Intermittent VVT rattle only when warm
 

Hi gents I bought a 2002 volvo v40 a few weeks ago which on the drive home I found had a VVT rattle with a P0011 error, I cleared the code and then it came back again so I changed the (extremely dirty) oil and cleaned the VVT solenoid & cleared the code and the code didn't come back after that but the noise remains.

One thing that has been predictable the whole time is that the VVT rattles along with an Oil light on the dash, the sound is only there when the oil light is on. Also, this rattle generally won't occur until about 11-12 miles into a trip after a cold start in the morning, when I unplug the vvt solenoid the rattle disappears and a check engine light comes on.

This sounds a bit unusual in that most blokes seem to get the rattle from cold whereas I've only really had it when the engine is warm along with a check oil light. I have no liquid cross-contamination in the oil or coolant and the engine runs great normally so it's left me a bit confused. I'm going to dump the oil out again tomorrow and put on a new oil filter.

I've ordered a new VVT solenoid & gasket to get that out of the way first incase the old one is sticky or catching debris, but i suppose it'd be safe to assume that the VVT pulley needs to be changed at some point?

I'd be checking engine oil pressure if your light is coming on!
You should have saved your money, VVT replacement only cures a rattle, nothing else!

Luckily I found out what the issues were and solved them, the oil pressure light was caused by a previous owner running the car for 1000s of miles with a stuck-open thermostat, the engine was running cold which presumably helped to cause engine sludge on top of some really old/black oil. I know this because you could scrape the black grit off the oil filler cap & grill with a screwdriver plus there was a little bit of gritty crap coming out of the sump plug.

The VVT rattle is a separate issue which I have solved temporarily by unplugging the solenoid, again probably ruined by the engine running on bad oil & stone cold temperatures.

Anyhow, I changed the oil/filter, the oil light issue eased off somewhat, did another oil change with an over the counter oil flush 200 miles later & then changed the thermostat so that the car would run at normal operating temperature, again eased off some more. However it only took roughly 13 miles to have the oil light come on and i would have quite a rough running engine anyway. I then decided to take drastic action about 700 miles after this change :tounge_smile:

I bought 3 litre of diesel and then added 2 litres of some spare cheap oil to the mix, shook it about, then dumped my old oil out and replaced it with the diesel mix. Ran the engine for 20 mins and dumped all that crap out and replaced it with 20w50 mineral oil. Now about 300 miles later my car is running much smoother and no oil light and rarely rattles on start-up now. It's not perfect but the oil is staying very clean so far which surprised me. The diesel/oil flushing mix though not recommended is far more effective and affordable than that snake oil you buy from the motor factors. I'm going to do it again in a month's time to keep flushing the crap out of it.

I was tempted to sell the car when I first posted but to be honest it's redeemed itself quite well, I didn't think it would come back to life like it has and it is a pleasure to drive. I don't worry at all now I've done the diesel flush.

TLDR

1. VVT Rattle? Unplug your VVT solenoid.

2. Oil pressure light? Flush engine with diesel/oil 60/40 mix then re-assess.

I have the rattle but she still here when solenoid are unplugged... Any Idea ? Only 80k miles on the clock

I bought a new solenoid first but it didn't do much for me so I replaced the intake camshaft VVT pulley with a Ridex aftermarket part and it has been good as new with no rattles for 400 miles so far.

I never knew that there was an aftermarket VVT pulley alternative to original volvo VVT pulley. Or is this a non VVT pulley that does away with VVT function completely?.. Where are these available from ?

The "genuine" part is manufactured by Aisin and can be branded VOLVO in the bag.
I paid £100 or so for mine. Waste of money.

Instead of using 20W50 mineral oil, try either the recommended oil or 10W40 semi-synth, whichever is heavier when you next do an oil change. However, for the first 0.5L into the sump, replace it with Carlube ATF-U so that's 0.5L of ATF-U then top up to the level with 10W40 semi-synth.

Works a treat on Honda VTEC and any engines with hydraulic tappets. Keeps things clean, moving, rubber seals supple and many other things. I use it all the time in both of my beasts, only one of which has hydraulic tappets. However i do know many that use it to help the VTEC keep working. :thumbs_up: