Flathead motor spewing coolant, but not overheating....

[phartman]

I'm having a problem with my '34. 21-stud motor. Motor rebuilt by a reputable shop about 6,000 miles ago.No thermostats, treated distilled water. Engine runs 160-180 degrees, but will puke water when it is as low as 140. Rev related. Will only puke at the top end of the rev scale, under load.

The guys at The Pit Stop in Texas suggested that there was something (sand, gunk, crud) moving around in the cooling passage(s) and blocking a passage. He reckoned that the blocked passage was preventing coolant from circulating, until it got hot enough from the steam that it blew coolant back through the system and out the cap.

I had Skip in Florida rebuild the water pumps and I replaced the original radiator at the same time. Prior to these two changes I had zero problems. Approximately 25 miles after replacing the pumps and adding the radiator, the system puked. I believe that due to the better efficiency of the pumps, the original aluminum heads shed quite a bit of scale and electrolosis gunk. Reverse flushed the system and quite a bit of scale came out.

Changed the aluminum heads to newly machined cast iron heads. Used the graphite head gaskets, retorqued after the heat/cooling cycle to 50lbs. Motor ran great for maybe 35 or 40 miles or so, and then today, puked coolant.

I will run a leak test to see that there are no combusion gases in the coolant due to a cracked block. However, the puking issue seems to be rev related on the coolant side. My thought is that if there were a crack, it would have shown up before I replaced the radiator and had the pumps rebuilt.

Ideas? I keep thinking that there is something moving around in the motor, coolant wise. Or maybe the radiator can't handle the flow from the newly rebuild pumps. Put the thermostats back in the motor? I'm open to other ideas. Very puzzled right now.

Thanks for your help here.

[Dave72dt]

The scale may have partially plugged the replacement radiator. Put the original back in and try it that way or the thermostats. You've made at least 3 changes to the cooling system and you'll need to eliminate the variables one at a time.

[flatjack9]

I would bet that the new pumps (which pump more water) are overloading the radiator. Did you replace the radiator with another original type radiator?

[phartman]

flatjack, no, I did not use an original type. Well, I take that back...the Griffin design is to '34 Ford specs. However....we noticed that the original has a baffle in the top of the radiator and the Griffin does not. The original Ford has a plate, if you will, immediately beneath the cap opening. A baffle that deflects water returning from the top inlets. The Griffin does not. With the Griffin you more or less see further down into the top chamber of the radiator. It does have an overflow tube, but it is at the top of the chamber immediately underneath the radiator cap. The original Ford design was the overflow tube to the side, on top of the baffle at the top of the chamber.

So I was wondering if these newly rebuilt water pumps at top rpm are moving so much water that the overflow tube at the top of the radiator is not enough to handle the flow. The water finds the path of least resistance and spews out the cap. Dunno.

It is an intermittent problem, but it definitely only occurs under full power at the top of the rpm range.

And, again, the engine temp gauge is running 160-180 degrees.

Design flaw in the radiator??? Solution? Tomorrow we were going to run the leak test. Then try termostats or flow inhibitors. We had in mind using the 160 degree tractor units.

And, again, many thanks for your help here.

[cmbrucew]

Try putting the thremostats back in.

[Brendan]

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i had that trouble in my 35 21 stud motor, i put freeze plugs in the water pumps and drilled a 5/8 inch hole in them it seems to like the change. now the water is just to the top of the baffle right at the little hole
Brendan

[phartman]

Yes, Brendan, thanks for reminding me. While the truck is a '34, the motor is a 21-stud '36 with insert mains, cam bearings and adjustable lifters. I have receipts from the rebuild. Quality parts. And the distributor was converted to the later style by The Pit Stop fellows in Texas. I'm running the Stromberg 48 carb, Fenton headers and otherwise stock motor.

[Mike in AZ]

perhaps after it pukes out coolant, don't add any back??....if it still runs cool and doesn't puke any more out, run it like it....good luck....Mike

[JWL]

Is there a pressure cap on the new radiator? I don't see any puking to be possible with a pressure cap unless the cap does not fit or the engine is hot or there is combustion pressure getting into the system.

[Walt Dupont--Me.]

If the cap is tight the water is going out the overflow. The pumps do pump more volume and blows the water out the over flow. Ship has a 3# pressure valve that goes on the end of the overflow pipe. That will fix your problem. I had the same problem with my Model A with a warmed up B engine, I was always adding water, installed the pressure valve and never add water. Walt

[OhioRick]

Yes,
Skip always recommends adding the 3 pound overflow valve at the drain hose. The old style radiators have a design that has the overflow hose above the radiator cap seal. The Overflow will still throw out coolant. Unless your newer radiator has the neck design that also controls the overflow.
Your coolant height is normally lower than what you'd expect it to be. You have to leave room for expansion or you could damage your pressurized radiator. If you will be using the 3 pound valve, a cap should be close to the same pressure.

[chuck stevens]

There's a chance that under high load and rpms the head gaskets are leaking compression into the cooling system. I have an 8BA bored to 3 3/8 that has this habit, on long hills and full throttle, just a thought, Chuck.

[phartman]

JWL, Walt, I believe that this system is unpressurized, or at least runs with very little under load. The cap is the stock radiator cover with a new gasket. And there is no external expansion tank. It could be- just could be- that the water is going out the overflow hose until the volume reaches a point that the hose diameter can't handle it. The water seeks another exit and the cap is the point of least resistance. After it pukes out the radiator cap, we did check and the overflow hose was wet, so some water is coming out that way. I can't tell how much.

We've been filling the radiator to the top of the upper tank so that you can just barely see water, but that still may be too much. After it blows, I've had to add back maybe a gallon or so. Too much coolant in the radiator is causing the problem?

Again, the coolant temp has never, ever gotten over 190 degrees or so. And, yes, it wants to puke at high rpms or on a long pull up a hill. Last time it did it, I was at the end of the acceleration lane getting onto the Interstate.

The overwhelming recommendation is to put the thermostats back in and slow down the flow of the coolant. I guess ol' Henry's engineers in 1933 figured that out, too.

[Chris Marshall]

Originally Posted by chuck stevens

There's a chance that under high load and rpms the head gaskets are leaking compression into the cooling system. I have an 8BA bored to 3 3/8 that has this habit, on long hills and full throttle, just a thought, Chuck.

I think Chuck hit the nail on the head. I've had the same problem in the past. I built an 8BA bored to 3 5/16, merc crank, etc. Never ran hot, but when you really got on it at high revs, or on long runs around 70 mph (again semi hi revs) it would suddenly puke antifreeze out the overflow. Had a pressurized system with a 7 lb cap. I fought this for several months. Looked into water pumps, thermostats, etc. Finally pulled the heads and found evidence of compression leaks on both sides between the rear cylinder and water passage. This was using copper head gaskets. Went to Best composite gaskets and cured the problem.

This engine is in my T-V8 roadster. My wife really hated the sudden green "showers"

[37don]

If you have an original top tank the overflow is below the cap seal so the Skips 3lb valve is all you need as was posted above. A pressure cap won,t help at all, you need a good gasket on the radiator cap. I have a freind with a nice original 36 and he said he tried everything without any luck. Put on the Skip valve and problem gone.
Good luck, Don

[Fibber Mcgee]

I had the same problem as you.Trust me put the thermostats back in.I put new pumps and it started spraying water out overflow same as you,as soon as I put in tstats it quit.

[FRANK PKNY]

You can buy a kit to test for exhaust gas in the cooling system. It's about $35.00 works perfect . Then you will know if you have a block or head leak and go from there. Frank pkny

[phartman]

Frank, yup, we're going to run that test first. At least eliminate that as a possibility.

Trying to find thermostats for the '34-'36 Fords. Tried Joe Smith Early Ford and Mac's. Neither has them. The tractor application will work, but the size is too small for the hose. Other sources? Other places that might have the thermostats?

Also, the '36 LB run such low oil pressure...I wonder if I'm better off with the 140 degree thermostat or the 160 degree. Any opinions?

And, fellas, again, many, many thanks. Yesterday my buddy Warren and I were wondering where to go to get guidance on this sort of motor problem. Hands down, Fordbarn has come to the recue.

[FRANK PKNY]

phartman, Can't help you with the thermostat's . But I would recomend talking to skip about the flow rate Possibly need just a plain restrictor plate? Do the exhaust gas test first. Then call Skip. Frank

[BrianCT]

I also have Skip's pumps in a 21 stud and had much the same problem when I removed the 'stats. Put them back in.

[40ford]

Phartman,there is two thermostats on ebay now which may solve your problem.Item # 350456738138.

[phartman]

Skip rebuilt my water pumps. I'll give him a call.

[B-O-B]

I have a 36 LB that did exactly as you have described. I sent a pair or nos cores to skip for a rebuild but they are still on the shelf. This was several years ago. I also got the 3# pressure valve & put that in the over flow hose with a recovery tank. So far I haven't had any more problem with over flow. I do not run thermostats & have a 50/50 mix of water & anti-freeze along with some water wetter.

[flatjack9]

I had this problem with an engine I built for a 35. He had an after market aluminum radiator that we used on the test stand. Started blowing water out almost immediately. About drove me nuts checking for pressure leaks in to the system. Couldn't find anything. Finally put on one of my stock 36 radiators and presto, problem solved. I think you have a poorly designed radiator.

[phartman]

Uhhh, Flatjack, the for the price I paid, it shouldda been a really well designed radiator.

Anybody running a Griffin with a '36 LB?

[1931 flamingo]

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I would question why there isn't a baffle in your radiator. What the others have said about your rebuilt pumps may be contributing to your problem, the pumps are pushing more water to the top and it's going out your o/flow tube (I assume, and not the cap itself. On a model A 4 cyl they will puke until they "find" their own level. JMO
Paul in CT

[flatjack9]

Originally Posted by phartman

Uhhh, Flatjack, the for the price I paid, it shouldda been a really well designed radiator.

Anybody running a Griffin with a '36 LB?

You are definetly right on that. I think I would be talking to Griffin. I know my friend paid a good deal for his, but it wasn't a Griffin. I believe he sent it back. And his pumps were stock items, not high flow.

[Brendan]

Originally Posted by phartman

Frank, yup, we're going to run that test first. At least eliminate that as a possibility.

Trying to find thermostats for the '34-'36 Fords. Tried Joe Smith Early Ford and Mac's. Neither has them. The tractor application will work, but the size is too small for the hose. Other sources? Other places that might have the thermostats?

Also, the '36 LB run such low oil pressure...I wonder if I'm better off with the 140 degree thermostat or the 160 degree. Any opinions?

And, fellas, again, many, many thanks. Yesterday my buddy Warren and I were wondering where to go to get guidance on this sort of motor problem. Hands down, Fordbarn has come to the recue.

thats why i am running the freeze plugs drilled out, i can't find thermostats, Brendan

[phartman]

1931 Flamingo, nope, when she spews, it's out the radiator cap. It's ugly. No doubt about what is going on when it happens. Very unlady-like, I'd say.

[wga]

phartman - I've used the radiator fluid that checks for exhaust gases. What worked the best was getting a shop to use their exhast gas analyser. Ran the car hard, removed the cap and they inserted the probe - came up to 60 PPM of exhaust gas.

[David J]

Yeah on this and if your windshield is open your in deep Do-Do with your passenger . I don't like anti-freeze in the face either . The 34 4d used to do this if you ran it hard or held a fast idle and it was all from someone REALLY greasing the water pumps with Hi-temp grease in the past and it turned into a semi-petrified YUK .. It restricted the radiator flow enough to cause the top tank to try and overfill . No good comes from this . Like yours it was not overly hot when it did this .Doesn't sound like you have this exact problem but it boils down to water going into the top tank faster than it can drain through the core . The cures for this are pretty well covered already so izza gonna quit ramblin David J

Originally Posted by phartman

1931 Flamingo, nope, when she spews, it's out the radiator cap. It's ugly. No doubt about what is going on when it happens. Very unlady-like, I'd say.

[1931 flamingo]

I'm still going to question the lack of a baffle and why it's puking at rad cap and NOT the o'flow tube if you say it's not boiling. Have you tried a different cap or double gasket??
Paul in CT

[phartman]

That is a very good point, Paul. I think another gasket under the cap is in order. We'll try that, too.

[phartman]

Motor passed the "no combustion gases in the coolant" test, so we called Skip Haney about the pumps and the cooling system. No questions asked, no discussion, very short conversation. He simply said, "You need one of my 3# valves. I'm sending it out to you. No charge." What a great guy. He's the best. Hope that, 160 degree thermostats and a better, tighter cap do the trick.

[Bill in Al]

A common Model A problem.Put in a baffle,thermostat,lower the coolant level or install an overflow tank.Good luck.

[Bill in Al]

Whups--Didn't see Skips solution!

[phartman]

An update on the motor spewing coolant. We put 160 degree thermostats back in. Added Skip's low pressure relief valve. And switched out water for 60/40 coolant (60 % water)

The spewing stopped immediately. And the motor runs consistently at 160 degrees. I'm keeping the coolant in the motor this summer. Seems that the coolant is a much better heat sink and is much more effective in carrying away heat from the motor.

This experience flies in the face of so much advice I got about no thermostats/only run water, but I can't argue with how well the motor runs. I'm guessing that what caused the problem before was the new pumps moving the water too quickly through the block. Adding the thermostats back slowed the flow and increased the transfer of heat out of the block. Diumo.

[G.M.]

Skips pumps almost double the amount of coolant flowing through the entire system. There are 3 things that improve cooling on these old Fords. 1 more water in the system, 2 more water flowing through the system and 3 more air moving through the radiator. There are aproxmently 144 tubes in the old Ford radiators. If you add the area of these up it comes to 3 1/2 square inches, the hose provide 4 1/2 square inches of water into the top tank. This is like 4 lbs of dung in a 3 lb bag. Along with the smaller opening there is also the length of the tubes and dirt restricting the flow inside of the tubes. With the poor stock pumps the water wouldn't flow through the radiator. The water came in to fast and not going through the tubes backed out the overflow. Now it was low on water and overheated. Restrictions were put in the heads or the impellers cut off or holes drilled into them. This reduced the amount of water going into the radiator and not as much went out the overflow and it didn't boil over but ran at elevated temperatures do to 18 quarts of water in a 22 quart system and very slow flow through the tubes. A 4 lb pressure cap was interduced in the 40's, not to pressurise the radiator but to keep the water from backing out the over flow tube. This allows the water to be forced through the radiator and the radiator filled to the top. There are a LOT of pressure caps that are to short and the extended rubber pressure end don't seat down on the washer seat about 1" down in the neck. Stock 32 to 36 pumps move 55 gallons each in 5 minutes and Skips 92 gallons. The 37 to 53 pumps stock move 65 gallons each in 5 minutes and Skips 110 gallons. The over flow must be closed by either a 4 lb pressure cap or Skips 3 lb valve to seal the system so the water can be forced through the radiator. The radiator can now be filled up to the neck. The engine should now run below 200 even in traffic on warm days. At 200 degrees there is about 1 1/2 PSI in the radiator. The pressure cap or valve only keeds the water from excaping and is a safty valve if problems occure. The water stays filled for months. Skip has done thousands of pumps with great results on old Fords when instructions are followed. Why would someone buy his pumps to increase the flow for better cooling and restrict the flow with washers or thermostats with small openings? [email protected] makes new heavy duty high flow 180 degree stats that hold the temperature right on 180. I have used them down in Florida from 50 to 90 degrees and my 39 stays on 178 to 182 all the time. If the coolant temperature gets over 180 the stats stay in the full open position providing a full flow. When the outside tempertures get up near 90 your small 160 stats are going to cause the engine to run up around 200 and there is no margin for traffic. Been there done that. G.M.