Overheating 4.6L V8-Suggestions?

[pet575]

My engine is overheating no matter what I do. It doesn't cool down with higher RPMs. Coasting at 30-40MPH in neutral does not cool it down either.

Once it heats up and I shut it down, coolant is boiling back into return bottle. It will bubble over quickly if I open the cap.

I'm suspecting either a thermostat that isn't opening or a bad fan clutch. When I stop the fan while the engine is running, it will start spinning again but it seems slow to get back up to speed. Then again, I have no idea how quickly it should start turning again.

Any thoughts?

 

[wangbungal]

when is the last time you check the water pump? I got that boiling thing in my ford ranger and pulled the water pump, the impeller is almost gone, it rusted out due to age, it could also be your thermostat stuck closed, but im betting on the water pump

 

[pet575]

It doesn't cool down with higher RPMs but it takes longer to overheat at 60 mph and 3k RPM (not in O/D) than it does at 30-40 mph at the same or lower RPM.

 

[pet575]

I replaced the water pump approx a year ago when I replaced my intake. I'm leaning toward the thermo not opening but could be something as big as a blocked radiator I guess

 

[pet575]

Started the engine w the cap off the radiator and coolant started rolling out of the return bottle. Indicates to me that coolant is not making either past the thermo or completely throughout the radiator.

 

[wangbungal]

does it overheat when youre running or when youre at a stop?

 

[pet575]

It doesn't matter whether I'm moving or stopped.

Possible alternate theory time. I've discovered I was very low on coolant and that I have a very slow drip leak. Would being so low on coolant cause things to get so hot that it was just boiling out what little coolant it had in it and that is why I couldn't add any?

After total cools own, the coolant bottle has drained completely without leaking out of the system.

UPDATE: There was less than one gallon of coolant left in the system!

 

[esclamada]

did you try taking out the thermostat? if it runs without overheating then the thermostat is stuck closed. If taking the thermostat out and it still boils in the reservoir tank then you have a blockage somewhere (radiator, heater core, hoses or near the intake manifold)

hopefully it's not a head gasket issue.


-----------------------------------------------------------
MY MOUNTY
http://www.facebook.com/diyfordexplorer/photos_albums

 

[fusseli]

You definitely need to top of your coolant and make sure to get air out of the system. Did you replace thermostat at same time as the intake?

 

[pet575]

I did replace the thermostat back when I did the intake.

I determined over the weekend that I have a very small and relatively slow radiator leak. Whenever the system has enough coolant that the bottle also has some coolant in it, then there is no overheat at all.

I got some Stop Leak over the weekend to see if I could get it resolved. I've heard the theories out there about using Stop Leak but I figure the worst that could happen is that I still have to replace the radiator if it doesn't work. This thing has 230K+ miles on it and I'm just hoping to drive it for about another 4-5 months and then retire it.

 

[pet575]

UPDATE: today I had temp increase almost to HOT, but not all the way there and no overheat while driving in the city with full coolant bottle. It was 89 degrees here in KCMO today.

Going back to the original plan and pulled the thermostat tonight. Ran at idle for several minutes with no temp increase above normal. Will test for sure in the heat of the day tomorrow. Supposed to be hot here again.

 

[01sporttracguy]

if that doesnt work id first get that radiator checked out go for a full radiator flush and only use water so as to not spend butt loads of money on coolant if you find any leak replace it if that doesnt solve your problem then its most likely a head gasket had the exact same issue with my f150

 

[pet575]

Well I'm still getting high temps despite removing the thermostat. Odd thing is that I don't seem to have any issue at highway speeds except for a slight heat up when I come out of O/D going up a big hill or something, but then it will cool back down.

Bigger concern is that if I stop at a light or slow down for stopped traffic it will heat up. Not an immediate overheat but a heat up and eventual overheat if I don't get going sometime relatively soon.

This indicates a circulation problem to me so I guess I've got to head the route of pulling the radiator and getting it checked out.

 

[esclamada]

Well I'm still getting high temps despite removing the thermostat. Odd thing is that I don't seem to have any issue at highway speeds except for a slight heat up when I come out of O/D going up a big hill or something, but then it will cool back down.

Bigger concern is that if I stop at a light or slow down for stopped traffic it will heat up. Not an immediate overheat but a heat up and eventual overheat if I don't get going sometime relatively soon.

This indicates a circulation problem to me so I guess I've got to head the route of pulling the radiator and getting it checked out.

sounds like your fan is not kicking in when you're at stop/idle. Did you check if the fan clutch is still working?


-----------------------------------------------------------
MY MOUNTY
http://www.facebook.com/diyfordexplorer/photos_albums

 

[esclamada]

When I stop the fan while the engine is running, it will start spinning again but it seems slow to get back up to speed. Then again, I have no idea how quickly it should start turning again.

Any thoughts?

There should be resistance when stopping the fan (or you can't stop it all) I think this is your problem. If it freewheels (again no resistance) with engine on/off then your fan clutch is toast.


-----------------------------------------------------------
MY MOUNTY
http://www.facebook.com/diyfordexplorer/photos_albums

 

[pet575]

I've checked it by trying to stop it while running. It will stop and then restart slowly. I have not really figured out whether it is normal or not. It starts back up somewhat slowly and when you kill the engine in spins for a little bit after the engine has stopped. Again, I have no comparison so I don't know whether it is normal or not. I'd prefer not to use money to guess.

I had suspected my fan clutch initially but when I saw the coolant loss issue I started concentrating on that instead. Once I found it, it was a very very small radiator leak. I did a radiator flush and then used some Stop Leak and I think the coolant loss has stopped. I have not noticed any coolant dripping or any loss of coolant from the bottle since I did that over the weekend.

Anyone have any guidance on figuring out whether this fan clutch is bad or not?

 

[pet575]

Just did a quick follow-up Google search and those results indicate that if I can stop the fan at all the clutch is bad. I don't know why, but I didn't think this was the case. I thought I should be able to stop the fan and that it was good if it restarted itself somewhat quickly after that.

Is it possible for my fan clutch to be defective and behave in the following ways:

1. Be too "weak" or "loose" or whatever you want to call it so that it is not turning quickly enough at low speeds; and
2. Lock up at higher speeds so that it blocks airflow at 40+ MPH?

Seems to me like a bad fan clutch would do either 1 or 2, but not both.


???????????

 

[esclamada]

bimmers are notorious for this kind of problem..

http://www.youtube.com/watch?v=-DxLe3R8QOM


If you could stop it by hand, then it's bad. At 40+mph (or +45) the fan will not turn on, the incoming air will cool the engine, it's the reason why on the freeway it's not overheating (in some cases) and when you slow down or idle the clutch is too weak to turn the fan on faster. At higher speeds, the fan speed will be proportional to the engine rpm to cool the engine as required (it might not do this if the incoming air is sufficient enough) if the clutch is not strong enough it will not be able to cool it quickly.


-----------------------------------------------------------
MY MOUNTY
http://www.facebook.com/diyfordexplorer/photos_albums

 

[pet575]

I agree with all of you on the fan clutch. Like I said above, it has been my first instinct all along. I guess I got sidetracked by the coolant leak. I went back and did the rolled up newspaper test last night and was able to stop the fan with the engine running and then hold it there relatively easy. Also confirmed that it spins for about 5-7 seconds after the engine has been shut down.

To address the coolant leak issue, I'll be replacing the radiator at the same time. It has 230K+ miles on it and I'd prefer to spend a few extra bucks to replace it rather than going through a removal, leak/pressure test at a radiator shop, etc. I just don't have the time to wait it out. Plus a radiator is $150 at my local O'Reilly Auto so it isn't really all that cost prohibitive.

Hopefully this will eliminate the problem as the summer heat approaches. I'll report back. If it works I will probably never really know which one it was-even though I know that fan clutch is bad. I'll be hoping it goes away so I don't have to start wondering about a blown head gasket even though the only possible sign I have of that (besides overheating) is a rough idle.

Anyway, I'll let you guys know and I thank you for your help.

 

[01sporttracguy]

ahhh good ole fords... hahaha my advice for you is to def change out that fan clutch and radiator if you have any mechanics in the family or friends with one ask them to buy the part for you(if they have an account with oreillys) if they have an account they get a pretty damn good discount i got mine from there for i think 100-115. fan clutch is also a must, especially since your already gonna be working that area. for fan clutch and radiator it takes about 1-3 hours depending on your skill level. once you have everything hooked back up use distilled water only dont bother with coolant just yet and check for leaks and overheating symptoms. If that all appears to be good give the vehicle a good flush and flush all that crap thats been sitting there especially that stopleak and fill it up with coolant. hope everything works out for you let us know how it turns out