Oil cooler rebuild for dummies!

[gamudslinger88]

Whats up fellas. Im new here and just purchased my first diesel today from a friend of mine. I have helped him with this truck for sometime now and now I own it so its another prodject that needs finishing. Anyway I need the procedure for rebuilding the oil cooler on this 85 F250 with a 6.9 n/a. We pulled the old motor out becouse of water in the oil and oil in the water at operating temp. We thought it may have been the head gasket or a cracked block but the dang thang ran great. we pulled the motor and installed another 6.9 that was for sure good that he bought from another friend and wala the same thing. does this sound like the oil cooler to any of yall. I am new to the idi so any help would be great. also I just want to add that before purchasing this truck I looked on here for a good 2 weeks and this is a great site with tons of info on these badboys.

 

[Camarogenius]

Just subscribing to the thread. I'm going to have to rebuild the one on my F-800. Same basic design, just lots bigger.

 

[jimraelee]

I sounds like a oil and water issue. If you have a oil cooler that uses coolant of rad to cool it... I dont know your application. I have seen this before where a oil cooler mixes with the coolant after warmed up. I would remove the two lines of the cooler and mate them together so the oil will still flow... and change your fluids, monitor this and see what happens. BY NO MEANS DRIVE IT HARD. the oil cooler is there for a reason, but could be bypassed temporarly. U could also get a replacment external cooler and plug it in.

 

[gamudslinger88]

Yea I dont think that you can bypass the oil cooler well I have not seen a kit to bypass the cooler. Anyone have any pics, I know that its just a few O rings but I would like a picture of the cooler and some directions/advice before tearing into her.

 

[argve]

Jim you can't do that with these oil coolers they are bolted on the side of the block with headers and a large diameter tube type cooler (bundle).

Mud -

Ok it's fairly easy job - messy but not too bad.

First remove oil filter - drain all coolant and oil from system (use coolant drain plugs on side of block to empty)

Now take loose (I'm doing this from memory so hang with me here) the three bolts that hold the rear header to the block - now take a pry bar and pry the bundle and rear header assembly out of the front header. You can wiggle the rear header and tube assembly out from the truck but you can't if you have the front header still on the bundle this is why we just break it apart while the front is still bolted to the block.

Now with this out - pull apart the bundle from the rear header on the bench - replace all four o-rings on the bundle - if the gasket on the front header was leaking now is the time to yank it and replace. If not just leave it be it will be fine. Now take the header and bundle under the truck (loose) and sort of wedge the bundle in the front header and take a 2x4 and pry the rear header on to the bundle while shoving the bundle in the front header (all three pieces go together at the same time).

Now that you have them together just rotate the rear header to the correct position and bolt it back on the block. You can either use a new gasket or use form a gasket (smurf poop as I call it) and enjoy...

Now little tip... grease up the o-rings before you start shoving things together to make thing go a little easier. Also put the o-rings on th bundle not in the header like the factory service manual says - that was a misprint that they caught in later revisions.... Because if you stick them in the header then try to shove the bundle in it will cut the o-rings and you will have another internal leak and be doing this job over again...

 

[suv7734]

Here are some pics of what it looks like apart, post a while ago. Thanks 'yaric008'

http://www.samantha.cc/Engine1.html

 

[gamudslinger88]

Thanks yall. the oil cooler is off the truck and It had 1 O ring and "smurf poop" sealer on the other. Would this cause the coolant and the oil to mix or just leak? I have another bundle thats good for sure so I will prob just use it in the rebuild instead. Thanks again

 

[jimraelee]

sorry, I was thinking it was like cadalic that used a rad cooler just like the tranny coolers inside the rad...

 

[argve]

I think you found the source of the leak - there are 4 o-rings total on them. The o-rings both go on the bundle - one on the inside seal the oil and coolant from each other and the one on the outer seal the oil from the outside world.

now I think it was 1983 and 1984 model years had double o-rings for the oil to outside world seal on each end for a total of 4 large o-rings and 2 smaller ones. but you should be ok no matter what to just use 1 larger and 1 smaller on each end. I can't see a reason to double the o-rings on the end.

 

[gamudslinger88]

Argve. you dont think the internals of the bundle are bad. that would be good news! thanks for the insight.

 

[The Warden]

FWIW, I've never heard of the bundle internals going bad on an IDI oil cooler before. When there's a problem, it's always been the O-rings in some way shape or form.

Also...this is irrelevant for what you're doing but the '83 and early '84 coolers have four small O-rings and two large O-rings, not the other way around. In fact, the large O-rings are the same part number as that used on later trucks, but the small O-rings are unique to the earlier trucks...and, the ends of the bundle and the headers are completely different.

This is what the older-style oil cooler assembly looks like...