The Ford Barn - View Single Post - 59AB Cooling System Advice Needed from the Experts (not an overheating issue)

anothercarguy · 06-26-2019, 01:13 PM

Been awhile since I posted on this site (I'm more active on the HAMB, but you guys are the flathead gurus...and thank you for that!).

The combo is a 59AB + .080, 500 miles on rebuild, Eddie Meyer heads and intake, 2 - 94's, Isky Max-1, HC dual point/dual coil, 78-8501-n, & 78-8502-n waterpumps, 180 degree thermostats, custom built brass rad, with 7lb rad cap, and coolant recovery tank.

Engine runs cool, 170-175 degrees on the gauge in traffic or the highway.

Last weekend we were on a 5 hour highway trek to a car show, travelling at around 60 mph (29" tall tires, 3.78 gears, revving between 2600-2700rpm...a speed where the flatty seemed pretty happy and was pulling in some nice fuel economy). The road included climbing sustained mountain passes where the temp would go to 180-185 (still pretty cool). But then one of the guys that was following me told me I was losing fluid. Stopping to check, I discovered that I was losing coolant out the overflow of the coolant recovery tank. Engine temp was still good, hand on the rad confirmed it was not overheating. I made it to the destination, but upon checking the coolant level there found that I had lost a gallon of coolant, and the green drops of coolant on my black chassis where the overflow of the coolant recovery tank dumps indicates that it continued to drip for the balance of the trip.

After topping up the system with water (had been a 50/50 mix of water and Prestone antifreeze), with the rad cap off and the engine running, I saw the coolant foaming. Fearing a head gasket issue (copper, big bore head gaskets), I left the car in the driveway for the weekend, and then rented a trailer so the car had a stretcher ride home.

Yesterday, now in the shop: I did a compression check - 6 holes are 170lbs, #6 hole is 165lbs, and #2 hole is 160lbs. All 8 plugs look identical (none have telltale of water or steam. I did a CO test for the coolant and found that there wasn't any exhaust gas present in the coolant. I was unable to duplicate the coolant dumping from the overflow while running in the shop (in neutral) at higher rpms. I pressure tested the cooling system and it held 6lbs of pressure for 15 minutes. The coolant was not foaming.

I've not yet checked the rad cap (will do that when I get back down to the shop).

I was thinking that if I replace the head gaskets, I would go with Felpro composite rather than the copper, and replace the grade 8 bolts with an ARP stud kit (boy they want a lot of $ for those!), but want to be sure that this will cure the issue before I go through the effort and expense. There is also the possibility that the water pumps are overpowering the rad flow at that RPM, but I would have thought the 7lb rad cap and the coolant recovery system would have dealt with that.

What do you experts think and advise? Please and thank you in advance.

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06-26-2019, 01:13 PM	#1
anothercarguy Member Join Date: Jan 2013 Location: Bowen island, BC Posts: 74	59AB Cooling System Advice Needed from the Experts (not an overheating issue) Been awhile since I posted on this site (I'm more active on the HAMB, but you guys are the flathead gurus...and thank you for that!). The combo is a 59AB + .080, 500 miles on rebuild, Eddie Meyer heads and intake, 2 - 94's, Isky Max-1, HC dual point/dual coil, 78-8501-n, & 78-8502-n waterpumps, 180 degree thermostats, custom built brass rad, with 7lb rad cap, and coolant recovery tank. Engine runs cool, 170-175 degrees on the gauge in traffic or the highway. Last weekend we were on a 5 hour highway trek to a car show, travelling at around 60 mph (29" tall tires, 3.78 gears, revving between 2600-2700rpm...a speed where the flatty seemed pretty happy and was pulling in some nice fuel economy). The road included climbing sustained mountain passes where the temp would go to 180-185 (still pretty cool). But then one of the guys that was following me told me I was losing fluid. Stopping to check, I discovered that I was losing coolant out the overflow of the coolant recovery tank. Engine temp was still good, hand on the rad confirmed it was not overheating. I made it to the destination, but upon checking the coolant level there found that I had lost a gallon of coolant, and the green drops of coolant on my black chassis where the overflow of the coolant recovery tank dumps indicates that it continued to drip for the balance of the trip. After topping up the system with water (had been a 50/50 mix of water and Prestone antifreeze), with the rad cap off and the engine running, I saw the coolant foaming. Fearing a head gasket issue (copper, big bore head gaskets), I left the car in the driveway for the weekend, and then rented a trailer so the car had a stretcher ride home. Yesterday, now in the shop: I did a compression check - 6 holes are 170lbs, #6 hole is 165lbs, and #2 hole is 160lbs. All 8 plugs look identical (none have telltale of water or steam. I did a CO test for the coolant and found that there wasn't any exhaust gas present in the coolant. I was unable to duplicate the coolant dumping from the overflow while running in the shop (in neutral) at higher rpms. I pressure tested the cooling system and it held 6lbs of pressure for 15 minutes. The coolant was not foaming. I've not yet checked the rad cap (will do that when I get back down to the shop). I was thinking that if I replace the head gaskets, I would go with Felpro composite rather than the copper, and replace the grade 8 bolts with an ARP stud kit (boy they want a lot of $ for those!), but want to be sure that this will cure the issue before I go through the effort and expense. There is also the possibility that the water pumps are overpowering the rad flow at that RPM, but I would have thought the 7lb rad cap and the coolant recovery system would have dealt with that. What do you experts think and advise? Please and thank you in advance. 20190625_151520_resized.jpg Last edited by anothercarguy; 06-26-2019 at 07:05 PM.