Engine oil cooler leak question ....

[bugdewde]

I've heard these are prone to leaking, but I don't know if it's from the rubber hoses, fittings or crimps.

Found lots of oil under my front driver's bumper today while at the vet.

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After getting home and investigating it, I found the line going into the radiator was loose.... like finger turning loose.

The rubber lines are covered in plastic wire loom .... and appear to be in good condition.

My question is how tight should this line/connection be????
And how do I keep it tight?
Concerned about the plastic of the radiator and breaking it.... is this "normal" ... or common?

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[454cid]

Typically what leaks are the crimps, or maybe it's the rubber under near the crimps that actually goes bad? Loosening up isn't common. I don't think you'll have an issue with the plastic tanks due to over tightening. The way these are put together, I don't think tightening stresses the plastic at all. The larger sheetmetal hex nut is what keeps the oil cooler attached to the tank.

I'd recommend using a flare nut wrench not an open end wrench. You don't want to round off the fitting.

Degrease the area and then check it periodically to see if it's leaking, or if it's loosening up. I had a transmission line that wasn't sealing until I got it very tight, after a couple of tries.

 

[Supercharged111]

There's an o-ring inside there sealing it up, it's not an inverter flare like the trans lines if that's what you're thinking.

 

[454cid]

There's an o-ring inside there sealing it up, it's not an inverter flare like the trans lines if that's what you're thinking.

Yes, I did forget that. I don't have mine connected anymore. It could be the o-ring has gone bad, but I'm not sure that would cause it to be loose. I would still tighten it, clean the area up and go from there.

 

[Reega]

Usually it’s the rubber hoses that “weep”. I cut off the crimps and replaced the hose and put barb fittings in the oil filter adapter. Easy replacement

 

[east302]

My question is how tight should this line/connection be?

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Factory torque spec is 18 ft-lbs for oil cooler lines to radiator.

 

[454cid]

Usually it’s the rubber hoses that “weep”. I cut off the crimps and replaced the hose and put barb fittings in the oil filter adapter. Easy replacement

He has a 454, and the lines go directly to the block. The threads are pipe threads, but it's my understanding that using hose barbs would eliminate any flow through the oil cooler. One of them has to have a fitting with a baffle looking thing on it that goes into the block. It's kinda hard to see in this picture because it's white plastic on a light background.

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[alpinecrick]

It's best if the O-ring is replaced, then tighten down--not farmer tight, just good and snug.

 

[Aparke4]

I am in the middle of replacing my oil cooler lines on my 1996 454 vortec 7.4 k2500

Yes- you need a new barb fitting for the line closest to the filter in order for the cooler to operate properly. There are more additional steps to bypass but big block create a lot of heat and if you tow its a no brainer. I am updating mine to all AN fittings as if and when I wanted to run a larger cooler external to radiator, the hard works and leaks are done!

Here is the fitting you need:

https://paceperformance.com/i-51462...vy-oil-cooler-connector-3-8-npt-to-10-an.html

I am keeping hard lines of rad side and ordered two new hoses (they are cheap and truck has unknown miles on oil lines) and got two lines from rock auto that have metal lines

https://www.rockauto.com/en/catalog...p,7.4l+v8,1160637,engine,oil+cooler+line,5516

Using 3/8 NPT to AN 8 for the other return line on block, and one AN 10 to AN 8 I am using a generic 40ft 1/2 braidied line kit with an assortment of AN to hose fittings to rebuild the lines. The rad side is getting hoses trimmed before crimp and comporession fitting put on to convert to AN 8 (lines are 1/2 inch metal/ alum). I am keeping metal lines to rad as the fitting size inside or at rad is kinda unusual and i did find a thread here that foung the actual size if you want to go braided line all the way. But, my leak currently is at crimp and with body lift lines might be stretched which is promoting the issue further so I can make my own lines to length!

While I am here I am replacing oil filter gasket adapter and 0-ring: a few items off of a long list of oil leaks I am fixing!

 

[Aparke4]

Oh and a flare tool as you need to flare the line for the compression fitting. Block side will be all adpaters and snug up using teflon tape or high temp thread sealant.