Hey Guys,

So my truck has run consistantly around 160 degrees for the year that she's been on the road. Ocassionally, the temp has reached as high as 190 but that was when I was stuck in LA traffic midday in summertime style heat.

Recently I removed the heater assembly from inside the cab since I never use it and I wanted to clean up a lil more room in there. Everything was working fine and I added a little resevour overflow which I knew was a little small but would hold me over. I noticed that the temp did increase a little after removing the heater set up (prob. because it acted like an overflow anyways) but nothing that was cause for concern.

The other day I had to drive midday to an appointment across town and noticed the temp started rising slowly then JUMPED to the 230....240....245. Then I pulled over to check things out and saw radiator fluid pouring out of the truck and expected the worst. Luckily it seemed simple enough though, the hose fell out of the resevour and was just dumping the excess onto the ground. Not one leak out of the radiator, radiator cap, or manifold the hose connected to. I got the car home and installed an after market overflow from Pep Boys and topped off the radiator and overflow but didn't flush it completely.

When I was driving home that night the heat rose to 220-230 and stayed right there. I drove the truck up on ramps thinking maybe there was air stuck in the system and tried to "burp" it the next day but running the motor with the cap off. The level
dropped a bit so I drove it around town. Sure enough the temp rose again but only to about 190-220 so it's going down but still running way to hot for normal, when the normal was a steady 160 on the freeway. Would draining the radiator, shoving a water hose in it and through the motor to flush anything out possibly solve the problem? I can't imagine what else it might be other then possibly sediment, air..etc...

The water pump is less then 6 months old as is the thermostat and up until the hose popped out of the overflow it was running fine. I thought maybe it sucked air into it somehow but I could be wrong...

Thoughts?

 

If you took out the heater, did you drain out the fluid from the radiator to do it. When you put the fluid back in,did you warm up the truck, let the thermostat open up and fill the engine block, then top off the coolant again?

How did you plug the outlets going to the heater and the water pump bypass?

 

I didn't completely drain the radiator when I pulled the heater out. It lost a lot of fluid when I disconnected the hoses though at the water pump. I did let the truck warm up a bit and added coolant to the radiator yes. I didn't plug the outlets persay since there wasn't a plug to do so. I bought a prebend hose, cut it to fit and ran it from one outlet to another. It's small, no bends/kinks, and I checked it all out before I started up the truck. Since there was a hose going into the heater and one going right back. A Ford mechanic informed me about just getting the prebent hose and doing it.

My plan tomorrow is to drain the radiator completely and wash it out, stick a hose near the tube that is going from the radiator top to the water pump and let the water run through that. I noticed the radiator fluid was a bit more orange and dirty. Hook everything back up and adding the radiator fluid and turn on the truck to let it cycle through without the cap on ad add as needed. Right move right? =)

 

typically there is a valve near the heater core that STOPS the flow of water from the water pump. When you use the bypass hose, you remove this valve and hot water flows back into the engine without going thru the radiator.

one thing you could try, if the bypass is rubber, is to clamp it closed as a test and see what happens..

I've seen suggestions on putting a washer into the pipe to close the hole to a smaller diameter.

Sam

 

Ok if you looped a hose from themanifold output to the water pump input, that means you are recirculating a fair portion of hot fluid back around through your engine constantly without it seeing the radiator. You need to plug that outlet and inlet with plugs.

Might solve it might not. But irregardless, needs to be done that way.

Flushing will always help. Just be sure to not let th eengine set exposed to air for more than a few minutes - rust. And don't use any pressure on the hose flush, ao you may bust a radiator seam. they are used to 7 pounds of pressure or less.

Good luck.

 

I was going to plug them but how would I do that? Theres no plug that can fit into it I mean I know it's a 5/8" hose that fits over it but it's doesn't have any threats that I could put a fitting into. I was brainstorming some sort of cap idea but wouldn't the circulating pressure be to much for it and possible blow a cap off?

What could I use to cap it?

 

I used a little copper water pipe with solder on caps, and then pushed that up into the rubber hose and clamped it.

its only 7-15psi.. home water pressure is like 50 so no problem.

and you should still be able to test this, with a pair of crimp lock pliers.. crimp the hose closed so the pliers are out of the way, and drive and see the results..

sam

 

Your local parts house should have rubber caps for closing off heater connections.

 

Ok, this makes sense now. I see how if the fluid is hot fluid is just being run back into the motor less of it is circulating through the entire system. See I thought that since there were two hoses that were running to the heater it was already just circulating. Maybe it was just going into it but not going back. So it was acting like an overflow reservoir.

I'm off to Home Depot to see about getting some sort of rubber caps or something. I'll drive it around like that first before flushing it out to see what happens.

 

That's true - a valid point. But, did the heater have a temperature control valve on it that was closed when you took it off? If so there was no flow or very little. Even if not, it will cool some in the heater and tubes, and there is a little flow resistance in the heater.

I could be completely wrong too.

Also, the intake manifold outlet and the water pump inlet nipple hole should both be threaded to accept a 1/2 inch MIP fitting......you should be able to thread 1/2" brass plugs into both - I think....Sam?

 

I did get some heavy duty rubber plugs to cap the outlets. They will fit over them and I got some claps to keep them in place. I was going to do this first, top off what coolant I'll prob loose when taking off the hose that's on it, then drive it around to see if I notice an immediate change. I'll be able to tell in the first 10 minutes. If everything is back to "a-ok" I'll wait for it to cool and then flush it all out and put in new coolant since I prob should anyways.

Wish I could have made some time to do it this afternoon but I've been on some hardcore deadlines with design work. Argh!

 

yes, both are threaded, whether you can get the old fitting out or not I don't know..
maybe when the engine is hot would be easier.

caps are a better choice short term.

Sam

 

Outlets were capped and the system flushed. What is a good temp for the engine to run at? I know it's been really insanely hot in Southern California so I've taken that into consideration. Normally it was at 160ish but with the heat it's been about 190 then when I hit traffic it went up to around 210 but cooled off when I got moving again. I don't have a radiator shroud...would that help at all?

 

I'm down south from you in Poway which is about 30 mintes north of downtown San Diego....107 yesterday and yes my truck ran hot too. About 20 -40 degrees higher - like yours, remember you have a gallon less coolant in your system now too.

A fan shroud would help, but it has to be the right depth and positioned on the fan right. If you still have a stock set up then a stock shroud would be really helpful.

With the light thing fixed and this back to normal things are looking good for you!

Great job!

 

If you can get to a boneyard, just pull any old 5/8" heater control valve, similar to the one shown. Put it in the hose and close it (wire the lever to keep it shut). I'm sure AutoZone etc sell them too.