Coolant Leak! Can't find it.

[Kawika]

I'm having trouble finding a coolant leak. I own a 1993 FJZ80 with 97,000 miles. Every 100 miles I lose enough fluid from the resevoir to lower it to just under low, and enough fluid to lower the radiator level about 3/4 of an inch. I've pressured tested the vehicle and it held the pressure and I couldn't find any visible leaks. I noticed some fluid sitting on top of the thermostat housing and cleaned it up. After driving it noticed a very small amount of fluid leaking from the area indicated by the arrow in the picture. It seems as if the fluid is leaking from just behind the stud that holds on the lower raiator hose inlet. If the leak is in fact at this point, shouldn't a pressure test cause fluid to flow from that area during the test?
Anybody have any suggestions on where else to look?
The radiator and upper and lower radiator hoses have been changed recently.
I don't know if it overheated prior to my purchasing the vehicle. I just hope it's not a head gasket. I don't know if this is related, but the number 6 spark plug went bad. It looks chewed up.

 

[cruiserdan]

There are 2 orings in the aluminum pipe that comes down from the head (about 12 o'clock in the circle you drew). Perhaps you have a bit of seeping going on there. Have you done the "bubble test" yet?

 

[Kawika]

Bubble test?

 

[e9999]

Bubble test?

the dreaded head gasket syndrome test... bubbles in the overflow res under high rpms...

 

[Kawika]

There were bubbles. What other tests can I do to confirm that it is the head gasket? Damn it, I just spent $680 dollars on parts for a front end rebuild and brake job. I'm going to go and cry for a little while.
THanks,
Kawika

 

[cruiserdan]

Bubbles in the coolant overflow jar with the engine running at around 3,000 rpm is a bad head gasket.........

 

[Kawika]

Dan,
Well I just received the front end parts I ordered from you. If I knew, I could have ordered the gaskets as well and saved on the shipping to Honolulu. Anyway, I'm getting bubbles at idle and when I rev the engine. Bubbles at idle would indicate more damage?

Ian Kawika Hunt

 

[landtank]

Bubbles in the coolant overflow jar with the engine running at around 3,000 rpm is a bad head gasket.........

SLOW DOWN! If you just filled a low system you'll have air to purge from the system so what you are seeing might not be a head gasket just normal purging. What you need to do is several drive cycles making sure your recover tank is always above the bottom of the tube. This should eliminate any bubbles do to this purging.

I had a leaky PHH because I didn't tighten down a clamp properly. Lost a lot of fluid and no signs of any drips because it was evaporating before it hit the ground. This is no uncommon with slow coolant leaks.

Also how does the exhaust smell once it has warmed up?

 

[Kawika]

Landtank,
By drive cycles do you mean the car needs to completely cool and then run to normal opperating temperature about 3 times. I smelt the exhaust and it smells normal. I smell a little of that old catalytic converter smell, a litlle like sulfur. What would it smell like if the head gasket was bad?
Ian

 

[landtank]

Yes as far as the drive cycles go. You need to heat up the coolant so it will force out the air and then cool itself to draw some of the coolant from the reseviour back in place of the air. Once you have done this a few times if you still have bubbles then the HG is probably toast. Other wise you have a leak somewhere.

Antifreeze in the exhaust has an almost sweet smell to it.

 

[cruiserdan]

Constant bubbles in the overflow jar with the engine spinning at +/- 3,000 RPM = a toasted head gasket, period.

 

[landtank]

constant for how long? I'm only harping on this as with my recent trouble with my coolant leaks I had checked an seen bubbles coming from the radiator. And since I just put on a HG it wasn't a welcome sight.

Once I found the bad lower radiator hose, loose clamp on the PHH and the leaking coolant line going to the throttle body and finally was able to maintain a constant level in the resevoir did my bubles go away.

I think his HG is toast but I'd hate to see him not read the situation correctly. Didn't Robbie once post a list of 3 or more other things that he uses for collaboration, leak down test and crusties come to mind.

 

[cruiserdan]

Constant for, well, constant.......

If it don't stop, buy a valvegrind set and tear it down........

 

[IdahoDoug]

I'm with Rick on not jumping the gun here. I get bubbles each time I change and flush the coolant for a few days. I too had a leaking hose it took me a while to find and during that time I had bubbles.

Fix your leak, and keep looking for others as well. After you're SURE you have taken care of all the external leaking, and the tank's no longer full, then revisit the HG possibility. During this time, send a sample of your oil to Blackstone Labs (google search their site) and they'll tell you positively if you have coolant in your oil.

Also, tell me more about the #6 spark plug. "Chewed" is vague. Do you still have it? If so a photo or two would be excellent.

DougM

 

[CJF]

PHH

 

[IdahoDoug]

Search function....Pesky Heater Hose - a difficult to access heater hose that frequently leaks around 120,000 miles.

 

[CJF]

Thanks Doug...

Curtis

 

[robbie]

You could also get some dye or have a shop put dye in to see if there is external leaks better. Also some shop can either use test strips or a CO detector in the recovery tank. I use the bubble test as a indicator then do a compression test and look at spark plugs, look at side of block. I use more than one means to say hey you need to spend lots of money you would rather spend some where else. later robbie

 

[Kawika]

After about two drive cycles. I haven't seen any bubbles in the overflow tank. I have yet to run it today. I pulled off the DS tire and looked at the PHH. It seemed OK. The clamps were rusty, but I couldn't see any signs of leakage. I've been reading up on the HG threads and it appears that many fail at the number 6 cylinder. Here's a picture of the # 6 spark plug. All the other plugs looked fine. Thank you all for your advice.
Kawika

 

[landtank]

unless you know the age of the plugs that doesn't say much. Hell maybe a do it yourselfer didn't have the right tools to get the #6 plug out easily and just left it in and that's the original.

Keep checking for bubble though, and that die Robbie spoke of might come in a florescent so you could go out at night woth a black light and find the problem with your eyes closed.