Head gasket leak/issue?

824 Views 25 Replies 10 Participants Last post by evsnova74, 2 d ago

PBMunicorn

Discussion Starter · 1 mo ago

So as of the last couple weeks I’ve been noticing on the passenger side head (2004 m6 GTO, 74k miles, bone stock engine/JBA shorties/CAI intake) right where the head meets the block I’ve got this VERY subtle “leak” of coolant right on the corner edge where the corner of the head gasket is visible.

I noticed a couple weeks ago when I popped the hood while the engine was running cuz I had a wire burning up on the headers.

my coolant level is completely fine and has not diminished at all.. no oil in the coolant. No milkshake. Oil looks good. No overheating. Engine runs fantastic.
But everytime I drive the car, when I get home I now check that area on the passenger side head and it’s wet on that same spot. Slightly crusted coolant and just visibly wet. It’s so minute that I’m hoping I needn’t worry, but I worry about every little thing on this car as it means alot to me and I’ve had it since very low miles. I should probably post a pic but you can barely tell what I’m talking about in the pictures I have taken.
I added 4 ac Delco coolant system tabs to the system crushed up in fresh dex.. waterpump is only a couple years old, coolant has been flushed twice since 2020. Still looks relatively new.
Im just wondering if I should take it to a trusted shop and have the heads looked at/address the head gaskets.. or if it’s completely fine and due to a 20 year old aluminum block/aluminum heads with steel GM gaskets?
driver side is fine. Waterpump and surrounding areas are bone dry. And I’ve never heard of a stock LS having head gasket issues. My parents have had 4 or 5 Tahoes and Yukons and Silverado’s none of them have ever leaked coolant at the head gasket.
Looking for some advice of what I should maybe do here or if y’all would end up just having your head gaskets replaced if this happened to you.. (if that’s the case, I’ll probably get the heads worked possibly p&pd and add some performance to it while doing a refresh if the heads have to be pulled). Any thoughts or comments are greatly appreciated.

will post up a pic of necessary.

See less See more

1 - 20 of 26 Posts

Phoenix

· #2 · 1 mo ago

Rent or borrow a coolant pressure tester from the parts store and with the engine off pump it up to the pressure I dicated on the cap on the coolant expansion tank. You may have to purchase an adapter for the expansion tank as it's not a common size in a lot of kits.

Throuly clean the area in question and see if anything leaks out. Also keep an eye on the gauge and make sure it's not losing pressure.

Reactions: 1

PBMunicorn

Discussion Starter · #3 · 1 mo ago

Phoenix said:
Rent or borrow a coolant pressure tester from the parts store and with the engine off pump it up to the pressure I dicated on the cap on the coolant expansion tank. You may have to purchase an adapter for the expansion tank as it's not a common size in a lot of kits.

Throuly clean the area in question and see if anything leaks out. Also keep an eye on the gauge and make sure it's not losing pressure.

Will do. It’s just so subtle that I’m curious if it’s an actual like, leak.. weak spot to worry about or if it’s just a 20 year old engine matter without real cause for immediate concern… obviously no engine should ever leak anything. But just like light oil residue and other engine fluids can secrete insignificantly over time I just don’t want tobe driving in the 100+ degree heat here in CA this summer and have a head gasket fail.

PBMunicorn

Discussion Starter · #4 · 1 mo ago

Automotive tire Line Electrical wiring Gas Auto part

This is as wet as it’s gotten. After using the little tablets it doesn’t seem AS wet, but it is still visibly wet.
No actual visible coolant leaks or drips anywhere. Not losing coolant. Temp is proper. Just unsure of how serious it is or if I should address it

See less See more

vanrah

· #5 · 1 mo ago

Greetings; Any extra moisture coming out the tail pipes?

321Goat

· #6 · 1 mo ago

Could be your water pump gasket starting to fail towards the upper part of the gasket...

PBMunicorn

Discussion Starter · #7 · 14 d ago

321Goat said:
Could be your water pump gasket starting to fail towards the upper part of the gasket...

Nah the waterpump and gaskets are bone dry. It’s not coming from that side the entire water pump and mating surface to the block are bone dry. It’s specifically wet on the edge of the head gasket.
Just like all LSs that I’ve seen, if you look at the passenger side head, under where the casting numbers are (241/243/799 etc) and go down to where the head bolt is, you can see a little tiny corner piece of the head gasket in between the head and block. It’s wet right there on that corner and only there.
There are no other leaks or wet areas anywhere in the engine bay and the driver side is bone dry. Im completely lost as I’ve never seen this or gotten any feedback on what it may be.
All symptoms of head gasket failure I haven’t experienced any. It’s simply just wet.
Haven’t even lost any coolant.

PBMunicorn

Discussion Starter · #8 · 14 d ago

vanrah said:
Greetings; Any extra moisture coming out the tail pipes?

Not anymore than it’s always had since I’ve owned the car (6 years now)

rednari2

· #9 · 14 d ago

Pull the plug. It'll tell you if its leaking.

Reactions: 1

PBMunicorn

Discussion Starter · #10 · 14 d ago

rednari2 said:
Pull the plug. It'll tell you if its leaking.

Freeze plug in the head?

MuhThugga

· #11 · 13 d ago

It is probably the gasket/o-ring for the steam vent. When those dribble, the coolant will run down the block and collect in that location.

Reactions: 1

PBMunicorn

Discussion Starter · #12 · 11 d ago

MuhThugga said:
It is probably the gasket/o-ring for the steam vent. When those dribble, the coolant will run down the block and collect in that location.

This is what a bunch of people have said but the gasket/o ring for the steam port is not wet. I would be able to tell if it was leaking down the block and it’s not. I will try to get some better pics tomorrow after I drive it in the 95° heat and it’s daylight out. It’s strictly wet right on that corner head gasket edge and nowhere else. The valley pan cover is grimey but dry grimey like years of oil mist/gunk. There is no wetness around the steamport vent tube/water pump/etc.
In fact, a solid way to tell its coming trim that corner head gasket edge is that after I added 3-4 ac delco stop leak tabs, the gunky coolant mixture they seem to create (to stop pinhole leaks) was excreting out of that same spot and would sort of create this little inch long line of coolant gunk that when cool you could pick off the block mating surface.
I wish it were the steam port vent or waterpump but it only seems to be wet on that headgasket edge..

I turn on secret menu now everytime I drive. Coolant temps are perfect (190° to 220° depending on outside temps and driving conditions) e fans turn on around 230°. No oil in coolant, oil looks good, etc.

See less See more

MuhThugga

· #13 · 11 d ago

Have you watched the suspect area for bubbles while the engine is up to temp and running?

Sturdy

· #14 · 11 d ago

Just fixed a buddy's failed head gasket. Was the freeze plug behind the PS bracket.

Even with lots of boost or nitrous the head gaskets really don't go on these, would be surprised if that's your problem but I guess anything's possible.

See less See more

PBMunicorn

Discussion Starter · #15 · 10 d ago

MuhThugga said:
Have you watched the suspect area for bubbles while the engine is up to temp and running?

Yea totally. That’s why I’m so baffled. I’ve left the car running for 20 mins while checking that area. I’m gonna try and get a video if I can. It’s just so subtle that even when I sent it to my dad he’s like “I think you’re being paranoid most people wouldn’t even notice that” but the thing is it never did that before. I’ve had the car since 6k miles in 2016 and am currently at 73k miles, do all the maintenance and what not myself.
The car still runs like normal and I popped the hood about a month or so ago (when I first noticed this) to check on a spark plug wire and all of a sudden that’s when I noticed one single drip of coolant, threw in the ac delco tabs and that seems to have helped a bit. But that little corner is just wet and it’s the only thing I can notice.
I’m not too familiar with freeze plugs other than I know what they’re for..
I know there are two freeze plugs on the block right behind the waterpump and then each head I think has one. If the freeze plug was “going bad” in the head, IE rusting or whatever, would that or could that cause such a thing? I’ve tried the search on here but am out of ideas of what to search

See less See more

PBMunicorn

Discussion Starter · #16 · 10 d ago

Sturdy said:
Just fixed a buddy's failed head gasket. Was the freeze plug behind the PS bracket.

View attachment 526701

Even with lots of boost or nitrous the head gaskets really don't go on these, would be surprised if that's your problem but I guess anything's possible.

Yea man that’s what I’ve always said. I’ve been around LSs for years, my parents have had a ton of 5.3s, this is my second LS and I’ve never seen a head gasket go on them on an other wise stock engine. Sorta lost what to do next.
someone mentioned pressure testing or whatever but I’m unsure how that would yield any different result than just having the engine running ..

what worries me is that it’s already 90°+ here in Sacramento, and my car is my daily driver. I try to keep the miles off as much as possible.. but as the summer approaches and it gets to 110°+ outside and I’m sitting in stop and go traffic I’m worried that what’s fine at the moment will have a catastrophic failure at some point while the engine’s trying to keep cool which I don’t want.
If I took it to a reputable shop say like Sac Speed shop or something, what would I even ask them to do? Just diagnose a potential head gasket leak?

HMBLGOAT

· #17 · 10 d ago

Aside from the typical checks(look for bubbles in rad while warming up, check coolant for exhaust gas contamination(for lack of a simpler term), pressure testing just see any seapage while not running, taking the accessories off for further inspection) I’m afraid a shop isn’t gonna do much more.
I also side with your pops. You’re a little paranoid for nuthin as it’s highly unlikely that seapage is gonna turn into a high pressure/volume leak at a stop light.

I suggest keep monitoring & take a chill pill.

Reactions: 1

Sturdy

· #18 · 10 d ago

GF managed to do a head gasket on a little BMW motor (25 years old but only 50,000 miles, German engineering...)

Anyway, with the engine off, if you quickly squeezed the coolant hose and let go, you could hear a slight bubbling / fizzing sound. Took that to identify confirm that it had actually gone, as it was right at the back of the head and just a tiny dribble.

Might be worth a try, get your head in the engine bay and give the coolant hose a good squeeze, might be able to hear something.

The factory coolant temp gauge will stick at 3/8 throughout the entire normal operating range of temperatures (so I think it's ~180 - 220*F). Keep an eye on the needle and things and you're unlikely to have a catastrophic problem if you ask me (which you shouldn't

!)

Reactions: 1

PBMunicorn

Discussion Starter · #19 · 8 d ago

HMBLGOAT said:
Aside from the typical checks(look for bubbles in rad while warming up, check coolant for exhaust gas contamination(for lack of a simpler term), pressure testing just see any seapage while not running, taking the accessories off for further inspection) I’m afraid a shop isn’t gonna do much more.
I also side with your pops. You’re a little paranoid for nuthin as it’s highly unlikely that seapage is gonna turn into a high pressure/volume leak at a stop light.

I suggest keep monitoring & take a chill pill.

haha thanks dude I appreciate it. Yea it’s weird. One day I check, it’s wet. The next day it’s dry looking. Still very strange as this just started to happen after 6 years of owning the car ..
Another thing too, is I’m having this subtle feeling of a rough idle. The analog gage just shows the regular 800rpm idle but if I put it on tacho in the secret menu, it’ll fluctuate from 750–820ish. Not that that seems off, but there’s this ever so slight rough feeling that occurs every few seconds only while idling.
My plugs are like not even at 50k and they’re regular ac delco iridiums.. put them in in 2020 @ around 30 or 40k miles. doubt they’re bad. I know that if I’m losing compression somewhere it can cause that exact feeling.. and I know if there are problems with the head gasket that it can cause low compression.
Guess I should do a compression test next.
im also gonna flush the rad and put a new set of acdelco tabs in. Hoping all is well.
the reason I worrry is I like to drive the car very spirited. I don’t drive like a slow old low performing daily driver camry. I often like to street race and take the car to its 2004 limits which mean the occasional redline and hard downshifts. I just want the engine to be in its most optimal condition for spirited driving and to be okay In the 100° + conditions here in cal. The hoses all need to be changed soon and the coolant was flushed last when I did the waterpump in 20’ or 21’ so I’ll refresh the cooling system and get back to y’all.

See less See more

PBMunicorn

Discussion Starter · #20 · 8 d ago

HMBLGOAT said:
Aside from the typical checks(look for bubbles in rad while warming up, check coolant for exhaust gas contamination(for lack of a simpler term), pressure testing just see any seapage while not running, taking the accessories off for further inspection) I’m afraid a shop isn’t gonna do much more.
I also side with your pops. You’re a little paranoid for nuthin as it’s highly unlikely that seapage is gonna turn into a high pressure/volume leak at a stop light.

I suggest keep monitoring & take a chill pill.

Also

Sturdy said:
GF managed to do a head gasket on a little BMW motor (25 years old but only 50,000 miles, German engineering...)

Anyway, with the engine off, if you quickly squeezed the coolant hose and let go, you could hear a slight bubbling / fizzing sound. Took that to identify confirm that it had actually gone, as it was right at the back of the head and just a tiny dribble.

Might be worth a try, get your head in the engine bay and give the coolant hose a good squeeze, might be able to hear something.

The factory coolant temp gauge will stick at 3/8 throughout the entire normal operating range of temperatures (so I think it's ~180 - 220*F). Keep an eye on the needle and things and you're unlikely to have a catastrophic problem if you ask me (which you shouldn't !)

yea I turn the secret menu on regularly to monitor coolant temps while driving. Everything seems normal otherwise. Stays cool. All gages are normal. It was just weird to spot that leakage after never seeing anything like it before. All my hoses are stock so I need to change those out asap. Shitty thing on the 04s is I don’t think we have a petcock valve on our radiators so we have to do the draining and coolant flush through the bottom hose. I don’t trust any shops anymore after the nightmares I’ve dealt with at numerous shops with this car.
Will have to assess everything myself

1 - 20 of 26 Posts