7m-ge coolant Leak around thermostat.

painknight · 10-08-2010, 01:23 AM

I've replaced the lower radiator house, which was also leaking, and that wasn't the problem. My current belief is the small hose that runs from (I'm not a gear head, so assuming the thermostat housing is simply where the thermostat goes in) right under the thermostat, and goes into the block between the lower radiator hose connection to the block, the distributor, and the exhaust manifold. I can feel coolant dripping from where the lower radiator hose connects, and it only leaks after the thermostat opens. Any tips on if I am going after the right hose or where my leak may be coming from? If there is a way to get the car to drive 300 miles to my grandfathers shop, then I would appriciate that as well.

Metaphysico · 10-08-2010, 03:26 PM

There is a small 90 degree hose that attaches to the back of the thermostat that is a pain to get to but it leaks and is almost impossible to pinpoint. Also it connects to a metal pipe that goes all the way around the motor, the pipe sometimes rusts and leaks. In this pic it is just below the cps its the rusty pipe with the hose below in on the right side middle of the pic. The hose is already off the pipe in the pic.

rjSupra · 10-11-2010, 10:10 PM

Hey check this out for a good read - I have your problem and am dealing with it. Was stranded in a city too, royal pain.

http://www.toyota-supra.info/forums/...lter-area.html

SO, here's what you could be able to do, it's a pain.
Have a shitload of coolant and distilled water, and then top of the car, and then ease it slowly on the backroads at speed under 2k rpm, so under 45-50 mph ideally. My car started to blow it's stack after I'd hit hwy speed very quickly or huge hills. I was able to idle the car a long time and not overheat. But I could generally only drive 10-15 miles before the pressure would build and I'd lose coolant and overheat (always a huge hill or hwy). I had to go 60 miles. 300 is a long way. I think you'd be better off finding a sympathetic property owner and leaving it to return with a solid tool kit.
The 90 hose is not impossible to replace without even taking out other stuff. It COULD be done without removing anything else. It's a pain. I am removing my PS reservoir (pushed out of way and removed bracket), the CPS aka Cam Position Sensor which will give a lot more access, and taking out the water outlet housing and replacing the gasket that joins the CPS to the head there, to be safe. This coolant leak has sucked for me. I did the Water pump, the thermostat, and the belts all to no avail. It's been nearly impossible for me to see exactly where it's originating from. My 90 degree hose did not look totally shot when I removed it but I am very hopeful that was the cause. I got a Gates replacement hose for $4.39 from a Robbins auto parts. the actual part # is in my thread if you need it. Let me know how you do, and I'll try to do the same. I am trying to get back on this repair tomorrow night.
What specifically were your symptoms? How fast did you overheat? and are you sure / sort of sure where it's leaking from?
Thanks, and good luck.

10-08-2010, 01:23 AM	#1
painknight Stock Join Date: Oct 2010 Location: Rifle, Colorado Posts: 7	7m-ge coolant Leak around thermostat. I've replaced the lower radiator house, which was also leaking, and that wasn't the problem. My current belief is the small hose that runs from (I'm not a gear head, so assuming the thermostat housing is simply where the thermostat goes in) right under the thermostat, and goes into the block between the lower radiator hose connection to the block, the distributor, and the exhaust manifold. I can feel coolant dripping from where the lower radiator hose connects, and it only leaks after the thermostat opens. Any tips on if I am going after the right hose or where my leak may be coming from? If there is a way to get the car to drive 300 miles to my grandfathers shop, then I would appriciate that as well. __________________ 1987 Supra 7m-ge, manual trans, LSD. Sorry the banner sucks I made it with paint.

10-11-2010, 10:10 PM	#3
rjSupra 3" Exhaust Join Date: Sep 2010 Location: NH Posts: 86	same coolant leak problem - most likely I am having - see included link. Hey check this out for a good read - I have your problem and am dealing with it. Was stranded in a city too, royal pain. http://www.toyota-supra.info/forums/...lter-area.html SO, here's what you could be able to do, it's a pain. Have a shitload of coolant and distilled water, and then top of the car, and then ease it slowly on the backroads at speed under 2k rpm, so under 45-50 mph ideally. My car started to blow it's stack after I'd hit hwy speed very quickly or huge hills. I was able to idle the car a long time and not overheat. But I could generally only drive 10-15 miles before the pressure would build and I'd lose coolant and overheat (always a huge hill or hwy). I had to go 60 miles. 300 is a long way. I think you'd be better off finding a sympathetic property owner and leaving it to return with a solid tool kit. The 90 hose is not impossible to replace without even taking out other stuff. It COULD be done without removing anything else. It's a pain. I am removing my PS reservoir (pushed out of way and removed bracket), the CPS aka Cam Position Sensor which will give a lot more access, and taking out the water outlet housing and replacing the gasket that joins the CPS to the head there, to be safe. This coolant leak has sucked for me. I did the Water pump, the thermostat, and the belts all to no avail. It's been nearly impossible for me to see exactly where it's originating from. My 90 degree hose did not look totally shot when I removed it but I am very hopeful that was the cause. I got a Gates replacement hose for $4.39 from a Robbins auto parts. the actual part # is in my thread if you need it. Let me know how you do, and I'll try to do the same. I am trying to get back on this repair tomorrow night. What specifically were your symptoms? How fast did you overheat? and are you sure / sort of sure where it's leaking from? Thanks, and good luck. __________________ 88 Supra 7M-GTE Turbo, TEMS, Targa stock

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10-08-2010, 03:26 PM	#2
Metaphysico Stock Join Date: Oct 2010 Location: Georgia Posts: 27	There is a small 90 degree hose that attaches to the back of the thermostat that is a pain to get to but it leaks and is almost impossible to pinpoint. Also it connects to a metal pipe that goes all the way around the motor, the pipe sometimes rusts and leaks. In this pic it is just below the cps its the rusty pipe with the hose below in on the right side middle of the pic. The hose is already off the pipe in the pic.