Leaking oil cooler lines behind fan shroud

[Enforced_Leo44]

Hi everyone,

M1008 owner here, just noticed a pretty annoying oil leak on the passenger side of the aluminum oil cooler lines that run across the radiator, behind the fan shroud, I still have to determine which one is leaking (if not both).
Looked around the internet to find a pair to buy and soon found out that they are quite expensive (around 200$ on hillbilly wizard).
And the first question that pops up is: do I have to replace them with a OEM part or can I go with a pair or oil resistant rubber lines with steel fittings? That sounds a whole lot cheaper, but I guess that there is a reason for them being made out of aluminum and not some good ole rubber.

Any suggestion/shared experience would be greatly appreciated, thanks in advance,
Leo

 

[Barrman]

The aluminum line across the radiator is a built in cooling feature of the set up.

The stock hose and line oil cooler lines have had a bad history. There was a recall on the hoses next to the block. (If you want to waste some time, call a Chevy dealer with your VIN. You might have a truck that never was recalled and Chevy might replace the lines for you.) Then the aluminum lines have been known to crack like it seems you have.

Your option are to find nice used or NOS stock parts. Or, do what Chevy did with the GMT 400 trucks. Remove the oil cooler from the radiator and have an air to oil cooler in front of the radiator. You can build your own set up or places like Leroys Diesel in Houston will sell you a kit for about the same price you quoted above. Just tell Leroy to make the AN braided steel hoses to 60 inches instead of the 52 inches the GMT 400 trucks used. The square bodies are longer in the nose.

Here is a video I did about the longer hoses:

 

[Enforced_Leo44]

The aluminum line across the radiator is a built in cooling feature of the set up.

The stock hose and line oil cooler lines have had a bad history. There was a recall on the hoses next to the block. (If you want to waste some time, call a Chevy dealer with your VIN. You might have a truck that never was recalled and Chevy might replace the lines for you.) Then the aluminum lines have been known to crack like it seems you have.

Your option are to find nice used or NOS stock parts. Or, do what Chevy did with the GMT 400 trucks. Remove the oil cooler from the radiator and have an air to oil cooler in front of the radiator. You can build your own set up or places like Leroys Diesel in Houston will sell you a kit for about the same price you quoted above. Just tell Leroy to make the AN braided steel hoses to 60 inches instead of the 52 inches the GMT 400 trucks used. The square bodies are longer in the nose.

Here is a video I did about the longer hoses:

So you say that replacing the stock aluminium lines with some rubber or even steel lines could cause the oil to overheat? I live in Italy so hot summer days could touch or even go slightly above 100 F

 

[WWRD99]

Hi everyone,

M1008 owner here, just noticed a pretty annoying oil leak on the passenger side of the aluminum oil cooler lines that run across the radiator, behind the fan shroud, I still have to determine which one is leaking (if not both).
Looked around the internet to find a pair to buy and soon found out that they are quite expensive (around 200$ on hillbilly wizard).
And the first question that pops up is: do I have to replace them with a OEM part or can I go with a pair or oil resistant rubber lines with steel fittings? That sounds a whole lot cheaper, but I guess that there is a reason for them being made out of aluminum and not some good ole rubber.

Any suggestion/shared experience would be greatly appreciated, thanks in advance,
Leo

If you are in Italy I don't think he'd ship to you but if he did I bet the shipping would be nuts since the lines are solid and can't be bent. I have a hydraulic shop I would go to to have one made. I would take the line off and they would make one with the correct fittings and length. If you don't have one around you then making your own can work as well with hydraulic hose and slip fittings. The stock line only does a little to disapate heat so swapping to a different material isn't a big deal...gotta figure it's getting cooled by 190 degree coolant.

 

[Enforced_Leo44]

If you are in Italy I don't think he'd ship to you but if he did I bet the shipping would be nuts since the lines are solid and can't be bent. I have a hydraulic shop I would go to to have one made. I would take the line off and they would make one with the correct fittings and length. If you don't have one around you then making your own can work as well with hydraulic hose and slip fittings. The stock line only does a little to disapate heat so swapping to a different material isn't a big deal...gotta figure it's getting cooled by 190 degree coolant.

I do have a trusty hydraulic/hoses making shop nearby so I could go and ask them hoping they can make one, for sure they can copy the fittings, length and curves and craft a steel one, not sure about a cooling aluminium one

 

[WWRD99]

I do have a trusty hydraulic/hoses making shop nearby so I could go and ask them hoping they can make one, for sure they can copy the fittings, length and curves and craft a steel one, not sure about a cooling aluminium one

They may have aluminum never know!! Really it runs 80 psi tops when its cold out so it doesn't take much to hold it together...it's way over played on how much is needed to make it work...they could use your old ends if they needed to it's just a crimp away and a few o rings

 

[cucvrus]

I have used rubber hydraulic hoses on snowplow trucks for transmission cooler lines and oil cooler lines. On my off-road truck, I added an auxiliary trans cooler up front to make up for the heat entrapment in the rubber/metal wound hydraulic hoses. I even put a power steering fluid cooler on my off-road truck because it had a mile marker hydraulic winch from a HMMWV. That winch is now serving as the winch on a firewood processor. Italy is a long way, but I have a few of the aluminum lines. Good Luck. It may be just the O ring allowing it to leak at the fitting going into the radiator.

 

[Enforced_Leo44]

I have used rubber hydraulic hoses on snowplow trucks for transmission cooler lines and oil cooler lines. On my off-road truck, I added an auxiliary trans cooler up front to make up for the heat entrapment in the rubber/metal wound hydraulic hoses. I even put a power steering fluid cooler on my off-road truck because it had a mile marker hydraulic winch from a HMMWV. That winch is now serving as the winch on a firewood processor. Italy is a long way, but I have a few of the aluminum lines. Good Luck. It may be just the O ring allowing it to leak at the fitting going into the radiator.

I'll try to check and replace the o rings, but probably while i'm there, since they are known to crack, i'll have them re-made out of steel

Thanks for all the help, I'll keep you updated in case I stumble across additional troubles

 

[Enforced_Leo44]

I have used rubber hydraulic hoses on snowplow trucks for transmission cooler lines and oil cooler lines. On my off-road truck, I added an auxiliary trans cooler up front to make up for the heat entrapment in the rubber/metal wound hydraulic hoses. I even put a power steering fluid cooler on my off-road truck because it had a mile marker hydraulic winch from a HMMWV. That winch is now serving as the winch on a firewood processor. Italy is a long way, but I have a few of the aluminum lines. Good Luck. It may be just the O ring allowing it to leak at the fitting going into the radiator.

Looked around some forums and thought about one thing: what about bypassing the cooler and just looping the two ports at the oil filter assembly? Would that overheat the oil too much? Keep in mind that the hottest summer day here rarely touches 100*F

 

[Barrman]

Oil is the life blood of an engine. Looping the cooler lines is ok for test running an engine on a stand. But, for a vehicle under load I think it would be a bad idea.

I have a stand alone air to oil cooler on one of my trucks with an oil temperature gauge. Driving in 20° F air still has the oil going back to the engine at 150° F or more. Driving in 100° air has oil temps after the cooler around 200° F. That engine has a turbo so it might skew it a little high. But, I personally feel the 6.2/6.5 needs the oil to be cooled.

Running synthetic is something I also do in mine just because it handles heat better.

 

[WWRD99]

Looked around some forums and thought about one thing: what about bypassing the cooler and just looping the two ports at the oil filter assembly? Would that overheat the oil too much? Keep in mind that the hottest summer day here rarely touches 100*F

Gotta remember that the oil is being cooled by 190 degree coolant...so is it really being cooled or is it being kept at a certain temp the engineers want it to be. Diesels don't like to be cold or to hot but like to be kept right at the coolant temp it's being run through. So is it really being cooled down? I haven't tested the output temp of the line at the engine to know for sure but we do know the oil going back won't be much less than the coolant temp it's going through. If you run a basic synthetic blend oil I don't think it's possible to over heat the oil in the stock configuration, i.e., no turbo. Bypassing the lines because they break is a lazy move. They break right at the block because the person replaced the lines and didn't install the bracket at the block to hold them tight and the engine vibration cracks them apart. If you're worried about the truck over heating I'd be looking at a high flow water pump, making sure the radiator is not clogged and have a functioning clutch fan and shroud.

Sent from my SM-S906U using Tapatalk

 

[Enforced_Leo44]

Gotta remember that the oil is being cooled by 190 degree coolant...so is it really being cooled or is it being kept at a certain temp the engineers want it to be. Diesels don't like to be cold or to hot but like to be kept right at the coolant temp it's being run through. So is it really being cooled down? I haven't tested the output temp of the line at the engine to know for sure but we do know the oil going back won't be much less than the coolant temp it's going through. If you run a basic synthetic blend oil I don't think it's possible to over heat the oil in the stock configuration, i.e., no turbo. Bypassing the lines because they break is a lazy move. They break right at the block because the person replaced the lines and didn't install the bracket at the block to hold them tight and the engine vibration cracks them apart. If you're worried about the truck over heating I'd be looking at a high flow water pump, making sure the radiator is not clogged and have a functioning clutch fan and shroud.

Sent from my SM-S906U using Tapatalk

Yeah if they hooked the oil lines to a cooler there has to be a reason.
The lines connected to the block are actually dry and clean, the problem resides in the two aluminium lines that run across the radiator, I’ll start by changing the 4 o-rings at the connections, if that doesn’t fix it, I’ll replace the 2 aluminium lines with some custom made steel lines or steel braided hoses

 

[87cr250r]

Make sure you use Viton o-rings if you want them to last.

 

[Enforced_Leo44]

Make sure you use Viton o-rings if you want them to last.

Just removed the fan shroud and soon found out that the o-rings are not the problems, the aluminium lines are dirty up until 60% of the way, time to pull them out and have them re-made
For the o-rings, I found some 013 size (which should be the correct size, 0.426 ID and 0.07 section) oil resistant and stands up to 400*F, so I think I should be good

 

[vanaisa]

Dirty is dirty. Try to find actual leak points. Clean lines, run engine and check.

 

[Enforced_Leo44]

Does anybody know what thread sizes are the fittings that connect the aluminium lines to the radiator?
And also the fittings that connect the aluminium lines to the rubber hoses going to the filter

 

[87cr250r]

When I made oil cooler hoses I believe I used this fitting. The compatible hose is expensive, 221FR. I had some scrap which helped ease the pain. The engine side is NPT thread so I suggest using adapters to JIC flare.

 

[Enforced_Leo44]

When I made oil cooler hoses I believe I used this fitting. The compatible hose is expensive, 221FR. I had some scrap which helped ease the pain. The engine side is NPT thread so I suggest using adapters to JIC flare.

View attachment 926527

This screws right into the radiator?

 

[87cr250r]

No, they connect to the original oil cooler pipes by oil sample valve.