Heads done for?

[TallKDR]

Hi everyone. Ive been hiding behind the scenes reading things around here for a while, and finally realized I should just ask you guys instead of wondering and figuring things all out by myself.

I bought a 91 explorer that obviously had water leaking into the oil, and also into the combustion chambers because it was going out the exhaust.

I took the heads off, and the gaskets look horrible. Obviously they were leaking. However, then when looking at the heads, there are small (hairline) cracks between about 4 intake to exhaust valves. so 4 out of 6 cylinders DO have small cracks. 1 of them actually has very minute traces of rust around it.

Are these heads done for? Do they leak already? Will they leak soon? I hear these cast heads are different than the aluminum ohc heads im used to in my 280Z.

What do you guys think?
Buy aftermarket casts online? (both heads for $450 shipped), or put in nice new gaskets and take my chances?

thanks in advance
Pawel

 

[Doug]

Once the head is cracked its pretty much done. if you can get both heads for 450 bucks I'd say do that instead you'll be better off.

 

[TheRookie]

Replace them. No doubt. If the new ones are just the casts then change out the lifters too. They are a common problem on that truck. Would suck to have to pull them again in 6 months.

 

[Alec]

I agree with what they said

 

[Rick]

The OHV motors were all susceptable to cracked heads. The '91 was the worst of the bunch. Go with the new heads or you will continue to burn water.

BTW, I moved this to the Under the Hood forum.

 

[Muskrat]

yep, once the heads are cracked, time to buy a ste of remanned. even if the crack is tiny while clod, remember that heat will cause it to expand. I have heard of people brazing crakcs, and it will work for a while, but do you want to be pulling the heads off every couple of months? My B2 had a craked head, 2.9s were notorious for that, and I got a good deal on a set of the upgraded heads, much thicker than stock. Then again, what do I know, I rebuilt that truck when I was 16, by myself, with the help of my trusty Haynes manual.

 

[Doug904]

4.0 Performance sells new stronger castings for $395 a set rather then $450, not to mention they have experience with the 4.0 rather then just selling a set of heads. Check them out at www.4.0Performance.com.

Later Doug904.

 

[james t]

if there's any cracks, especially ones you can see, they're toast. even if there was a somewhat reliable fix, it would not be worth the cost. personally, id get the ones from Doug.

 

[Glacier991]

A cracked head is a cracked head, and unless repairable and repaired it is junk. Never put a head with known cracks back on any engine unless you want to be working on it again real soon.

Happy exploring

Chris

ps. On earlier Explorers, almost any significant engine overheat problem resulted in head cracks.

 

[Maniak]

Heads cracked between the intake and exhaust valves are toast. You won't even get any money for the core.

If it is cracked betwene water jackets, you will get a little money for the core, but not much (I think I got $100).

When you get your new heads, get heads called 93tm (thats the 1993 version of the heads).

I paid about $500 for my set of heads (with valves, springs etc) with 1 bad core and one $100 core.

~Mark