04 4.0 overheating intermittantly

First off, Hi to everyone! Although I am new to signing up I have used this forum for many of my fixes for my explorer for years and love the information I have received. Also sorry if this has been repeated again and again but I'm on a tight schedule for getting this baby back on the road!

To the point, My explorer has been running just fine and the on my way home for lunch I was pulling onto my street and I see 'check gauge' lit up on the dash, I first thought gas, I was running low but not that low! Too Hot!!! so I pulled over and turned the motor off right away. Since then I couldn't get it to get too hot again but it will every now and again, Its only been 3 days. From what I can see its only when I'm sitting at a stand still in traffic and only for a good while like a few minutes. Motor was rebuilt last year, think I have 10k on her since and she had a new water pump, fan clutch (I think but I'm pretty sure). Thermostat is still original to my knowledge.

From what I'm seeing, I'm thinking its not the thermostat as the top radiator hose is hot right after she gets warmed up and I have also noticed that if the gauge starts to climb, if I rev the engine it will go down. I'm not ruling out water pump or fan clutch as the replacement water pump lasted 5 days and failed and was replaced with another new one (think it was from advanced)

I'm pretty handy but have not replaced the fan clutch myself so if were thinking it is then I may need some pointers. If anyone else has any ideas then please, I will be most appreciative!

Thanks again for everything!

Ali

When you checked to see if the thermostat was working was it overheating ? i have seen those start sticking could be a reason for the intermittent over heating and for how cheap they are to replace should maybe give that a shot first.

as far as the fan clutch Im no pro and correct me if im wrong anyone but to what i understand the way to check it would when its cold gives it a little spin and it should have some resistence then drive get it up to temp and check again and it should be tight so its working all the time. If it spins freely i would replace. Just something to try before you commit to replacing. Hope it Helps

I didn't check the thermostat yet, I was thinking I would just replace it anyway. Doesn't sound like a thermostat to me (I'm no mechanic) but why would it just start to overheat while sitting still for a good while. When I stop and sit in traffic its ok unless I'm sitting for a few minutes.


The fan is loose when the motor is hot but it spins when running (I don't know if its going at its full operating speed) When its cold it spins the same. I keep reading that the fan should be the opposite of what you said also, now I'm confused!!

Appreciate it though, I need it fixed this weekend its our only car!

Thanks all!

once again anyone correct me if im wrong but the reason for the over heating at idle would be due to fan not working the way it should. then once you start driving the air starts moving threw the radiator again and starts to cool the engine. Sounds to me like the fan/clutch needs replacing. and yeah the thermostat is cheap and easy and its problably not the problem because that never the way it works haha but just saying i have seen it and didnt want to rule it out.

In no way am i trying to confuse you at all haha sorry if i did but i do believe that when the engine is at operating temperture the fan should have more resistence/tight to keep spinning with the hot engine to cool that hot engine would also check base of the fan for cracks and so on

Ok just wanted to double check myself. Before I left work tonight I popped the hood and spun my fan and it spins freely then after driving home (35 miles) fan has much more resistance I can still move it but not nearly as easily as cold. Once again hope ot helps good luck and let us know what you find out

Definitely sounds like the fan clutch to me (had same symptoms and the clutch fixed it) if there is any "free spin" in the fan it needs replaced IMO ... I have the 4.0 sohc and have had every overheating issue I can think of and have had to replace all cooling related components with the exception of the water pump and fan itself in the last year and a half. (knock on wood lol) too many plastic parts! I swear I'm still gonna design an aluminum magnesium allow thermostat housing for this motor and get rich.

Haha, I'm going to double check the fan but last I remember it had the same resistance hot or cold. What confuses me is that it is spinning when the motor is running. Going to tackle it tomorrow, any tips on replacing the fan clutch? possible write up on it?

Thanks guys for your help.

Looks like it was the thermostat. Pulled it out in two prices. So far no issues but I have not yet taken the truck out enough to be convinced. Thanks for all the help!

If that doesn't solve it look at the radiator cap as well. I had a car that I replaced everything on it and it overheated no matter what unless I turned on the AC to make the fan run faster. After several months trying to figure it out, I finally gave up and had it pressure tested at the dealer. Failed the pressure test due to the radiator cap being bad. Never had a problem again after replacing it.