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Darn Freeze plug
#1

Took the Bird for a quick test run and blew out the center freeze plug doing over 6000 rpms in 4th gear today. Thought it would of been a hose or something.

But as fast as I poured water in it was coming out (LOL) and it was a little hard to see because of the E6 manifold. So I put a expandable plug in to get her home. 

150 MPH or Bust
87 TC 5 speed at 203000 miles, BoPort Stage 3 Head, 2.1 cam, 50 trim Turbo, Stinger Pimp, 3" exhaust, upper and lower ported manifolds, FMIC, 66lb injectors, 255 pump, 20 psi at 4K, 25 psi at 4.5k. Temp is 93c and IAT is 50c. Great freeway flyer on pump 93 gas.
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#2

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The only thing that usually goes wrong with core plugs ("freeze plugs") is that they corrode, become "holy" and leak......seeping slowly at first, then more as time passes. If one 'em blows completely outta the machined hole in the water jacket, however, it's a pretty good indicator of excessive cooling-system pressure......most likely caused by a blown/leaking head gasket. I suggest monitoring for gradual coolant loss &/or bubbling in the overflow/recovery bottle after shutdown. <shrug>
Placerville, California
(former)  '78 2.3T Courier w/blow-thru carb ~ (current)  '87 2.3T Ranger w/PiMP’d EFI
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#3

After not seeing any blown hoses I was thinking a head gasket issue too. The oil level was good and no mixing. When I got this car I replaced the radiator cause it had 20 pounds of mud in it when flushing out the engine so I'll be putting in some good freeze plugs next and do some checking.

I had a Escape with a blown head gasket that would bubby too so I put a gauge on the cooling system with a cold engine idling I had 12 psi. I think I read anything above 5 psi means something is wrong.
87 TC 5 speed at 203000 miles, BoPort Stage 3 Head, 2.1 cam, 50 trim Turbo, Stinger Pimp, 3" exhaust, upper and lower ported manifolds, FMIC, 66lb injectors, 255 pump, 20 psi at 4K, 25 psi at 4.5k. Temp is 93c and IAT is 50c. Great freeway flyer on pump 93 gas.
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#4

FYI I checked the other 2 plugs and their knocked in about 1/4" from the edge of the holes.
87 TC 5 speed at 203000 miles, BoPort Stage 3 Head, 2.1 cam, 50 trim Turbo, Stinger Pimp, 3" exhaust, upper and lower ported manifolds, FMIC, 66lb injectors, 255 pump, 20 psi at 4K, 25 psi at 4.5k. Temp is 93c and IAT is 50c. Great freeway flyer on pump 93 gas.
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#5

I put a pressure gauge on the radiator and at idle, max pressure was only one pound at 94C once the fan turned on it dropped down to a vacuum. This probably doesn't mean much cause I'm not at 25 pounds of boost but I'll do a leak down and compression test next.

I might just run a longer hose to my gauge and tape it to the windshield and see what it reads at full boost.

I do have new studs in the box and may just replace the head gasket just to be safe.

Gotta Love these old 2.3 cause they can take a licking and still run like a bat out of hell !
87 TC 5 speed at 203000 miles, BoPort Stage 3 Head, 2.1 cam, 50 trim Turbo, Stinger Pimp, 3" exhaust, upper and lower ported manifolds, FMIC, 66lb injectors, 255 pump, 20 psi at 4K, 25 psi at 4.5k. Temp is 93c and IAT is 50c. Great freeway flyer on pump 93 gas.
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#6

(10-20-2020, 12:11 AM)Racingjake Wrote:  I put a pressure gauge on the radiator and at idle, max pressure was only one pound at 94C once the fan turned on it dropped down to a vacuum.  
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I have no idea where you're connecting a gauge to get those kinda pressure &/or vacuum readings from a hot (94° C) cooling system, Jake! The pressure of modern pressurized cooling systems .is regulated by the cap and is usually set to run between 13 & 18psi by most OEM's when the system is up to operating temp. Soooo......when hot, the system should reach - and not exceed - whatever pressure is printed on the cap, unless the pressure is not able to bleed off fast enough.......which virtually never happens unless there's a combustion leak into the system. 

Vacuum? There should only be a very minor .vacuum reading during the cooling period AFTER shut-down. This is caused by the coolant "shrinking" in volume. If the recovery system is operating properly, that cool-down .will draw the coolant back outta the recovery bottle that was routed there, due to expansion, during the warming cycle.  This back-and-forth exchange of coolant from/to the recovery bottle prevents loss of coolant during expansion and prevents air from entering the system during contraction (which was NOT the case back in "the day" prior to coolant-recovery systems). <shrug>
Placerville, California
(former)  '78 2.3T Courier w/blow-thru carb ~ (current)  '87 2.3T Ranger w/PiMP’d EFI
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#7

Hey Ray

I got a radiator cap that I removed the vent disk and hooked up a gauge to the overflow spout on the radiator so see how much pressure is in the system.
So it's a sealed system when I'm checking pressure. So the gauge is showing expansion and contraction of fluid from a low heat load when the fan comes on. The pressure should be higher with a bigger heat load when going down the road.


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87 TC 5 speed at 203000 miles, BoPort Stage 3 Head, 2.1 cam, 50 trim Turbo, Stinger Pimp, 3" exhaust, upper and lower ported manifolds, FMIC, 66lb injectors, 255 pump, 20 psi at 4K, 25 psi at 4.5k. Temp is 93c and IAT is 50c. Great freeway flyer on pump 93 gas.
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#8

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As you may or may not know, there are three separate sealing strategies on a modern recovery-system radiator cap, Jake:
  
  1. The rubber gasket directly under the "lid" that isolates the system from ambient/outside air pressure by sealing against the top of the radiator neck.
  2. The rubber gasket on the spring-loaded pressure-regulating poppet valve that seals against the recessed seat at the bottom of the radiator neck.
  3. The lightly-sprung disc that seals against the above-referenced poppet-valve gasket and serves as a one-way check valve to allow unpressurized coolant in the recovery bottle to be drawn back into the radiator during "cool-down".
Removing what you're referring to as the "vent disc" (#3 above) should've theoretically exposed the entire radiator-neck cavity and recovery-bottle nipple to the cooling system at all times, thus providing your gauge with a correct system-pressure reading. BUT ~ your "hot" 1-pound pressure reading is way off, so there's something else going on that I don't understand........possibly a leaking top seal (under the cap's "lid")?? DUNNO. Did you start out (cold) with the gauge already plumbed as described, or......did you connect it after the system had already warmed/heated up?  <puzzled>
Placerville, California
(former)  '78 2.3T Courier w/blow-thru carb ~ (current)  '87 2.3T Ranger w/PiMP’d EFI
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#9

Yesterday the engine was warm when I tested it and coolant was a little low. So today I topped it off and a cold engine pressure climb to 13 psi and when the the fan turned on the pressure dropped to 5 psi with the engine idling. I need to take if for a test run and see what the real numbers are.

Thanks
87 TC 5 speed at 203000 miles, BoPort Stage 3 Head, 2.1 cam, 50 trim Turbo, Stinger Pimp, 3" exhaust, upper and lower ported manifolds, FMIC, 66lb injectors, 255 pump, 20 psi at 4K, 25 psi at 4.5k. Temp is 93c and IAT is 50c. Great freeway flyer on pump 93 gas.
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