Vauxhall Insignia - Engine oil type - Gary Gunning

I am looking for help with a very new (possible) issue. On my way home tonight my car (14 plate Insignia 1.8 petrol) started going funny in the 1500-2000rpm it's like it starts stuttering and almost cuts out but then nearer 2000rpm is fine. It appears it does it at will as there's no pattern to it. A side that is yet to be resolved is a coolant leak (been on a pressure test for 2 hours without finding a leak) which needs topped up as only half full and I think (will double-check later tonight) the engine oil needs topped up. Could the coolant and/or the possible requirement of engine oil cause the stuttering? The car is booked in for a service 2 weeks on Friday but wondering if I should get it done sooner? Any/all help appreciated, thanks.

Vauxhall Insignia - Engine oil type - elekie&a/c doctor
Engine oil should not have any effect on running, assuming it’s up to the correct level . Unidentified coolant loss could be getting into the cylinders , this could possibly be the cause of your stuttering. I would remove the spark plugs and inspect for wear and corrosion.
Vauxhall Insignia - Engine oil type - Deryck

If not the leak to cylinder, have you checked the expansion tank for cracks? I had it when I owned a 1.8 Insignia. Not immediately obvious but the telltale on mine was water on the ABS modulator which was just underneath on my 2010 model.

Vauxhall Insignia - Engine oil type - Gary Gunning

I will have a look on to what you both have suggested. After some research and speaking to my local garage it would seem the issue is the coil pack and possibly the spark plugs as well. The car is booked in for Monday with the garage to get a full service, MOT and to get the issue looked. The garage seem to think that although my service book says the spark plugs were done in October 2018 they might not be as I bought the car from a well known car chain, who apparently don't always do what they say they have and the car might have the original spark plugs from new!

Vauxhall Insignia - Engine oil type - edlithgow

Sorry to be alarmist, but coolant and oil loss, taken together, might indicate a leak where these two meet, such as an oil cooler or a head gasket.

I assume there's no sign of cross contamination?

As an aside, I don't get your title. Engine oil type doesn't seem to feature at all in your post.

Edited by edlithgow on 18/06/2020 at 19:12