Blown Headgasket?

sLcREX

sLcREX

Formerly Maldito X
Location
Utah
About two weeks back my 4Runner started over heating, getting maybe 3/4 of the way up the gauge on temps, or just under the top white line before entering the red zone. I replaced the antifreeze and thermostat thinking that might be it, but it kept doing it. The problem just continued to get worse, where it would get hot on shorter distances than before.

3 days ago coming home from work it got really hot to where it did reach the red mark on the temp gauge just as I pulled into my driveway. I shut it off and popped the hood and I could hear the water boiling in the reserve tank. During this whole time I checked the antifreeze level when it was cool and the radiator always seemed to be low on antifeeze. I didnt drive it again until today. And it had not been smoking out the exhaust.

So today I took off the radiator and washed it out from both ends with a hose and it was looking clean enough in there and flowing. So I took off the thermostat and I hooked up the hose from the top end and let water run through the motor to exit out the bottom hose and then did the same thing from the bottom to the top to make sure there wasnt any silicone or other garbage that could've been plugging up the flow. Once I did that I put in another new thermostat in case the first replacement was no good and I topped off the fluids and started it up again.

When I started it, it had a horrible time starting up, it had a very rough idle at about 500 rpm and when I gave it gas it would bog alot before accelerating. It was puffing white smoke and only got worse as I kept it on longer, when I went out back the exhaust smoke smelled like burnt sugar or something smelly sweet so I'm guessing water/antifreeze.

When I was running water through the hoses is it possible something got messed up from the pressure? I took off the intake tube when I removed the radiator and I unplugged that small tube that goes to that jug looking thing that is next to the motor, I put a bag over the throttle body but I forgot to plug the jug, I think it's for emissions and recirculating the engine's pressure, could water have gotten into that causing this problem?

I checked my antifreeze and oil and neither are mixed with the other, I heard there's a headgasket sealant that you can run on the car somehow and it can plug up the headgasket if there is a leak somewhere.

Sorry for the long post, I just wanted to be detailed in how this all came about to see if I can get any ideas based off the diagnosis if it is in fact my headgasket or if I just screwed up something small?
 
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Yeah I thought that could be it too. It wasn't smoking yet when I came home the last time, would it have warped once it cooled down, right? Aside from pulling the head is there another way I could check this?
 
You can run a compression test. They also make this chemical that you add to antifreeze in a bottle, kit comes with a big turkey baster type thing. The antifreeze will react and change colors if it is contaminated. Since you changed the anifreeze, it may not be accurate with the short amount of run time. I am not sure how quickly after a head gasket leak that it will work.

http://www.arrowheadradiator.com/head_gasket_or_combustion_leak_test.htm

You can also use a pressure tester on your radiatior. Although this is not an exact answer as to where the leak is. If your system is loosing pressure and you do not see any leaks then I would assume it is internal. Becareful with this though as you will be pushing coolant into your cylinder. If you try to start it you could bend a rod. If you were to try this method I would remove all the plugs, run the pressure test, then turn it over to see if water shoots out some where.
 
The day before I last drove it I ran a compression tests and all 4 cylinders were at 100, so that's a good idea, I'll check it again and if it's changed then that's probably what my problem is. I need to get my truck back alive and healthy before the cold weather comes in.
 
I had a civic back in the day that blew a head gasket due to a cracked head bolt. Took me 3 gaskets to figure out the bolt. Anyways, everytime I blew the gasket it would overheat before and then start spitting out white smoke all the time. That's how I always knew it was blown, white smoke.
 
Has anyone had success with the advertised rebuild kits found in eBay? If I take this engine out to replace the HG, I might do a full rebuild.
 
So I went out and checked my compression, all my cylinders are reporting 120 compression, but I used a different compression tester. While pulling the plugs 3 of the 4 plugs looked fine but the sparkplug in the 1st cylinder closest to the radiator was wet and it was not gasoline. While checking the compression on the motor that same cylinder was spittin out vapor or a fine breeze and an occasional drop of water would fly out.

So it definitely has water, but could it be a warped head or just a bad gasket since the compression is good across all 4 cylinders? I guess I ought to remove the head anyways?
 
Maybe the reason it is overheating is the water pump is going out? If you replace the head gasket make sure you replace the head bolts. They are a one time use item. Make sure you check the head and deck tolerance with a straight edge and feeler gauge. I have the FSM printed out and in PDF if you need the instructions.
 
Yeah, the pump could be going bad too. Another thing I noticed is that when I put on my heater on full blast it does not blow hot....?
 
Thanks for the tip. As a last ditch effor to see if the damage was minimal or severe I went to autozone and bought one of those liquids you pour into the radiator that is supposed to fix headgaskets or cracked heads and I put half the bottle into the radiator and leveled off the antifreeze. I let it run for about 15 mins or more while checking the antifreeze levels and the white smoke started going away. I took it out for a drive around town and it did not overheat anymore and by the time I got home it was no longer smoking at all.

Seems that thing did the trick, I dont know how reliable or safe those are to use. So I am thinking of ordering parts to do a full rebuild in case the motor craps out I will have everything on hand ready to do it if things go wrong. Hopefully this lasts though, and I will check up on it for the next few days to see how it behaves.

Thanks everyone for your input! And feel free to add any more info I might benefit from :)
 
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