First 4g63 build. Head gasket issues?

gadams · May 20, 2019

Hello everyone,

I built my first DSM over the winter, was a pretty good experience overall. Currently runs and drives (don't have tags yet so it hasn't gone far) But I'm facing an issue with my cooling system that is leading me to believe I'm having head gasket troubles. When I built the motor I had both the head and the block machined + I checked to make sure the deck was flat before installing the head gasket. I used a Cometic head gasket (86mm bore) and ARP head studs. I was doing a lot of reading online about what the right torque spec was. What I ended up doing was following the FSM and torqued the nuts to 75 ft/lbs in 3 steps and then 90* turn past that. In the specified torque pattern.

As mentioned before the engine appears to run pretty good (I don't know these motors very well so maybe I'm wrong) it makes plenty of power to move it around, doesn't seem to be misfiring, no codes etc.

The issue I'm facing is upon reaching operating temperature the cooling system begins to overflow significantly, Almost filled up my big spill-free coolant funnel before I shut off the motor, when I shut it off the system bubbles a ton then drains down. Furthermore, as the engine warms up I begin to see some white smoke coming from the tailpipe, this becomes more and more prevalent the hotter the engine gets. I've heard its normal for a freshly rebuilt 4g63 to smoke a bit while being broken in so initially I didn't pay it much mind but I'm wondering if its actually a part of the issue.

I've done a combustion gas test on the car and it does appear some combustion gasses are getting into the coolant its not turning a bright yellow, it stays mostly blue with a small bit of yellow seeping in every little while. (Do with this information what you will)

I've bled the cooling system pretty extensively (at least until it starts overflowing like crazy at op temp) so I don't think there is air in the system causing this.

I'm about this close to pulling the head off the motor and checking out the head gasket but if anyone has some pointers/experience they want to share I'd really be appreciative. If you want more info, pictures, etc. Let me know and I'll make it happen. I'm so close to having this car finished I'm really excited just want to drive the damn thing.

DSMPT · May 20, 2019

There are some possibilities. Head gasket sealing issue, bad thermostat, bad water pump or coolant leak etc. But it sounds like a head gasket sealing issue to me.
Do a leakdown/compression test. A leakdown test will tell you if the issue is the head gasket sealing. If it is not easy to do it then remove the radiator cap and put that spill free coolant funnel instead, like you mentioned. pour coolant a bit more to raise the level to check and start the engine. if you see a lot of tiny bubbles (really tiny. like beer bubbles, become creamy look) endlessly come up to the funnel then the head gasket is not sealing.
And as you said you see smoke "more and more prevalent the hotter the engine gets". This could be vapor, one of typical symptoms of blown head gasket. If this is vapor, then let the engine cool down and after the engine gets cold, remove all spark plugs and check inside of cylinders with a flashlight. If you see some liquid on piston top, that is probably coolant. you have a head gasket sealing issue.

donniekak · May 20, 2019

Those head studs are ruined for one...

Why wouldn’t you torque them to the figure arp gives you?

The manual doesn’t give that torque either. For 7-bolt Dsm it’s 14.5lb/ft +90* +90*

For 6-bolt it’s 69lb/ft

weasel1G · May 20, 2019

Pressurize the cylinders through the spark plug hole and listen/watch for bubbles in the coolant.

ThunderChild · May 20, 2019

donniekak said:
Those head studs are ruined for one...

Why wouldn’t you torque them to the figure arp gives you?

The manual doesn’t give that torque either. For 7-bolt Dsm it’s 14.5lb/ft +90* +90*

For 6-bolt it’s 69lb/ft

Agreed, idk where you got that method, you need to use ARP's installation specs. Prolly way over tq'd and wasted the gasket or distorted the sealing surfaces.

gadams · May 20, 2019

Looking back I honestly don't even know if the method I described is accurate to what I did :banghead:

I checked the torque on the studs as is and they all sit at about 80 ft/lbs from what I'm reading that doesn't seem far off from where it should be no? Does anyone know ARPs specs off the top of their head. I'll definitely try the leakdown test next see where that gets me.

ThunderChild · May 21, 2019

Problem is they may already be stretched or the head/block may have yielded a certain amount. Only thing I can think to do is pull the head and see what's going on in there.
A leakdown is a a good idea but at this point it seems pretty self explanatory given the symptoms.

gadams · May 21, 2019

You're right. Well guess the head is coming off. At this point does anyone object to me reusing the studs? I'll measure them before reinstallation, If its iffy I'll get new ones but given the torque they were at when I checked them the other day I have a hard time believing they're trashed. Obviously going to put a new gasket on.

gadams · May 29, 2019

Well I replaced the head gasket last night to find no change. This result is very discouraging. I will probably do a leakdown test but I find it hard to believe that I'd put two gaskets on and find exactly the same results. I'd like to believe the culprit is something other than the head gasket. Any ideas where to go next diagnosing this?

gadams · Jun 1, 2019

Just in case anyone is still reading this, I did a leakdown test, all 4 cylinders measured good at about 20% leakdown. This is a big relief and a note to anyone in a similar situation always do tests like this before replacing the head gasket. It more than likely was fine to begin with. Next step it to put a new thermostat and radiator cap on and try to bleed again.

Dreams Realized · Jun 2, 2019

donniekak said:
Those head studs are ruined for one...

Why wouldn’t you torque them to the figure arp gives you?

The manual doesn’t give that torque either. For 7-bolt Dsm it’s 14.5lb/ft +90* +90*

For 6-bolt it’s 69lb/ft

Woah woah woah woah.... you nearly gave me a heart attack.... Where did you get those torque specs from?

According to the OFFICIAL ARP instruction booklet the head studs should be torqued to 80 ft/lbs (preferably done in a 3-step fashion with a proper torque wrench) [90ft/lbs for 93' and under]:
https://cdn.arp-bolts.com/instructions/207-4203.pdf

Just a nerdy tidbit to de-escalate the situation, lb/ft refers to a vector as in the movement of a vehicle whereas ft/lbs refers to torque in working force-

OP make sure you torque your head properly- use the ARP instructions- if you have the L19 head studs or custom aged ones the torque specs will be higher. I have the L19's and if I remember correctly I had to torque them to either 95 or 100 ft/lbs. Also I am still a novice at cars so take my advice with a grain of salt, I don't think you have a head issue I think you have an issue with your water pump or somewhere in the coolant system, check thermostat and water pump first. When coolant is overflowing my first thought is not that it is leaking into the engine but that it isn't circulating enough

donniekak · Jun 2, 2019

I gave stock specs. I know the arp specs. My point was he didn’t use arp specs or stock specs. So what spec was he using?

Dreams Realized · Jun 2, 2019

14.5 ft/lbs sounds off to me.. I could hand tighten to that spec, perhaps a typo? But you are right, he under-torqued his studs, they should be tightened to ARP specs.

donniekak · Jun 2, 2019

Dreams Realized said:
14.5 ft/lbs sounds off to me.. I could hand tighten to that spec, perhaps a typo? But you are right, he under-torqued his studs, they should be tightened to ARP specs.

The manual for stock 2g 7-bolts calls for 14.5ft/lbs plus a 90 degree turn plus another 90 degree turn.

gadams · Jun 11, 2019

Just figured I'd update this thread because I believe I have settled my issue. It looks like I torqued my head just fine the first go around and the second time too. I ended up bleeding my cooling system using an AirLift tool and then just running it with the cap on. Sure enough it maintains operating temperature. If I run the engine with the cap off with the funnel on it still overflows when it gets hot. Turns out this is due to the coolant beginning to boil at about 190F This is normal for modern vehicles to behave this way (although this is a first for me) and the reason why the coolant system is pressurized. The rising coolant level was due to the water expanding and creating steam as it started to boil.

As for my smoke, 99% sure its oil being burned off from the rebuild. I'm going to drive it 100 miles or so and expect it to go away.

Anyone who maybe finds this thread later on. Be sure to bleed the cooling system well. If you have access to one use and Airlift or similar to verify you get all the air out before filling with coolant and DON'T try to bleed by running it a long time with the cap off. Just run for maybe 2-4 minutes till you stop seeing air bubbles.. Thanks to everyone for the help and advice. Looking forward to becoming a more involved member of this cool community.

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