here's a video of mine. 250K now and still going. coolant reservoir does need topping off but never had issues
Interesting, that is almost the complete opposite to my issues, the smoke in your case doesn’t appear immediately upon startup and persists for significantly longer than mine…
How cold was the ambient temp? In my video I think it was high 60’s low 70’s.
Dead cold, overnight start. I’m having it towed to a friends shop, where we can do a compression/leak down test. As long as it’s contained to one bank, I can get away with one headgasket right?
Possible, but not a great idea. The way the gaskets fail on these is from slow mechanical friction, as the iron block and aluminum heads warm up they expand at different rates, so each heat cycle gives the HG a little bit of a scrub. And eventually that wears the HG out and it fails. Toyota went through 4(?) different HG styles on them, trying to lengthen this interval, starting with a largely conventional style and ending up with a full MLS (multi layer steel) design by the last few years.
So really, if one side gave out, you're very likely to be close on the other side since it's had the same number of heat cycles. And by the time the engine is far apart enough to get one HG done, you're about 95% of the way to the other HG as well.
When my wife's '96 needed HG's, one side was failed, but the other side had signs of damage on a couple of cylinders where the fire ring had moved a little, but not quite enough to fail yet. It would have gone before long though, if not replaced.
EDIT: Meant to add on - regardless of what various parts sources say - you should replace it with the last version of the HG, the full MLS style. No point in putting one of the earlier style gaskets on, even if they're still being sold. The MLS style gasket will last longest in that situation, pinched between an iron block and an aluminum head, and getting scrubbed a bit on each heat cycle.
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Possible, but not a great idea. The way the gaskets fail on these is from slow mechanical friction, as the iron block and aluminum heads warm up they expand at different rates, so each heat cycle gives the HG a little bit of a scrub. And eventually that wears the HG out and it fails. Toyota went through 4(?) different HG styles on them, trying to lengthen this interval, starting with a largely conventional style and ending up with a full MLS (multi layer steel) design by the last few years.
So really, if one side gave out, you're very likely to be close on the other side since it's had the same number of heat cycles. And by the time the engine is far apart enough to get one HG done, you're about 95% of the way to the other HG as well.
When my wife's '96 needed HG's, one side was failed, but the other side had signs of damage on a couple of cylinders where the fire ring had moved a little, but not quite enough to fail yet. It would have gone before long though, if not replaced.
EDIT: Meant to add on - regardless of what various parts sources say - you should replace it with the last version of the HG, the full MLS style. No point in putting one of the earlier style gaskets on, even if they're still being sold. The MLS style gasket will last longest in that situation, pinched between an iron block and an aluminum head, and getting scrubbed a bit on each heat cycle.
Thanks for the advice! I didn’t realize it was one of those things where replace one might as well replace both. I’m mostly a BMW I6 guy where there’s one headgasket. Anyway I’m absolutely in love with the truck and want to keep it going for another decade at least.
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Last edited by CoCoCo4Runner; 07-06-2021 at 01:20 PM.
I know my one 4 runner has a bad head gasket. It smokes white smoke that lingers like fog when I fire it up. Its poor engine was really beat and I plan to swap its engine and transmission when I fix it.
The white smoke is like a fog machine on that one. I suspect warped heads on my issue.
On mine that smoke never stops.
So some good test especially a leak down test should help you find the location of the leak.
You do have smoke upon startup. It's not a lot, but that initial start in your video does shows some lingering smoke. You most likely have a very small leak that pools up as the engine sits hot overnight. I would start buying the parts now if you intend to keep driving it as that leak will only get larger over time. I do not recommend any sort of head gasket stop leak product as it clogs up the radiator fins as well.
You do have smoke upon startup. It's not a lot, but that initial start in your video does shows some lingering smoke. You most likely have a very small leak that pools up as the engine sits hot overnight. I would start buying the parts now if you intend to keep driving it as that leak will only get larger over time. I do not recommend any sort of head gasket stop leak product as it clogs up the radiator fins as well.
Hypothetically speaking what if a PO already put stop leak into the radiator?
Mine had the same symptoms, but ended up being a cracked head between the valves on cyl #3. Very slow loss of coolant, but nothing external, and smoke on startup that would go away within 5 seconds or so. Pull the spark plugs and look into the cylinder to see if there’s any moisture or if any of the pistons look pressure washed- a good indicator that coolant is seeping into the combustion chamber. Either way, you won’t know if it’s a cracked head until you pull the heads and have them inspected/resurfaced.
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2006 4Runner Sport V8 4WD, Salsa Red (sold)
2004 Tacoma TRD Double Cab 4x4 (sold)
Take off the radiator cap and take a gander down the top of the radiator. If you still see mostly shiny aluminum you are ok. If it looks dirty, rusty or even blocked, replace it. Flashlight helps.
Last year I rebuilt an engine that had been ruined by Blue Devil stop leak. The owner had a head gasket leak in cylinders 5 and 6 so put a bottle in. The product will harden anywhere it comes in contact with air. Problem was, there was air bubbles trapped in the coolant system. Some of it made it into the combustion chamber like it was supposed to and created a quarter size welt inside the chamber. Not so good for the spark plug or the cylinder head. The rest solidified in the cylinder heat passageways completely blocking the coolant passages on the passenger's side head, and in the radiator clogging it up so it couldn't cool off. So it went from just a head gasket leak to severe overheating issues and needed new hoses and radiator.
Last year I rebuilt an engine that had been ruined by Blue Devil stop leak. The owner had a head gasket leak in cylinders 5 and 6 so put a bottle in. The product will harden anywhere it comes in contact with air. Problem was, there was air bubbles trapped in the coolant system. Some of it made it into the combustion chamber like it was supposed to and created a quarter size welt inside the chamber. Not so good for the spark plug or the cylinder head. The rest solidified in the cylinder heat passageways completely blocking the coolant passages on the passenger's side head, and in the radiator clogging it up so it couldn't cool off. So it went from just a head gasket leak to severe overheating issues and needed new hoses and radiator.
Long story short, don't use it. Fix the problem.
Knew I was in for a good answer. I've never used the stuff or known anybody that has, just something I see every time I'm in Napa and the like and always wondered what the deal is. Must be why the same 5 bottles never get moved or picked up
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