Head Gasket Replacement

[stkline81]

My engine overheated & is now sucking in coolant & blowing it out the tailpipe in a cloud of white smoke. I also have bubbling in my coolant reservoir. How involved is a head gasket replacement, assuming that is the only thing that was damaged - I shut it down quickly, popped the hood & towed it home after it cooled down. Do I need any special tools? I do have another car to drive for the next month or so while I'm working on this one.

 

[stk33069]

I just did this on my 99 OHV. If you the basic tools i.e., wrenches, sockets, and a good torque wrench you should be fine. I might suggest that atleast with mine, i didnt want to take the top end apart, just to replace the gaskets, and having the heads sent out to be checked for cracks. I didnt feel like finding a shop to have them checked and pay for the checking just to find out they are bad. from what i hear on this site thet heads on our trucks are prone to crack. I ordered my replacement heads from Clearwater Cyclinder heads, i believe they were $210 a peice for complete heads, and they dont charge a core deposit for a month, giving time to UPS your old ones back, which they pay for too. Since your taking the top end off youll need to replace all the other gaskets too, check Autozone for any special deals they are having on free shipping or 20% off if amount is over a certain point. I ordered a complete top end gasket kit from Fel-pro and a set of rubber valve cover gasket, because the kit comes with cork...

 

[keleko17]

I have been dealing with what I assume is a cracked head for over 2 years. Most recently I used Bar's Leak head gasket repair. They say it will work for any problems as long as it can run for 15 minutes and not have to put coolant in, or over heat. It has been a good band-aid for me, lasting almost 8 months before the symptoms returned.

If someone on here responds with a good tutorial, or step by step, I can turn a wrench, and would love the challenge!

 

[bill06447]

It's not too bad a job, just takes patience and lots of PB Blaster. Look at it as many small jobs and it will go smoothly. I did the heads on my Mustang V6, probably the biggest hassle was tight quarters and big hands. With that I got lucky and didn't have to unbolt the exhaust, just the manifolds and left them hooked up in the car. I also bought rebuilt heads from Clearwater Cylinder Head can't speak highly enough of them. Don't forget new head bolts; when you torque the heads down on these motors you tighten to a value, loosen, then tighten a certain number of turns which actually stretches the bolt so they can't be reused.

Bill

 

[stk33069]

Thanks Bill, I forgot to mention the head bolts. July20 is the code for 20% off and free shipping over $75 purchase.

 

[Flash]

All the good answers were taken so I'll just add that now would be a good time to replace the timing tensioners to make sure nothing goes wrong there.
Obviously you'll be replacing the intake manifold seals as well.

 

[Dono]

I bet you have a cracked head also. Be prepared for this.
Im no master mechanic, and I was able to do the job. I would say do it. Gaskets and head bolts. Exhaust manifolds, and getting the upper intake off are the most challenging, but not bad at all.

There's a how to pdf on replacing the lower intake gaskets on a 4.0 ohv around. If you use that, your absolutely golden. The step by step doesn't get any better.

Take the heads to a machine shop to have them checked before you put them back on though.

Flash, Im not sure I'd want to replace the timing tensioners on this job. Id be replacing the timing tensioners if I were doing the cam. The ohv doesn't really see much wear on the timing tensioners and chain. Pretty tough part of the motor. No real reason to pull the front of the motor apart.

 

[Abbondanza]

This thread may help: http://www.explorerforum.com/forums/showthread.php?t=357323

 

[Flash]

It's an OHV, disregard what I said about the tensioner.

Good catch Dono.

 

[Dono]

It's an OHV, disregard what I said about the tensioner.

Good catch Dono.

No worries Flash, I figured you had SOHC on the brain when you were replying.

 

[stkline81]

I've started pulling parts off the engine. By saying there is no need to pull the front of the motor apart does that mean I don't need to remove the fan & everything behind it? I didn't have any rattling so I think the timing chain & tensioners are still in decent shape.

 

[Dono]

Id just pull the alternator, and take the bolts off the air conditioning compressor to move it around. Leave the fan on.

 

[stkline81]

That sounds great. Any idea what size torx the head bolts are?

 

[Dono]

I can't remember for sure. t5 comes to mind, but i'm not sure anymore.

 

[Abbondanza]

Head bolts are T55

 

[stkline81]

I drive for UPS & delivered to a mechanic today & asked him about removing the front of the engine - he said it will be necessary to remove the front of the engine in order to get the timing right after the heads are put back on. Is this true?

 

[Dono]

Nope. The guys on glue.

The cam (valve timing) is not part of the heads in any way.

Im 110% that you don't need to do that. The mechanic was obviously thinking you have a different motor than the Ford 4.0 ohv. The ohv kinda gives it away that you don't need to reset timing. The cam is timed to the crank. Then the lifters and push rods move the valves up and down off the cam. No way do you have to re-time anything.

 

[Runnin'OnEmpty]

X2 on Dono's post.

If you pull a head, one thing to remember is
to keep the pushrods in order so you can keep
them in the same orientation when you reassemble.
A cardboard box with holes punched in it makes
this easy.