Au xr6 head gasket

2002au · 19-03-2015, 07:36 PM

Hey guys, need to replace the head gasket on my au xr6, has about 175,000 on it and is leaking at the front intake side of head leaving a nice white stain down the block.

Has never ever been over heated and oil and water isn't mixed at all. Figure I'll fix it before it gets really bad and I'm up for a new head.

I've ordered a acl gasket kit and new nason head bolts.

Wondering what size socket fits the head bolts? Going to need a decent socket cause I image they will be tight as hell. Obviously any tips will be appreciated

Cheers

Sox · 19-03-2015, 08:01 PM

You'll very likely need to have the head skimmed.
A 6 sided socket is good for the head bolts.
Stone the block deck.

Lastly, a metal layered head gasket is mandatory. If they supply you with a normal graphite gasket, do not accept it.
AU's take a metal gasket.

Evgeni · 19-03-2015, 08:40 PM

From memory the head bolts are 14mm. I normally use a 3/8 breaker bar with a pipe or a large ring spanner for leverage to get the head bolts out.

mik · 19-03-2015, 11:29 PM

Yep, aluminum head, mandatory head skim.

**aussiblue** · 19-03-2015, 11:40 PM

ACL Gasket kits generally uses a graphite or composite head gasket that will eventually erode, delaminate and leak. You should use a multi layered steel (MLS) one as came with the AU and available from Ford or Permaseal. (e.g. http://www.ebay.com.au/itm/Ford-Falc...item2c6a4867be) While many shops will skim it as a matter of routine, it is not mandatory to skim the head; you just need to carefully very check it for flatness (a laser light is a good way to do it).

2002au · 20-03-2015, 07:20 AM

Yep cheers guys know all about the head shaving etc. ordered my self a kingcrome 6 point impact socket, hopefully should do the job.

And to think I brought an au over e series because of better head gaskets lol.

Spurious · 20-03-2015, 02:37 PM

See my youtube channel:
https://www.youtube.com/playlist?lis...h_9x6GV_omXtRU

I went through this last October as my AU2 was leaking oil under the inlet.

Now, the head gasket debate will rage on, MLS V's Grahpite.

Draw your own conclusions & do your own research but you'll learn that what type a gasket to use depends on who you speak too.
I personally will say that the MLS is the one of choice, but I have also heard many people (ford owners & mechanics alike) say that the graphite ones are ok. Even the head machinist said they are ok....there's better, but they're ok.

I went with the graphite as my mechanic said this:
If mine were a new car then the MLS is best as the block is perfect. BUT as my car had done some 300,000km he recommended the graphite 'cause they're slightly thicker & will better tolerate an "imperfect" block surface.

As it stands, I've been using my car every day since the graphite gasket was used (mid' Oct 2014) & so far no problems to report. Time will tell.

After looking closely at the graphite head gasket I also took note that the holes where coolant passes through has an extra outer layer on the edge of the ring, this allows greater pressure to be applied to these areas once the head is torqued down.

Yes these gaskets have a reputation for failure at the coolant passages, but manufacturers have addressed this.

Once your head is removed, a shave is mandatory & I used Irwin bolt extractors ($55) to remove the old head bolts. I ruined a socket & a large ratchet prior to buying them.

I also recommend using a modern ratcheting torque wrench (the ones that "click" when torque setting is reached) to fit the new head bolts as the 2 bolts at the rear of the head will result in the wrench head hitting the firewall, so you'll have trouble getting a full 90 degree turn on the bolts.

Ratcheting ring spanners are also a godsend when removing/refitting the inlet manifold bolts. Moving the coil pack aids your access to these.

See my YT channel playlist & sit back & watch.

**aussiblue** · 20-03-2015, 02:51 PM

The other problem is that most head bolts (and there TTY tightening specs) for an AU assume a MLS gasket and the compression pattern associated with a MLS gasket which is different to that of a graphite or composite one.

http://www.felpro-only.com/proper-in...e-t-t-y-bolts/

Quote:

Typical bolts can be an issue when you use them on aluminum heads and with a gasket that doesn’t relax, like an MLS gasket. The expansion rate of aluminum heads will stretch typical bolts past their yield point and can snap them. Plus newer engines require high clamping forces (due to increased combustion pressure) which cannot be achieved with the smaller diameter bolts normally found in engines.

http://www.rlengines.com/Web_Pages/C...L_Engines.html etc

I have replaced dozens of head gaskets and have never had a subsequent failure when I have used a MLS even on the earlier E series. I rarely (never on a Ford so far) have the head machined but do take a lot of time in meticulously cleaning the old gasket of the head and block and checking both for flatness with a laser light. I also use a light spray coating of gasket paint on both sides of the head gasket to ensure any unseen small scratches on the head or block are filled.

Quote:

After looking closely at the graphite head gasket I also took note that the holes where coolant passes through has an extra outer layer on the edge of the ring, this allows greater pressure to be applied to these areas once the head is torqued down.

Yes these gaskets have a reputation for failure at the coolant passages, but manufacturers have addressed this

That is not the failure point it where the gasket blocks of the front redundant coolant passages.

99AUXR · 20-03-2015, 03:13 PM

Fitted multiple MLS gaskets to engines over 300000km and they are still fine. . .

**aussiblue** · 20-03-2015, 03:34 PM

And the graphite composite gaskets have always had those reinforcing rings. I was probably one of the earliest people (but certainly not the first; somebody else here suggested it) to fit a MLS gasket to an E series (my NB Fairlane in 2006) and I remember the Ford parts guy and the Ford mechanics at the dealership saying they thought it wouldn't fit but if it did to let them know as they would try it too. That MLS gasket is still holding fast and it had previously had three composite gaskets fail on that car (they'd last about 3 or 4 years).

2002au · 20-03-2015, 03:39 PM

This gasket paint stuff, never heard of it but seems like a good idea. Just brought from sca or repco etc?

**aussiblue** · 20-03-2015, 03:51 PM

Quote:

This gasket paint stuff, never heard of it but seems like a good idea. Just brought from sca or repco etc?

Yes this stuff http://www.permatex.com/products-2/p...sealant-detail or http://www.brandsport.com/vhtp-sp21.html

Like many others I used to just use aluminium spray paint like this http://agaus.com.au/product/weicon-a...h-brilliance/; or this http://www.amazon.co.uk/Autotek-AT0V.../dp/B004ZJIPJA that is probably how VHT got into the business.

Just make sure you only use a very light single coating; too much will create new issues. Like a light spray painting guide coat. You should still be able to see the original gasket colouring through the coating.

99AUXR · 20-03-2015, 06:44 PM

^ Pretty cool never seen or used that stuff. Any reason for it or just extra assurance if the block has been skimmed but just used a stone?

Sox · 20-03-2015, 07:35 PM

Quote:

Originally Posted by 99AUXR

Fitted multiple MLS gaskets to engines over 300000km and they are still fine. . .

Same.
There is absolutely no reason to use a graphite gasket unless the block deck is in very poor condition.

2002au · 20-03-2015, 07:56 PM

Thanks aussi blue, I'll be sure to get a can.

**aussiblue** · 20-03-2015, 09:27 PM

The idea of the spray is to fill any microscopic scratches etc (any of those made when scraping off the old gasket for example) ; it should not be needed if the block and head have been machined. If only the head has been machined I would suggest you at least use it on the block side of the gasket.

I see by googling that spraying with aluminium paint is considered a 50's , 60's and 70's thing and has been replaced with the purpose made sprays. from VHT, Permatex etc Makes me feel old. See https://answers.yahoo.com/question/i...9203815AACkzIi , http://www.jalopyjournal.com/forum/t...askets.791868/ , http://www.460ford.com/forum/archive...p/t-97758.html http://sbftech.com/index.php?topic=14485.0;wap2 etc

Spurious · 21-03-2015, 10:11 PM

What did I say about the debate on gaskets!

To trump others some more I'll also say this:

Spray on sealants shouldn't be needed!

when I had the head of mine, I meticulously prep'd the block , I was lucky that the old gasket came off 99% clean & I took my time using WD40 & about 1000 grit wet/dry with a sanding block.
Before the head went back on, after wiping the block clean I left a coating of WD40 on the surface, laid some rags down & sprayed them with it too. Keeps the block protected until the head goes on.
Wiped the block off with metho & hit it with compressed air moments before head went back on.

I will also add, just to stir the pot, that the old gasket that came out of my engine was an MLS & the outer rubberised coating was non existent.
The individual metal layers delaminated in my hands when gasket was removed from the block.

In defence of MLS I will also state that it held up well right to the end.
My engine was weeping oil, next to cylinders 2 & 3, down the block under the inlet. It did this for 3 years.
When removing the head I noted that the 3 head bolts along that side of the head were on the looser side of tight.
ALL other head bolts gave an audible "crack" when turned, those 3 did not.

So, MLS is the way to go, but graphite will get you out of trouble & keep you on the road for a few years at least!

Spurious · 21-03-2015, 10:17 PM

Have a read: http://scegaskets.com/wp_super_faq/w...ket-materials/

http://scegaskets.com/products/

Seriously, how bad can composites be if the pro's use them.

**aussiblue** · 22-03-2015, 12:02 PM

Quote:

Have a read: http://scegaskets.com/wp_super_faq/w...ket-materials/

Yes; but more carefully than you though it seems. Gasket Paint is not gasket goo or a silicon sealant (it is applied in an extremely thin layer) and as that page says:

Quote:

. We recommend a light coat of anaerobic sealer designed for the purpose Copper Coat (SCE p/n G1612) or Aero-Grade Hylomar. These sealants remain pliable rather than curing so it will ‘flow’ out of where it’s not needed and stay where it needs to be

Quote:

2. Metal head gaskets which are strongest

And the pictured pros are using copper gaskets like most race engine builders mainly because they can be reused after every engine tear down.

In any event, you have to take what a gasket manufacturer says about their products with a pinch of salt as they are about promoting their products not be objective. And SCE products appear aimed at older engines that do not use TTY fasteners (they recommend re-torqueing something you don't do with TTY fasteners).

I gather you've replaced just one head gasket and I don't think it has been on your car long enough yet to call it. I doubt it will last much more than 3 or 4 years. I have replaced many on Ford 6's (using composite one before the AU MLS ones became available) and I am convinced from that experience the MLS ones outlast the composite graphite ones (in fact I haven't had a MLS one fail yet).

**aussiblue** · 22-03-2015, 01:43 PM

I just asked a friend who has a machine shop what he thought. He said he gives the customer the option of the type head gaskets but advises them that the MLS one will last much longer but will cost more (due to the price of the MLS gasket and the labour costs in being more meticulous in cleaning and checking the head). Most customers (around 90%) choose a graphite gasket to a) save the $100 (prime reason) and b) because they are so put off their Ford by having the gasket fail and the cost of the repairs, they plan to replace the car before it fails again and within the 6 months warranty he gives on the repair. Although his business is about machining head etc he does not routinely machine or skim them but does put a lot off effort into steam cleaning them, servicing the valve train and checking the head for flatness and hardness. As he said, on many of the cars he sees the head has previously been machined and it can only be done a few times. So as he see it unnecessary skimming reduces the life of the head and just adds unnecessary costs to the job. And he says most of his customers are price rather than gasket longevity focussed, and have shopped around for the best price. He also noted that the warranty provided by the actual gasket makers were usually longer for their MLS gaskets.

**aussiblue** · 22-03-2015, 01:55 PM

Some makers even give a lifetime warranty on MLS gaskets e.g. http://mr-gasket.com/mr-gasket-warranty.html. For the commonly used ACL gaskets ACL MonoTorque head gaskets have a 3 year 100,000km warranty while ACL Ezy-Fit head gaskets have a 12 month 20,000km warranty. Permaseal MLS gaskets are warranted for 3 years http://www.aagaskets.com.au/PDF/AA00...20Warranty.pdf the Crossfire ones from the same company AAGASKETS from 30 days to 12 months http://crossfiregaskets.com/terms.aspx.

Sox · 22-03-2015, 02:02 PM

I find this strange debate, a debate where there shouldn't even be one.

Multi layer steel head gaskets are simply better. Period.

If you want the job done properly, an MLS gasket is the only gasket which should be used.
Anything less on an AU is substandard, a patch up.

AU's have far far less head gasket failures than earlier Falcons for a very specific reason.

AU's have the MLS head gasket standard, and this is how they should be repaired.

Earlier Falcons can also have the MLS fitted, which improves them.

We build a variety of engines in our shop, anything even slightly worthy of decent power output and reliability will have an MLS gasket. No question. The very best engines we build use MLS gaskets where available.

Anything that uses an MLS gasket from factory, will also leave with an MLS gasket, no ifs or buts.

Using a graphite gasket on an AU is dumb.

Sox · 22-03-2015, 02:04 PM

Quote:

Originally Posted by FlivverFord

Have a read: http://scegaskets.com/wp_super_faq/w...ket-materials/

http://scegaskets.com/products/

Seriously, how bad can composites be if the pro's use them.

They're not bad as such, but MLS are better, and standard on AU's.
Which is why it should be the only gasket used at repair time.

Going backwards is dumb.

**aussiblue** · 22-03-2015, 02:45 PM

The other interesting observation from my machine shop friend was the need for machining the head on these Ford sixes was most often that someone had previously gouged or scratched the head (and block) when removing old gaskets. When this damage was minor, many customers also chose to go with a composite gasket to avoid the high cost of machining both the scratched/ damaged head and block (especially) to use a MLS gasket. If the head were warped from overheating he noted that machining was often not a fix as the head frequently had also gone soft from the overheating and needed replacing (although customer often asked for a short term fix avoiding the cost of a new head and planning to sell or trade the car before head flutter from the soft head caused another head gasket failure). He observed that these head often seemed to survive overheating without warping more than expected but when it was so extreme that the head warped the head was also usually also softened or even cracked.

**aussiblue** · 22-03-2015, 02:51 PM

Oh and I agree that a light application of spray gasket paint may be unnecessary but it just something I have been doing for 40 plus years and has become habitual. So until I see evidence it is harmful will probably keep doing it.

2002au · 12-04-2015, 07:27 PM

Just an update guys, got the head off it today. Taken me 2 weekends just working slowly. Engines in pretty mint condition so pretty happy with that, still has very visible machining marks in the bores.

Sending the head away tomorrow to get checked out so hopefully by next weekend it's pretty close to being together again.

**aussiblue** · 15-11-2019, 09:19 PM

BTW I no longer spray the gaskets even though none of them that I did ever failed. I just accept that is no longer necessary or good practice especially when most MLS gaskets now already come with a coating of some type.

Interceptor · 16-11-2019, 01:23 PM

Quote:

Originally Posted by aussiblue

BTW I no longer spray the gaskets even though none of them that I did ever failed. I just accept that is no longer necessary or good practice especially when most MLS gaskets now already come with a coating of some type.

Generally any of the guru's at the gasket companies these days will tell you to use the gasket as supplied, and will refuse warranty if anything extra is found to have been used

Logic bring that if the gasket company thinks any extra sealant will be needed, they'll apply it themselves so they can claim responsibility instead of hoping the end user uses the correct supplementary sealant

**aussiblue** · 16-11-2019, 01:37 PM

Quote:

Generally any of the guru's at the gasket companies these days will tell you to use the gasket as supplied, and will refuse warranty if anything extra is found to have been used

Logic bring that if the gasket company thinks any extra sealant will be needed, they'll apply it themselves so they can claim responsibility instead of hoping the end user uses the correct supplementary sealant

Yes; but the first available MLS gaskets in the market that I saaw were just plain riveted together layers of bare metal and I was not the only one using a fine coating of aluminium sprays with them and it was also recommended by many of the manufacturers in those early MLS days. These days most MLS gaskets comes coated with a .001" thick viton rubber or similar that is bonded to the outer stainless steel layers.

**aussiblue** · 16-11-2019, 02:06 PM

Also interesting https://www.enginebuildermag.com/201...s-gasket-cant/ and https://www.enginelabs.com/engine-te...ns-mls-copper/ and https://www.enginelabs.com/engine-te...ns-mls-copper/

The first MLS head gaskets I saw were uncoated ones from the US I bought on USA based ebay motors an advertised as for a Buick V6's (and used for a Commodore V6 with ongoing head gasket oil sealing issues) and that MLS gasket actually came with instructions to spray them with a light coating of aluminium paint and that's where I started doing it with plain metal uncoated MLS head gaskets. I think if uncoated ones were still in the market I will still spray coat them this way.

It might also be that copper head gaskets were used earlier and even when used these days still usually require the application of spay coatings so when head gasket manufactures that had previously made copper head gaskets started making MLS gaskets some initially used and recommended similar coating processes.