hi i have a quick question regarding spark plugs. i have a 2016 volvo t5 cross country wagon. 2.5 turbo, i brought in to firestone and thdf changed the plugs. they used 4704 denso iridium tt plugs. one is bent and i’ve been told these mighty not be correct plugs. i am told they need oe metal iridium. when checking this out i’m coming up with different plugs. i’m also getting websites thsf say the 4704 no not fit thst model. any suggestions? please help in desperate need of answers

 

Looking at Densos' online catalog - the 4704 is listed as a compatible plug.

 

i’m getting there not

 

also
the manufacturer is bosh. 4704 are not on there

 

I simply went to the denso website - address is at the top. Personally - my shop ALWAYS purchased (and installed) spark plugs only from Volvo. With my discount they were about the same price as denso or bosch plugs from my wholesale supplier.

 

in your opinion would denso sparks any good? or would they fail at all?

 

Any part can fail - spark plugs not very often. But of the thousands and thousands my shops have replaced (99% from Volvo in a Volvo package, except for the redblock cars - those are NGK/Bosch) there have only been a few (2or3) that had a problem BEFORE they were installed. (And I'd bet they were damaged by one of my techs BEFORE installation) None after installation.

 

would you think someone from firestone damaged of the spark plugs? only one is bent. it also ran great for 3 days. now engine is knocking very bad

 

Knocking very bad? No problems for 3 days? It's probably not the fault of the spark plug.

Spark plugs get "bent" and knocking noises can happen from a foreign object being in the cylinder - but there is usually considerable damage to that cylinder from that object bouncing around and that causes major problems - usually most economically solved with a different engine. Hopefully your "knocking" is not what i think it is.

This guy on you tube took apart an engine like yours - it would have been knocking where 2 of the pistons were hitting the cylinder head due to spun rod bearings. (and the excess clearance between the rod and crank making knocking noises also) The engine was toast and would have been more expensive to fix than a used engine installed. That blown engine had 100k on it -

 

if a foreign object got down there is there a chance that woukd have happened when they installed thr plugs? this didn’t havd a problem until after firestone fixed it and changed the plugs

 

You may want to rent an inspection cam (pretty sure autozone etc can provide a loaner/rental) to see if there's any signed of scoring on the top of the piston and on the walls and whether anything is still in there.

+1 on going Genuine Volvo for plugs. You can shop Volvo dealer web stores (I use Tasca Parts since they are here in New England but they are easy to find with a Google search) - You'll be happy to see most do provide competitive pricing with a guaranteed correct fit for your engine. Volvo plugs also come pre-gapped but its always a good idea to check just to make sure.