Nut sizes on oil cooler
 

My apologies for not looking this up sooner, but I am internetless at the house so I can't check EPC for this.

What is the nut size for the bolt on the oil cooler hose? My friend has flare nut wrenches from 5mm to some huge size. He was going to mail me a wrench that I could borrow for my cooler line job, but I don't know the size of the bolts.

So what are the nut sizes? :)

All four should be 27mm. In a pinch, 1-1/16" SAE will work as well.

Thanks a ton!

I stripped about 3 of threads on one of my Oil Cooler Nipples when I remove the Oil Cooler Line Nuts.
I would read up on some of the ways to decrease the chances if it happening.
If it does happen there is a repair for that in the DIY section.
When I did Mine I had a 1-1/16 Combination Wrench and also a 1-1/16 Crows Foot (this fit better on the bottom one as it allowed mor positions).

The lower oil filter housing fitting is best tackled with a 16 point flare nut wrench. Or a box-end wrench modified to line wrench characteristics.

On the hoses on the Oil Filter Housing you may need a wrench to keep the Fittings that screw into the Oil Filter Housing from turning. I do not remembe what size it was but I bought a cheap wrench so that I could thin the end of it so it fit between the Hose Nut and the Oil Fileter housing.

I have a 1 1/16" Blue Point Box wrench I made into a flair nut wrench. I cut the wrench in 1/2 so it`s about 6" long or so.

Use a 7/8 open end as a back up on the oil cooler, so you don`t twist and break off the threaded part of the cooler when cranking down with the 1 1/16" wrench.

Charlie

if they are clean and dry dont think about turning them. soak them for weeks in PB blaster. every day several times aday soak and resoak them...

PB blaster is weak. I would use liquid wrench, its second only to Aero-kroil.

I use aerokroil, but it's not easy to find. pb blaster is. is LW better? cool, I didn't know that. WD40 is total water... useless. this I know.

Have you tried Free-all? It's suppose to be one of the best. In my experience, it is definitely better than Liquid Wrench and PB Blaster. The oil cooler has steel nut on aluminum, not a good combo. I had to work the nut back and forth 2 to 3 degrees at a time with the 2 wrenches, took about half an hour of that to get the nut off. If I didn't do that, I have no doubt it would have stripped the oil cooler's aluminum threads.

Thanks for the tips guys. I think I might end up getting the 1 -1/16 wrench too.

I've been researching this for ages since I knew the job had to be done. I would prefer to not strip any threads off the cooler.

I know judging by the other problems I've had with the car that the hoses will not come off without a fight. I've been soaking them with PB for awhile, but I'll start using liquid wrench instead.

I think I'm going to cut the hoses and remove the entire cooler with the fittings still attached so I can attack the lines standing up. I'm anticipating the worst however so I called the farmer down the street to see if he could help me if I strip them.

I don't need the car for the entire month so I am going to take my time.

I've found that a simple large crescent wrench works perfectly OK.

Reason: If you need more torque than a crescent wrench can provide, you'll likely tear the fitting out of the cooler unless you're using a backup wrench on the fitting itself.

On a W123, it's not an issue of torque, it's limited range of motion. You cannot get a 60 degree swing due to chassis-related obstructions. This applies to the lower oil filter connection, not the oil cooler fittings.

Thanks for the correction. Definitely........the oil filter housing presents swing issues with a crescent wrench. I believe I had to use a very short crescent wrench and hope for the best regarding sufficient torque on the fasteners.

Your solution with a flare nut wrench or a 12 point box (16 point??) wrench is much preferred.