Water temperature

[1 gti]

Bought a golf diesel last week and had nothing but bad luck so far. Temperature needle wouldn't go over 70c so changed thermostat. The day after it overheated on me, water temp light was flashing on me and expansion tank nearly empty. No water leaks or pressure in the tank. Radiator was stone cold so thought the waterpump had gone, changed that today. It hasn't overheated yet but sits between 90c and 100c. Water has gone down a bit in the expansion tank but will just top up to check again. Any ideas what it could be? Blocked radiator in parts maybe? Help would be appreciated, cheers.

[sharki786]

not sure on diesels but on petrols you ment to bleed the system by holding revs on 2k and massaging every pipe that you can get your hand on, the bottle should bubble up and keeps topping the coolant up 1ce the fan kicks in and bubble have stopped close cap. Make sure you keep an eye on the temp!!!!

[GolfGL]

I had the same problem on a petrol car and the thermostat sorted it. Like above the problem could be the bleeding procedure.
1.) fill slowly
2.) Leave cap off
3.) turn heater on and up to the max
4.) squeeze hoses when cold
5.) start car and let the engine get upto temp - will take a long time. Keep eye on coolant level
6.) squeeze top hose pull the throttle cable and hold around 2.5k rpm for a couple of seconds and release
7.) repeat number 6 on different hoses
8.) leave engine running till bottom hose is hot
9.) make sure temp gets upto 90 and rev till fan kicks in.
10.) with the cap still off leave the engine to cool down and screw on once cold - 30 mins later

[search]

Bought a golf diesel last week and had nothing but bad luck so far. Temperature needle wouldn't go over 70c s

Can someone explain to me why it be a problem if the temp didn't go over 70c?  im petrol and its always on 90c i though this was normal and anything over 90 would be bad. (im a noob just dont understand why 70c would be bad?)

[itavaltalainen]

70 is not full operating temp, mechanical bits are designed to work best at 90, also oil will be colder leaving more water and unburnt petrol in it, reducing visco and shear stability - i.e. increased wear.

Not sure also why everyone here leaves the filler cap off... not needed and reduces the boiling point of the coolant as pressure cannot build up
Also it is pointless to turn your heater to max, if you know how the heater in a Golf works (air flow being regulated, NOT flow to the heater matrix).

It has always worked well for me to pour a liter of water, a liter of concentrate until exp tank full, start engine and knead hoses until you can just see coolant going out of expansion tank, turn engine off, use a towel to open expansion tank slowly, then fill upto max again, start engine etc.
Ater filling with quite a few liters, take it for a 5-10 mile spin with another 2l of coolant, check every mile or when light comes on. Well replacing revving engine aimlessly.

[Bandit127]

70 is not full operating temp, mechanical bits are designed to work best at 90, also oil will be colder leaving more water and unburnt petrol in it, reducing visco and shear stability - i.e. increased wear.

Not sure also why everyone here leaves the filler cap off... not needed and reduces the boiling point of the coolant as pressure cannot build up
Also it is pointless to turn your heater to max, if you know how the heater in a Golf works (air flow being regulated, NOT flow to the heater matrix).

It has always worked well for me to pour a liter of water, a liter of concentrate until exp tank full, start engine and knead hoses until you can just see coolant going out of expansion tank, turn engine off, use a towel to open expansion tank slowly, then fill upto max again, start engine etc.
Ater filling with quite a few liters, take it for a 5-10 mile spin with another 2l of coolant, check every mile or when light comes on. Well replacing revving engine aimlessly.

+1.

I filled mine, let it tick over while i tidied the tools away. Topped it up and went for a slow drive. The light came on at about 2 miles but the temp was stable so I finished the journey home (another mile). Topped it up to the top when I got home.

It eventually settled down to the seam around the middle of the expansion tank and has stayed there ever since.

[search]

70 is not full operating temp, mechanical bits are designed to work best at 90, also oil will be colder leaving more water and unburnt petrol in it, reducing visco and shear stability - i.e. increased wear.

Not sure also why everyone here leaves the filler cap off... not needed and reduces the boiling point of the coolant as pressure cannot build up
Also it is pointless to turn your heater to max, if you know how the heater in a Golf works (air flow being regulated, NOT flow to the heater matrix).

It has always worked well for me to pour a liter of water, a liter of concentrate until exp tank full, start engine and knead hoses until you can just see coolant going out of expansion tank, turn engine off, use a towel to open expansion tank slowly, then fill upto max again, start engine etc.
Ater filling with quite a few liters, take it for a 5-10 mile spin with another 2l of coolant, check every mile or when light comes on. Well replacing revving engine aimlessly.

cool thanks for taking the time to explain to me thanks.