I was wondering if anyone else has had problems keeping a leak free radiator in their diesel pickup? I'm the original owner of a 1986 F250 6.9l with the wide radiator, typical radiator model number 1166.

The original radiator was perfect and leak free for 15 years and 200,000 miles. A water pump failure sent the fan into the radiator and I replaced it with an aftermarket radiator I got from a ford dealer. That radiator lasted for a few years but began to leak at the upper tank to core seam. I milked it for a while longer using stop leak products. Finally took it to a radiator shop and they recommended replacing it. The replacement Molina Radiator came with a lifetime warranty. That radiator started leaking in the same location, top tank seam. I used stop leak on it and milked it for a while but eventually took it back to the shop where I bought it. They replaced the radiator for free but charged me for removal and replacement and coolant.

The replacement started leaking in the same place...top tank seam...after a few thousand miles. Again I bought some time with sealant products. Molina went out of business so eventually I had to buy a replacement. For some reason radiator shops don't want to repair this radiator. Just sell you another cheap Chinese replacement.

I'm now on my 5th radiator. This one is leaking at the same spot, top tank seam. I did the same thing as before using stop leak to get down the road a little further. Eventually the leak can not be stopped with stop leak as before. The radiator shop that installed the current radiator wants to sell me another replacement. I'm not sure I want to go down that road again. I am going to ask them to repair this radiator. Not sure that it will fair any better than the aftermarket replacements.

Any advice on replacement radiators would be appreciated. Seems the long seam gets stressed over time and leaks. Anybody else having this problem? What are the best solutions?

 

I have seen that problem when the top radiator hose had a problem. Either it didn't fit right, or someone was using one of those accordian universal fit hoses. They put too much strain on the top connection on the radiator.

How is the fan shroud condition? Something is putting too much strain on the top of the radiator, you just need to figure it out.

I have the tall type diesel radiator. I had to replace my original radiator about 7 years ago and I used one of those all aluminum champion radiators from ebay. No problems from it in all these years so far. And it sure is easier to install, the original radiator weighed a ton.

P.S. How old is the upper radiator hose? If it's old and stiff you might want to get a new one that may be more flexible.

 

The upper hose is in good condition. Still soft and pliable. The upper hose has a bend in it too so no lateral loading on the tank. Did you convert to the tall radiator from the wide?

Been thinking of changing out to the tall one or going to aluminum. Sounds like it's working well for you. You have a towing package and the 7.3 on your rig? Turbo or naturally aspirated?

Thanks,
BB2

 

Not the shroud either, it's light and self supporting. I think it's the bending stress from the long span. The mounts are 40" apart and the leak always starts in the middle third of the span.

If the tank has well soldered joints it should last for decades. But the aftermarket ones are lighter built and the solder joints are not very well executed.

 

I am not sure you can go to the tall radiator without changing the radiator support. And they are special diesel radiator supports. You would have to find one 86-dwn, the newer supports don't fit with the different frontend. Unless you wanted to take two and do a little welding.

I am surprised an old guy from a local radiator shop can't fix it for you. Sad to say, they are all passing away though.

 

It has been suggested by a couple radiator shops to either change the mounts and get the tall radiator and or go to aluminum.

I'm first going to try to get an old radiator guy to repair it. Hopefully next week. And yes they are dying off. Good old guys are getting harder and harder to find.