Bad Head Gaskets?

[Daskuppler]

Hello Everyone!

This post is more for clarification than anything as I'm pretty certain my head gaskets are failing. 2002 Impreza TS

Heat is intermittently hot, though almost always warm.

Top radiator hose is harder than usual, but doesn't stay hard once cooled down.

Lower radiator hose is intermittently cold when top is hot

Overflow tank is full and overflows when on the highway

Temperature gauge is rock steady

Current gaskets are Felpro triple layer steele and are about 10 years old with 70kish on them.

If this is indeed bad gaskets, what else should be done at this time? Car has 142k on it. Timing components, thermostat, water pump, and radiator are all new within 10k. No visible leaks on anything.

 

Cheers

[idosubaru]

Subaru headgaskets, resurface heads, clean head bolts and holes, lube threads.  Cam seals, reseal the oil pump, or replace with 10mm oil pump if that engine got the dinky 7mm variety which I think was used on some early 2000's ish +/- engines, Subaru went musical chairs after the 90's so i'm unsure which models have the 7mm.  You can read the numbers on the rotor to tell you.

Valve cover gaskets are easy but also easy to replace if you just want to wait them out or inspect how brittle/soft they are. 

If the 10k timing components aren't Subaru I'd replace them with Subaru. 

If AT - check or replace the AT lines behind the drivers side head.  It's always the ends that are hard, brittle, showing fatigue, so I've even just clipped 3/4" off and reused the lines before if the rest is supple and there's enough slack.

If you're pulling the engine then I'd ask if it's MT and about the clutch and rear main, though they very rarely leak.

Pull the knock sensor and check for signs of cracking or rust compromising the metal ring to rubber interface area. They give a check engine light/code and can't strand you so no need to replace but it's an easy chance to check for cracking under the base with the head off and only one bolt. 12mm. 

[Daskuppler]

11 hours ago, idosubaru said:

Subaru headgaskets, resurface heads, clean head bolts and holes, lube threads.  Cam seals, reseal the oil pump, or replace with 10mm oil pump if that engine got the dinky 7mm variety which I think was used on some early 2000's ish +/- engines, Subaru went musical chairs after the 90's so i'm unsure which models have the 7mm.  You can read the numbers on the rotor to tell you.

Valve cover gaskets are easy but also easy to replace if you just want to wait them out or inspect how brittle/soft they are. 

If the 10k timing components aren't Subaru I'd replace them with Subaru. 

If AT - check or replace the AT lines behind the drivers side head.  It's always the ends that are hard, brittle, showing fatigue, so I've even just clipped 3/4" off and reused the lines before if the rest is supple and there's enough slack.

If you're pulling the engine then I'd ask if it's MT and about the clutch and rear main, though they very rarely leak.

Pull the knock sensor and check for signs of cracking or rust compromising the metal ring to rubber interface area. They give a check engine light/code and can't strand you so no need to replace but it's an easy chance to check for cracking under the base with the head off and only one bolt. 12mm. 

 

Thanks for the input! All timing components are Subaru OEM including the water pump. Does the oil pump need to be from Subaru if I upgrade it?

I was planning on leaving the engine in since I don't have a cherry picker.

It is a 5mt, clutch was replaced not terribly long ago and has no signs of needing replacement.

I planned on having the heads resurfaced, hot dipped, and inspected by a local machine shop. Should they just do the cam seals as well?

 

Edited January 17 by Daskuppler

[idosubaru]

12 hours ago, Daskuppler said:

 

Thanks for the input! All timing components are Subaru OEM including the water pump. Does the oil pump need to be from Subaru if I upgrade it?

I was planning on leaving the engine in since I don't have a cherry picker.

It is a 5mt, clutch was replaced not terribly long ago and has no signs of needing replacement.

I planned on having the heads resurfaced, hot dipped, and inspected by a local machine shop. Should they just do the cam seals as well?

 

Engine in, timing components all Subaru - that significantly reduces the list I made. 

Don't know, never installed an aftermarket pump and probably wouldn't. I'd install a used Subaru oil pump before I did that.  They don't really fail if the engine isn't detonated and sending shards into the pump. I just wouldn't want the 7mm pumps. 

For $5, 1 bolt, and 20 years old, I wouldn't skip the cam seals while it's staring at me and already removed from the engine. But they don't leak often nor typically catastrophically so it's not a huge over sight to leave it.

[Daskuppler]

Okay, sounds good. What about Subaru vs aftermarket coolant? Does it matter as long as it's silicate free? Is the conditioner necessary with the MLS gaskets?

14 hours ago, idosubaru said:

 

 

[nvu]

Any silicate free coolant is fine.  Subaru coolant conditioner was a rebranded stop leak to keep the composite gasket from flaking off.  Subaru MLS shouldn't need any conditioners.

[Daskuppler]

23 minutes ago, nvu said:

Any silicate free coolant is fine.  Subaru coolant conditioner was a rebranded stop leak to keep the composite gasket from flaking off.  Subaru MLS shouldn't need any conditioners.

Great, thank you! The old head bolts are Fel-pro, I know r gadgets are bad, but I would assume the bolts are fine to reuse? This would be the second time.

[nvu]

It's not recommended to reuse headbolts, but I've reused headbolts before.  You'll know you have a bad one when you do the final torque and it squeaks too much or just doesn't feel tight.  I have a bunch of used ones laying around so it's not a big deal.  It might be a show stopper if you don't have spares on hand.

[Daskuppler]

1 hour ago, nvu said:

It's not recommended to reuse headbolts, but I've reused headbolts before.  You'll know you have a bad one when you do the final torque and it squeaks too much or just doesn't feel tight.  I have a bunch of used ones laying around so it's not a big deal.  It might be a show stopper if you don't have spares on hand.

I thought that was the case as well,  it then looked it up and it seems quite common to reuse them along with the FSM not requesting new ones. Seems like there's no real definitive answer 😔

[el_freddo]

13 hours ago, nvu said:

It's not recommended to reuse headbolts

That’s an internet fallacy - there’s known tech bulletins posted around that state conditions that head bolts can be reused and when they should be replaced. 

If you know the engine wasn’t cooked badly I’d reuse the head bolts. GD talks about cleaning them up of any scale and running a tap (or modified old head bolt) down each thread to remove any gunk in there. 

As NVU says, if they squeak or squeal while torquing at any stage that head bolt won’t be done to proper speck and you’ll end up with the same issue. I’m not 100% sure on what the required action in this situation is - eg: back off all bolts, replace offending unit then restart the procedure or do that ^ and replace the head gasket you just fitted. 

I hope this helps. 

Cheers 

Bennie

[idosubaru]

17 hours ago, Daskuppler said:

I thought that was the case as well,  it then looked it up and it seems quite common to reuse them along with the FSM not requesting new ones. Seems like there's no real definitive answer 😔

Subaru says reuse them.  So reuse is the correct answer here unless there's compelling evidence otherwise - which there isn't. They're basing this off of way more applications specific data and experts than Fel Pro has. 

Fel-Pro says not to reuse them - but they're a supplier making their bread and butter off of parts and wanting their "kits" to seem "competitive" by also including head bolts.  They have a much higher marketing and financial incentive than subaru. 

Subaru's recommendation wins by a 1,000 miles because there's no compelling reason otherwise. 

Oddly I've seen a few Fel Pro bolt users have quick repeat failures, so I wont' use their bolts and would recommend replacing yours simply so you're not using an inferior quality bolt. Pure speculation on my part but it's unlikely Fel pro has the same, or higher, foundry, machining, finishing, hardening standards as Subaru. But that's pure speculation, i could be wrong. Honestly, it may not be the bolt. It's probably hack jobs who think since they're buying a good gasket and new bolts they don't need to clean the holes or surface well because they're going above and beyond.  I've heard people talk like this before and exude over confidence in their parts selection when their other choices probably need more attention.  It very well may be the over confidence leading to lack of focus on what matters, like cleaning the holes, good torque wrench, and cleaning the heads properly...than the actual bolt.  But still I have no reason to use aftermarket bolts and never will. 

[Daskuppler]

24 minutes ago, idosubaru said:

Subaru says reuse them.  So reuse is the correct answer here unless there's compelling evidence otherwise - which there isn't. They're basing this off of way more applications specific data and experts than Fel Pro has. 

Fel-Pro says not to reuse them - but they're a supplier making their bread and butter off of parts and wanting their "kits" to seem "competitive" by also including head bolts.  They have a much higher marketing and financial incentive than subaru. 

Subaru's recommendation wins by a 1,000 miles because there's no compelling reason otherwise. 

Oddly I've seen a few Fel Pro bolt users have quick repeat failures, so I wont' use their bolts and would recommend replacing yours simply so you're not using an inferior quality bolt. Pure speculation on my part but it's unlikely Fel pro has the same, or higher, foundry, machining, finishing, hardening standards as Subaru. But that's pure speculation, i could be wrong. Honestly, it may not be the bolt. It's probably hack jobs who think since they're buying a good gasket and new bolts they don't need to clean the holes or surface well because they're going above and beyond.  I've heard people talk like this before and exude over confidence in their parts selection when their other choices probably need more attention.  It very well may be the over confidence leading to lack of focus on what matters, like cleaning the holes, good torque wrench, and cleaning the heads properly...than the actual bolt.  But still I have no reason to use aftermarket bolts and never will. 

All good points! I should. Probably just order OEM bolts. This engine has never overheated on the gauge, but it has pushed some coolant. Out of the overflow reservoir.

[nvu]

11 hours ago, el_freddo said:

I’m not 100% sure on what the required action in this situation is - eg: back off all bolts, replace offending unit then restart the procedure or do that ^ and replace the head gasket you just fitted. 

I don't know if there's a definitive procedure for creaking bolts.  I could tell the if a creaking bolt has gone beyond it's yield, it just feels springy when you tighten.  A good bolt can creak too, it's sometimes due to the threads in the block not matching the threads on the bolt.  Good bolts that creak still feel as stiff as ones the didnt creak.  I run them in and out a couple times lightly with a drill and clean/relube the threads.  then try again.

Be aware MLS gaskets deform as part of sealing, and then bite a bit into the aluminum at final torque.  You shouldn't loosen the bolts all the way once you started, if you need to work on a problem bolt, back off the other bolts as little as you need to and always leave them in tension. 

At the torque wrench stage, try and keep everything creak free.  Keep cleaning and relubing if needed.

After that is the 1st 90 degree stage, some likely creak, you need to remember the feel of the good bolts and decide.  It's the last chance to back off and redo.

The second and final 90 deg stage, if it's a bad bolt you will definitely feel it.  Never go more than 180deg total for those two stages, if it felt loose after the two stages... it's overstretched already.

Edited January 19 by nvu

[idosubaru]

5 hours ago, Daskuppler said:

All good points! I should. Probably just order OEM bolts. This engine has never overheated on the gauge, but it has pushed some coolant. Out of the overflow reservoir.

Also, Fel Pro, by nature of being a many-manufacturer supplier, they're going to lean towards more "one-size-fits-all" solutions since they supply parts for most vehicles ever produced.  That doesn't lend itself to making precise recommendations on a specific year/engine. And - they can't control what users will, or won't do with "resused" bolts.  The implication of reusing bolts is the bolts and holes are properly cleaned.  Plenty of aftermarket guys are gonna just gasket slap it without cleaning the bolts at all, and if Fel pro can convince some of it's buyers to replace the bolts they may be better off in the long run than trying to assume or cover warranties for the used car lots that gasket slap with dirty bolt threads.  So I don't necessarily fault Fel Pro or even say they're wrong - they may have reasons for doing so.

[Daskuppler]

I got the last set of Subaru OEM bolts at the local dealership just to be safe!

[idosubaru]

3 minutes ago, nvu said:

I don't know if there's a definitive procedure for creaking bolts.  I could tell the if a creaking bolt has gone beyond it's yield, it just feels springy when you tighten.  A good bolt can creak too, it's sometimes due to the threads in the block not matching the threads on the bolt.  Good bolts that creak still feel as stiff as ones the didnt creak.  I run them in and out a couple times lightly with a drill and clean/relube the threads.  then try again.

 

In a clean room with all the time and tools in the world - clean all the bolt and hole threads. Chase the threads with a tap. Then properly lubricate the bolts. And you might find no creaking. 

In practice, it's not unusual to have some creaking, some good lubrication is the best antidote to limit it. 

Technically that noise is friction which is probably slightly decreasing the clamping force transferred to the head. But I highly doubt it matters unless it's badly hacked. 

[idosubaru]

4 minutes ago, Daskuppler said:

I got the last set of Subaru OEM bolts at the local dealership just to be safe!

Nice. I was about to say even a used set would do but I don't think I have any ATM.

[Daskuppler]

Fun facts after visiting Subaru for head bolts:

Green coolant is discontinued and no longer available.

Valve cover gasket set will run you nearly $200 for two gaskets, 12 grommets, and 4 tube seals....

And... Subaru only guarantees parts for 10 years then they start discontinuing parts.

[idosubaru]

17 minutes ago, Daskuppler said:

Green coolant is discontinued and no longer available.

Valve cover gasket set will run you nearly $200 for two gaskets, 12 grommets, and 4 tube seals....

Good to know.   wow they are proud of those valve cover kits. 

[Daskuppler]

Just now, idosubaru said:

Good to know.   wow they are proud of those valve cover kits. 

Yeah...I thought so as well. $6/grommet. The new blue coolant is $40/gallon premixed as well.

[Daskuppler]

I received part number 11044AA633 from Subaru Parts Deals for my head gaskets. They are steel but don't appear to be triple layered... Is this the right gasket? It's the part number the dealership quoted as superceding all other parts numbers..

[idosubaru]

47 minutes ago, Daskuppler said:

I received part number 11044AA633 from Subaru Parts Deals for my head gaskets. They are steel but don't appear to be triple layered... Is this the right gasket? It's the part number the dealership quoted as superceding all other parts numbers..

yeah that's what they supply for some like those early 00's EJ25's.  the 642 or 770 gaskets are the ones often used instead.   11044AA770.  the coolant ports don't line up the same but it's a benign difference.  Subaru has a decent track record going in their own shops so I wouldn't write off use what they supply.

[Daskuppler]

2 hours ago, idosubaru said:

yeah that's what they supply for some like those early 00's EJ25's.  the 642 or 770 gaskets are the ones often used instead.   11044AA770.  the coolant ports don't line up the same but it's a benign difference.  Subaru has a decent track record going in their own shops so I wouldn't write off use what they supply.

Sounds good, just wanted to make sure.

 

What's the best way to prep the block? Plastic scraper isn't doing anything not is a blue brillo pad... In afraid to use green or a razor blade like I see recommended a lot... These seem to be safe if used intelligently... https://www.amazon.com/3M-18733-Roloc-Bristle-Disc-Grade/dp/B01MSU3PYQ/ref=asc_df_B01MSU3PYQ/?tag=hyprod-20&linkCode=df0&hvadid=167141040944&hvpos=&hvnetw=g&hvrand=14711658656758044995&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9028789&hvtargid=pla-312385222261&psc=1&mcid=c1428ec972263d6c8b5dccd014b22426&gclid=Cj0KCQiAwbitBhDIARIsABfFYIJIDH0VZfVX7PGo1YJ-ylkZgNR2p5JtUto48s8sSAk59RwD6djxLkQaAimuEALw_wcB

 

Edited January 23 by Daskuppler

[idosubaru]

On 1/22/2024 at 6:25 PM, Daskuppler said:

Sounds good, just wanted to make sure.

 

What's the best way to prep the block? Plastic scraper isn't doing anything not is a blue brillo pad... In afraid to use green or a razor blade like I see recommended a lot... These seem to be safe if used intelligently... https://www.amazon.com/3M-18733-Roloc-Bristle-Disc-Grade/dp/B01MSU3PYQ/ref=asc_df_B01MSU3PYQ/?tag=hyprod-20&linkCode=df0&hvadid=167141040944&hvpos=&hvnetw=g&hvrand=14711658656758044995&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9028789&hvtargid=pla-312385222261&psc=1&mcid=c1428ec972263d6c8b5dccd014b22426&gclid=Cj0KCQiAwbitBhDIARIsABfFYIJIDH0VZfVX7PGo1YJ-ylkZgNR2p5JtUto48s8sSAk59RwD6djxLkQaAimuEALw_wcB

 

Yes, if that’s the white ones that’s exactly what to use on the block.

Im not sure of the current “consensus” on EJ25 headgaskets, but I’d be tempted to get the multi layered ones. But, as said before, subaru uses them. 

Id love to know the technical reasons for single layer on some and multi layer on others. 

good luck getting it done.

[Daskuppler]

31 minutes ago, idosubaru said:

Yes, if that’s the white ones that’s exactly what to use on the block.

Im not sure of the current “consensus” on EJ25 headgaskets, but I’d be tempted to get the multi layered ones. But, as said before, subaru uses them. 

Id love to know the technical reasons for single layer on some and multi layer on others. 

good luck getting it done.

The block cleaned up in about 5 minutes with those wheels... That was fantastic! Heads are on, I'll finish assembly today and start it up.

 

Last time I did this I had an old school needle style torque wrench... it's amazing how much easier and quicker it torques with a Snap On digital techangle haha.

Final torque was consistently about 80 ft. Lbs on outter bolts and about 85 in the middle