BlueWagon

Which part? Id think that the rattling suggests a problem. Maybe fix rather than remove? Got a photo

Then fix cooling system, don't add more fuel by tuning for more power

True...but any remap will be injecting more fuel. Gonna get hotter not cooler, so remap only gonna make overheating worse.

Remap only going to make it worse. More power comes from more fuel being burned so more heat generated. Cannot make power without generating heat. Id agree, need an upgraded cooling package if you want to work it hard. Likely nothing wrong with current system other than its only designed for 150 HP.

Like others have said, you need to verify this, otherwise of course it won't make sense. Fill to correct level, drive 1000km and recheck. Id suggest the garage didn't fill enough. Don't bother speculating on oil usage until you verify the actual usage, by filling and checking yourself.

If there is a bit on the stick it will be fine. It was only the oil level light and not the oil pressure light hey?? Oil level light is no biggie

Id say any 5w30 that meets VW 504.00/507.00 spec. Maybe 0w30 if really cold climate Look in the manual You may even get away with 502.00 spec as it's pretty old

Don't discount the fact disconnecting the cooler last time stopped coolant loss. Id see that as pretty good evidence the cooler is the problem. Maybe new cooler is no good/poorly installed

Why? I reckon coolant passes through it always.

123K isn't alot of miles. My Mk3 (Petrol) has 317,000km. Seems fine. My other car has 465,000km. Also fine. Id be more concerned with overall condition than mileage.

Bypass egr cooler. I think if your oil is not milky it's more likely an egr issue than head. Not impossible to be head gasket but bypassing cooler is simpler Id say. And cheaper to fix. I think the knocking when cold may be oil too thick (change it for thinner oil). Or, worn bearings. Engine likely quite worn out but if an egr cooler fixes water problem then keep driving it until it's done.

So this is confusing. You say fuel pump running but relay just clicking.... Which is it? Please clarify. Or, do you mean the relay runs when the car runs and then clicks when it stops? Is the power supply and or the signal to the relay and fuel pump being interupted when the engine dies? Check it with a multi meter or test lamp. Can you bypass this and power directly off battery with a jumper cable to run the engine. That would narrow down the problem. Does it stop quicker if you are driving or idling, or EXACTLY the same? Again, the devil and the clue is in the detail. If time is always the same regardless of engine load/driving/idling, and the signal to the fuel pump relay is interpreted then I'd be thinking immobiliser cutting in....

Ya...all good info to pop into the first post. Agree, needs changing. I think you can just change but to optimise life of new battery, recode or at least tell the car its a new battery. I think all you really need is to change serial no and make sure capacity (Ah or CCA) is correctly entered. We don't know what your background info is and often when someone says, my car needs a new battery, a good diagnostic mechanic will ask l, how do you figure. Plenty of punters say my car cranks for ages but won't start, must be the battery. Or, my car won't start, what could it be....well...kinda anything....

Probably oil and filter change Inspection of tyres, brake pads, quick look underneath for loose joints and oil leaks Check coolant concentration Top up fluids Check any fault codes Probably about it

How do you know?

Try a 2032 as it's a bit thicker. Sounds like loose contacts Mine did the same, just replaced with a 2032 (a good one, so maybe your new battery is flat too) and it worked. Didn't need to recode

Worn / broken engine mounts I reckon

I dont think the concentration of coolant helps cooling at all. Water is the best cooling medium due to its enormous specific heat capacity, but we mix it with glycol etc to prevent freezing and corrosion of cooling system. The mix also inhibits boiling to some degree but that is largely due to a pressurised cooling system. Really diluted coolant probably cools the best

It's not corrosive, otherwise it would destroy metalliccooling system parts like housings and water pumps.

It would be worse a low speed high temp. Oil pressure is higher at high speed, and higher with thicker(cold) oil

Under what conditions? Idle, high or low rpm?? Does it extinguished when you rev it up a bit? Sounds like low oil pressure, most likely to Manifest at LOW rpm where pump is spinning slower and oil is warm (thin). Normally engines have great oil pressure when cold as the oil is thick Id measure the pressure under a few conditions

Mine poped up the other day. As I looked at it and wondered what it was as I drove along, the washer fluid low light popped up. I topped up the washer fluid and all good. Maybe a past intermittent non serious warning like washer fluid...

Not sure older engine formula is that appropriate for a modern car. Does it need the VW spec your engine requires?

Brake....ha ha

I doubt that happened Maybe sitting around for a year lead to lack of lubrication in cam etc and maybe when they started it they didn't prime the oil system. Almost sounds like diesel engine injection clatter. Maybe give the fuel system a good clean out and give an oil change