WolfgangFox

Hey everyone,



I'm having a couple issues that seem all various cooling system components related.

#1 (Getting Hot problem) If I fill the cooling system up completely, it will run cool (n or o in normal) for about 2-3 trips of 10-15 miles round trip. The temperature gauge will never get above the N/O in normal at all, no matter how long it idles, or how hard the truck is driven. On the next trip, the engine starts running hot (a little past the l in normal), and I can physically see the needle moving. This usually happens when I'm in traffic, and does cool down to about the m or the a in normal after getting up to speed. When I let the engine cool and I check the coolant level, almost all of the coolant has disappeared from the cooling system (including reservoir). If I replace the system with the coolant, I'm good for another 2-3 trips again, but same problem happens after the coolant has disappeared again. (No leaks on the ground I can see anywhere. I have sat outside when the engine has been hot, and full of coolant, and physically just watched underneath the truck for 20-30 mins to make sure the leak hasn't dried up by the next time I'm out to drive it). I'm assuming coolant is leaking, but doesn't pose an issue until it gets to a certain level by the 3rd-4th trip out.
In the picture above, it looks like the fan is not even inside the shroud. I was wondering if there was either an aftermarket fan put on at some point, or the wrong shroud is on there, and if this adds to the cooling problem issue.

#2: (Engine loss of power) At various times I lose a lot of engine performance. I know what the a/c compressor feels like once it switches on, but the a/c isn't on, and so much power is removed, it literally feels like I'm almost running out of gas. I can barely get up hills, etc. Then, after a minute or so, power is restored back to normal. My a/c doesn't work at all, I can never get the compressor to start, but it almost feels like something is turning on (a/c compressor, etc) that robs the engine power, then shuts off and power is restored. I thought maybe it was the engine fan adjusting speeds because the truck seems to get a little cooler while this issue is happening.

I have replaced the radiator cap, as well as tested the fan clutch with the engine off (it stopped spinning and seemed to have a large amount of resistance while I was spinning it by hand).
I'm a newbie when it comes to repairing the truck, but it's really something I'd like to do myself. Rather then replace everything in the entire cooling system, I was hoping I could get some help in pinpointing the exact problem to fix. I know about the electric fan upgrade, and may look into that in the future.

Now, about the original engine fan and these issues. My fan doesn't seem to fit inside the shroud, and was wondering if that was correct? Is there supposed to be a spacer there to place the fan closer to the radiator? I couldn't find any pictures of this on the 'net.
Also, does the original belt driven fan have 2 speeds, or just one, in which it runs all the time?
And finally, can the heating up problem listed below be a sign of a failing thermostat / water pump?

WolfgangFox

Actually in the Chilton's manual, it does state the fan can be "sped" up with the clutch. The fan looks like it never speeds up at all, however this was just with new coolant added. Is it possible the fan clutch can be screwed up to rob the engine performance as well?

-Pat

Toplait

No leaks? Is the water leaking into the engine oil?

Radiator hoses okay? Collapsing radiator hose will make it run hot..Lower-Upper.

Clean the crud off the temperature sending unit.

Pull the Thermostat...If it is Double bridged I would replace it with a Triple Bridged Thermostat.

That is the factory shroud and fan by what it looks like. Heres a link that may help.

http://www.aa1car.com/library/cooling_fan_clutch.htm

fltdriver

Sounds like you have a blown headgasket, this would explain the disappearing coolant/water. Best way to limp it along is to refill the radiator every trip (before you ever start the engine.

You can verify this by "borrowing" what's called a Block Tester from the auto parts store, you will have to pay for the fluid it uses, about $10.

WolfgangFox

thanks. What I've decided to do last night is to list down each item in the cooling system, and then verify if it is working. It'll teach me a little bit about the cooling system as well. I'll start with your suggestions first.

Now for the blown head gasket. The coolant has disappeared yes, however after it gets very warm, and the loss of power happens, I can see the temperature gauge, at some times, go all the way back down to a "normal" reading (between the n and o in normal). Not very often, but it does happen. Most of the time it just goes down to the middle of the gauge. I'll try out the engine block tester, but do you think this is still the head gasket? I thought maybe the fan wasn't turning on its higher speed, or there was another issue.

-Pat

WolfgangFox

I don't have any jack stands yet, and I didn't get a chance to go to the auto parts store to borrow the block tester. It is supposed to rain and thunder like hell out here. I'll take a look into the rest when it clears up.

-Pat

Toplait

The bridge is the frame part of the thermostat. that holds every thing in place. Most thermostats have two bars that hold every thing in place. The Mr.Gasket ones are triple bridged.

http://images.oreillyauto.com/parts/...m/mrg/4365.jpg


The double bridged thermostats get stuck at a angle slightly open. Especially when the coolant flows at a 45 degree angle from the thermostat housing. Which forces the double bridged thermostat to stick at 45 degrees. To compensate for this issue I used a triple bridged Thermostat to reinforce how the thermostat opens and closes.

The Motorcraft one is a double bridged in this picture...Yes they will work fine. Just have a higher chance of the them getting stuck open in my opinion...I have no scientific evidence other then personal experience.

WolfgangFox

Thanks for that! I love details and learning how this stuff works!

I may be onto something. I went on a longer drive today. The coolant was refilled 2 trips back (couple days ago), so this will be the 3rd trip. After driving 30 miles, I pulled into an ace hardware, and there was a leak. It looks like it's leaking from the overflow reservoir, however in a strange place, out of the top where the cap is placed on the reservoir.

My impression is when the coolant gets hot, it goes into the overflow reservoir until it cools, then the radiator draws the cooler back into the system. Well, this was so full, it was actually overflowing out of the top. (Just a little bit, not dramatically but enough to cause a constant dripping). When I looked at the coolant level in the reservoir, it was about 1/2 in below the top of the reservoir.

When I got home, (30 miles back, did not refill coolant), she was running hot (about to the L in normal). I pulled into my driveway let her idle for about 10 minutes. It never cooled down, however it did not get any hotter, and the coolant was the same level in the reservoir the whole time, it looked like it never went back into the system.

It appears what is happening is the reservoir is drawing so much coolant out of the system it actually overflows, coolant seems to "disappear" and the engine starts running hotter.

So I guess my question is, how is the coolant drawn back into the radiator and through the cooling system again? If the reservoir keeps overflowing and losing coolant, that's a problem isn't it?

-Pat

WolfgangFox

I think I've found something, but everything looks original (except for the radiator).

On other cars there are 2 lines connecting the radiator to the reservoir tank, one for the drainage into the reservoir, and one for the refilling of the cooling system back from the reservoir.

Here is just below my radiator cap. There is a line that is capped off.



Here is the actual reservoir tank, but only one line connecting from the radiator.



Does the same line provide both the drainage, and the vacuum to pull the coolant back into the radiator?

WolfgangFox

I'm answering some of my own questions here.

The 2nd "port" goes to the throttle body cooler. I guess there is a special part that isn't available anymore, and that typically breaks. So people just cap it off.

The problem here is that the vacuum isn't pulling the cool coolant back into the radiator. I was going to approach this two ways.

The coolant recovery hose looks very old, but ok (no cracks etc). I was going to replace that, add a clamp to the radiator port and hose. I was also going to completely remove the thermostat for testing purposes just to see what happens.

More to come later.

-Pat