pushing coolant need help
Thread Starter
Instructor
Joined: Jul 2007
Posts: 193
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pushing coolant need help
Started my 72 350 today with the new cam and got 8 minutes into the break-in and it started pushing coolant out the over flow Temp was only 160 degrees or so) so I shut i down. This was hapening before the cam change and started all of the sudden as I had 600 miles on the engine prior. Based on advise from this forum before I changed the t-stat and thought that was it. I re-started the break-in run and as soon as the t-stat opened (right at 180 deg) it stoped pushing coolant. SAME AS BEFORE. I finished the break-in and I hope I didn't damage the cam by starting and stoping! Could this be the water pump? All seems ok once the t-stat opens. It seems as though the coolant isnt flowing through the expansion tank before the stat opens " or should it"?. Water pump was new when engine was rebuilt 600 miles ago. All was fine until about 50 miles ago!
I'm stumped!!
I'm stumped!!
Melting Slicks
Joined: Mar 2007
Posts: 2,100
Likes: 12
From: Frederick Maryland
You may have air trapped in the system. That can create a bubble that acts like a clog, restricting coolant flow. I so, the air has to be bled out.
Basically, you let the engine run with the radiator cap off and let water run out...the air will leave the system that way. You can run a hose of some kind from the radiator neck to away from the car to a container if you like, then refill the system after the air is bled out.
Basically, you let the engine run with the radiator cap off and let water run out...the air will leave the system that way. You can run a hose of some kind from the radiator neck to away from the car to a container if you like, then refill the system after the air is bled out.
Thread Starter
Instructor
Joined: Jul 2007
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i filled the system through the t-stat and tried all that before so I'm sure its not trapped air. It ran fine for hundreds of miles the all of a sudden it started doing this(before the cam change) I even pulled the heads and looked for cracks but all looked fine. Again once the stat opens it works fine.
Drifting
Joined: Jan 2002
Posts: 1,645
Likes: 11
From: Schaumburg IL
If you are very sure there is no air, then several issues come up..
- Stuck t-stat
- Exhaust gas in the coolant -go to a shop or rent an exhaust gas test tool for the coolant. While you pulled the heads there may be a crack that you can not see or ... sure the right head gaskets were used in the assembly.
- Still have air??? when you do the breakin put the front tires on ramps and run it. Air rises and if there is any this will allow a purge.
- Overheating an issue?
- Collapses lower hose or spring for returns
- Changed the water pump lately .. what if you were given a reverse flow one???
Good luck.
- Stuck t-stat
- Exhaust gas in the coolant -go to a shop or rent an exhaust gas test tool for the coolant. While you pulled the heads there may be a crack that you can not see or ... sure the right head gaskets were used in the assembly.
- Still have air??? when you do the breakin put the front tires on ramps and run it. Air rises and if there is any this will allow a purge.
- Overheating an issue?
- Collapses lower hose or spring for returns
- Changed the water pump lately .. what if you were given a reverse flow one???
Good luck.
Thread Starter
Instructor
Joined: Jul 2007
Posts: 193
Likes: 0
Its a new delco stat. If it was a crack or something wouldn't it keep doing it even after the t-stat opened? The w/pump was new 600 miles ago. All the fluids look fine. The strange thing is the infared gun says the temp at the engine block and rad is only 180 and the one side of the expansion tank is 270 and the otherside is 180. Again after the stat opens all seems to operate normal!!
Racer
Joined: Apr 2006
Posts: 340
Likes: 0
From: Warrensburg MO
Started my 72 350 today with the new cam and got 8 minutes into the break-in and it started pushing coolant out the over flow Temp was only 160 degrees or so) so I shut i down. This was hapening before the cam change and started all of the sudden as I had 600 miles on the engine prior. Based on advise from this forum before I changed the t-stat and thought that was it. I re-started the break-in run and as soon as the t-stat opened (right at 180 deg) it stoped pushing coolant. SAME AS BEFORE. I finished the break-in and I hope I didn't damage the cam by starting and stoping! Could this be the water pump? All seems ok once the t-stat opens. It seems as though the coolant isnt flowing through the expansion tank before the stat opens " or should it"?. Water pump was new when engine was rebuilt 600 miles ago. All was fine until about 50 miles ago!
I'm stumped!!
I'm stumped!!
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
Corvettes prior to 1973 don't have coolant recovery tanks (plastic buckets). Instead, they puke excess coolant on the ground via an overflow tube. In the OPs case, the system may be simply be overfilled or the rad cap is incorrect or weak. I presume the car has the correct, stock cooling system config.
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Racer
Joined: Nov 2004
Posts: 485
Likes: 1
From: Oakville ON
IR guns give different readings for surfaces with different 'emisitivity'. So a plastic surface vs. a steel surface at the exact same temperature will read differently by the gun.
Thread Starter
Instructor
Joined: Jul 2007
Posts: 193
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Alum tank! I pondered the situation today and put a presure tester on the alum expansion tank and it would only hold presure to about 14 pounds! leaking at the cap/seal. Cleaned the tank lid/seal area to no avail! Maybe its warped? I had three different caps all did the same thing however I bent the tangs on the cap to "create" more pressure and started it and no coolant spill! Knowing that the system was already hot this maybe a false solution but I will start tomorrow and report back. If this is the problem It will sure be simple solution to a problem that has plagued me for months and darn near drove me to drink (short drive).
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
this is just the nature of fluid getting hot and expanding, add some air in the lines and this sounds exactly like the problem unitl it finds its "level".
what kind of pressure do you want it to hold?
i do use the trick of drilling two small holes in the thermostat so there is no air getting trapped
what kind of pressure do you want it to hold?
i do use the trick of drilling two small holes in the thermostat so there is no air getting trapped
Last edited by bobs77vet; Mar 9, 2010 at 09:23 AM.
Melting Slicks
Joined: Mar 2007
Posts: 2,100
Likes: 12
From: Frederick Maryland
Water Wetter is not a cure-all for cooling system problems and won't correct problems. One still needs to find the cause of a problem and correct it...adding an additive like Water Wetter will only delay the inevitable.
Thread Starter
Instructor
Joined: Jul 2007
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Started the car tonite and fluid on the floor again even with the cap tweaked. pressure tested it the other nite and it would start to leak pressure at about 14 pounds. Has anyone had an expansion tank top warp? The coolant stops coming out the overflow as soon as the t-stat opens. I'm now trying two rubber gaskets on the cap. This is driving me to drink! I guess I would drink any way though!
Thread Starter
Instructor
Joined: Jul 2007
Posts: 193
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Had the car out tonite since it was in the md 50's in the northeast and since I installed two rubber gaskets no coolant on the floor, however now when I run it hard thru the gears or go up a long grade the temp climbs to 210 and higher if I don't get out of the throttle! When I get out of the gas the temp comes back down within a mile. I need help with this one!
This car has a new rad, heater core, and w/pump at time of rebuild (600 miles ago). Just changed cam to a lunati 60103 which is a little more than before. Even befor the cam change the temp would climb when idling on a hot day and as soon as I started moving it would come down to normal. Could this be a bad w/pump?
This car has a new rad, heater core, and w/pump at time of rebuild (600 miles ago). Just changed cam to a lunati 60103 which is a little more than before. Even befor the cam change the temp would climb when idling on a hot day and as soon as I started moving it would come down to normal. Could this be a bad w/pump?