Coolant By-Pass Kit

[modelageek]

I found this courtesy of Rockledge at FTE..........the first TSB is for a thumping..........I would bet that is your issue, Bad Waterpump, since it was fine for a while

http://www.ford-trucks.com/forums/2...e-fluctuation-thumping-in-cooling-system.html

 

[kimcrwbr1]

I can`t wrap my head around the power steering pump making the water pump slow down aren`t they both running off the same belt wouldn`t that mean the belt was slipping on the crank. And as far as steam the engine would have to be overheating to produce steam maybe the problem is the radiator is not able to cool the fluid going into the engine enough or the t-stat is not opening far enough. check the lower radiator hose when it is hot the temp should be alot cooler than the upper hose. I would change the water pump and t-stat and go from there. I`m a advocate on adding a flush kit in the heater hose coming from the t-stat housing and filling the coolant from there to force the air out of the upper block and heater core.

 

[gribly]

I can`t wrap my head around the power steering pump making the water pump slow down aren`t they both running off the same belt wouldn`t that mean the belt was slipping on the crank. And as far as steam the engine would have to be overheating to produce steam maybe the problem is the radiator is not able to cool the fluid going into the engine enough or the t-stat is not opening far enough. check the lower radiator hose when it is hot the temp should be alot cooler than the upper hose. I would change the water pump and t-stat and go from there. I`m a advocate on adding a flush kit in the heater hose coming from the t-stat housing and filling the coolant from there to force the air out of the upper block and heater core.

I spent a couple hours on this one myself since I couldn't wrap my head around it, either. The steam is being created near the exhaust valves according to what little I found. The stiff power steering pump really can cause the belt to slip on the crank, too.

 

[gribly]

I found this courtesy of Rockledge at FTE..........the first TSB is for a thumping..........I would bet that is your issue, Bad Waterpump, since it was fine for a while

http://www.ford-trucks.com/forums/2...e-fluctuation-thumping-in-cooling-system.html

First TSB doesn't cover his year truck, so it's a safe bet that it doesn't apply.

 

[CaymenBlueLongRanger]

Thanks gribly. I bought the truck about a year ago and have done plenty of maintenance on it with detailed records. The truck had everything that I wanted, except maybe auto tranny. I thought that the problem I'm having was more widely known than it is. Apparently, it's not that common. I just have the vague description of the bypass kit. I can install one pretty easy, but not too good at fabricating one. I have heard some squealing from time to time around the power steering pump area, so I'm hoping a new pump will help. I did research quite a bit before asking for help, but was not finding the answer. I really just wanted info on the bypass kit, but am now thinking like gribly, that it is just a band-aid. I'm sure the trucks did not have this problem when new, so there is something that loses it's ability to perform over time. Most likely one of the pumps. Thanks

I have the same problem on my '96 4.0. It has been there for at least 16 years (I bought the truck 16 years ago). I replaced the rad, water pump, and thermostat (OEM part). It is a non-A/C truck with no heater control valve. (I added A/C but did not add the extra controls) .With the service part not available I've just been putting up with it and hoping it doesn't do any damage (397000Km now, and still thumping along ). Just found a reccomendation to add a 3/8" bypass at the heater core using 2X6 47147 Dorman "T"s. Ordered them tonight from Rock Auto and will install as soon as they get here and see if it works!!!