Help me with my leak...

[derekjl]

Just bought a 1995 Tahoe and noticed a few drops of oil on the driveway, maybe 2-3 per day. Got under the truck and noticed a "collection" of oil on the frame, right underneath the belt pulleys. The leak appears to be from one or more of the lines on the driver's side, see pictures below. Whatever is leaking looks to be wrapped in that threaded black plastic covering. I am not sure if these would be called oil cooler lines, radiator lines, transmission cooler lines, etc. I have heard those terms followed by "leak" many times when discussing this generation of truck (I've owned 3 previously). Any input would be appreciated. Thanks.

 

[bigfootchiro]

Sometimes people mistake a coolant leak for an oil leak, because the coolant mixes with old oil/dirt on the motor and turns it dark. Put a piece of cardboard underneath the truck and see what you collect.

 

[derekjl]

Sometimes people mistake a coolant leak for an oil leak, because the coolant mixes with old oil/dirt on the motor and turns it dark. Put a piece of cardboard underneath the truck and see what you collect.

I actually did put some cardboard under it, only a few drops leaking in two days. The spots are dark/black. I'm guessing the next step is to smell them? To me coolant smells like pancake syrup and oil smells like...oil lol. You are right, hard to tell exactly what it is just by looking at it.

 

[derekjl]

Anyone else have any ideas?


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[east302]

You're probably going to just have to clean it all up and lay under it while it's running to try to spot the leak. Fun times.

Yeah, it could be oil cooler lines (left side of radiator, shown in your last photo) or the adapter at the oil filter. Your lines wouldn't be the first, they often leak where the hose is crimped.

The Transmission cooler is on the right side of the radiator.

Besides the oil cooler lines, there aren't a lot of sources for oil. At the front, it could be front (crank) seal or, less likely, the oil pan gasket...pretty much anything that can drip and get blown around by the fan.

If it's dripping at the back where it meets the transmission, that may be a rear main seal leak but is just as likely a leaking gasket as the oil will travel toward the back.

They do make UV tracer dyes that you can use for spotting oil leaks, but I've never used one.

Just from your photo, I'd guess it's the oil cooler lines but check the front lip of the oil pan (and kind of behind the harmonic balancer) to see if it's dripping there (crank seal).

 

[derekjl]

Don’t think it is dripping at the back at all. But, the front main seal possibility does concern me. Is it less likely with a truck that only has 66k miles like this one does? I was thinking of trying some ATP Reseal. We had a rear main seal leak on our 99, tried some of that stuff and it hasn’t leaked in well over a year. If I peak underneath this one though, there looks to be a trail of oil that follows the frame right near the driver’s side tow hook. From there it seems to sit on that piece between the two bolts in my first picture. You can see and touch a few droplets of oil just waiting to fall. Reminds me of rain droplets on a gutter or something like that.


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[east302]

I've heard mixed things about the leakstop stuff, so I'd pass on it.

Front crank seal is not difficult if you have an impact to break the nut loose. I'd guess $600 for a shop to do it.

Leaking oil cooler lines, to me, would be the more likely culprit.

 

[willxfs]

I've had those oil cooler lines leak at the crimped connections and at the radiator. Maybe it was the transmission lines leaking at the radiator... I think I'm on my third set of oil cooler lines in the 13 years that I have had my rig. 1998 2 door.

 

[derekjl]

You're probably going to just have to clean it all up and lay under it while it's running to try to spot the leak. Fun times.

Yeah, it could be oil cooler lines (left side of radiator, shown in your last photo) or the adapter at the oil filter. Your lines wouldn't be the first, they often leak where the hose is crimped.

The Transmission cooler is on the right side of the radiator.

Besides the oil cooler lines, there aren't a lot of sources for oil. At the front, it could be front (crank) seal or, less likely, the oil pan gasket...pretty much anything that can drip and get blown around by the fan.

If it's dripping at the back where it meets the transmission, that may be a rear main seal leak but is just as likely a leaking gasket as the oil will travel toward the back.

They do make UV tracer dyes that you can use for spotting oil leaks, but I've never used one.

Just from your photo, I'd guess it's the oil cooler lines but check the front lip of the oil pan (and kind of behind the harmonic balancer) to see if it's dripping there (crank seal).

I've had those oil cooler lines leak at the crimped connections and at the radiator. Maybe it was the transmission lines leaking at the radiator... I think I'm on my third set of oil cooler lines in the 13 years that I have had my rig. 1998 2 door.

Thanks for your input. I think I am just going to order the lines. From what I understand, there is an inlet and an outlet hose as well as the connectors. How many connectors do I need in total? Looks like they sell them in a package of 5...https://www.amazon.com/ACDelco-1552...coding=UTF8&psc=1&refRID=CM602Y8TK17DRZE554FS

 

[east302]

Not sure about that one...check YouTube for videos on the replacement. You'd probably get a better idea of the parts needed.

 

[derekjl]

After doing some careful peering around in the engine bay, I'm almost certain it is coming from these lines only. It looks like I need two of the connectors total, one for each oil cooler line. The other end of each line has the screw type connector and o-ring built into it. $75 bucks worth of parts from Amazon and free 2-day shipping, can't beat that.

 

[Kelsda]

I would agree with derekjl clean it up then be sure. I believe the crimped section is aluminum. There for over time they leak wether from vibration,oxidation,or expandtion and contraction I went to a hydraulic hose repair shop and had hoses made for about the same price as ordering new ones. I like oem.The guy in shop also stated he can also rework the crimped fittings I had but I had new ones made

 

[RED TAHOE LS]

Without a lot of expense, get a spray can of CARB/CHOKE cleaner and spray where the leaks are. This stuff dries quickly leaving hardly any mess and I would do them one @ a time for better results. Good luck, JMHO.
David g...........

 

[derekjl]

Without a lot of expense, get a spray can of CARB/CHOKE cleaner and spray where the leaks are. This stuff dries quickly leaving hardly any mess and I would do them one @ a time for better results. Good luck, JMHO.
David g...........

She’s getting all fixed up today. Just did the front rotors and pads to fix a shimmy, today is the oil cooler lines. Other than that this thing is tip top!


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