Mk 3 cooling system

[britishwardog]

Hi all,i recently bought a Mk 3 1.8 CL Golf (SPI), is it normal for the cooling system to be pressurised, i've noticed when the car's running that the hoses are quite hard to squeeze-is this normal for a Mk 3?, i've owned VWs in the past including Mk 1 and 2 Sciroccos and Mk 1 Golfs but never encountered this before,any advice greatly recieved,cheers.....Andy

[britishwardog]

Hi all,i recently bought a Mk 3 1.8 CL Golf (SPI), is it normal for the cooling system to be pressurised, i've noticed when the car's running that the hoses are quite hard to squeeze-is this normal for a Mk 3?, i've owned VWs in the past including Mk 1 and 2 Sciroccos and Mk 1 Golfs but never encountered this before,any advice greatly recieved,cheers.....Andy

Anyone?

[zollaf]

it is quite normal to have a certain amount of pressure in the cooling system, but if the hoses are rock solid or even swelling under pressure, then this is a sure sign of a problem, and is indicative of a head gasket failure, where combustion gases are getting forced into the coolant. a combustion leakage test would confirm this though, where a tube with blue fluid is held over the resevoir and air from the cooling system pumped through it. if it changes colour to green or yellow, then exhaust gas is present.

[britishwardog]

it is quite normal to have a certain amount of pressure in the cooling system, but if the hoses are rock solid or even swelling under pressure, then this is a sure sign of a problem, and is indicative of a head gasket failure, where combustion gases are getting forced into the coolant. a combustion leakage test would confirm this though, where a tube with blue fluid is held over the resevoir and air from the cooling system pumped through it. if it changes colour to green or yellow, then exhaust gas is present.

The hoses aren't rock solid but there's a fair bit of pressure there,maybe it's just me being a bit paranoid,cheers for reply tho'.

[billygri77]

try drain the coolant from the bottom hose and then press the hoses to check if got much softer than before

[britishwardog]

try drain the coolant from the bottom hose and then press the hoses to check if got much softer than before

actually i've just recently changed the thermostat and refilled the system with new coolant-that's when i noticed how pressurised the hoses were when i run the engine to normal temperature.

[billygri77]

i suggest to find another same engine and check this

[Jon Bradbury]

A certain amount of pressure is quite normal. You need not worry about this unless the car is overheating. In my experience old hoses can start to bulge (particularly at the connections to the radiator) but this often is due to age rather than a problem with the engine.

The easy way to check for a blown head gasket is to remove the oil filler cap and look at the underside. If it is covered in a light brown creamy gunk it means there is water getting into the oilways because the head gasket is blown.

I would expect the cooling system in all modern engines to be fitted with a pressure relief valve of some sort. In the olden days this used to be incorporated into the radiator cap. If the car overheats the coolant temperature (and pressure) will rise until this valve opens and releases lots of steam into the engine bay. That is your "stop the engine right now!" warning.

Anyway, to summarise : If there's no gunk on the underside of your oil filler cap and the car isn't overheating, don't worry.

[Housemaster300]

However sometimes you can have thick creamy gunkj on the underside of your oil filler cap if you just do short journeys and never get the car very hot,also if your breather from rocker cover to air filter isblocked or collapsing it can cause this.
Just a heads up

[Jon Bradbury]

Fair point Housemaster - Sur if he has a head gasket blown there will be catastrophic indicators like continual overheating). Soinds like the OP is in the clear on this one!