Head gasket - where's the leak?

[AZPete]

I had symptoms of a head gasket leak (overflowing expansion tank, erratic temp gauge & white steam from tail pipes) so I flat-bedded home. When I pulled the header I poured out a quart of coolant. I pulled the engine and the left head showed coolant in both cylinders but I couldn't see any obvious break in the metal gasket.

https://thefactoryfiveforum.com/attachment.php?attachmentid=87231&d=1528835664

https://thefactoryfiveforum.com/attachment.php?attachmentid=87232&d=1528835664

Next, I pulled the right head and found essentially the same - both cylinders had coolant and I couldn't see any obvious gasket break.

https://thefactoryfiveforum.com/attachment.php?attachmentid=87234&d=1528835709

https://thefactoryfiveforum.com/attachment.php?attachmentid=87233&d=1528835709

I'm puzzled by coolant leaks into all four cylinders. Is there anything that could cause that? Since I was trying to nurse the car home after the first symptoms, maybe it was when the second gasket blew that the steam erupted and the engine quit. I'd appreciate any experienced eyes to tell me where the leaks are, and why both heads leaked. Thanks.

[frankc5r]

One thing that it could be is a cracked head. Sometime they are hard to see. Maybe Wayne P or other expert can help.

[NevaLift2Shift]

I would also take a good machinst's straight edge to the heads and block and use feeler gauges on any gaps. There is a spec for warpage, but more than a few thousands and it won't hold, iirc. Head gasket leaks can be hard to see.

Frank is also right, need to make sure the heads aren't cracked. I would highly suggest a machine shop to test them if you are unsure if they are cracked or don't find an obvious problem elsewhere.

[tenncobra]

I second checking for warpage. I had my truck overheat and also had white smoke coming out of the exhaust. I pulled the heads and had coolant in multiple cylinders. When I checked the gasket, I could not find any evidence of damage to the gasket. I eventually checked the heads with a straight edge and found them to be warped from corner to corner.

[DMC7492]

Look at the bottom of all four cylinders the black area on the fire ring sealing surface is black,indicating combustion gasses were passing into the coolant ports. See attached image. What boost pressures were you running?
87242

[AZPete]

DMC, thanks! Now that you pointed out the black areas, it's obvious to me now. I've located a straight-edge and found that both heads are warped with low points at the bottom of the cylinders. I'm now looking for a good machine shop in the Phoenix area and searching for parts. Thanks! Only 13 pounds boost.

From searching NASIOC and other sites, it looks like best timing belt and head gaskets are OE. You agree?

[longislandwrx]

I've used the gates kits for timing belts with great success,

https://www.flatironstuning.com/p-3909-upgraded-subaru-gates-timing-belt-kit-oem-subaru-tensioner-water-pump.aspx

Get the master kit from subaru... all the good stuff.

https://www.flatironstuning.com/p-1972-subaru-master-gasket-kit-for-the-subaru-wrx-forester-xt-all-years.aspx

you need valve covers and half moons... i like getting it from flatirons cause they built a nice package

pick up a Subaru t-stat and gasket, they are thick rubber. everything else is junk paper

[NetWRX]

While you're in there, you may want to install a set of these:

https://www.flatironstuning.com/p-1925-arp-head-studs-for-the-wrx-and-sti.aspx

Factory head bolts on forced induction motors stretch over time and can cause symptoms like this.

[AZPete]

I've filled my cart at Flatironstuning with the master gasket kit, ARP studs, water pump, timing belt, idlers and tensioner . . . and maybe more.
I'm hoping they have a discount for a CU-Boulder alum, who has climbed the Flatirons!
Thanks guys.

[Sgt.Gator]

I have a few thoughts on this. Post up pics of your block. They frequently crack where they are scalloped for the bolts. Here's an example:

https://u4tfbg.by.files.1drv.com/y4mKzanr5w6W4oTahplsYkw9SQZQzD0649oG_8zsUn4VjDQH0U LLw-Li3KjzNV603YwKARiUfOb557Gi6HqD9ov4gMhq7r0aS6HdGT2s D2k1fr8tgyWZQx58l5X_jM9-nVHLSUNpi33x91GSkD7X91C-tth8iD_R59HKvRvGaRrQqCa_ZJ1jxo5C4s_AgekdUqcrJols_i S0Imcf0RgLta2kw?width=750&height=697&cropmode=none..https://vitfbg.by.files.1drv.com/y4miJMMwUBUOHuohP4B1OdkDdLPQZXA88E-mrXJGYLkke1f_QX_jzxKcqexQLMKs86sEBtRdDClX0CIS8X_Qg XTkX0drGDqIrZJBbI3Z17oHmFn9VV4UtxNvrMfExeVikFC37D4 RQFQeOZtDxQJRrxdmi0doS1NV_PI4dmXF8zOxU9uPWMHEI-91H-srdJVonou3m7FFJ-_ac6bb_M39-tQ-A?width=1112&height=900&cropmode=none

Also check your heads close around the spark plug hole. This won't cause the leak you have but it's an inspection to do while the heads are off. Some folks say these cracks can be left alone and no issues will come from them. IMHO they are cause to toss the heads:

https://uytfbg.by.files.1drv.com/y4mLAdwv7bLaMIDj8u1KHOaygK-hVzMLStOnf727Rh4gZ3OwvNQO5ud4kWi6vgmleTMMn-Lcy39tbSUz8GgT7Y04vyCauT02zDkFOuWltqsmo6uRQn41Ea23 QTUIMS09e3MTX2yUrSVKLIKl0xPoTChltZh8oUqvKmH3AUA0GI myzE0cmGlyP8lyMmIH46cHJye1szcNRnu6JtIHq0zlL7LVw?wi dth=886&height=410&cropmode=none

The spec on the heads:
Warping limit: 0.035 mm (0.0014 in)
Grinding limit: 0.1 mm (0.004 in)

and the block is:
Warping limit: 0.025 mm (0.00098 in)
Grinding limit: 0.1 mm (0.004 in)


I have used Gates timing kits in the past but no longer recommend them. They are using crappy Chinese junk water pumps and tensioners now. Either use OEM Subaru or the Aisin kit. The Aisin kit is made in Japan. I see that Flatirons has that all figured out. Just don't get the standard or the racing Gates kits. I lost an engine at Pacific Raceways either because the tensioner failed or the tech who installed it didn't use Loctitie on the bolt. Gates has recognized that problem and includes Loctite in the kits now. Be warned, the Subaru factory repair manual does not mention using Loctite on any of the timing bits bolts, but IMHO you should use it on all of them!

[longislandwrx]

gator, the link i gave on flatirons is the gates kits with the oem subaru parts. tensioner and wp, its a $60 upgrade over the std gates kit.

sorry read the rest of the post. you saw already.

yes get the subaru oem parts i think its still cheaper than the aisen kit.

[AZPete]

Thanks, Sgt Gator, for the heads-up on head & block cracks. I've checked both carefully and found no cracks, plus the machine shop that is doing my heads they will check also. (whew.)