Spark plug blown out - 2006 S60 2.5T AWD

[scot850]

Strange one. A friends son called me last night to say his car was running really rough and he didn't feel comfortable driving it home about 10 miles or so.

I threw some tools, a MAF, and other potential parts as I had no idea what was wrong and no codes read.

Picked up my friends son and drove to his car. Put the car onto OBD2 and Autel and came up with a cylinder 3 misfire.

Pulled the plastic covers off (got to love how Volvo position 60% of those T30 bolts so you can't get to them).

First thing I noticed was the coil pack in cylinder #3 was sitting up and at an angle. Weird!

Pulled it out and it was destroyed! The boot looked at the bottom like it had exploded:

Exploded coil pack boot

Naturally, this DA had forgotten to pack a spare coil pack and a 60km round trip to get a spare from home.

Fitted the coil and started the car. Slightly rough running (assumed some fuel left in cylinder) and then engine settled down. And then, there is was, a slight chuffing like a distant steam engine going up a hill! Oh, dear.

I had brought a spare plug and went to pull the old one to find it loose (is this common on these engines as I have found this on cars before I have not owned). Removed the plug and it looked ok. NGK Iridium?

Checked the threads and very slight evidence of aluminum shards in the threads but hardly any. Went to put the new plug in and it literally dropped all the way in!!

Oh, DEAR..............Crap............!!

So now weighing up cost of repairs or just scrap the car. I have heard of repairing the plug threads with the head in situ. It obviously has risks as the plug fits vertically and it is set way down in that plug hole. So that may not be an option.

The only other option, other than scrapping the car, is to pull the head and rebuild. Pulling the head and having the repair to the sparkplug hole done is not terrible (I think a machine shop said $2-300 for decking and repair). But what are the costs for a rebuild??

What head gasket kit do we need, and it would be crazy not to do the valve seals and maybe check the valves while it is in bits.

Then it gets dangerous! If it were my car I would do the PCV while in there. This is where costs can escalate quickly.

Curious on any suggestions and input on this and way to go with it and recommended parts/brands.

Thanks,

Neil.

[volvolugnut]

I do not think a helicoil repair is good practice UNLESS the helicoil tap can cut a full thread in the head.
If you do try helicoil, coat the tap with heavy grease and back out to clean and replenish grease after every few turns.
You may have to get creative for the tap holding tool.
I did the helicoil thing on a Honda once after a SHOP striped the plug threads. I ran fine for many years.
volvolugnut

[jonesg]

A time sert is supposedly better.
see you tube.

[Vova585]

At this point I would look at the car in general and estimate how much money it needs in a nearest future. Then look in my pocket and decide if I am able to afford different repairs. Most likely I would settle to pay some reputable shop to attempt to fix the threads with the cylinder head attached(some purist will yell here and speak about possibility of metal shavings scraping the cylinder wall...honestly look video from PHAD where banjo bolt "granaded" and caused rampage inside the cylinder. Yet that car drove for close to 20k after that if I remember correctly). Next alternative for me would be to try to find a good fresh roadkill and transplant the entire engine. Any advanced work on engine mechanics will be a crazy experience.

[scot850]

I have spoken to several machine shops and basically the same reply. Pull the head and bring it in as doing a repair is too difficult due to the depth of the sparkplug hole to the threads. That included a specialist who advertises in situ plug thread repairs.

So as a minimum to repair this it will require a top end rebuild and the associated cost and labor of my mechanic friend. He has built many 5 cylinder Volvo engines.

Currently there are no engines worth having locally for a 2.5T. That is the cheapest route, but ideally you would like to hear it ran before installing it.

The mention of how is the rest of the car. I just looked it over about 2 weeks ago and it currently needs nothing much else. No oil leaks, trans is working fine, timing belt was done about 6 months ago (don't know about the water pump). It also just had the fuel pump installed by Volvo as a replacement on the previous one under warranty. It also has a new Volvo throttle body and the MAF was cleaned. The car was good before this happened. Body is not perfect on the car but not terrible either. Brakes are also good for now and >50% remaining and rotors are good.

The crunch in speaking to the dad is that he has lost belief in the car and is wondering if he should cut the losses. I have said I will explore the options and costs with my ex-Volvo mechanic buddy and try to give a budget cost for repair. But before going any further I want to do a cylinder check with a camera to make sure the bore is not scored and the valves are good to eliminate them from being the cause of the failure.

Neil.

[abscate]

How many kms are on the car?

Under 250,000 KM and no oil use I would skip stem seals and valve job unless inspection shows otherwise

Rant on. These 100k mile spark plugs lead to this stuff. There is no way any of my cars are having plugs in disturbed in an engine for 100k miles. I stay with cheapies and FreeCP them at 30k

[scot850]

I agree an the longlife plugs. Also I have read of issues with iridium plugs with some brands. But for me the biggest issue is they are in the engine too long and too hard to remove without possible damage to the plug threads.

I had thought about skipping the valves and stem seals but at 20 years old and I believe it is near 270kkm. Valves will be checked for build up and valve seal face condition.

Neil.

[vtl]

If you pull the head, do the full rebuild. Use only Volvo stem seals on exhaust side. Intake can be Elring. Would need to replace tappets or grind a bit from old ones. The shop perhaps knows that already.

While the head is off in shop, drop the pan, remove pistons, wash in ultrasound bath, replace the piston rings. Look at the rod bearing, may want to replace them. My compression rings were terrible at 280kkm, the thermal gap at BDC was 0.9 mm. At TDC it was much bigger, because of bore taper.

Apparently replace O-rings in pan. May replace the pickup tube with plastic version, which dips deeper in oil bath.

[scot850]

If it were my car and it was worth keeping I might go that far. But my friend has 3 sons in school and a ex-wife who hates that car because he bought it without her input.

Realistically it makes more sense to do the minimum, but do the head repairs as you suggest and I would have done anyway. But good to know. With some of these P2 engines where we live getting well north of 400kkm and some beyond 500kkm I'm less likely to go that far, but if it was my car I would certainly pull the oil pan and refresh the oil seals and oil pick-up. I might even go as far as pulling a few caps to check condition.

All I can now do is work out with my mechanic buddy if he wants to tackle the job, and I can organize the parts needed and get the machining work done for him.

Appreciate the help everyone.

What I am still looking for is if the Elring or Victor Reinz sets are any good? Rock Auto only lists Elring for R models and a few others they have are also only for the R.

https://www.rockauto.com/en/catalog/vol ... t+set,5416

I was thinking based on reading a lot over the years on P80 threads, is to buy the Volvo OE head gasket and the valve stem kit. We could save a bit maybe buying just the individual valve stem seals for the exhaust as vtl suggests. Does that make any sense?

Neil.

[vtl]

If it were my car and it was worth keeping I might go that far. But my friend has 3 sons in school and a ex-wife who hates that car because he bought it without her input.

Realistically it makes more sense to do the minimum, but do the head repairs as you suggest and I would have done anyway. But good to know. With some of these P2 engines where we live getting well north of 400kkm and some beyond 500kkm I'm less likely to go that far, but if it was my car I would certainly pull the oil pan and refresh the oil seals and oil pick-up. I might even go as far as pulling a few caps to check condition.

All I can now do is work out with my mechanic buddy if he wants to tackle the job, and I can organize the parts needed and get the machining work done for him.

Appreciate the help everyone.

What I am still looking for is if the Elring or Victor Reinz sets are any good? Rock Auto only lists Elring for R models and a few others they have are also only for the R.

https://www.rockauto.com/en/catalog/vol ... t+set,5416

I was thinking based on reading a lot over the years on P80 threads, is to buy the Volvo OE head gasket and the valve stem kit. We could save a bit maybe buying just the individual valve stem seals for the exhaust as vtl suggests. Does that make any sense?

Neil.

Make sure you get an MLS gasket (multi-layer steel). And no RTV. Have to use an anaerobic sealant. Permatex is good.