Head Gasket Replacement

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RxGPoblet
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Head Gasket Replacement

Post by RxGPoblet » Sun Nov 17, 2019 3:41 pm

Hey all. Getting ready to replace the head gasket on my '15 T to fix a external coolant leak. Some advice appreciated.
What type of gasket is best?
Use a sealant spray like copper seal?
Use antiseize compound when replacing head bolts?
Torque spec?
Other handy tips?

As always thanks for the help in advance


Dan Hatch
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Re: Head Gasket Replacement

Post by Dan Hatch » Sun Nov 17, 2019 3:43 pm

Be sure and put it on right way. Big hole to rear.


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Re: Head Gasket Replacement

Post by Norman Kling » Sun Nov 17, 2019 4:06 pm

Check the straightness of the block and head. It won't seal if warped. The head can be easily resurfaced, but best to wait till you rebuild the engine to do the block. If you have a low spot along the edge, you can get some permatex form a gasket and fill in that area. Just do areas around the water jacket where it is low, not the entire surface. Usually will find those places along the front or rear edge of the block. The spray is a good sealant for the gasket. Torque the bolts starting in the center and working out from side to side till you get all tightened. Usually torque to about 20 ft lbs the first time around then start at the center and tighten to 25 and work out to the ends again increase by 5 ft lbs each time you go around until you get to 50 ft lbs. Then fill the water and oil and start the engine up and warm up completely. Then check torque of each bolt again and tighten to 50 ft lbs. Then start and drive a few miles and when it cools off tighten again. If you have an aluminum head, torque with the engine hot, but with an iron head, let it cool completely before you re-torque. Do this after each time you drive the car until it remains at 50 ft lbs. Then you are OK to drive as much as you please.
Norm


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Re: Head Gasket Replacement

Post by Norman Kling » Sun Nov 17, 2019 4:10 pm

One important thing I neglected to say is before you install the bolts, clean out the threads in the block with a bottoming tap. blow out the dirt. If you are using new bolts or if the head has been resurfaced, try the head on without the gasket and check that the bolts will go all the way down and touch the head. If they are too long, grind off a little from the end of the one which doesn't go all the way down and shorten the others to the same length. Then when you install the gasket as I posted above, the bolts won't bottom out but can be torqued down against the head to seal the gasket.
Norm


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RxGPoblet
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Re: Head Gasket Replacement

Post by RxGPoblet » Sun Nov 17, 2019 4:12 pm

OK. Thanks Norman. Which permatex do you use for this application? Is there one specifically for head gaskets?


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Re: Head Gasket Replacement

Post by Kerry » Sun Nov 17, 2019 4:21 pm

Norm.
You got that around the wrong way :o
Cast iron head is re-torqued hot.
And aluminium is re-torqued stone cold.

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Re: Head Gasket Replacement

Post by Mark Gregush » Sun Nov 17, 2019 4:41 pm

Silver paint or copper coat. 45 to 50 ftp is good enough, any more you risque pulling the threads in the block. Torque from the center out if you dont have a chart, if you do follow the chart. On a known good head/block you can even use grease on a stock engine.
I know the voices aren't real but damn they have some good ideas! :shock:

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Re: Head Gasket Replacement

Post by John kuehn » Sun Nov 17, 2019 5:01 pm

Don’t know how long the head has been on your 15 but if it’s been on for many years now is a good time to check the water jacket holes in the head and block. You can use a 1/4” drill bit to carefully clean out the holes. You might be surprised how the small holes can get encrusted and get stopped up. A T needs all the water circulation it can get and cleaning out the water jacket will help.


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Re: Head Gasket Replacement

Post by MichaelPawelek » Sun Nov 17, 2019 5:32 pm

If you usually use antifreeze or soluble oil in your cooling water don’t bother adding it to the radiator until you have gone through 2-3 head bolt tightening sequences first and you know you have no leaks. No use fiddling with the chemicals until the leak is fixed and the mess it can cause.


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Re: Head Gasket Replacement

Post by Scott_Conger » Sun Nov 17, 2019 6:00 pm

Michael

that is very good advice. Coolant will find a leak that water will not. If the car was prone to small weeps, often times with the new gasket and water for about a week will cause the weep to clot due to natural corrosion, and once drained and replaced with coolant, the coolant stays put.

A common place for this is at the very back of the engine. Often times the block is eroded a little and when it's cold will weep and when hot will seal up. If your car has done this in the past, it will in the future, even with a new head gasket, and the water-first trick will sometimes stop this.
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RxGPoblet
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Re: Head Gasket Replacement

Post by RxGPoblet » Sun Nov 17, 2019 6:05 pm

The leak is at the front right corner of the engine where the head meets the block. It doesn't leak when cold but leaks when you run it and it gets to operating temp. It does not overheat with normal use. It would probably be fine for the next 20 years like it is but these kind of things bug me.

Thank you all for the help/hints so far
Garland


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Re: Head Gasket Replacement

Post by Allan » Sun Nov 17, 2019 9:47 pm

Garland, if you put a straight edge along the block face you may be able to determine the area which might be low and its depth. This can be compensated for by cutting a brass shim of suitable thickness, and inserting that under one layer on a copper head gasket. This is not a permanent fix, but will work . Even if it does not, no harm is done.

Allan from down under.


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Re: Head Gasket Replacement

Post by Tlitwin » Sun Nov 17, 2019 10:12 pm

You might check out Irontite all weather seal. The person who rebuilt my motor told me about this stuff and it worked really well for me. https://www.napaonline.com/en/p/NCB468913016
Tom


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Re: Head Gasket Replacement

Post by Norman Kling » Mon Nov 18, 2019 11:42 am

The old fashoned permatex. The color is reddish brown. Not the sylicone type, I had a similar leak only mine was in the rear corner behind the exhaust manifold and I did not see where it was except that it leaked out. The leak was not enough to cause a problem because I checked the coolant level before I drove the car every time until a tour where I checked the coolant Friday, then trailered the car all day Saturday and started on the tour Sunday. I thought that since I had topped off the coolant Friday, it would be fine, but not so. The car overheated. Every time we stopped on that tour I checked and topped it off and had no more trouble the rest of the tour. When I got home, I pulled the head and fortunately the problem was on the head and I had it re surfaced. No problems since then.
Norm

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Re: Head Gasket Replacement

Post by TRDxB2 » Mon Nov 18, 2019 1:24 pm

torque chart
Attachments
Head bolt sequence.jpg
Head bolt sequence.jpg (48.22 KiB) Viewed 1269 times


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Re: Head Gasket Replacement

Post by SurfCityGene » Mon Nov 18, 2019 2:35 pm

Allan, Great idea inserting a shim!!
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Re: Head Gasket Replacement

Post by RxGPoblet » Wed Nov 20, 2019 2:46 pm

Does anyone have thoughts on using antisieze compound on head bolts

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Re: Head Gasket Replacement

Post by DanTreace » Wed Nov 20, 2019 5:22 pm

Don't leave home (garage ;) ) without it!

IMG_2517 (1280x960) (550x413).jpg
IMG_2517 (1280x960) (550x413).jpg (119.47 KiB) Viewed 1066 times

Helps remove bolts later, as carbon crust, moisture too, may let the head bolt thread lockup.

Who wishes to have a busted head bolt :o
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Re: Head Gasket Replacement

Post by DanTreace » Wed Nov 20, 2019 5:30 pm

Frank

Regarding that old torque sequence chart the artist left off bolt #15 :(

So here it is redone......

fg84 (620x480).jpg

Most important to always tighten the center head bolts, 1-5 first.....to squish the gasket at the middle tightly then alternate around the edges, your sequence can very, but never vary the center line of bolts first............


reason........the head gasket is thinnest at the center between the cylinders.....most gaskets blow at the thin spot.

tyer0) (480x640).jpg
tyer0) (480x640).jpg (84.86 KiB) Viewed 1061 times
The best way is always the simplest. The attics of the world are cluttered up with complicated failures. Henry Ford
Don’t find fault, find a remedy; anybody can complain. Henry Ford


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Re: Head Gasket Replacement

Post by Allan » Wed Nov 20, 2019 6:22 pm

Garland, whenever I fit a Z head, I always have pistons one and four at the op of the stroke to position the head gasket so there is proper clearance. There is enough variance in gaskets and heads to cause interference problems if things are not aligned. Hand crank the motor over before you tension the head bolts, and again after they are drawn down.
Hope this helps.
Allan from down under.

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Re: Head Gasket Replacement

Post by TRDxB2 » Wed Nov 20, 2019 11:55 pm

Dan, Thanks for the correction. Page replaced in my file. Also I heard that it helps to simplify positioning the head on the new gasket if you put 2 dowels (headless bolts) in head bolt postions


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Re: Head Gasket Replacement

Post by Kerry » Thu Nov 21, 2019 1:20 am

Sure that works when the engine is out of the car, a bit hard to use head bolt dowls when trying to get the head under the fire wall as well, if you have help to hold the head up off the gasket and then screw in a couple of dowl bolts then all will work.

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