Loud "drilling" type noise coming from Suzuki Grand Vitara 04 reg, 35,000 miles, timing chain maybe.
It sounds like an issue with the timing chain tensioner!
Is the vehicle still under warranty? If so, take it to the dealer and have it checked out. If not, here's what I would recommend to try.
First, hopefully you have been maintaining the vehicle well, changing the oil as recommended and using Synthetic oil?
What I would try first is adding a can of engine flush to the engine, pick up a can at any parts store. Go ahead and pick up everything you will need to do an oil change too.
Ask for 10w30 Synthetic oil, (I know it calls for a lesser weight but trust me, any weight oils with multi-numbers is a seasonal oil, which means it can be used any time of the year). The heavier weight oil will give you or your engine more oil pressure which in turn will help by giving it more protection!
Plus, pick up a QT. bottle of Lucas Engine Oil Stabilizer while your at the parts store picking up the other stuff.
Hopefully you know how to change your own oil?
If not, you can go to a good shop and request for this to be done and they will do it for you.
If you do it yourself, you first want to use the engine flush and let the engine run with it in there for about 25-30 minutes, do not drive it just let it idle. You can rev the engine a little to help it work but do not rev it really hard.
After it has run for the allotted time, drain oil and replace oil filter, make sure to look at your old oil filter to make sure that the old gasket is on it and not stuck to the engine. If it is stuck to the engine you will need to remove it before putting on new oil filter or you will have a severe problem!
Most of the time the old gasket will come off with the old filter, I just always tell my mechanics to check and make sure! Add a little oil to the new oil filter gasket and screw new oil filter on hand tight and then tighten it with a oil filter wrench another 3/4 turn.
Then start by adding the Lucas Oil Stabilizer, it is thick like syrup so be careful not to spill it. Then add the oil but also be careful not to overfill the engine! I will usually add 4 qts. in total, so 1 qt. of Lucas and 3 qts. of oil, then crank the engine let it run about 30 seconds or so, shut it off and let it sit for about a minute and check it and add more oil as needed to top it off from there.
See if that stops the noise! That will be the cheapest way to try first!
If that does not work, I think the issue is going to be with the timing chain tensioner and it would have to be replaced, but I've had some luck in doing what I've said above as most of the tensioners use oil pressure from the engine to tighten the chain and the hole to prime the tensioner is really small so it doesn't take much to stop it up.
Hopefully the flush and then the thicker weight oil and Lucas will do the job, if it does, I would recommend to continue using it at each oil change! And, if you use these quick lube places, you will have to either bring your own Oil and Lucas Oil Stabilizer as they may not do as you ask!
Hope this helps