Auto Supra Coolant hose pressure and return leak to oil pan and filter area?

[rjSupra]

Got a new thermostat and gasket 192/195 degree. It was cheap! $7 something. But now I've checked the car again, I can see that it was never leaking from this area where the gasket would be on the thermo - drat. Might just do it anyway since most people recommend that should be done with older car.

Also, just noticed that there is a electrical line just under what sort of looks like a spark plug into the thermo larger housing. It's labeled as the "light green wire for aux fan sensor" by another poster's pic.
Wait a minute someone else's posted pic here labels it a "A/C Sensor Switch" in the photo I've attached here. So can this be related in any way to overheating and large volume of leaking coolant in this area (about 3-6 inches away towards back of motor/back of car from the front, and about 2 inches below it (an area I can't see into).
This cable was sheared off. Nice. By the looks it's been exposed to the elements for awhile. So, dumb question here, can that be related to a fan not being sent a signal to go on and therefore overheat or something? I've not run the A/C whatsoever on this car - don't keep interior temp setting in auto either. (don't know what that connects or engages). I know before the main alt fan on the engine spins fine. There is a small upper driver side fan that is electric and that was spinning when I overheated with the motor 'off' and the key in the accessory position. There is one fan in the skinnier full size radiator in front of the main back one, and I've never seen that fan spin, even with the car overheating, at normal idle etc etc. So I am going to re-wire that wire back too. Not sure if that could have caused any of these problems - I doubt it is so simple and such an easy fix with this car.

Thanks for the additional help Bill UK!! I super appreciate it. And I finally noticed there is a coolant large hose I can barely see under that CPS unit. Maybe that's where it's been coming from. Will check out that spot thoroughly that you recommend in the last diagram.

Will update if I ever get this sorted and fixed.

[btwilson86]

That hose you're referring to went out on my 87 turbo, it was a little difficult ot get too but luckily it was in stock at a parts store in town (had to trim it to fit, of course). In any case, if that's not the problem this time around, it's likely to be in the near future so I would suggest replacing it and the other small coolant hoses around the engine bay. These cars are in their 20's now, and for some reason people never think to change those while they own the car

[rjSupra]

Argh. She blew her top again twice tonight. I thought I had it 'managed' to a 'small' leak. Boy was I wrong.
Lots and lots of coolant loss, I was done after 15 miles. I actually went over the red on my temp gauge because there was nowhere to pull over on this hwy. Finally did get it pulled over, let it cool 90 minutes, had to get a jump (batt still dead), and then drove it another 12 miles before it started getting near the red and I pulled the plug for the night in a small city street.
Now my current suspect is the water pump. I am going to replace the water pump, the belt and the thermostat and gasket tomorrow first thing and then drive her out with 4 gallons of extra distilled water and coolant on standby, to try to get the rest of the way north.
My plan had been to try to limp it quietly home at 50 mph up the highway 40 miles to my parents house where I've got nice floor jacks, full tools etc etc... That plan - fail.
I can only hope that it's just the water pump. It was steaming right behind it, and coolant was all below it and I saw a stream coming down just below it as I was idling to cool her down after pulling over.
I will update more tomorrow. I hope this saga ends on a better note quickly. I had been contemplating a 'best offer' sale on her in the car I was so frustrated and I have only really run her a week. I suck.

[rjSupra]

My car is not working. I put in a brand new Water Pump today along with a new thermostat, which I cut the toggle off and enlarged the hole by drilling it as suggested here (the drill bit). I put in a new alt drive belt, and the A/C belt (Would have done the P/S but I guess you have to be an elf or underneath the car - and did I mention that the car was marooned in a strange city overnight?).
The stupid invisible leak is back. It never left.
Check this data:
After I replace all this stuff above, I burp the car with the radiator cap off, heat on high for about 55 minutes. (flat - no hill, can't roll it etc...)
Everything is fine, nice usual temp 33% up or so. With the new thermo with the drill hole to replace the older thermo totally stock, instead of my heat coming on strong within a few minutes, it takes about 20 minutes at idle, or that was when I started to gas the car to about 1500 rpm to speed up the burping. A fair amount of bubbles came up for about 40 minutes of it. Finally capped it off and headed back to home very gingerly.
Drove fine, really well, nice temp for 20 miles on back roads about 40-50 mph. I felt a little more confident, so I took it on the highway and got to 55mph and a little over 60mph for a few miles. I exited, made a hard long left sweeper a bit fast, and something sounded and felt wrong or bad, but can't say exactly what. Within 20 sec or so, the temp gauge is up 1/2 way. Uh oh, I've seen this film before. It went up rapidly up to that, and within 1 mile or less I was all the way into the red zone trying to find spot #3 to abandon the car without it getting towed.
Can't spot the leak no matter how I crane my neck, shine my light from any angle. It seems to be centered or rather slightly passenger side and right under the CPS and water pump. But the water pump and thermo are not leaking. And the old thermo and water pump looked to be functioning ok as it happens. This really frustrating me, and naturally making my car undriveable. Is there some stupid little hose I can't see all up in that area? The large rad hoses look normal / dry as does all the radiators - as usual.
Aidez- moi
The last 3 over heats have all happened after highway speed. Time does not exactly seem to be a factor, but then again I'd be willing to bet I could drive it stone cold on the hwy and get more than a few miles before it would erupt again. (?) Maybe time or I don't know... This car was running over 1 + hr, more like 1.5 hours before it overheated and sprayed everywhere again. I can't figure out this problem...

[rjSupra]

finally drove her last 10 miles home with filled up coolant. she blew up again on the final large hill. I drove it as gingerly as possible all over, coasting in neutral (which it likes), and under 2K rpms everywhere. It threw heat fast today because I jumped it and took off immediately. It was throwing interior heat faster than the temp gauge registered. still mystery leak. I am sure it's not related to the turbo - that's all dry everywhere. seems to be the motor itself ??? or under the water housing ?? but I don't think it's the water housing gasket for some reason. every hose I can see does not look like it's leaking. but it poured a gallon out up the hill suddenly as the driver behind me told me after I got it to home.

still in need because I can't drive this and I can't figure out what the leak is.
It drove a week at high speed hwy for 500 + miles and then erupted one day. My batt is dead, alternator is good. I have been missing the rad fan shroud - but it ran fine before anyway. something blew or leaks at over 2000 rpm and higher pressure. what is going on??

[btwilson86]

Since you can't see the leak, I still would pull that little 90 degree hose off that's right under your thermostat and housing and make sure it's not blown. That's the only thing that I can think of that's in that area that can cause it to leak like that

[Bill UK]

Originally Posted by btwilson86

Since you can't see the leak, I still would pull that little 90 degree hose off that's right under your thermostat and housing and make sure it's not blown. That's the only thing that I can think of that's in that area that can cause it to leak like that

I agree with btwilson86, that’s what I would do, (the 90° elbow hose in red)

[rjSupra]

thanks btwilson and BillUK! I can really use advice right now. The last few days were pretty upsetting thinking about the car. I had to work today on a location shoot and had no car. Not good. Public transit out here is a royal pain, slow and hard to get to locations.
I am going to try to get back on the horse the next day and / or two and try to fix this problem.
Two other questions: If 2 previous owner's ago noticed a bit of 'loss in power' when he sold it 6 years ago to the owner before me, and I test drove it and thought it was a dog and slow as Sh*t - like a small engined pickup might beat it - that's probably not a good sign? However, when I cleared the stupid jammed up floor mat under the gas pedal and really tromped the gas, after a sizeable turbo lag where nothing much happens, that thing is fast as sh*t. The turbo kick in is almost unreal and brings a huge smile to my face. But it's the turbo that makes it feel fast, normal driving it's pretty weak and unimpressive. I'm ok with that if that's normal, but I expected a lot more out of a '6' with 232 horsepower after driving a '4' 138 hp Acura Integra for 15 years.
So that's note 1, question 1.
Note 2 is that when i swapped the water pump out ALL nuts and bolts (10 in total I think) were barely more than finger tight. The least well bolted in bolts I've ever seen. When I replaced the WP and put back in the nuts and bolts, the large size bolts I could tighten up really well. Same with a nut or 2 - 3 of the small bolts. However. most of the small bolts tightened to a degree and then got no tighter. But it didn't exactly feel like it was or was just stripped out. Am I deluding myself here and there stripped? I could go either way on the judgment there but leaning towards not. If some, say half, are stripped out could that be causing a good old WP and the new WP to leak the same? I STILL do not see any coolant leaking through the gasket area - certainly none on the top or sides, and none on the bottom although I should crawl under the car on stands now it's home to 110% sure - but I never saw it leaking there in the old WP either, when I was under it before. Again, I feel almost sure it's not that area but an area several inches behind where the WP is and probably near the top or even slightly above the WP.
Is it possible for a hole or crack in the block to be shooting out coolant but only after driving at 2000 rpm with enough pressure to broach whatever thing is holding in the coolant fine at under 2k rpm? I would bet i could idle my car overnight and not loose a drop of coolant, but throttle hard the motor cold or warm and it will piss out coolant almost instantly. Does this mean anything to anyone? Just a loose clamp or tiny hose tear somewhere that needs a lot of pressure on it to bleed??

So, to eliminate another suggested possibility I will be attacking that small bent angle hose. (My friend said it couldn't be rubber since it can't bend 90 degrees so tight so must be plastic? - either way that sucker is gone and I putting in a fresh one).
Will post my results, and if anyone else thinks of anything in next 2 days, Please! do submit a reply here.
It's going to be hard for me to trust the car to take it out again to test. It was such an ordeal to get it back here the 60 miles from Boston, took 4 days of driving and overheating spread out over a week... And I live on a huge hill out here that eats wimpy cooling systems for breakfast...

[btwilson86]

The hose is most definitely rubber. It's a preformed hose, so you need to be sure you buy a hose that has the 90° bend already formed into it. If you use straight hose and bend it, it'll kink up and restrict flow.

The engine was rated at 230ish peak horsepower (utilizing the turbo), so around town driving with your foot out of it will be producing much less than this. My former turbo supra was a little doggy when I first got it, properly setting the ignition timing helped TONS. Not saying that's what is going on with yours, but it's easy enough to check and adjust.

[rjSupra]

Ah, thanks. That's encouraging to know, some other ideas besides the BHG. It was bit of a tease and sad the other day, after wrenching on it on public roads in a not very nice city with a bad rep, for about 7 hours, I hoped I had fixed it. In fact, it drove with a lot of zip that night - the strongest it's driven at low rpms since I've owned and driven it. It definitely was running well, I was not just imagining it. But yeah, something is bad, and that 90 degree house is public enemy #1 right now for me.
I know I need to get a proper well formed hose, I've read about getting kinked if you try to use a straight hose and bend it, that makes sense. Thanks again for chiming in, this site is very helpful!