Volvo V40 T4 hesitant when cold

[jimbo8405]

Hey

My Volvo has developed an annoying thing!
Really is as per the title, when engine is cold (or only slightly warm) she starts perfectly, idles as she should etc but I can feel her hesitating/stuttering when accelerating. As soon as she warms up, all is good and drives like a dream.
Not really a major issue but would be nice to get sorted.

So far Ive replaced the coolant temp sensor, no difference,
Changed the Coil pack and spark plugs for some old spares I had, no change.

I'm semi competent at car stuff so anything easy-ish I need to check or change?
Not wanting to spend a fortune as I bought the Volvo as a cheap estate just over 3 years ago and was toying with getting something quicker and newer so this may be what makes my mind up!

Oh, no warning damp lights are on.

Any help would be great
James

[Alex121]

Don't want to jump to conclusions or anything but those symptoms sound like early head gasket failure. You may have a very small leak between one of the coolant tracks that gets into the cylinder causing a misfire but seals up when the engine is hot.

Get a hydro carbon test done, this'll let you know if any exhaust gasses are in the system.

Do you have any pressure in the expansion header in the morning when the engine is stone cold?

[DXMachina]

yeah, what he said - mine's also dying of a CH gasket failure (in earlier stages but other issues are in play as well) and mine has felt that way for about 6 months, since a bad misfiring incident on the coldest day of winter

(I suspect ice formed in coolant and damaged either the head, the gasket or the cylinder liner TBH - it was about minus 12 that night)

if it isnt that, its plugs - unlike N/A Volvos, the turbo ones are supposedly very finicky about plugs. The plugs arent made by Volvo, they are relabels of aftermarket ones, but it has to be exactly that plug or it'll run poorly

[magnuz]

I often find that cleaning the MAF sensor can be beneficial with these kind of symptoms.
Don't touch the internal sensor element of the MAF, & don't use any harsh solvents !
I spray them with electrical contact cleaner (dare i say halfords own brand)

http://www.halfords.com/motoring-travel/engine-oils-fluids/lubricating-penetrating-oil/halfords-electrical-contact-cleaner-400ml

Leave it to dry for 30 mins after spraying before reconnecting it

[jimbo8405]

Hey
Thanks for the replies and info.
Will open the expansion header tomorrow morning and report what happens.
Will also spray the Maf (have the very same electrical cleaner from Halfords) then take it for a spin after its drive and post the update here
James

[jimbo8405]

Morning
Ok, opened the header expansion tank and was a very little fizz, but not much. No idea if thats good or bad?!
Sprayed the maf and checked all coils/connections.
Ran so much better from cold so maybe the maf cleaning sorted it.
Did however find that 2 of the coils have cracks running down the outside. Check my other pack and exactly the same. Does this just happen and have no affect or should I get replacements?
Cheers

[Alex121]

There shouldn't be any pressure in the expansion header which implies to me that there is a slight leak, though very minor.

I'd keep monitoring your coolant and oil levels. Mine ran nearly 6 months and did over 5000 miles on a leaking head gasket. It did get progressively worse, to the point where I was putting a liter of water in it every morning before going to work - When you get to that stage though, you risk being at the side of the road everyday.

Definitely get a hydro carbon test done, that'll confirm if it's the head gasket or not - Shouldn't cost much at all, 5 minute job.

[t4owner]

I would also consider fuel super unleaded seems to help these cars no end my old t4 used to hesitate when cold switch to v power all was fine

[jimbo8405]

Afternoon all, just a quick update in case anyone cares!
I had actually decided to replace the Volvo so was just going to drive it until I found a replacement but on a long run last night to pick up some audio equipment it started hesitating when my foot was down around 4k in all gears.
Started annoying me so today had another play around with the coil pack and plugs and also removed the fuel pump to clean the bottom filter.
With the pump apart I noticed there was a little sticker around 1cm squared at the bottom of the pump next to the filter. Looked mega old so no idea how long its been swimming around.
Cleaned the filter, sticker removed and took the Volvo out for a rag and the hesitation when heavy acceleration has gone :)
Not sure about the cold start yet but will see later today or tomorrow.
Will update accordingly
James

[jimbo8405]

Here comes the according update........
Just started the Volv from cold and ran perfectly :) Guess the stupid lil sticker was the problem but at least it was a easy fix (wish I had check earlier but hey ho!) Actually ran better then it has for ages so guess a combo of filter clean, sticker removal and coil/plug tinkering has helped.
As for the slight fizz from expansion header when cold, well........the water stinks to high heaven (of fish, I know, I know) and Ive been advised this could be causing the lil fizz so plan to change that asap for some lovely fresh stuff and hopefully that will sort that too!
Anyways, all is good again, yay. Thanks for everyone's help :)
James

[Alex121]

What colour is your coolant? Do you have any brown in your expansion header?

[jimbo8405]

It was pretty much just clear, stinky water. Tbh I haven't touched it since Ive owned the car so whether it actually currently has any coolant or antifreeze with the water i dont know, probs not!

[Alex121]

Fair enough, I'd start with a coolant change and see if things improve from there :thumbs_up: