Cooling Problem ...........

I'm going another direction on the sucked in top hose. Lets look at it has started pulling a vacuum on the top hose. So the pump is able to suck plenty of coolant. Reason I look at it this way is the top hose is sucking flat or near flat. So where is thew rectriction to flow. Could maybe be the radiator. We do not know how many tubes. How many rows or much more. Its just asumed it ok because its new. But could it maybe be underrated and not able to flow enough?? Flushing is a fair idea. Doing it with the old radiator is ok too. But if you had the same issue with the old radiator things wont change. So I'm not sure changing the water pump is going to do much if anything for you.
Now about the recovery tank and hose. These systems make enough pressure to force coolant out of the system. But they REQUIRE a clear hose and a tight system to suck it back thru a closed radiator cap. May want to install a hose clamp on the hose to radiator cap neck end of the recovery hose. Might need to remove the hose from the radiator and blow.. Don't suck thru it but see if the line is clear. They do crap up from time to time. Then coolant or what resembles coolant can be forced into the recovery tank but it can't be sucked back. Hard to believe till you prove it.

I read this whole thread, tried not to miss anything. Here are my thoughts;

The waterpump is working. Why do I think this? Because when he revs the engine the hose sucks flat, the water drops in the radiator. When the rpms go down, the water comes back up, the hose inflates. What can cause this? Only the differential pressure from the pump pumping.

The radiator is good. Besides both radiators doing the same thing, there is one thing sucking the upper hose shut, the waterpump. The only way the waterpump can suck on the top hose is to pull on it through the radiator and the bottom hose, so all that is clear.

It seems to me there is a problem with the continuity of the coolant loop. The pump is pumping against something, it should be circulating the water through the block, but it's like there is a restriction or blockage to the output of the pump. The output of the pump should eventually connect to the input of the pump in a big circle through the radiator and back to the lower radiator hose and the input.

Now what this blockage to the coolant is I haven't a clue. We know he is good to the upper radiator hose, he has suction there from the pump and it's collapsing the hose.

The waterneck that connects to the top hose; I would think he would have noticed a blockage in that, but maybe not?

The thermostat; That has been changed and checked. The problem is not there.

After that, you are up inside the engine. I don't know where to go from there. Can the wrong head gaskets be installed and block a lot of the holes? Not sure what else could almost completely block the coolant loop through the engine. Does the waterpump look new? Maybe someone messed a gasket up or something when they installed it.

For sure you have a project that was unloaded on you because of this problem. I have gotten vehicles like that before. They get handed from one person to the other, a problem like this can be difficult to figure out and they give up and sell it.

laserjock said:

I'm with OLDBULL on this one, you have a flow problem. If the top of the rad is hot and the bottom is cold, you aren't moving fluid. It's probably a real pain in the butt, but for diagnosis purposes, If I were going to trouble shoot this, I'd pull the thermostat. If it still gets hot then the water pump is clearly not pumping for whatever reason. The water could get that hot out to the top of the radiator probably by simple diffusion (heat soak) if the thermostat is in fact opening. It gives you another chance to verify the thermostat is functional and installed correctly. I've been down that road before where I just knew I did something right and then it would work. On re-teardown finding out I did something silly. It happens.

If the water pump is just really weak (I have hard time thinking of a reason why this would be but a worn out impeller or maybe impeller spinning on the shaft.... I'm not 100% sure how these are made) it may not completely answer the question but you ought to be able to open the radiator cap and see copious flow throught the radiator with the thermostat removed. If it isn't, then I'd say signs are pointing to the water pump.

Different perspective. Hopefully it's helpful.

Click to expand...

I'm with Laserjock on this one. It's a PITA, but removing the thermostat as a test would eliminate it as an issue.

Took a hard look at a spare block and waterpump and came to a couple conclusions:

1- water pump draws coolant in from the front of the heads, right behind the water neck, and the thermostat directs flow either to the upper hose or back into the pump

2- with a closed (cold) t-stat, the pump can draw from the upper hose if the check ball is faulty

3- a poor seal to the block on an open (hot) thermostat will allow the pump to draw directly from the upper hose, instead of through the lower hose. If the rubber boot on the thermostat is bad, it won't seal right.

4- if there is a restrictor plate on IDI's (don't remember), and yours is missing, the thermostat will not seal.

Here are 2 Pic of the block nuts one i broke the wrench on . I cant get these to budge any tips . Also does the hole for the block heater look normal for 1985 ?

That's one of those expandable rubber freeze plugs to the left correct?

Quick update. Purchased new overflow bottle. Hose was clear no blockages. Was still not flowing. I removed thermostat and check bleed ball reconnected everything .started with cap off and I could now see coolant flowing put slant vent cap on hose wasn't rock hard anymore or sucking in on throttling .
Took cap off and I could see gray matter floating in radiator . Call previous owner he said he pull Alumiseal in old Radiator. So should I add a coolant filter or flush. My new 3 row aluminum radiator is still installed.

If it were my truck, I'd PULL that nice new radiator before any more of that Alumaclog can get in it. I would also pull the heater core and bypass it. Then I'd flush the rest of the system just by sticking a garden hose into the top rad hose. It'll drain out the bottom hose of course. Then several cycles of remove the block drains, reinstall, flush again. And separately reverse flush the radiator and heater core.

Oh, but you couldn't get the block drains loose eh? Hmm, shoot 'em with some PB-Blaster or Kroil, maybe some localized torch heat. Maybe a series of impact adapters, 1/4"-3/8" then 3/8"-1/2", won't break

madpogue said:

If it were my truck, I'd PULL that nice new radiator before any more of that Alumaclog can get in it. I would also pull the heater core and bypass it. Then I'd flush the rest of the system just by sticking a garden hose into the top rad hose. It'll drain out the bottom hose of course. Then several cycles of remove the block drains, reinstall, flush again. And separately reverse flush the radiator and heater core.

Oh, but you couldn't get the block drains loose eh? Hmm, shoot 'em with some PB-Blaster or Kroil, maybe some localized torch heat. Maybe a series of impact adapters, 1/4"-3/8" then 3/8"-1/2", won't break

Click to expand...

someone suggested Dawn or would u just use plain water , Prestone flush? I have PBS blaster I will try with that.

OK... Now it starts to make sense.

Previous owner had coolant leak issues, replaced one of the rotted freeze plugs with a "sure to fail rubber plug" and dumped in a load of "aluminacrap block sealer" to stop the other leaks long enough to sell the truck... to you..

The block / radiator seal crap is made to bunch up and make a ********* where coolant is leaking .. and in this case.. likely formed a ball below the thermostat, or at the block to head passages...

Thus... you have a block in the normal cooling path which the water pump is trying to push past, but can't. SOoooooooooo .. it sucks the top hose flat... and since water can't circulate, quickly, you get over heat at the block, like in 10 / 15 minutes..

Make sense yet?

Pull the good new radiator out.. flush the hell out of it to get crap out. Pull the lower and upper hoses and thermostat. bolt down the thermostat housing and go to hardware store and get some connections [plastic pipe works] to hook a garden hose to the lower hose. Hook it to water supply and flush the living hell out of the block. Move the garden hose to the top hose connection and flush the living hell out of it the other direction.. get all the crap out...

Replace the freeze plugs with proper FORD freeze plugs... PROPERLY .. use the right tool to do it.. someone on here has the plans to make one.. I remember..

Once all the "aluminacrap is out of your engine cooling system.. put it back together properly, fill with plain water and do a coolant flush with Prestone or one of the other cleaners, by bringing the engine up to operating temperature.. and flush it all again... This should leave the walls of the cooling passages clean which will pass heat to the coolant properly.

Remove ALL the plain water you can, seal up the system and fill with the proper mix of antifreeze and DISTILLED WATER... only... You should then have a cooling system that works.