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Spark Plug #3 keeps fouling- '87 22R

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Old 08-12-2015, 06:42 PM
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Spark Plug #3 keeps fouling- '87 22R

Hello Yotatech!

I have been doing some needed up keep/ mini-restoration on my 1987 Pickup 2wd 22R.

Today I am finishing up an almost complete brake system overhaul on my truck (all original but somewhat mechanically neglected ) and decided to take a look at my spark plugs again. I found that the spark plug on cylinder # 3 has fouled up again with what looks like oil and smells like oil. These spark plugs were changed out about 3,000 miles ago as I discovered the #3 spark plug's outer electrode was in very sad shape (Last pic, NGK). I will post pictures below. The first four pictures are the plugs that I just removed (OEM DENSO).

Here is a little back story:

The truck has been in the family since new. This truck was driven by my great grandmother and only has 75,000 original miles and is my first and only vehicle. The oil has been changed every 3000-4000 miles.

The truck did overheat about 5 years ago when my dad was driving and blew a head gasket. The head gasket was replaced at a local shop and the head was pressure tested at the time.

The truck burns about 1.5-2 quarts of oil every 3000 miles now where it didn't used to 3 years ago. I occasionally see blue smoke on startup.

Even though this may not help, dry compression is right around 175 psi for all cylinders.

Now to my question: In your experience, what is the most likely cause for the oil burning and the fouled plug? I know I will not get a definite answer until I tear it part and I did google it but I am looking for a direction to go.

Thanks for any input!

-Jake













Old Spark plug from cylinder #3:





My Truck:

Old 08-12-2015, 11:32 PM
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Red face

Did this sit for some time before you started driving it??

It can only be either the oil ring is rusted and not sealing like it should allowing oil into the combustion chamber.

Valve seals and guides worn allowing oil to enter from the head.

If your not planning to pull things apart a hotter plug in #3 might be a temporary fix till you decide what to do
Old 08-13-2015, 10:01 AM
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Thanks wyoming9!

The truck hasn't sat for long periods of time but there were a couple years where it only got driven about once a month. I would like to fix this sooner rather than later so I don't have to worry about it.
Old 09-13-2015, 01:46 PM
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I know this is about a month old but felt like chiming in since I just dealt with this recently.
Start with the easy things first. I have a 87 with a 22r too. When I took the engine apart I found that my oil rings were clogged up with goopy build up and my second rings were all recessed in the piston.
My first easy suggestion is to get some seafoam and add about a quart to your fuel but before you start it dump some into cyl # 3 and let it sit for a while. After some running much of the built up oil should be gone. Lots of smoke out of the exhaust so don't be surprised. Also replace that plug again. You may get lucky and the valves will re-seat and everything will be good.
Run it for a while and check the plug. If its all oiled up then significant oil is getting in there somehow, this isn't from long years of build up. Either the rings have failed/very worn or the seals are worn out and leaking into the cylinder. There is only a 50/50 chance of replacing the valve seals without removing the head. When you take the headbolts off the seal may be broke, many times it won't and you will be able to replace at least the seals on that cylinder. This would be the easiest thing but if you are burning 2qts per three thousand miles it really does sound like the rings. Try the easy things before you feel compelled to take the engine out and apart.
I've replaced the valve seals on a few ohc engines but none of them have a rocker arm assembly that has to be removed to get to the valves.
Let us know how this works out.
Old 10-25-2015, 02:15 PM
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Hello,

Just a quick update.

I just finished a routine oil change (regular 10w-30 with Toyota oil filter) and have not done anything else to the engine yet. Up until the last two months the truck was almost always driven in city traffic. I have been driving on the highways more and the consumption seems to be less. It also seems to run smoother and have more power after highway driving too. I will be monitoring how much oil I add between now and my next oil change and will pull the spark plug then to see how things are looking.

I will also test the catalytic converter with an infrared thermometer to make sure it is not clogged (or at least working properly) since it is still the original converter and to make sure I have good flow through the exhaust.

(BTW no more "yellow wall" tires!!)

Last edited by old87yota; 10-25-2015 at 02:17 PM.
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