97 Explorer 4.0 ohv overheating

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Oct 23, 2006 | 07:16 PM

edgewound

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From: Southern Calif

97 Explorer 4.0 ohv overheating

Hi all...I'm new here....first post....great forum.
146,000+ miles.
I had the CEL po171,174 codes, cleaned the MAF sensor and drove awhile....so far so good...we'll see.

However, the A/C is bypassed with smaller belt....it's siezed...the heater stays hot when temp is adjusted(blender door problem?) and the engine overheats after turning the ventilation system on.

I just put a new thermostat in....still overheats.

There are no codes showing EGR system....but could that be the problem?

Still maybe running too lean and combustion chambers too hot?

Water pump seems to work fine, I recently replaced the fan clutch with a new Hayes unit.

Any help you could give is greatly appreciated. This is driving me nuts.

Trying to avoid dealer service costs, and unscrupulous mechanics that can't fix anything right the first time.

Thanks in advance.

Oct 25, 2006 | 09:43 AM

aquanaut20

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Joined: Aug 2003

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From: BC Canada

2 Questions
1. are you losing any fluid?
2. have you done a compression test?

Oct 25, 2006 | 12:47 PM

edgewound

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From: Southern Calif

Quote:

Originally Posted by aquanaut20

2 Questions
1. are you losing any fluid?
2. have you done a compression test?

No to both questions.

Change oil every 5000 mi with Mobil 1. Never any coolant in the oil....doesn't leak oil. Stopped a coolant seepage from the driver side head gasket with Bar's stopleak.

Are you thinking bad head gaskets?

Oct 25, 2006 | 01:03 PM

aquanaut20

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Joined: Aug 2003

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From: BC Canada

That was my initial thought, and now we have stopleak (never had any good results), usually caused more headaches like the one you are having.

I have an identical rig with 330k using Mobil 1, just did the lower intake gaskets to clear the lean codes.. Would pull the plugs and look at the colour and condition (just to see what is happening inside the combustion chambers).

Nov 1, 2006 | 01:45 PM

edgewound

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From: Southern Calif

Thanks for your input, aqua...I think you nailed it.

Talked to a reputable local mechanic today. He told me new head gasket replacement with new bolts would run around $1100...maybe have to machine the heads too.

Gaskets and bolts run about $150.00. Could be my son and I will spend a weekend doing it ourselves. It'd be good experience for him as it will probably be his first driver, and I can't see dumping this truck as it's long paid for and has really been a great vehicle. I love how easy it is to drive, although the mpg isn't all that great.

I'll keep you posted on my slow progress when I have a free weekend to do it. Does anyone really have a "free" weekend?

Thanks again.

Nov 1, 2006 | 02:08 PM

aquanaut20

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Joined: Aug 2003

Posts: 3,263

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From: BC Canada

YES! This is a doable task, take you time.

get yourself a good torque wrench for final assembly

get the heads magna fluxed and if not cracked have them planned, replace the valve seals and guides, and lap the valves.

keep us informed on you progress, good luck.