LB4Runner05
New member
Did you change the long life anti freeze at 100K miles? Plugs?
Another Blown Head Gasket
- Thread starter nated05
- Start date
Did you change the long life anti freeze at 100K miles? Plugs?
CookieRoe
Senior Member
I know what you are alluding to (taking preventive measures so it doesn't happen). I think the consensus is that it WON'T HURT to perform all those service items, but it isn't necessarily the REASON why the HG go. They "go" because they are poorly designed.
I thought I saw somewhere that mostly 03-04's go. I haven't seen MANY 05's+ HG fail. I could be wrong (I can't find that thread now........)
good read:
http://www.toyota-4runner.org/4th-gen-t4rs/149415-preventing-blown-head-gaskets-v6.html#post1466167
Moral: Just drive you truck and enjoy it!
I'm not convinced there is a widespread HG problem on the 4th gen V6. Earlier V6s, well, that's a different story................
BlackWorksInc
New member
I mentioned this in the other thread, all we really know is that potentionally all Single VVTi 1GR-FE motors (because we don't know when the new HG design was implemented and when the new HG was used on production motors) have the "faulty" HG installed; but only MAYBE 5~10% are actually failing. But when they do fail, they consistently fail in the Number 6 Cylinder, and often on a small bridge section of the gasket. I'd love to have members who have had the HG replaced post pictures of both the old damaged HG and the new superseded HG design for us to review. If we had enough pictures, we could see WHERE exactly they are failing and try to backwards engineer HOW they are failing. Because obviously only these small sub-section of vehicles are failing and there must be some sort of "tipping point" that burns out this section we're seeing cause the failures.
In my experience, on a stockish engine with fairly low cylinder pressures (i.e. a 1GR definitely fits in this category), they usually fail due to the head surface warping. THEN the gasket is not compressed and it's on borrowed time. The long term failure mode they seem to go through supports this, as the head tweaks enough to start a problem (probably well before you get the cold misfires), then it slowly gets worse.
The fact that you get misfires when cold kinda lends itself to a gasket that leaks when the head twists as well. It likely experiences more warping as it cools off after a drive, then the still under pressure cooling system slowly leaks in the cylinder. Crank it up, and lots of misfires until you burn off the water. Leaks like this also usually won't show up on HC tests in the coolant.
The fact that you get misfires when cold kinda lends itself to a gasket that leaks when the head twists as well. It likely experiences more warping as it cools off after a drive, then the still under pressure cooling system slowly leaks in the cylinder. Crank it up, and lots of misfires until you burn off the water. Leaks like this also usually won't show up on HC tests in the coolant.
Hi RPS13,
quick couple questions to clarify things for me.
Regarding what I've highlighted in your first paragraph in bold, are you saying that the 1GR's are low compression reading engines to begin with? Or are you referring to the low compression readings from the OP after the symptoms began?
Also, as highlighted in your second paragraph.. are you concluding that the 1GR cyl heads begin to warp under normal operating conditions? Or are you saying it happens after an overheating condition first happens?
Thanks.
Interesting suggestion on what is occuring but what do you know that supports this theory? Are the folks with head gasket problems finding there heads are warped and need redecking before reinstall?
My experience (with subaru engines) is that when everyone starting switching to alum blocks with alum heads they didn't think about mismatching thermal growth that utimatly wears out the gasket under the thermal fight at the block and head interface. Subaru switched from a closed deck motor to an open deck in the late 90s as a means to reducing casting costs and casting time. What followed is the block now heats up faster than the head in certain spots and physically wears the gasket out and the seal fails over time. Ironiclly Subarus leak an oily coolant brown mix on to the exhaust as the first sign of gasket failure. Nearlly all the failures happen on the thinest head to block gasket area far away from the cylinder. The first fix was a coolant sealent and then they updated the gaskets with more robust sealing material. When I did a few HG replacements I used a flexible gasket sealer with the new gasket to futher decrease the likely hood of failure.
I'm not sure if the head gaskets problems that have occured on the v6 are due to the warping that you descibe or something similar to what occured on the Subaru motors.
LeF-T_4X4 if I had to speculate he is saying our motors being Naturally asporated are low compression and his experience (judging by his signature) is with higher compression engines (turbo charged) where the failure tend to occur from the cylinder into the coolant not coolant into cylinder. Force induction engine tend to have better gaskets and higher clamping forces applied to the gasket due to the large internal cylinder pressures.
Possibly, but I am confused with part of your response.. from my experience with Honda motors the turbo guys were all running low compression setups (8:1) and the n/a guys were always higher (sometimes much higher...10+:1... I personally ran an 11.1:1).
True-true. I see what you're saying.
Upon further review, RPS13 did say "lower cylinder pressures" ...not low compression. derp! :doh:
Low cylinder pressure - as in an NA, fairly low revving, not really high volumetric efficiency engine. The 1GR is 10:1, which is high for regular pump gas (i.e. 87 octane), but it's pretty sedate compared to higher performance engines.
As for supporting evidence, the symptoms match it. If it was a substandard gasket on sealing combustion pressure, you'd pressurize the cooling system and blow coolant everywhere under the hood (BMWs are famous for this with hard usage - but the I6 heads typically warp more with high temp relative to the iron block, so it's under hard usage, not on cool down). Losing coolant tends to point towards something happening while the engine isn't operating.
I also believe a few people who had a HG job done had the heads resurfaced, and they were out of tolerance for flatness. So something is causing the heads to warp.
What you describe on Subarus is exactly what I'm describing. Differential thermal expansion causing gasket failure. The leaking area is going to be the spot that falls below the minimum clamping pressure to form a seal with that gasket.
A head having a permanent warp means nothing other than the strain in some part of it exceeded approximately 0.2% so that it plastically deformed. You can have the same phenomenon happen and not have a permanent warp. But usually a gasket problem has moved things around quite a bit, so there is usually some out of flatness condition.
It's just a working theory, and it's worth exactly what you paid for it. :humble:
Kevin82647
New member
5th gen head gasket blown
SO Im driving a 5th gen sr5 4runner, 2010 with 135k. I cycled the antifreeze at 100k using the special pink stuff, performed the dealer recommended 90k maintanence, and I do oil and fluids every 10k using premium synthetics. Im the second owner and the original owner had all recommended services performed at the Toyota dealership in Nevada up until he sold it at 112k (I bought it at 113k).
ANYWAYS, I'm driving up I70 and suddenly my thermostat drops to zero. I pulled over immediately and the car shut off. Turns out the head gasket in the right cylinder bank blew out, causing coolant to explode through the valve cover gasket on the upper cylinder head.
Is this a somewhat common issue? I have shops telling me to swap engines for quotes around 6 grand and the dealership said it wont cover anything under warranty. Has there been any recall on this?
SO Im driving a 5th gen sr5 4runner, 2010 with 135k. I cycled the antifreeze at 100k using the special pink stuff, performed the dealer recommended 90k maintanence, and I do oil and fluids every 10k using premium synthetics. Im the second owner and the original owner had all recommended services performed at the Toyota dealership in Nevada up until he sold it at 112k (I bought it at 113k).
ANYWAYS, I'm driving up I70 and suddenly my thermostat drops to zero. I pulled over immediately and the car shut off. Turns out the head gasket in the right cylinder bank blew out, causing coolant to explode through the valve cover gasket on the upper cylinder head.
Is this a somewhat common issue? I have shops telling me to swap engines for quotes around 6 grand and the dealership said it wont cover anything under warranty. Has there been any recall on this?
