Second time in 1 year spark plugs fouled up.

[shiloh51933]

2004 XC70 w/200k on odometer, this vehicle is very well maintained and I use almost all Volvo parts or the Original Manufacturer parts when needed. A year ago I had an issue with this vehicle after my father in-law started poking around while I was replacing the water pump. I decided to replace everything(WP,TB,tensioner, idler pulley & VVT cam plug) while I was in there replacing WP. Well my in-law made a mess for me to clean up after...he removed one of the VVT cam sprocket/hub. So I had to lock up cams at rear and lock crankshaft to reset everything. Anyway in the end he fried a few coil packs it turned out and had them replaced. 6 months later a few spark plugs fouled up(NGK's DBL PLTM), I was thinking maybe she doesn't like the plugs so I replaced those w/Bosch DBL PLTM. Here we are again 5 months later with a random misfire on #3 & #5. I'm ordering the Bosch FR7DC+, I figure I'd give the copper a shot. She did have an emissions issue for a while, the fuel filler cap had to be replaced and the canister purge valve I just replaced. I was thinking maybe she was running way too rich causing plugs to foul up. I need to examine these plugs closely because I don't remember what the last set looked like....Any suggestions?

[93SCMax]

I'd recommend using only OEM (Volvo) plugs. I have a 2001 V70 T5 (turbo) and have not had any issues from day one. 15 1/2 years and 143k miles later, they are still clean as a whistle. Service manual says change every 30k miles. I'm even doing less often than the recommendation. For less than $50 for a set of 5 from IPD, it's worked out real well for me....then again I haven't had an in-law messing with the engine.

Some engines just don't like non-OEM plugs so my recommendation is to stay with the correct Volvo plugs.

Good luck.

[MadeInJapan]

Yes, the best plugs are the Volvo ones, but still they shouldn't be fouling. With the coil packs misfiring and plugs fouling I might guess that the PCV system hasn't been serviced and you might also have some valve stem seals leaking. It would be good to check these things. To change the valve stem seals the valve cover will have to come off (not a head job) and you'll have to have the proper cam hold down tools. the PCV overhaul is a bit more involved than that, but doable.

[June]

You are putting platinum plus where they don't belong. Way back when in the 1980's and platinum plugs were the new thing I took my father's 1976 Buick Electra Limited Park Avenue through one of those drive through oil change places and got talked into a tune up with Bosh platinum plugs. I was taking the car to Daytona for the weekend and I barely made it to Daytona Beach from Tampa. 200 miles. All the plugs fouled and the car finely just died as the pipes under the car glowed almost white, smoking the carpet under the seats. It was a horrible experience but I learned a lesson about spark plugs and salesmen treatment of females. Dad made a call and had the Buick dealer come get it and the mechanic explained the Buick engine was not designed to run that type of plug. They put Buick ones back in and the car ran perfectly there after. I know no Volvo I have owned has had platinum plugs. Mine is a 2004 as well. Try a normal type plug, my cars have always had Volvo replacement without ever having any trouble nor have I had a coil ever go bad before. What could it hurt to try a set of oem Volvo plugs? Good luck, June

[shiloh51933]

Yes, the best plugs are the Volvo ones, but still they shouldn't be fouling. With the coil packs misfiring and plugs fouling I might guess that the PCV system hasn't been serviced and you might also have some valve stem seals leaking. It would be good to check these things. To change the valve stem seals the valve cover will have to come off (not a head job) and you'll have to have the proper cam hold down tools. the PCV overhaul is a bit more involved than that, but doable.

Thank you for your response and I agree with you about factory plugs being the best on this engine. The last set of plugs I installed was Bosch FR7DPP w/0.7mm electrode gap specified in the FSM. To my knowledge Bosch is the manufacturer of the Volvo branded/labeled spark plugs and I've used them in the past with our '96 850 GLT sedan. Now the PCV system has been serviced/replaced on this vehicle once but it's possible I guess it could be getting to that point again. To my knowledge a PCV system can't cause a misfire but what your saying is a clogged PCV system could cause excess pressure inside the crank case which could lead to leaky valve stems. Yes I have a set of cam locking and crankshaft locking tools and I will be looking further into this.

[shiloh51933]

You are putting platinum plus where they don't belong. Way back when in the 1980's and platinum plugs were the new thing I took my father's 1976 Buick Electra Limited Park Avenue through one of those drive through oil change places and got talked into a tune up with Bosh platinum plugs. I was taking the car to Daytona for the weekend and I barely made it to Daytona Beach from Tampa. 200 miles. All the plugs fouled and the car finely just died as the pipes under the car glowed almost white, smoking the carpet under the seats. It was a horrible experience but I learned a lesson about spark plugs and salesmen treatment of females. Dad made a call and had the Buick dealer come get it and the mechanic explained the Buick engine was not designed to run that type of plug. They put Buick ones back in and the car ran perfectly there after. I know no Volvo I have owned has had platinum plugs. Mine is a 2004 as well. Try a normal type plug, my cars have always had Volvo replacement without ever having any trouble nor have I had a coil ever go bad before. What could it hurt to try a set of oem Volvo plugs? Good luck, June

Thank you for your reply and I hear what your saying about every vender trying to upsell the premium plug. AS far as using the Bosch FR7DPP(double platinum), this is what the FSM recommends for the Turbo models. The FR7DPP's are the factory plug with "Volvo" stamped on the side instead of Bosch in a Volvo package. The n/a models have the Bosch FGR7DQE0 recommended in the FSM. Anyway I ordered the Bosch Super Plus Copper plugs yesterday going on the same thought that you have just mentioned in your reply., I appreciate your input but comparing an old Buick that calls for copper plugs is quite different than an '04 XC70 that calls for the platinum plugs from the factory for all V70 turbo models. The Volvo Engine: B5254 T & T2 2.5 litre (2521 CC), 20-valve, turbocharged was designed to use the Bosch FR7DPP platinum plugs. Something is causing the spark plug on cylinder #5 to foul up, I just haven't found the source.

[abscate]

Thanks for sharing that one, June

Also remember:

Single electrode only for Turbos

Three Electrode ok for NA (Non Turbos)

[goldxc70]

Once, I picked Bosch plugs with platinum double electrodes as the "best" option (according to the parts store guy's computer) for my 2004 and it ran really badly. I pulled them immediately and replaced them with Volvo plugs. Had no problems with those.

[shiloh51933]

Once, I picked Bosch plugs with platinum double electrodes as the "best" option (according to the parts store guy's computer) for my 2004 and it ran really badly. I pulled them immediately and replaced them with Volvo plugs. Had no problems with those.

The Bosch FR7DPP double platinum plugs are single electrode, the "double" platinum doesn't stand for double electrode.

[shiloh51933]

Thanks for sharing that one, June

Also remember:

Single electrode only for Turbos

Three Electrode ok for NA (Non Turbos)

The factory spec spark plugs for the 2004 XC70 are the Bosch FR7DPP, these are a single electrode plug.