1985 720 2.4 Head Gasket

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Jlfcopter - 17 Jan 2005 22:51 GMT

Hi all, About 10 months ago I replaced my head gasket with help from this
group(many thanks to everyone) Well, it went again last week :-( Everything
went very good last time so not sure what happened. I followed great
directions in my manual and used all necessary tools. The only thing different
this time was that the truck did not ping at all, just burning antifreeze, but
seemed to have all power. I also experienced a bit of hydro-lock when starting
to put in my garage. I parked it, let out remaining antifreeze and started it
up to burn any coolent left in the cylinders. Last time was blown between # 3
and 4 cyl so I assume this is a different spot? I also had the head re-done
last time so will not have to do that again. I used a Fel-pro gasket last. I
expect the job to go quicker due to short time span and my memory,lol Agian I
would appreciate any insight or advice. I will wait till it warms up around
here as it has been around -10 to +10.

I will post my results again along with any insights I may have. Jerry

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Steve T - 19 Jan 2005 04:45 GMT

>also had the head
> re-done
> last time so will not have to do that again.

Let me guess, the first time it overheated and then blew a head gasket.

> I used a Fel-pro gasket last.

Bad move.

> I
> expect the job to go quicker due to short time span and my memory,lol
[quoted text clipped - 3 lines]
>
> I will post my results again along with any insights I may have.

Common problem, The cylinder head is made of heat treated aluminum (after
it's cast it's heat treated). Once you get one REALLY hot you anneal the
metal and it becomes MUCH softer than it was originally and it therefore no
longer stable. Also more prone to threads pulling out etc. Anyway most
machine shops never test the rockwell hardness of heads before they work on
them, nor do they reheat treat them. So even though the head is flat, it's
no longer dimensionally stable and it will repeatedly blow head gaskets.
I've learned most of the time if an engine overheats to the point of
blowing a head gasket with an aluminum head, it's best to go find another
head than spend any money in vain attempts at repairing it. I'd suggest you
do the same unless you enjoy replacing head gaskets! :-)

Signature

Steve

http://www.atlantaracing.com

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Jlfcopter - 19 Jan 2005 21:39 GMT

Steve T wrote>Let me guess, the first time it overheated and then blew a head
gasket.

Hi Steve, This truck has never overheated in the 18 years I have had it. This
will be the 4th head gasket and the 2nd for my install. Each time it just
started pinging and blowing smoke except this time there was no pinging, just
smoke. Which gasket would you suggest I purchase if not Fel-pro? I will also
look around and ask about another head if possible. Thanks for the
advice...Jerry

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Steve T - 20 Jan 2005 03:05 GMT

> Steve T wrote>Let me guess, the first time it overheated and then blew a
> head gasket.
[quoted text clipped - 4 lines]
> pinging, just
> smoke.

I'd still replace the head with a used one. Something is wrong. I just went
through this with my own truck, an old mitsubishi. I too wanted to save
money and kept replacing the gaskets. After the third one, I bought another
head and it's been fine ever since.

> Which gasket would you suggest I purchase if not Fel-pro?

Original from the dealer.

Signature

Steve

http://www.atlantaracing.com

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Pacific Sun Automotive - 01 Feb 2005 23:24 GMT

Go to Nissan and get one of their head gaskets, yes they are more money,
clean the head and block just like Pete said, put in a quality antifreeze
(something that will last more than a year) mix it right to your conditions,
check your rad cap too, make sure it is right pressure range for your
truck..... You shouldn't have any more problems. Dave.

> Steve T wrote>Let me guess, the first time it overheated and then blew a head
> gasket.
[quoted text clipped - 5 lines]
> look around and ask about another head if possible. Thanks for the
> advice...Jerry

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speedy - 21 Jan 2005 01:04 GMT

That was a strange reply by Steve T. I disagree.

ANyway to get to the bottom of the problem, I saw no mention of checking
the mating surfaces to make sure they are FLAT. Aluminum heads are VERY
prone to warpage. Typically if you can turn the cam easily, the head is
not warped. DONT do this check without making sure the pistons are down
from TDC. You have to check the block since it too, may not be flat.

Next is to run a tap in all the head bolt holes to make sure they are
clean. Its easy to torque up a bolt against a piece of sludge that fell
down the hole and get a false torque reading. Also spend $7 for a tube
of ARP assembly lube. Ths is the best stuff to make sure you have
accurate torques.

The only other cause would be that you missed a piece of the old gasket
before your last assembly. Not typical but could happen if you were
careless.

I've NEVER had to replace a Fel-pro gasket, and because of that I use
them exclusivley. I cant say the same for other brands.

I hope this time your repair lasts for good.

-Pete

> Hi all, About 10 months ago I replaced my head gasket with help from this
> group(many thanks to everyone) Well, it went again last week :-( Everything
[quoted text clipped - 11 lines]
>
> I will post my results again along with any insights I may have. Jerry

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