Leaky Leaky Coolant

I've got a 96 stock 4.0 with 137K still running strong. However, I have developed a coolant leak that shows up as a drip from the front of the transmission near the oil pan plug. It sounds as if there is coolant leaking inside the front transmission cover until the pressure bleads off. Any thoughts on where to start. I will try to get a picture of the drip, but the description should be adequate. Thanks.

you sure its coolant??

Pretty sure it is coolant. It's not oil or tranny fluid either. The spot on the driveway has dried after 4 hours, so I am pretty sure it is coolant. Not many other choices left.

well my xj leaks power steering fluid could possibly be that as well.
but leaky coolant could be a hose thats become too soft or brittle, cracked radiator, leaky coolant pump, maybe a leaky overfill tank or you could have a combustion leak...
youre best bet is to use a pressure tester on the radiator.
and also check your pressure (upper), suction (lower), bypass and heater hoses.
maybe one of them is loose or broken.

first check coolant reservoir, heater hoses to heater core. You really need to trace the leak up to the source because it could leak anywhere and still run off the oil pan. It is not leaking inside the tranny. Good luck.

It can leak there, as I remember there are two freeze plugs back there, one for oil and the other for coolant, rare but I have heard of it happening. If the hoses are OEM original it's time to do some R&R on the system, new hoses sound like they may be in order.

There is a drain for the engine block water jacket (I think that is what RichP is calling a freeze plug) on the back of the engine block on the driver's side. At least the 2.5L, I think its the same spot on the 4.0L. As well, there are freeze plugs on the block that can leak.

Do you have an aluminum head? Iron heads are NOT nearly as likely to have head gasket failures, but its possible. A head gasket failure can leak fluids out of the engine, more often it leaks fluids into the cylinder or swaps fluids, so that you get coolant in the oil and/or oil in the coolant.

A leak anywhere bad enough and leaking long enough, can collect on the motor. Clean it well and watch it, try to find the source by spotting the fluid stain as it starts again.

Rick Anderson said:

There is a drain for the engine block water jacket (I think that is what RichP is calling a freeze plug) on the back of the engine block on the driver's side. At least the 2.5L, I think its the same spot on the 4.0L. As well, there are freeze plugs on the block that can leak.

Do you have an aluminum head? Iron heads are NOT nearly as likely to have head gasket failures, but its possible. A head gasket failure can leak fluids out of the engine, more often it leaks fluids into the cylinder or swaps fluids, so that you get coolant in the oil and/or oil in the coolant.

A leak anywhere bad enough and leaking long enough, can collect on the motor. Clean it well and watch it, try to find the source by spotting the fluid stain as it starts again.

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They are actually on the back of the block and get covered up by the flywheel. They very rarely go bad but when one does it can be a bear to find without dropping the tranny and bellhousing. I've only known it to happen twice and that was from owners using well water in their cooling systems up here where the mineral content is carries 5 times the minimum daily requirements of One a day vitamin

freeze plug is up in there.

yeah thats what i remembered today at school...
could be a leaky freeze plug

bad head??

RichP said:

They are actually on the back of the block and get covered up by the flywheel. They very rarely go bad but when one does it can be a bear to find without dropping the tranny and bellhousing. I've only known it to happen twice and that was from owners using well water in their cooling systems up here where the mineral content is carries 5 times the minimum daily requirements of One a day vitamin

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Which brings up my favorite pet peeve, probably yours as well; Folks, when mixing coolant, please go to the grocery store and spend the $0.69 a gallon for DISTILLED WATER a.k.a. Demineralized or De-Ionized Water. The minerals in tap water, and some parts of the country its a huge mineral content, reacts with the anti-corrosion additives in the anti-freeze and forms all sorts of goop, it creates SCALE that will coat and clog the system, and since it turned the anti-corrosion additives to goop, rust and corrosion will start in the system sooner.

Softened water is even worse, they soften water by adding even more minerals to it, to neutralize the minerals already in it.

As well, completely drain your cooling system before adding new coolant. Remove the water jacket drain plug, hard the 1st time easier after, and drain the half gallon trapped in it. Disconnect a heater hose and shoot a little compressed air in there and it will force out the half gallon of coolant trapped in there.

I'll back flush with tap water from the hose, since my Jeep has so much scale in it I have to do it repeatedly every time. BUT, the last flush, I fill up with all distilled water, that way any left over water in the system is almost all distilled, NOT tap water with minerals in it.

I'm still trying to flush out all the goop in the cooling system caused by the previous owner of my jeep. I just flushed out the coolant a 2nd time in a year and it was full of brown and rusty deposit that is still flaking off the coolant system because the PO never changed the coolant and kept driving with a leaking radiator.

BTW, many stores are selling All Makes and Models Anti-Freeze, that mixes with All Colors of Anti-Freeze don't buy it, its a Dex-Cool derivative. Do NOT use Dex-Cool, especially in a vehicle that did NOT come OEM with Dex-Cool. Check the ingredients in the fine print, if it says it has 2-EHA or 2-Ethylhexyl Acrylate its Dex-Cool or a derivative. If it says it has Silicates and Phosphates or a chemical compound with those, then its the Original Green Anti-Freeze your suppose to use, some manufacturers have started to put Original Green on the label to let the buyer know. If your NOT going to change your Anti-Freeze every 2 years, then retro-fit to Zerex G-05, the long life anti-freeze that Chrysler and Ford has adopted as their factory fill. From my research that is the best long life anti-freeze and the best to retro-fit to older cars. Make sure you completely flush all old coolant out. Although G-05 mixes just fine with other anti-freezes (except dex-cool, dex-cool does NOT mix with any other anti-freeze and it reacts to form goop), other anti-freezes will dilute it and it won't last the full 5 year life span.

not likely, but since it hasn't been mentioned yet, it could be leaking from around the temp sender in the rear top of the head