Mystery Coolant leak

[TX87R10]

87 TBI R10.

I've always noticed a small coolant leak but today I ran to the store and when I got home I realized there was a line of fluid in the driveway and my truck had peed the driveway pretty good. Not sure if the line got there when I was leaving or returning home.

Looking under the truck I found a sensor of some sort dangling but honestly I'm not sure what it is appears to be a sensor but the only place I see it could go would be in to the exhaust.

I checked and everything forward of the front axle is dry. I also have an oil leak but I checked all of this fluid and it is definitely not oil and does not smell like gas. I don't quite see where it is coming from and my mustang is already on the jacks so I'm having a hard time really looking around, any suggestions on where to look?

Pics to follow

 

[TX87R10]

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[TX87R10]

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[Terry Wilkerson]

If no coolant on top of the engine you might have a freeze plug leaking.

 

[TX87R10]

Yeah I looked up the freeze plug locations and that makes sense. I see that looks about where it seems like this fluid must be originating from.

There is no way I am pulling the motor if I don't have to to replace the plugs so I wonder how hard it would be to plug the plug...

 

[Terry Wilkerson]

I think it can be done but someone with more experience than I will have to tell you how. Getting old one out might be harder than installing the new one.

 

[fast 99]

It's in a horrible area for access. There are rubber replacement plugs that might work for a while but even getting the old one out won't be easy without removing the manifold. At best it will be very difficult to put in a steel plug. Get a real good look at it first. Make sure it isn't a head gasket. There are coolant dyes available.

 

[RecklessWOT]

Intake gasket? Very common place for coolant to leak from. Would most likely be running down the back of the block. Generally starts as a small weep, the occasional drip here and there. Eventually it gives out entirely and can start gushing

 

[TX87R10]

Cool thanks for all the replies guys I will try to feel behind the intake and see if I can feel any liquid.

 

[deerejohn]

it looks like your oxygen sensor is broke? thats the wire hanging down.

 

[fast 99]

The leak appears to be on the side of the block ahead of the oil filter area under the exhaust manifold, not at the rear.

 

[TX87R10]

Just in case anyone runs across this thread later -

The leak for me was a freeze plug directly under the motor mount. It was nearly impossible to see until I used my phones' camera to make a video and held it up right there and pointed it towards the crack.

I used Blue Devil Head Gasket Sealer in the coolant and was able to get it leaking much less but I don't think it will hold up very long. I bought new freeze plugs from Summit but I have no idea how tf I am going to do this (I have an engine cherry picker but I really don't want to pull the motor on my truck)

I bought some gray RTV as well... I know it's a hacky thing to do but I am considering filling up the freeze plug for now until I can find someone who can pull the motor and fix it correctly. I'm guessing with one starting to open up the others will soon follow.

 

[Bextreme04]

Just in case anyone runs across this thread later -

The leak for me was a freeze plug directly under the motor mount. It was nearly impossible to see until I used my phones' camera to make a video and held it up right there and pointed it towards the crack.

I used Blue Devil Head Gasket Sealer in the coolant and was able to get it leaking much less but I don't think it will hold up very long. I bought new freeze plugs from Summit but I have no idea how tf I am going to do this (I have an engine cherry picker but I really don't want to pull the motor on my truck)

I bought some gray RTV as well... I know it's a hacky thing to do but I am considering filling up the freeze plug for now until I can find someone who can pull the motor and fix it correctly. I'm guessing with one starting to open up the others will soon follow.

Did you replace the broken O2 sensor as well?

The head gasket sealer is going to cause more problems then it will fix. It is very unlikely to clog an actual leak, but does a great job of clogging all the small passages in the radiator, thermostat, and heater core. RTV is also unlikely to seal a leak in that spot, as it is pressurized. Your best bet is to pull the motor out and do it right the first time. It will be faster in the long run than trying to hack a fix in there. Its probably going to cost you a weekend to do it in a driveway.

 

[mtnmankev]

Won't fix his problem, but whenever I build an engine, I install brass freeze plugs.
They will NOT rust out and leak, and cause a headache such as this.
Been doing that for over 35 years and never once had an issue, it's a do it once thing and forget about it.

 

[80BrownK10]

That looks like the plug for a lock up TH350 transmission. My guess is that your was replaced with an older non lockup transmission. Mine has the same sensor and non lockup th350

Edit: the connector looks different than the plug on mine maybe it is an O2 sensor. Mine didn't have those so I don't have any hanging for those.