Overheating, intake or head gasket? How? | Ford Explorer Forums - Serious Explorations

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Overheating, intake or head gasket? How?


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February 11, 2010
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Year, Model & Trim Level
2003 Explorer XLT
2003 Explorer XLT 4.0 V6. 215,000mi, temp gauge had always spiked hot for 10 sec every morning. The other day it stayed at HOT. I pulled over and whited smoke came out tailpipe. Coolant leaked out below reservoir. Car novice hear. Checked oil and had no water or grey substance. Towed truck home. Have not touched it since. Read a few threads here that said to start by changing intake manifold gaskets. Bought from Autozone for $17.(6 of them). Any help would be appreciated and if somebody could point me to the thread for step by step instructions. Otherwise if somebody wants to pick up a project from my house, let me know! (but I really want to fix this thing, if possible without pulling an engine!)

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Sounds like your thermostat was sticking. Have you changed it? It's easy. I had best luck with the motorcraft brand. Change that first and see if you still get the spikes. Get a Scangauge so you can monitor real temps. Drive it and then take it some where that can check for exhaust gas in the coolant. Good luck.

I will start there this morning. Let you know what happens.

there is no coolant going into the intake. white smoke sounds like head gasket.

I replaced thermostat, drained coolant and put new coolant in. Drive truck for 10 miles. Still has white smoke, but no overheating. Is this residual coolant? Looks like all coolant is staying in reservoir. Maybe I need to drive it longer. Any thoughts from anyone?

It looks like the thermostat stuck and then the engine overheated and blew a head gasket. The white smoke is caused by coolant in combustion chamber.

I would replace the temp sensors, thermostat w/ Motorcraft only (looks like you already replaced it)

I would then pull the heads, have them checked for cracks and uneven mating surface, then install the heads with new head gaskets and bolts.

I would also check your coolant hoses and water pump why you are at it, as you can see what happens when a coolant system failure happens. If I remeber correctly the number one cause of roadside breakdowns is coolant system failure.

best off getting a used engine. parts are expensive for these 4.0, and labor is intense. it is just easier to swap engine. any 4.0 sohc will work strip it down to the block and use all your parts from your old engine.