Guys,


I have a 38 Olds F-38, with a flathead 6. I have had head on/off twice because the corners of the head gasket start to leak. I am using copper head gaskets and copper spray both sides of gasket. No leaks when I break in the head gasket. Then after 24 hour cool down, I retorque head and run engine. After awhile the leaks are back on all four corners. I have had the head and blocked checked and they are flat. I a using thread sealer on all bolts. I have also had the head magnifluxed for cracks and there are no cracks. I'm at wits end. Any advice would be appreciated. Some say to use Permatex hi-Tack spray. Others say to use Duplicolor aluminum spray paint.
Thanks in advance!!!

 

Are you sure your torque wrench is accurate? Are you following the torque sequence?

 

This will probably stir up a lot of comments but I would try some Barr's Leak in it.

 

Me too, why not? Back in the 80's I worked as a mechanic at a Montgomery Ward auto center. We used to "power flush" the cooling system as a maintenance service. It was a complete kit (WYNNS) that we used a gismo attached to the car's heater hoses and used city water and shop air. Anyway after the flush was done the last step was to add the antifreeze, water pump lube and stopleak.

 

When you say "leak" I'm assuming that you mean engine coolant. I'm also assuming that when you say "copper head gasket" you mean a metal only gasket. I'm wondering if it is mandatory for you to use a metal only gasket? The reason I ask is that the Oldsmobile chassis parts book shows three possible gaskets for the 1938 6 cylinder engine, but none of them are metal only gaskets. There is one called "Terne-plate-asbestos"; another is "copper-asbestos"; a third is just called "special thick". If you have the shop manual, perhaps it comments on which type of gasket is appropriate to use. A different gasket may give different results. What was there when you disassembled it? And had it been leaking in the corners?

 

Guys
Yes, it's a coolant leak. I have checked torque wrench and it is accurate. Also, following the correct torque sequence.

I'm using the copper-asbestos type gasket. That is what came off the car originally back in the day. This car has been in family since 1960 and Dad says no problems with leaking on the head.

Not sure what to try next.

 

Are you torqueing them to 65-70#'s?

 

Are you using the original head bolts? How many times have they been torqued? Could they be fatigued to the point that they no longer have elasticity and will no longer keep the head tight? Just spitballing here.

 

Thanks for the added information. It helps.

The metal/fiber gaskets often specify which side should go "up". I hope that you have followed their recommendations.

If it's never leaked like this before, and you didn't damage anything during dismantling & cleaning, you should be able to restore its previous condition. Does it leak coolant only to the exterior of the engine? (no coolant in the oil or cylinder?)

 

Guys
Yes torque head bolts to 65-70 FP. Head bolts are new, old bolts were in very bad condition. Found head bolts at ARP. The gaskets that I have seen don't have an up and down side stamped on them. I was also curious about that issue. I was told to put lapped edges toward head. No signs of coolant leaking into cylinders but I don't know that for sure either.
What do you guys think of using the Permatex Hi Tack spray on copper head gaskets? I haven't tried that yet, only used copper spray.

 

I hope this will help you with your problem . Ive done a huge amount of flat head engine work in my 28 yrs of owning my own machine shop . You say the head is true & also the block.the head will be out of shape far quicker than the block. Going on that info i would suggest that you get your self a can of spray copper coat by permatex , make sure all is ready to go {clean} lay you gasket down block side facing up { i put mine on spray can tops} coat the gasket as evenly as possible let it tack for 5 minutes or so.spray a second coat flip the gasket over & do the same . You say the bolts are new but do all the bolt holes go into water . As for the bolts clean & dry them i always used thread sealer with teflon in the little white plastic bottle from napa you dont need alot just brush it on evenly . Once you are ready i suggest that you use a coulpe line up bolts cut off or line up dowels i dont know how your set up like take the gasket & put it on put all your bolts in & snug them down then start torquing them to 1/3rd the final setting after you have got you final setting you should be good. When you are ready to run the motor bring it up to temp shut it off & retorque the head again . 1 thing i failed to mention make sure the threads in the block are good. I dont know how motor minded you are so if some things i typed seem childish to you i'm sorry to have made it sound that way . Hope this helps you

 

I hope this will help you with your problem . Ive done a huge amount of flat head engine work in my 28 yrs of owning my own machine shop . You say the head is true & also the block.the head will be out of shape far quicker than the block. Going on that info i would suggest that you get your self a can of spray copper coat by permatex , make sure all is ready to go {clean} lay you gasket down block side facing up { i put mine on spray can tops} coat the gasket as evenly as possible let it tack for 5 minutes or so.spray a second coat flip the gasket over & do the same . You say the bolts are new but do all the bolt holes go into water . As for the bolts clean & dry them i always used thread sealer with teflon in the little white plastic bottle from napa you dont need alot just brush it on evenly . Once you are ready i suggest that you use a coulpe line up bolts cut off or line up dowels i dont know how your set up like take the gasket & put it on put all your bolts in & snug them down then start torquing them to 1/3rd the final setting after you have got you final setting you should be good. When you are ready to run the motor bring it up to temp shut it off & retorque the head again . 1 thing i failed to mention make sure the threads in the block are good. I dont know how motor minded you are so if some things i typed seem childish to you i'm sorry to have made it sound that way . Hope this helps you

 

Presumably you had the head off because of a problem.
I'm guessing it came off because it was leaking?.
Have you had the head checked for warping?. Come to that, how about the block face?.

If the head and block are true then you should only need the correct gasket, properly torqued with good bolts into good threads and all should be well.
You've ticked all the boxes apart from block/head distortion. Has it overheated badly recently?.

Roger.

 

By chance did you use the same gasket twice? Sometimes you can get away doing that sometimes not so much..... Just a thought ...Tedd