2002 V70 2.4T misfiring ....Distributor Cap? ( coil on plugs) Topic is solved

[Messerschmitt101]

Hmm, (Abscates punctuation has me concerned) coolant reservoir empty (you then refilled), but you never made mention of receiving the "low coolant, stop safely" message.

You can get a compression tester pretty inexpensively at HF, not super accurate, but just to get an idea if any of your cylinders are scoring better or worse than others. This here might be a noble thing to do, I mean since you're gonna have the coils unscrewed, not that much more work to take a gander at the plugs. And while doing that, just measure compression on the 2 suspect cylinders.

Low PSI on 4/5 could possibly indicate you are leaking psi into the cooling system, or elsewhere. This scenario (head gasket) is typically pretty unlikely though, as Abscate has said, but don't rule it out yet.

You also mentioned several times a "dealer mechanic" .... This was at a Volvo dealership? Or just an auto repair facility? If it was a Volvo dealership, I'd be pretty surprised if the tech used anything BUT Bosch coils & Volvo plugs (which was probably a $6-700 invoice).

Work was done at a volvo dealer. PCV, Cam seal, and spark plugs have all been done at a Volvo dealer after I got the car (yes, I know expensive, and easy to do myself but I am not at a level where I can comfortably do timing systems). When they replaced the spark plugs they ran a compression test on all the cylinders and found them to be good.

I did get the "low coolant, stop safely" message. And then when I did stop it changed to "low coolant, turn engine off" or something like that.

[Messerschmitt101]

Okay, so a little update: I swapped the coils from cylinders 4 and 5.
However, I got the repair invoice from the dealer which I left at work over the weekend, and they said that cylinders #4 and #5 were misfiring and that the coils were OK. The compression was listed as 150+ PSI in all cylinders.

This makes me think that either: The dealer mechanic lied, or there is something more serious going on with this car.

[- Pete -]

I need to apologize. Then I need to go back and edit that last post of mine.

Sorry, the way I worded that was terrible & could be easily misconstrued as me encouraging only taking compression readings from cylinders 4&5. This is not what I meant, sorry for adding confusion & misguidance.

I know what I meant at least

Absolutely take readings from allcylinders, regardless of the quality of the gauge.

You have your numbers from the tech, but if it was me I’d just measure them again when the coils are off.

Swapping coils 4&5 into each other’s holes is what you did? If so, and both were misfiring prior & now after swapping, you’ve been told & have accomplished nothing. Odds are most likely you have a dead coil or two. I’ve never had 2 at the same time. But out of all the coil failures I’ve had it’s most often #5, I’ve had a #4 die as well though.

If the tech simply “ohm’d” the coils this is not a definitive means of declaring a coil good or bad.

Do the tops of the coils have writing/etching on them? Most of the coils I’ve replaced say Slovenia on them I believe.

[Messerschmitt101]

I need to apologize. Then I need to go back and edit that last post of mine.

Sorry, the way I worded that was terrible & could be easily misconstrued as me encouraging only taking compression readings from cylinders 4&5. This is not what I meant, sorry for adding confusion & misguidance.

I know what I meant at least

Absolutely take readings from allcylinders, regardless of the quality of the gauge.

You have your numbers from the tech, but if it was me I’d just measure them again when the coils are off.

Swapping coils 4&5 into each other’s holes is what you did? If so, and both were misfiring prior & now after swapping, you’ve been told & have accomplished nothing. Odds are most likely you have a dead coil or two. I’ve never had 2 at the same time. But out of all the coil failures I’ve had it’s most often #5, I’ve had a #4 die as well though.

If the tech simply “ohm’d” the coils this is not a definitive means of declaring a coil good or bad.

Do the tops of the coils have writing/etching on them? Most of the coils I’ve replaced say Slovenia on them I believe.

I have no idea about how they tested it, all the invoice says is "Checked compression. Compression 150+ PSI in all cylinders".
And what I did is moved the coils from cylinders 4 and 5 into cylinders 1 and 2, as I said above. I am not sure as I didn't look very closely at the coils. I noticed they had Volvo branding on them, but that's about all I remember, I will have a look later tonight when I get off work.

For what it's worth, there is a slight oil leak coming from middle left of the engine (if you are standing at the front of the car, its dripping in the middle left sector of the car, 1/3 of the way to the middle). Not sure if thats indicative of anything, but worth mentioning.

[- Pete -]

Another simple test for when you suspect a bad coil is with the engine running, unplug one coil at a time. If the smoothness of the running engine changes (becomes more choppy) when you unplug a coil, that coil is good. If the smoothness (or choppiness) of the running engine remains the same, that coil is bad.

So in your situation, with the suspected bad coils in #1&2 now, when you unplug them with the engine running, the running smoothness should stay exactly the same.

Also, keeping those coils on #1&2, if you now unplug #4 or 5 it should run dramatically worse, or not at all. I’ve never tried to run one of these on only 3 coils, let alone 2!

If the symptoms follow the coils, the coils are to blame. New coils run about $46 I believe through FCP/IPD. I have seen genuine Volvo coils (sets of 5) for slightly less than that/coil on eBay.

I think you said they did PCV, the oil leak you mentioned sounds like it may possibly be emanating from the vicinity of the PCV black box, or one of its tubes. Get one of those inspection mirrors with the flexible head & telescoping handle. Use that & a flashlight to see where the oil looks like it’s coming from.

Edit, or if they didn’t replace the PCV “nipple” that has the banjo bolt securing it to the underside of the intake manifold, it’s possible the hard plastic tube cracked or broke. Could be a long shot, could be a possibility, could be a lot of things.

One time after a PCV job I did, I seemed to get a small oil leak in roughly the same location you mentioned. A picture of yours would help people help you figure it out.

[Messerschmitt101]

I'll see if I can get a picture, but it may not be until later.
I am not driving the car right now (my NA 850 still has life!), but I should be able to test it after work.
First thing I am going to try is unplugging each coil. Fingers crossed that this is the problem, but with my luck on this vehicle so far....

Fingers crossed. I'll see if I can get a video and some pictures of when I do everything so that you all can see as well.

[Messerschmitt101]

Okay, I made a marvelous meal for the mosquito's tonight, but the car failed (or passed?) the coil test. I removed the coil from cylinder 1 and the idle immiedietly became rough.
Not a coil problem.

I drove the car around my apartment complex (no plates, so I can't do much else as of yet) which was all of .2 miles and nothing abnormal happened.
I'm getting annoyed enough I may just try to sell it and find another one.
What kills me though is that I have the full maintenance history for the car so I know most everything that has been done since 2002. Nothing in the history leads me to believe there was any overheat issues (there was a breakdown tow slip, but overheating wasn't circled). Unless the seller deliberately removed one of the records so as to make the car look better than it actually was.

[Messerschmitt101]

I feel it is worth mentioning: when I started the car, there was a lot of exhaust smell coming from the engine bay.
Pretty sure that doesn't happen when I fire my 850 up.

But it's very strong at the front, and not nearly as strong at the rear. Could this point to the problem?

[- Pete -]

It’s awful early to throw in the towel.

I’d be willing to bet the strong odor (exhaust smell) is unburnt fuel you’re smelling. That, plus the cat beginning to get gooped up on the proximal end of its honeycombed face makes for a nice aromatic experience.

[abscate]

If this is a new to you car the history is unknown. Misfiring will make exhaust smell all around the car, yes.

That’s a nice model year to keep if you can get your purchase bugs worked out. Give It some time.