Pelican Parts Forums - cannot stop coolant leak

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- - cannot stop coolant leak (http://forums.pelicanparts.com/showthread.php?t=943899)

I use a thin layer of hylomar on leaky hose connections.....for decades. A ski boat life thing.

Quote:

Originally Posted by Jfrahm (Post 9450299)

If something leaks in multiple places all at once, inexplicably, it is either pressure or something is compromising the seals. Or the fluid is not what was expected (like hydrogen in a helium balloon) but this is not likely in your case.

If your cap is lifting check the overflow hose maybe? Grasping at straws but honestly what could it be other than pressure? I can't remember the last time I had a coolant leak caused by a loose clamp that *wasn't* a result of someone just forgetting to tighten the clamp.

Some sort of solvent in the coolant that is softening the hoses is the next crazy notion. That certainly causes problems with power steering and fuel system leaks at the clamping points.

My money is on something like a blocked overflow and a head gasket leak and it's a wonder the reservoir has not cracked yet.
There is no oil in coolant and no coolant in oil.

Idling with the cap loose to see if it chooches out coolant would be my next step.

-Joel.

The cap is at a very high spot that coolant (even at operating temp) does not reach. Therefore if pressure was excessive it would only vent air at the moment. Right after the coolant system restoration I did have coolant very high and did see some come out of overflow.
Coolant is fresh non concentrate blue beck arnley no phosphate. Entire system was flush with hose then flushed with distilled water before refill.
I don't understand the purpose of the last test, please explain.

Sucked out the excess coolant to min level at cold, will monitor.
Opened bleeder valve and coolant came out right away, bled for 1second and closed. I've been driving it for about 2months now (since last bleeding) so if there's any air bubbles it would have collected up top.

**New finding** the coolant vacuum valve by the side of oil filter feeding the heater core does not operate when I turn the temp gauge to cold or hot (I didn't try it with A/C on). When is it supposed to operate? Maybe I should post in a new thread since this likely won't affect the coolant leaks. The temp adjustment still works but I hover only around cold and 22degrees and the air temperature does fluctuate a bit (after warm up).

Btw, I do thank everyone for trying to help me out.

2 possible causes:

1 - the system has not been bled correctly (heater on full, fan on high, etc)

2 - combustion chamber pressure leaking into water jacket. could be head gasket related. you will not see coolant in oil or anything like that.

bleed the system. if that fails to solve problem, do a leak down test

Quote:

Originally Posted by flash968 (Post 9450934)

I will manually open coolant vacuum valve to heater core, rev engine and bleed.
- correction, the heater control valve is default open by spring pressure, which makes sense since I do get heat.

to bleed the system, the engine has to be fully warmed up, thermostat open, heater on full high, and heater fan on high. it is also best to have the nose of the car elevated. also, make sure you have an actual bleed screw in there, and not just a regular screw. many mechanics stuff a regular one in there in a pinch, rather than wait for the right one. the problem is that it won't bleed right like that.

just to be clear, the heater control valve is default open, when there is no vacuum applied. it closes when the engine is running and the heater is off.

I dropped the coolant to min. level at cold. at hot it doesn't even reach half way between min/max. Anyway, there's no leaks right now so I'm happy.

btw I bled the system twice following what clarks garage and advice here. As I had thought, no air in the system, but just to recap, because someone mentioned trapped air could cause excess coolant system pressure...I couldn't really understand because air can be compressed and liquids cannot. Hence if there were air in the system it would provide a cushion in the system and "prevent" excess pressure / leaks.

Another thought is that these cars, the heater control valve is open by default (cold), so how would turning up the heat and fan speed assist in bleeding air in the coolant system?

Open by default but closed when the engine is running and heat is not turned on. So to bleed the system, you must turn the heat on to allow the coolant to circulate through the heating circuit to purge the air out of it. Max fan isn't really necessary but it helps confirm HOT air is coming out of the vents a lot faster.

Hose clamps, +100.....

imprez - the heater control valve is NOT open by default, when the engine is running. it is closed. vacuum closes it.

cantrell - i haven not looked into why the fan has to be on (at least on the 968 it does) but it is in the procedure. i saw no reason not to do it, so i have never questioned it.