weird fluid oil leak

[Blackmagic94]

So after driving yesterday once it was stopped I noticed a fresh oil puddle, passenger side frame rail is where it was dripping off of, behind the control arm but before the firewall.


Looks like a dark fluid but feels lighter like ATF but wasn't red, could be dirty though.



Engine runs no oil leak, shut engine off, and within 10-30 seconds it starts to drip a large amount that equals a 1 sq ft puddle of wetness.


Engine was at operating temp but not over heated.


Started again this morning and shut off after one min, no leak






So I am thinking maybe a oil cooler leak from the trans? Or the trans is puking fluiding once shut off, all fluid levels were fine prior to this leak.

 

[Retiredwarhorses]

So if a quart of whatever ended up on the ground, did you not check Trans, PS, engine, Tcase fluid levels?
because a quart Of anything will register as being low...

 

[Blackmagic94]

I doubt its a quart low, I would say a 1/4 to 1/3 of a quart total since oil loves to spread out and show more then it really is.


What lines are running by the passenger frame rail?

 

[Blackmagic94]

Without getting on my creeper as its 109 out today, just a check look under the wetness is near the two transmission cooler lines behind the engine but in front of where the cooler lines connect on the passenger side, The oil levels don't look out of wack, but tranny fluid is hard to judge on a cold temp.



It reminds me of when a C4 trans on my drag car had a over pressurizing valve body and would cause erratic line pressures, when the trans got hot it would puke a small amount of fluid out of the over flow vent tube on the trans after the car was shut off.


Just ran it for 2 mins and zero leaks again.

 

[olewhiskey]

Cooler leaks and lines can leak in weird places, trace that back. On the passenger side its likely a transmission line or PS Line.

 

[ClarkeF]

A puddle under the air cleaner can indicate a problem with the cooler loop in the t-case - which has ATF circulate out of the transmission to cool the t-case. If the cooler loop develops a leak, pressurized ATF fills the t-case and then get's pushed through the vent lines to the air cleaner. In the Hummer world this is known as the dreaded Vampire problem (the lifeblood gets sucked out of the tranny causing the tranny to burn up if you still drive it). On the HMMWV's with the dust excluder valve at the bottom of the air cleaner, it drips out and forms a nice puddle. DO NOT drive your truck until checking the transmission fluid level. If you remove the FILL plug on the t-case and out pours your ATF then that's definitely the problem.

Otherwise the transmission cooler lines run along the inside passenger frame rail - Check for leaks at the fluid cooler and back at the trans.

 

[Retiredwarhorses]

I agree...make sure your trans level is good...i have had 2 trucks with that issue...it dont take long to empty the trans

 

[papakb]

You didn't mention whether your vehicle is Army or USMC. The Army HMMWVs without the fording option have a "duckbill" drain on the bottom of the air cleaner that will allow fluids to drip out. The USMC vehicles were mostly equipped with fording kits that put a rubber cap on that outlet port. There's a condition we called "the vampire" where the vent system would pull fluid back into the air cleaner and it would show up as a drip from the bottom of the air cleaner. The early transfer case cooling loop had a tendency to crack internally if someone overtightened the mounting nuts because of the way it was made. If that happened then ATF would be pumped into the transfer case and sucked out by the vent system. One way to test for the problem is to bypass the cooling loop with a short piece of hose and see if the leak continues. I always thought this was a bad way to do things and put an aquarium airstone in the vent line where it connects to the air cleaner. It lets the system breath but won't allow water to get back in.

 

[Retiredwarhorses]

All the trucks coming out at GP are for the most part Army...there was a USMC truck though that recently went out of Barstow. Army HMMWV's did not get equipped with fording kits....the easiest way to test for a broken cooler loop is to open the fill plug on your tcase, but if it's bad, get ready with a 5 gal bucket to catch a gallon or 2 in the face.
at the same time, just check the tranny fluid level...if it's low and you keep adding after driving....it's,going somewhere.