BroncoII4x4.com

Now that is getting colder, I noticed the truck was not warming up very fast. Pulled off the thermostat housing, sure enough, there was no thermostat at all. Went and got one, and a new gasket and the parts book showed there is a rubber o-ring, so got one of those,too. Which side does the rubber ring go on..block side, or water outlet/radiator side? Also, there is an obviously incorrect radiator in the truck, being that is a little too tall, so someone wire tied the top of it to the core support, and the 2 top radiator hold downs are missing. I have a 1984 model,the parts books show a 1984 only radiator, different from the 1985-1988 model. How different are they? I'd like to go to the junkyard and get the hold downs, but there are no 1984 models but plenty of 1986-1988 ones. I think the fan shroud isn't the same for the 1984 and 1985-1988 models,either.

The 1984 used a brass radiator with clamp mounts that bolted on from the core support. The 85 and up used a aluminum and plastic radiator with two posts that poked through the bottom of the core support into rubber grommets. The top bolted horizontally into the back side of the core support. The aluminum radiators tend to be 1 core versus the 2 or 3 core brass one. It isn't a direct swap. As for the o-ring, I had never used one on my 85. Couldn't tell you where it goes. the gasket however, goes over the top of the thermostat.

You wouldn't use the o'ring and gasket both, use one or the other. The o'ring, if I recall and it is the correct o'ring for the thermostat (-]), should have a slit on the inside (horizontally) that makes the ring fit around the thermostat. You then just drop it in place as a unit.

I guess I will have to keep checking the yards for a 1984 Bronco II for the rad parts, unless I want to change out the core support. It seems that the 1984 model has a number of minor differences from the later years. Also, how different are the exhaust manifolds between the 2.8 and the 2.9 ? I have a small crack in one of mine, new 2.9 manifolds are cheap and readily available, but the 2.8 ones aren't.

As you said, the radiator and mount is specific to the '84. I wouldn't let that deter you from pulling a newer radiator, just make sure you get all the pieces. The rads from 85 through the 94 Explorer are the same with the same mounts, so my way of thinking is that you can get up to a 10 year newer radiator that will fit for a bit more work (f you're pulling them). I do like the fact that the 84's is so simply mounted though.. I'm pulling the rad from my '84 tonight to take in and have repaired.
As far as the manifolds go, I am very sure that the 2.8 and 2.9 are NOT interchangeable. Find yourself an old welding shop, somebody there will be able to weld cast if you take it off... But of course that's one of the hard parts to it...