Engine knocking after spark plug change

Hey guys. I recently swapped all the spark plugs on my 2001 V8 4.7. The originals were down to the porcelain, so I didn't really have a choice.

I changed my oil while I was at it because my hands were already dirty. I've changed it "a thousand" times myself without issue.

I used platinum NGK's pre-gapped at 0.033 I believe. I have developed a mild knock upon cold-cold starting (about 20 degrees or less) that I never had before. The sound goes away as soon as it warms up. I am not getting any codes, check engine light is off and it seems to run great after it has warmed up.

It almost sounds like I am running too lean, that's just what it sounds like, mixture is probably fine. Sounds like a top-end knock, not a bottom end deep knock that would indicate lack of oil. Oil pressure gauge reads normal.

I've heard the gap is either 0.033 or 0.044 depending on the plug type, so I am reasonably confident that the gap is not the issue. The coils and boots looked fine, no cracks or abnormalities. The only variable besides the new plugs is, I used some syn-blend oil I had lying around in my garage, I usually just use dino oil. I used the same weight though.

I'm stumped. Any suggestions?

 

Interesting. I assume you checked oil level after running the truck for a few minutes post oil change?

 

I did. One thing that is very strange, my truck usually requires 7 1/4 quarts, not the 6.5 recommended in the manual (to show the correct level on the dip stick). This time, 6.5 brought it up to the full mark I park it in the same place when I change my oil, and I used the same type of filter I always use Fram TG3614. I've checked it several times since changing it, so I am confident the oil level is okay, at least based on the dip stick,.

 

Checking the oil when it’s hot? Synthetic oil expands and contracts more than conventional oil with temperature change, but don’t know if it’s enough to notice.

 

Did you get the plugs at fleabay or the 'zon? Might just be bogus plugs.

 

Good question.

https://www.tundras.com/threads/counterfeit-denso-spark-plugs.64225/

 

Since I owned my 02 (5-6 years) it knocks as well on a cold start when its that cold and goes away when it warms up. Almost sounds like a rod knock. I cant remember where I read it but a guy changed out his fuel dampener and he said that cured it.

 

If you think you're running lean, wouldn't that show up on thr OBD2 reader?

 

I always confirm gap before installing even though they are pre-gapped. Also, are you sure you got them all seated properly? Maybe a little chunk of rust or debris got under one of the spark plug washers?

 

How many miles total?

maybe with new plugs you are getting a bit of piston slap on cold start up.

a tad more thrust on power stroke could do it if you are at high miles.

 

I bought them at O'Reilly's. They are NGK's. The packaging looking legitimate and the quality looked pretty good too.

That's exactly what I am experiencing. I guess it does sound like rod knock.

I'm at 155,000, so it's getting up there. Previous owner went 7500 miles in between oil changes on regular oil, so I imagine the internals are probably not what they could be as far as tolerances. Even though it is only on cold-starts, it is cold in my area for 8 months out of the year. It doesn't sound terrible, but it definitely got my attention the first time I heard it. I'm just hoping to get 300,000 out of it. I can live with it as long as it is not tearing my engine to pieces.

 

If it was fine the day before you did plugs/oil then started up immediately afterwards (and the ambient temp was close to the same) then I would place my money on debris in one of the spark plug holes or not enough oil.

 

Just sounds like one bad plug. Not a counterfeit issue, just a random bad plug. Any product when you make a million of them will have a few bad ones as expected.

 

What brand and weight oil did you use? It could be its actual cold flow viscosity isn't as good as what you had prior.

 

Any chance there's an issue with the Fram oil filter? Maybe a partial blockage? Not really my choice of brands considering the numerous lawsuits against them.

 

Fram. A four letter word.

 

I would retorque the plugs- if you didn’t use a torque wrench.

On 2nd gen Ford Lightnings, the spark plugs tend to tick right before they launch. This is due to 03 and older have 4 thread heads. The spark plugs can back out and then launch.

This causes a repair to the threads by an insert. The repair is so common on Triton engines that Lock-N-Stich makes an oem repair kit that dealer uses. Helicoils are utter crap.

 

Not a bad idea to check @Jchetty ! Any sign of scorching around the coil pack boots that wasn’t there before should also be a red flag as well.

 

It was actually the first single digit degree day of the season, but it didn't give me any issues last year. I parked at a gas station today, right by the pump so it was completely level and the oil checked out okay immediately after shutting the engine off, and after 5 minutes. I'll pull the plugs tomorrow and check for debris. I used an air compressor to blow the heads out before removing the existing plugs but who knows, I may have dislodged something.

I used 5w-30. I used Castrol syn-blend which is much better than the stuff I usually use. I usually use SuperTech 5w30 dino or whatever is on sale at walmart. Fram has always been my go-to for filters, only because they are cheap, BUT, I haven't heard the greatest things about their orange filters. I watched a youtube video a while back where they cut open several brands of oil filters and the Fram tough guard wasn't great as far as filtration media, however, I would think that since they have the least restrictive element that they would be better for flow.

Thank you all for your suggestions. It is supposed to be warmer tomorrow, so hopefully I can figure something out. I've never used dielectric grease on plugs, but I'll put a thin coat on when I pull the coils. We'll see

 

How cheap is cheap? Toyota's OEM (Denso) filters stomp the living shit out of most aftermarket oil filters, and for my 4.7, part number

$32 90915YZZD3 Toyota Genuine Parts 90915-YZZD3 Oil Filter 1/2 Case (QTY 5)

90915YZZD3, I paid 3.89/per on my last order. I've seen guys get them under $3/filter from other places when sales or deals are going on.

I truly believe the high quality of Toyota's OEM maintenance products and parts are a huge contributor to the engine longevity.

 

I'm almost empty, so I'm going to fill up with some farm fuel tomorrow (91 and no ethanol). If the problem goes away, or lessens, I think it will be a slam dunk that the plugs/coils are the issue.

 

3.89 is a steal! So, yes if they are that cheap, I'll buy a flat of them. I think the Frams are slightly more expensive, maybe 4 and change, but hell yeah I'll go with factory for that price.

 

Get rid of that fram asap! And from supertech! Then pull your plugs and make sure they're gapped correctly and put a dab of dielectric grease on the tip(just the tip). Make sure your coils seat properly, and make sure the connector it seated on it good.

 

Ok I re read your original post.

Piston slap is a possibility at that mileage and being second owner no telling what the maintenance regimen was in reality (unless this was a close friend you trust).

However I would suggest changing the oil filter. I've had bad oil filters with the anti drain valve either missing or defective and it can enable a slight chatter in the bearings on start up.

My 2002 F 150 did this all the dang time if I didn't religiously fill the oil filter prior to starting or pull the crank sensor and spin the engine prior to a fired start.

I had 95k miles on it when I sold it.

Either scenario isn't a break-neck emergency. But swapping a filter real quick to rule it out is easy.

piston slap in general isn't a huge deal either.