HG replacment; 91 navajo LX | Ford Explorer Forums - Serious Explorations

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HG replacment; 91 navajo LX


October 11, 2006
Reaction score
City, State
keedysville MD
Year, Model & Trim Level
'91 navajo
i just 'bought' a '91 navajo LX as a DD and need to replace the HG

bought it for 500.00 in very good shape
166,000 miles
75% tread on stockish tyres[spare on wheel]
black with grey interior

was DD for a woman for a while untill she stopped at a gas station to get a drink and noticed[as women put it] a weird smell i.e. antifreeze and saw a little white smoke with some steam from under the hood. never overheated, didn't drive it after that, was tailered from the gas station to where i bought it from. sat for about a year and started right up while i was looking at it. almost know noise at all in the bottom end also.

anyway now to my question...

when i get to replacing the HG are there any tips or suggestions from any of the members?? anything else i should be looking at or for when i get the chance to tear things up and check EVERYTHING


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Assuming HG = Head Gasket

Haynes is reasonably accurate.

Biggest problem is removing exhaust manifold bolts. Use PB Blaster, remove tupperware and use impact wrench. If unavailable, a 6 point 10mm socket, 1/2 " breaker bar with
a 24 inch cheater works just as well.

Gasket Kit is $105 @ Autozone and includes valve stem seals and injector o'rings.

After removing heads, clean and inspect when absolutely dry. Heads crack real easy on the first gens and are not apparent until dry.

Locate automotive machine shop in phonebook and consider bringing them the heads for a rebuild and machining the surface, it should be about $100 and makes a really messy job easier. Bring the lower manifold along to be cleaned.

Buy a new Torx bit for torqueing down the cylinder heads, it will be twisted by the time your done.

Other than normal tools you will need:
T-55 Torx bit
deep 10mm socket
T5? socket for disassembling the fuel rail to replace the injector o'rings - lube with motor oil.

Use new Head bolts, they are torque to yield and cannot be reused.

Ask questions, the job's fairly easy.

i was really hoping to skip the machineing process as it was never driven hot and barely driven with the leak....

at the same time i under stand it is more of a good idea than something that is absolutly needed[experience with that one :( ]

105?? does that include new bolts, napa has a 'HG replacment kit' guy told me on the phone comes with everything you need to replace even the bolts i havn't gotten around to checking autozone and advance

there is a pretty good machine shop that i know of that i would go to, and i will probably only do that if the heads are warped out of spec.

are the internals of the head difficult to remove/clean/reassemble?? the only head work i have done is on my supra 24v DOHC....and a real PITA to move things around in there!!


My Navajo was run hot and both my heads were cracked and had to be replaced. If the heads were good I was willing to reinstall without machining. Next time however I'd bring to a machine shop to rebuild because of the mess involved.

Not noticing the cracks until they had dried the next day I stripped the heads all the way down, before cleaning. The tool to remove the springs is available as a loaner at Autozone.

The kit I got only contained all the relevant gaskets and valve seats. Buying the gaskets separately made the total cost unreasonable. the bolts were $35. The NAPA kit sounds like the way to go. In Friendswood both Autozone and O'Reillys had the same brand $105 gasket kit.

i'll be upset if the heads have cracks.... i mean i heard it running and it sounds solid and all. besides all i am doing right now is getting it running good to use as daily transportation

ill just have to wait till it is delivered to get into it

can't wait to start working on something though

Machining is a no-brainer to me after having done the a blown head gasket job on my old S10. If nothing else, though, get it pressure tested.