Did I blow another head gasket?

[BaldEagleMav]

Hi,

I am thinking that I blew another head gasket.

Some history: When I bought my '73 Maverick with the 250 I-6 and C4, it had a couple of problems. Among them, oil in the cooling system. The symptom of this was a dark brown scummy layer floating on top of the water in the radiator. I removed the scum a couple of times as well as I could, but the oil slick came back again everytime.

I wanted to hop up the motor anyway, so I ended up buying a head off a '78 Fairmont with a 200. (I grabbed the DSII dizzy and module off the same car). I had the head checked out at a local machine shop. The valves didn't leak and there were no cracks in the head. I had a port divider welded in and then had the exhaust manifold surface milled flat in addition to having about 0.010" milled off the head to ensure a flat surface. I installed the head with a Felpro composite gasket, along with a Clifford single-out header. I used hardened washers under the head bolt heads and torqued the head bolts according to the recommendations on this forum (including letting the first torque-down increment set overnight). With a rebuilt H-W 5200 from Tom Langdon, I was very happy with the performance of my mild hop-up. I constantly checked the cooling system for any signs of oil for over a year (not much mileage - maybe 2500 - 3000 miles).

This last weekend, I pulled the radiator cap and found a small(?) amount of scum again! To give you an idea of how much, the entire surface of the radiator opening is full (at least) and it's about 1/2" thick.

I am guessing the head gasket went bad (again), since this is not the same head that originally had the problem when I bought the car - and the fact that the engine went a couple thousand miles before the problem reappeared.

Any ideas on what (if anything) I did wrong? Any suggestions on how to ensure this doesn't happen again? Would retorquing the head bolts periodically help or hurt?

Thanks for any suggestions you may have. I enjoy reading everyone's posts and responses, and my Maverick has benefitted in many ways!

Regards!

 

[Ronn]

maybe re torque head bolts? but add 3 pounds. Just a thought.

Or maybe the block or deck needs attention like decking the block a bit. Some of the others here are better equipped than me to give you more detail but those are what come to my mind.

 

[BaldEagleMav]

Ronn,

Thanks for the input - any and all is welcome.

Does anyone else have any experience with this problem?

It seems I have most often heard about water in the oil when a head gasket blows. I have the opposite problem - oil in the water. Since it has now happened twice, I am wondering if the problem is the head gasket or something else.

One detail I failed to mention in my original post is that I was well aware of the possibility of installing the head gasket upside down (again, thanks to all of your input on this forum) - and I made sure that all of water & oil passages in the block matched those on the head gasket prior to setting the head down and torquing everything.

Anyone have any ideas?

I sincerely appreciate any feedback! Thanks!!!!

 

[MustangSix]

Oil pressure is higher than the cooling system pressure. A head gasket leak from the oil transfer passage to a coolant passage at the left rear of the block and head could cause that. The other more serious possibility is a crack in the block or head.

You may need to have the block itself surfaced. I've found that these inlines are usually pretty straight, but there is a tendancy for the blocks to "shrink" along the left side, causing weeping at the gasket.

 

[BaldEagleMav]

Hi Jack,

Thanks for the response - and it raises a follow-up question from me:

If a non-flat block surface on the rear left hand side is the cause of the leak, should I be able to see the leak path when I pull the head and look at the head gasket?

Thanks in advance - regards!

 

[addo]

The old school trick was fluorescing aniline dyes mixed into your oil. Under a UV light, the path of leakage could often be discerned. They're probably still available.

Cheers, Adam.