Oil on my piston head

Today I changed my spark plugs, wires, and coil packs. The engine has been a little “shaky” since I bought my 1998 Tacoma a few weeks ago. Since I didn’t know how old the plugs were, I figured I’d give it some new ignition parts and see if that helped the shake.

When the plugs came out, they all had oil on the threads. While I had the plugs out, I looked down with a flashlight and every single piston head had black grime on it that looked a little wet.

I had a bad oil leak from the valve cover gasket and the spark plug grommets were all old and hard and brittle too. Those have been replaced, and the leak seems to have stopped.

Is it possible to get oil down past the spark plug to the piston head from a leak like that? I will say that the plugs were not particularly tight when I took them out, so I thought it was at least a possibility.

I’m hoping that it’s not blow by from the piston rings. I’ve done about all the work that I wanna do on this truck for now!

It seems to run better after I got the new parts in. But with all that grime on the piston head, I wonder how long it is before the new plugs are all fouled up.

 

damn i feel like i have seen that truck before, you in florida? or GA?

 

Also you can do a compression test to see if your engine is still in prime. Compression should be between 127-178 psi. this can tell if your internals in the motor is still good to go. But before doing that did you get any cel light?

 

I think the pistons look okay given the view from that little pic through the hole. Used pistons typically have a black carbon coating. If it were actually wet with oil I think your plugs would be wet too (not just the threads) and you would be making some smoke for sure.

 

I’m guessing that the truck was owned by someone in the military based on the Carfax report. It was always registered at a military base for the first 12 years or so of its life. It’s been to Hawaii and California and even says it was imported from England at some point. It settled down in Illinois for the past 9-10 years and I think the green and black paint scheme was applied with house paint (and a brush!) pretty recently. Based on all the damage to the front end and the receipt for a new windshield in the glove box, I’m guessing the previous owner hit a deer and then tried to cover as much as possible to get it sold!

 

Spark plug looks ok to me, little worn but ok

 

No check engine codes from the scanner. One test was incomplete the last time I checked it, but it was fuel related if I recall correctly.

I may have to borrow a compression tester and give that a shot. Since it’s all 4 pistons, I’m hoping it’s unlikely that all the rings are allowing blow by, but you don’t know until you check I guess.

 

Good point. I don’t have any blue smoke from the exhaust.

 

I wouldn't worry about it unless you've got other symptoms. This is what mine looked like at 207k, and it burns no measureable oil