.

I suggest draining the anti freeze and replacing it with plain water before running the engine any more. Also check for evidence of coolant in the crankcase. I'd look at the condition of the oil AND loosen the drain plug to be sure that no coolant has accumulated at the bottom of the crankcase. Having done that, I'd drive it gently or at least run it at a fast idle for a while and watch for symptoms such as excessive steam, miss-firing, bubbles in the raidator, and any evidence of water getting into the oil. Do you have any information on the history of the engine, such as when it may have been rebuilt or had work done on it like a valve job? I would use the hand crank to turn the engine over several rounds with the ignition off before starting it. While doing so, look for uneven compression and listen for sounds of escaping compression. Doing this will also guard against hitting the starter and having a cylinder lock up due to water having accumulated in the cylinder. Such a situation could damage the engine or the starter or both.

I would suggest a cylinder leakage test. By adding compressed air to a cylinder that is at TDC on the compression stroke you can look into the top of the radiator and look for bubbles. If you see bubbles, the cylinder that you are pressurizing is leaking compression into the cooling system. Be careful though- if the piston is anywhere but exactly at top dead center, it will move down in it's bore. Be sure that the T is in neutral with the parking brake set. Don't get carried away with the air pressure that you use; I wouldn't go over 50 psi.

John Codman wrote: ↑

Wed Sep 29, 2021 10:23 am

I would suggest a cylinder leakage test. By adding compressed air to a cylinder that is at TDC on the compression stroke you can look into the top of the radiator and look for bubbles. If you see bubbles, the cylinder that you are pressurizing is leaking compression into the cooling system. Be careful though- if the piston is anywhere but exactly at top dead center, it will move down in it's bore. Be sure that the T is in neutral with the parking brake set. Don't get carried away with the air pressure that you use; I wouldn't go over 50 psi.

Thanks for that suggestion. I am an airplane guy and and that’s the standard way we check cylinder compression. With the spark plugs being pipe thread, it should be simple to make up an adapter for the compressed air.

Another thing which has not been mentioned is where the T is parked, the temperature outside and the humidity. If a car is parked outside, or maybe even in an unheated garage on a cool morning(a morning cold enough to leave dew on the grass and trees) you could also have some condensation inside the exhaust system and muffler. Then as the exhaust system heats up while driving, you will get steam.

It is odd that if you have a leak, either internal or external, you wouldn't notice the coolant level dropping when you first check the radiator. If oil is getting in the water, you will get a yellow foamy stuff rising in the radiator, and if it is in the oil, it will also foam up but when it sets, the water will settle to the bottom of the sump.

So check these things first then those mentioned above. It is unfortunate, but when there is a small internal leak, sometimes rust will partially plug the leak and then after it is cleaned, the leak will show up. However usually if a leak is in a cylinder or in the intake port, it could be drawn into the cylinder and cause steam. A very common place for a crack to occur is between the exhaust valve and the cylinder wall. Sometimes can be fixed by a valve seat insert and sleeving the cylinder.
Norm

I pulled the plugs and borescoped the cylinders and all looked fairly normal except that #4 seemed oily and it’s piston had more carbon on it than the others (which explains why that plug fouled last week).

I called a friend over who just finished restoring a speedster, and he agreed that it was steam, not smoke. We drove it about a mile and a half then immediately pulled the plugs and got a small amount of steam out of #4. We pulled the head and my friend noted that the head bolts didn’t feel like they had been torqued properly.

There was oil collected on the wall between #3 and #4, but no obvious defect in the gasket. Another friend (not a Model T guy) happened by and noticed a slight bluish white stain on top of the block at the extreme rear corner of the block on the manifold side, near the 1/4” hole into the water jacket. A close look at the gasket and head in location also show what might have been a leak.

It looks like the steam issue might be resolved with a new head gasket, but I’m wondering if the oil issue with #4 also needs to be dealt with, maybe a ring job on that cylinder?

Also, there’s a lot of loose scale in the water jacket forward of #1 that needs to be cleaned out.

I believe you've found your leak. The oily condition of # 4 may be due to rings having stuck due to coolant leakage into the cylinder. That cylinder may have sat wet during storage periods and developed enough corrosion to interfere with the rings. Running the engine would quickly sweep any light rust from the cylinder wall, but rust and aluminum corrosion residue would likely remain around, behind, and between the rings. I'd remove that piston assembly and give it a good looking over and also clean up that bore and look carefully for any damage or evidence of cracking. From here, I suspect you have a head gasket problem with perhaps some secondary damage to the piston/ring assembly in that cylinder. The uneven head bolt torque points to a simple gasket failure, but check everything, including the gasket surfaces and the bolt holes, bolts, etc.

Be sure to check the length of the bolts by putting the head on without a gasket and see if they can be turned down all the way to the head. If they bottom out before they hit the head, you either need to clean the block threads all the way to the bottom with a bottoming tap, and also might need to grind a bit off the bolts to shorten them.

That small hole in the block is called a steam vent. It is common to have a leak there. I have a car in which the entire engine was rebuilt and the top of the block was surfaced, however I did not have the head surfaced. I took it on a tour and it leaked in that place. I didn't even know it was leaking because it was against the firewall and covered by the manifold. I pulled the head and had it re-sirfaced and new gasket. No more leak. Yours might be ok if you use some heat resistant sealer in that corner above and below the gasket.
Norm

Thank you Norm, that’s very helpful information. I have tried to get someone from my local club to come look at it in person, but no luck so far.

I have noticed some oily crud in some of head bolt holes in the block, which I plan to try spraying out with contact cleaner or light oil. The center bolt between cyls. 3 &4 was oily along its entire length, apparently coming from #4.

Neither the block nor head mating surfaces show any erosion, and the machine marks are still visible, so I don’t think either will need resurfacing. What sealant would you recommend for the head gasket? And, should it be applied to the entire surface, or just around the steam vents and/or water passages?

Would it be good to take the head somewhere and have it boiled out before I reinstall it? What I can see in the water passages looks fairly good, but I may run my borescope through it just to check.

When you have the head off you will need to torque the head bolts in the proper seqence as per the Model T bible and then after running the engine and getting it warm you need to shut it down and torque the head bolts again.

I would suggest still checking the head with a straight edge.
Also run a bottoming tap in the bolt holes and blow out with compressed air. Also be sure all the bolts are the correct length and all tighten without a gasket in place.
Copper spray sealer on a copper head gasket and torque to 45ftlbs. Run till warmed up, let cool and retorque.

perry kete wrote: ↑

Thu Sep 30, 2021 5:10 pm

When you have the head off you will need to torque the head bolts in the proper seqence as per the Model T bible and then after running the engine and getting it warm you need to shut it down and torque the head bolts again.

219010.jpg

Thank you Dennis, the Model T “bible” was one of the first purchases I made after acquiring my Express Wagon.

For re-torquing the head after the engine has been run, should that be done while the engine is still warm, or allowed to cool?

As was mentioned above, seeing the original machining marks is no certainty of flatness. You can't do much about the block, but it tends to be far more stable than a head.

I agree with the use of a straight edge, so long as it really is a straight-edge and not the side of a framing square, and you inspect every possible angle across the head at every single spot combined with a set of feeler gauges. There WILL be low spots...how low? Not a quick or easy job. Alternately, a blemish-free cast iron or granite surface plate and very fine abrasive paper will show the high spots (but not the depth of the low spots)...it will just show where you need to look with the straight-edge and feeler gauges and remove the guesswork.

This is a straight-edge: https://www.zoro.com/starrett-steel-str ... lsrc=aw.ds

This is not: https://www.grainger.com/product/21XK17 ... lsrc=aw.ds

Since you do not know the history of the car, it is time, effort and money ahead to just send the head out to a quality machine shop and let them kiss it on their machine.

To re-torque the head, if it is an iron head do it while the engine is hot. If an aluminum head let it cool first. The reason for this is that aluminum expands at a greater rate than steel, so after it cools off, it will loosen up.
Norm

I’m picking up the head from the machine shop today, and new head bolts and gasket are on their way from Snyder’s.

Two questions:

1) Will baking the paint onto the head in a 170-degree oven cause warpage, or should I just let it air cure?

2) Couldn’t find any copper head gaskets anywhere, so Snyder’s suggested I try the silicone gasket. Is there any need for sealant with that gasket? Any different torque value or sequence?

mbowen wrote: ↑

Tue Oct 12, 2021 1:18 pm

I’m picking up the head from the machine shop today, and new head bolts and gasket are on their way from Snyder’s.

Two questions:

1) Will baking the paint onto the head in a 170-degree oven cause warpage, or should I just let it air cure?

2) Couldn’t find any copper head gaskets anywhere, so Snyder’s suggested I try the silicone gasket. Is there any need for sealant with that gasket? Any different torque value or sequence?

I dont bake paint. Would not unnecessarily risk it, even if a very small risk. If you are using a hi temp paint, it's not necessary. My preferred paint is a coat of cheap flat black, followed by 2 coats of semigloss/satin black(rustoleum)
No sealant on the "print-o-seal" gasket. Very good product. The colored sealing product is raised. Torque the same.