Coolant leak? (1 Viewer)

[Alex Fogg]

First of all, I searched...

Yesterday in 17 deg. weather my 97 overheated on the way to work, no heat, gauge all the way up in the red. I parked it asap and walked into work, later I had a flatbed pick it up and I looked for any puddles under, nope. I looked at the oil, honey colored and no coolant, engine bay was, of course greasy, but no evidence of coolant. My mechanic called later and said I was 2 gal low! He pressure tested the system and couldn't find a leak, or a leak under the truck. But where did the coolant go? Have I been low for a while and the below freezing temp was a factor? Low coolant/possible condensation causing ice block? But what about the 2 gal low?

Any ideas?

 

[whaler]

What does the PHH look like? How about the small coolant bypass hose to the left of PHH?

Good move shutting it down, but you got into the red part of the gauge so you could have overheated it enough to cause some coolant to be consumed in the combustion chambers.

 

[Alex Fogg]

I'll check those hoses, and I hadn't realized that I could burn up coolant like that, interesting!

 

[jpoole]

To try to rule out the worst answer for where the coolant went (head gasket failure) you or the mechanic can pull the plugs for inspection to see if any are steam cleaned by coolant getting into a cylinder via a head gasket leak.

 

[Alex Fogg]

jpoole, would there be any other sign? Coolant in the oil?

 

[jpoole]

Could be. HG failue can go a few ways since the head gasket separates oil and coolant passages and cylinders. 2 gallons low is substantial and there should have been noticeable symptoms. I guess it's possible that a small leak onto a hot part caused the coolant to vaporize over time in an unnoticeable way? In any case, I'd rec. trying to rule the HG out so that you can then focus on other causes that will be easier to fix and have the option of filling the cooling system and running the engine to help the troubleshooting. If it's the HG then water could get into the cylinder(s) and cause damage when you try to crank it, or seep into the crankcase and cause corrosion/etc. so it's good to figure out if that's what's going on and respond sooner than later.

 

[BILT4ME]

Fill it with coolant and do a pressure test.

May find it is a PHH or a hose somewhere that is leaking. If not, the pressure test will manifest itself SOMEWHERE. If no external leaks, assume an internal leak and pull spark plugs BEFORE trying to crank it over if no obvious external leaks.

If there is an internal leak (head gasket) it may want to fill a cylinder and if you crank it over without first pulling the plugs, you could hydraulic a cylinder and that would be a huge mess. (bent rod, cracked head, damaged piston)

Find the problem before you just assume it is something.

 

[Alex Fogg]

Mechanic did a pressure test, no leak he could find, and he ran it for a while yesterday after filling the coolant and he said it ran fine, heat worked well, and it didn't overheat.

 

[NCLX450]

When that happened to me it was the PHH. I had chased the leak (which would empty the overflow rapidly) and realized it occurred while driving and not so much at idle. Turned out to be the PHH. I did the bypass repair and all was good.

 

[Alex Fogg]

OK, what is the "actual" name of the PHH so I can have my mech look at it?

 

[Alex Fogg]

And I can't find a thread with any pics of the bypass repair, any help?

 

[ZackR]

It could be misting out under pressure from a leaky hose. If it were me I'd fill it up, add some dye to check for leaks and then take it for a drive (heat and pressure, vs just a cold pressure test). Once home pull into the garage and break out the UV light to see where its leaking.

 

[NCLX450]

OK, what is the "actual" name of the PHH so I can have my mech look at it?

Slee - PHH (Toyota 80 Series Land Cruiser)

 

[graham5david]

Mine was leaking from the phh and I never saw a drop until one day when it got hot and I could smell coolant. I saw nothing under the truck. I refilled it and drove it home and nothing leaked visibly but again it was low. I was worried it was the HG but saw no steam out of the tailpipe and the rate of coolant loss would have caused other issues in my opinion if it was leaking into the cylinder. I decided to replace all hoses as it was a cheap maintenance option before driving it further. And I found that the phh was the issue. It developed a strange bulge in it over time. Not really torn but once I got to where I could see it, it was obvious that fluid was leaking out of it from time to time.

 

[graham5david]

Bypass the hard pipe while in there. It's a much easier install in my opinion.