4.6L Coolant loss and Head Gasket Questions | Ford Explorer Forums - Serious Explorations

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4.6L Coolant loss and Head Gasket Questions


Explorer Addict
February 25, 2002
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BC, Canada
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Hey guys, last summer my truck had the OEM plastic intake crack and I lost all the coolant and overheated the motor. I replaced it with a Dorman replacement but what I didn't know at the time was that anytime you overheat your motor there is a good chance you have blown your head gasket. Without know that, I didn't even think to do it while I was in there. Over the last year the truck had a very minimal loss of coolant. I topped it up about twice in the year. Recently I was fully loaded in the summer heat and driving hard on the way back from a vacation when it overheated. I had plenty when I left for the trip but between driving there and back it had clearly gotten worse. Long story short, if I fill it full of coolant it lasts about 3 minutes down the road before it is empty again. I have never had a blown head gasket. Before I tear it apart I want to make sure that is the problem. Well, the only problem. Is that too fast of a leak for a blown head gasket? I have been under the truck a few times but I cant see anywhere else it could be leaking from (looking for a blown hose). It is coming out of the back of the motor, I believe on the passenger side. I will check again for water in the oil but I don't believe there is any. I think it is all coming out onto the exterior of the motor, both in the galley and onto the exhaust.

So question 1, do you think this is just a head gasket or could it be more?

Question 2, does anyone know of a write up for the head gasket replacement on the 4.6L? I am more concerned with the timing components and what all else should be done while I have it apart than the actual head gasket. The write up for the intake was very helpful, hoping to find one like that for the timing and head gasket. The truck has about 145,000 miles.

Thanks guys

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The head gasket is fairly easy to do, especially if you've done timing work. Most head gaskets blow internally, where they are the thinnest. Not externally to where they leak outside the block. You may have a cracked head/engine.

I don't know that I'd attempt to R&R it. Definitively find out where the leak is coming from. They sell a dye for it.

I just did the head gaskets on my '03 4.6 and it's still losing coolant.

Since you've replaced the intake manifold with a Dorman, have you checked the stupid little cap on the back passenger side of the new intake manifold -- those 'caps' are known to crack and also come completely off. (Assuming you have the V8)

Thanks for the replies guys. I haven't checked the back of the intake too in-depth I will definitely take a look at that. That would be amazing if that was the main cause of coolant loss.
Assuming it was back to being the head gasket, would running the entire cooling system dry in 5 minutes be too excessive for a head gasket or do they get to be that bad? For how slow of a leak it was before to this massive leak makes me feel that it is something more. Ideally the intake manifold, but I am getting nightmares on the idea of it being a cracked head or worse, the engine block. Could it still be the head gasket though?

edit: yes it is the V8.

When I changed my intake manifold, I found it real difficult to get the coolant/water mixture into the system. I thought it was good, but as I was driving along, the temp gauge shot to "hot", and the engine quit. Then a year later as I was out of town, and this has happened twice, that stupid ridiculous cap (to say it nicely) either blew off or it cracked, and both times, the temp gauge went to "hot" and the engine quit. That was a couple of years ago. The vehicle still runs like a champ. No issues. Ford tough. I can only conclude that Ford built in some kind of forgiveness/safety system just in case something happens. Original engine, approx 130k miles

Huge thanks guys. I will be checking for that cap at the back tonight. It sounds like it could very well be that as the outside of the motor was soaked of coolant coming from that general area including a white smoke from hitting the exhaust manifolds. It went into reduced power mode as mentioned above and allowed me to pull over and turn it off myself. I didn't want to leave it in the middle of nowhere though so I filled it back full of water and limped it down the highway 5 minutes at a time (stopping to refill) until I could reach a safe space to leave it to come back with a trailer. With all of the coolant spilling out the one side I hope I didn't do any damage by not letting the other side of the motor get any coolant. If this is the problem I will cap it and limp it to my buddies where I plan to do the head gaskets anyways in 2 weeks time. I will update tomorrow.

Also, thanks for the link above, Number4!

Well I was finally able to put the replacement cap on, same method as the above link. That worked perfect for the flood gates, which is good news. However it still has a steady drip. It is coming out somewhere near the front which I can't pinpoint, and becomes visible at the bottom front centre of the engine block, at 6 o'clock on the crank pulley. Given that I had to run it to get it to a safe spot would it be safe to assume it is head gasket or do u think it's maybe the water pump or something else?

I know you said you replaced the thermostat housing. Are you sure you got the gaskets on alright? That housing is right over the spot you say its leaking. Still suggest UV in coolant + black light....

I don't think it is anything from the intake because I did that last year and haven't had any drips since then until it overheated recently. I think I am going to pull it apart this weekend and do the head gaskets. I found one thread where the user pulled his engine to do his head gaskets. That isn't required is it? I cant seem to find any how-to threads for the head gasket.

You should really do a leak down test to confirm head gasket problem before pulling the heads. Its not necessary to pull engine to do head gaskets. Check YouTube.

I guess you are determined to change head gaskets - despite what anyone says. So get back to us when you are finished.