Car runs rough at idle and shakes. At highway speed I don't notice anything unusual. Reader said code P0303 last night and I pulled the plugs from cylinder #2 and #3. The tip from #2 was white-ish so I figured is firing, from #3 was black and oily. I've switched the plugs i.e. the one from #2 to #3 and vice versa (don't have new ones handy, have to order).

Reset OBD and now today I got CEL and still same P0303 code.

My rotor, cap, wires and plugs are about a year old (all OEM). I didn't have this problem before it ran fairly smooth till last night (a bit of vibration was always there but I thought this was the mounts).

Should I buy new plugs since I have 20K on them and will need new ones in the next 6 months anyway (I thought they would last 30K)? I doubt it is the plugs since the #2 was not giving me problems and would have thought switching plug would make the code "move" cylinder to P0302.

I'm afraid it is the valve gasket for #3? Do I need to do compression test next to rule that out? What else could it be? What should I do?

Thanks for your advice - has always been extremely helpful!

Matt

 

I would do a compression test. Maybe #3 is low. How many miles does the car have on it?

Compression Test - Volvo S70 GLT, 1998

 

Odometer has 138K but actual miles I estimate to be more than 150K (PO changed cluster without telling me only found out through Carfax after the purchase).

Regarding compression test... thanks for the link. Will report back.

You don't think I need new plugs right, the test with the switch was "good enough", right?

 

Just did a compression test (my first one ever).

#1 - 225
#2 - 215
#3 - hardly built any pressure, I read 20
#4 - 160 first test, 170 second test, then a wet test: 190
#5 - 215

Seems to me that I have a problem with #3 and #4. I didn't do a wet test on #3 because I figured it won't matter since it didn't built pressure. It also sounded different when cranking than the other cylinders.

I am thinking to bring it to a mechanic, I was hoping I could DIY but I think this is beyond me. May even need to get rid of the car, as I don't want to put too much money into it such as a rebuild, new engine etc.

What do you guys think?

 

Yes, as you know, swapping the plugs was a good enough test.

You have one of three problems;
1. Bad head gasket.
2. Bad piston ring.
3. Leaking/damaged valve.

My guess is #2 since it did not build up pressure. Let me find a link for you...

WC Engineering : Compression and Leak Down Testing

Fixing this motor will likely cost around $1,400 - $1,800. If you think the car is otherwise not worth the investment, then get something else and dump that one. I guess you can drive it on four cylinders untill it dies.

 

Thanks for the quick reply.

In terms of your suggestion #1 - headgasket problem - I am not losing any coolant, so would have negated that (I have driven it in this condition for about 200 miles so would think in that time coolant level would have dropped if headgasket problem, right?)

Also, my research so far tells me that a piston ring job is indeed expensive (engine has to come out of car etc) whereas a valve job may be something less $$ intensive which is why I am leaning to get a mechanic at least look at it to confirm / provide a quote... maybe I'll do invest in it - after all I did already put a lot of money into it... my threshold right now is about a thousand bucks though, if significantly above that I will indeed like you said just drive on 4 cyclinders for a while and look for something else...

Thank you so much again.

 

Read that link I posted. It has some good info about the whole poston/valve thing.

 

I did read through the link and things make a bit more sense now. Thanks again.

On another note, I'm exploring the idea of dumping my car and getting a different one... I found a 98 V70 AWD for about 1,000 dollars that I'll look at tomorrow. It needs a new radiator I was told and is due for timing belt replacement. It's at 177K miles. My thinking is that I could retire my car and the State of CA will pay about $1,000 so I'm not out any money but would have a car without the piston / valve problem plus get the benefit of a Turbo and AWD vs. my dull NA FWD. While I would like the AWD to go skiing I am also a bit vary of the transmission / AWD system being a problem area. Don't want a money pit... but am OK to spend let's say another $1,000 to get it to last for a while (after all still cheaper than spending $1,400 to $1,800 to fix my engine). I could also "transfer" over some of the parts I bought for my current wagon and install in the AWD prior to retiring it (such as the tires which I just bought a year ago, etc) - hence me thinking about getting another 98 model year.

Any advice on what I should look out for on the AWD stuff when I look at the car tomorrow? I've been reading all sorts of posts the last few hours and to be honest don't fully understand what all the components are...propshaft, driveshaft etc. - if you know of a link that explains it all for an AWD novice would be great.

 

I'm with you on switching cars. I'd do a compression test and take a code reader with you. Test drive it good, I mean for like 30 mins. Then check for codes again.

The good thing about the AWD system is that it can removed quickly if it goes bad.

$1,000 is not much for a turbo AWD '98 V70 if it's running so it may not be bad to get if you can do the reglected services yourself.

The 850 section has a buyer's guide that you can read.

 

Your V70 should have individual coils at each cylinder? I had this same code and the engine shaking at idle. Try switching the coil with another cylinder and then pull the spark leads one at a time.

 

Trevy: The '98's do not have coil packs. Also, he leaped to a compression test which came back bad/dead cylinder. You can do all the parts swapping, new coils (if it had them) new plugs, injectors, and even pour gold in there, if there is NO compression game is over until you crack the motor and do some rebuilding.

 

yes, rspi is correct I don't have coils. I am still deciding what to do. The AWD wagon was in bad shape, too much work for me so I passed. I also brought mine to a mechanic who quoted 1,800 to fix depending on what it needs, he would need more testing, open it up etc. or 2,800 for installing a used engine he has that has all the seals, timing, water pump done and 90K miles on it. The engine alone he would sell me for 1,000 but I don't think I can do an engine swap myself.... if I had some help locally, I would consider it... I don't want to spend 1,800 or more as I then rather put that towards a newer car. We may just get something totally different for my wife and I'll drive her '95 960.

My car still drives although it's making more and more noises so I don't know for how much longer

I also found out that the state of California offers 1,000 for vehicle retirement but the program is currently closed until July 1 when they have new funds again. I hope my car will last until then and I'll probably do that then as it's more than the junkyard or a mechanic would pay. It does still have to drive on its own to qualify so I hope it doesn't die before then.

If anyone in the bay area is interested in purchasing for 1,000 (or more ), it's not a bad deal... has new brakes, tires, complete tune-up, new MAF sensor, new 02 sensor, tranny is good, great interior, all new hoses, new coolant tank & cap, etc. Lot's of new parts. If you can put a another motor in it, it would be worth it.

 

just thought I share the fact that now 3 months later with probably another 5 or 6K I am still driving it with the broken engine. It is a bit slower than usual and makes a lot of noise but it still drives!

I actually think if it wasnt for the smog test I could probably drive without fixing it for a while.

We are now considering buying a newer S60 for my wife and my V70 will be retired.