1GRFE - Cylinder 6 - Possible HG Issue

Let's have a discussion about cylinder 6 on a late year manufactured, 2006 Taco. I am experiencing zero cooling issues, zero coolant or oil loss, and no loss of power. However, I did some routine maintenance this weekend and changed my spark plugs and plug number 6 was damp to the touch and smelled sweet. I have a head gasket tester kit on order (the kind with the blue liquid in the tester that you don't want to turn yellow) and it should be here tomorrow, is there a possibility of anything else causing this issue only at this cylinder?

Forgot to mention, 198K mile.

 

A compression test may also help out here.

 

I think a leak down test more than a compression test maybe.

 

Unless it is leaking somewhere, most likely you are burning coolant. Leaks can go unnoticed especially when it is a small leak from the water pump or a radiator. A small leak from the water pump can go unnoticed due to the fan pulley covering the weep hole. Same thing with the radiator as the shroud covers most of the side. I have observed both of these issues on my V6. My water pump leak was only found when I replaced my head gaskets several years ago.

Regarding the head gasket leak, my truck had no running issues other than mysterious coolant loss. That blue liquid exhaust gas tester did not work for me. Maybe it is due to the engine design or simply since the head gasket leak was very small. I only confirmed the head gaskets were leaking by pressurizing the cooling system and then inserting a borescope into cylinder #6 and #4. A single drip of coolant was observed every 5 or 10 seconds.

 

crap, sounds like the path to go is probably schedule for an investigation after i try this exhaust gas tester.

i can't think what else would make just that one plug damp. I'm trying to be optimistic, but i'm also being realistic about the situation.

 

Typically the first sign on these is a cold start misfire that goes away after a few seconds and/or gurgling noise in the heater core, they have to get pretty bad before they will show up on the color changing fluid.

If you have no coolant loss or other symptoms I wouldn't be too worried.

If your worried the quickest and easiest test is pressurizing the cooling system with the engine cold, removing the plug from the suspect cylinder, and looking in it with a borescope for coolant leaking in.

This is a pretty severe case but it demonstrates what I'm talking about.
https://youtu.be/Rurhi-IGaiU?si=vACg5JKgHLohlrnG

 

This sounds like a good idea, i'll check out this video to see what this would look like for the Taco.

 

how in the world did you get the liquid tester to work? The fitting it comes with is huge, way to big for these radiators.

 

It’s been a long time since I used one, but I don’t recall having a problem. I believe I rented one from Autozone. It had a big rubber cone which wedged into the opening. Even if you get a “good” result with this test, you still will be looking so I wouldn’t spend too much time on it.

 

That's a good point. I'll mess with it a bit since i ordered it before i posted this thread, but i won't lose my mind over it.

 

Actually, i wonder if i can put this in the reservoir bottle and still have a complete test. It would fit in there no problem.

I'm using the RELD kit, the rubber piece is quite large.

 

the dye tester may work, but he best any ony way is to do a leakdown test to be sure. it was the only way i found it. I had 2 engines head gaskets fail between cylinders at the cooling port before i went with cometic gaskets

 

Having only one plug damp, and specifically on cylinder number 6, makes complete sense for a Head Gasket leak. This is the cylinder that always leaks on the first couple years of 2nd gen Tacomas and 4th gen 4runners.

 

You can rent a coolant pressure tester for free from a parts store and get a borescope for around $100 or less from Amazon (30 day free returns for prime members ) and do this. I just did this for my 08 2tr. Kept the borescope however.
https://www.youtube.com/watch?v=CiwyPgrlbEM

 

yup, that is exactly what is on task for this weekend. i ordered an articulating bore scope because mine is just too hard to manipulate for this task and i picked up the radiator pressurizing kit. I plan to do a compression test to determine my method of repair. I"m pretty sold on fixing this. I'm not a huge fan of any of the new models (or an $8-900 a month vehicle payment), and i'd rather fix this truck that i have 150K miles of history with vs starting all over with a new to me second gen and then have to start the history process all over again.

 

Alright, got some updates. And I had my cylinders all mixed up, the plug that i had pulled out that was damp was cylinder 5.

Anyways, pulled plugs 1, 3 and 5 for my borescope test. When I pulled plugs 3 and 5, neither looked horrible and neither had any indications of moisture. they all looked basically the same.

Here is the plug from the offending cylinder #5



Cylinder 1, a bit cruddy but we are really close to 200K miles here



Cylinder 3, same.
This one was right below the head, there wasnt a lot of room to maneuver the camera.



Cylinder 5. I was initially worried that the top of the piston was clean, like squeaky clean, then i adjusted the light on the scope and realized it was making it look odd.



I panned around this cylinder for about 20 minutes with the radiator pressurized and didnt see a thing that looked out of place.

Here's all the plugs, these have between 4-500 miles on them.







So, after not seeing anything looking incredibly detrimental, I moved to conducting a compression test. I followed this from a previous post:



And the results, everything was either 180 or 182. So after seeing nice even compression, i'm just going to keep running the truck as is until something happens. Nothing I found seems to be horribly off.

 

Looks good to me, send it and keep an eye on the oil and coolant.