Does anyone know where the thermostat is?

Question

i have had a vauxhall omega for 4days & its not happy ive been told to try the thermostat before buying a water pump but i dont have the manual & have no idea where the thermostat is any ideas?

Answer 1

Having never seen a Vauxhall Omega ... the thermostat on every engine I have encountered has been in the housing under the upper radiator hose nipple, with 2 exceptions, one of which was the thermostat was in a housing with a separate cover right beside the upper radiator hose nipple, the other was the stat was actually clamped inside the upper hose about 2 inches from the engine block nipple.  

If your unstated question is why is my car running hot? Make the following checks first:  

Engine cool,  check the coolant level both in the overflow tank and if possible to check - in the radiator.  Top off if necessary.

Start the engine with the radiator cap and / or reservoir pressure cap removed.  Run the engine at idle for 10 to 15 minutes or until either the temperature gauge rises above the normal range or you can observe coolant movement through the radiator or tank.

If the temperature reaches an excessive level and little or no coolant flow is observed then the Thermostat (most likely ) or the water pump ( less likely ) is to blame.  If belt driven water pump - a loose drive belt can also cause this!

If the coolant flows before the temperature becomes excessive, our attention shifts to the radiator fan, If electric, the fan should come on when the temperature reaches the upper end of the normal range and also it should come on at any time the A/C compressor is operating.

If the fan is mechanical it may have a loose drive belt or a thermal clutch, if you do not hear the fan roar when the temperature is high ( hood closed to contain the heat ) the clutch may be bad ( but wait there is more! ), if too many tubes in the radiator are plugged the temperature may not get high enough to activate the fan, giving a false fail indication!  

This brings us to what I believe is the second most likely suspect: the radiator itself, a flush may help, but if the tubes are completely blocked, the cleaning solution will not be able to get to the blockage and in that event a flush will do little good ( flushing is great for maintainance - poor as a repair )  If you reach this point, the radiator IS suspect, try the following check - top off the coolant again if necessary because it may have burped out during the previous checks if the engine got hot,  replace the radiator cap / reservoir pressure cap then squeeze the upper radiator hose (use a rag or wear gloves to avoid being burned ! ) and rev up the engine to around 3 to 4 thousand rpm, if the hose gets hard (pressure inside) each time the engine is rev-ed up this is a near absolute indication that the radiator is plugged. If it is an all copper radiator, a radiator shop can remove the tanks and either rod out or replace the heat exchange tubes, if the radiator has plastic tanks the only practical repair is replacement with a reconditioned radiator.  

Hope this helps - feel free to e-mail me with your results or if you have a specific question regarding this procedure.  

Answer 2

This is a BMW engine and the thermostat is part of a plastic housing which bolts to the bypass hose at the rear of the engine .About 60 quid and a bit of a ***** to fit.No thermo fitted in top hose on this engine or quite a few other now.

Answer 3

end of top hose by the block or it could be in the bottom radiator hose

Answer 4

HI

the thermostat is under the top radiator hose in the thermostat housing.

Be sure to remove all the old gasket material, be sure the new thermostat is installed pointing toward the hose, install a new gasket, Make sure the thermostat is in properly. If it is in wrong it well leak bad and when tighten you can brake the housing as it is only pot metal. There is usually a grove the thermostat sits in.

good luck

Tim

Answer 5

follow the top radiator hose to the top of the engine where its clamped onto the thermostat housing- the thermostat is in there.

Answer 6

thermostat housing is usually  at the top of the cylinder head at the right had side but it could be on the left side as well. it is usually bolted on and a black rubber hose coming out of the thermostat housing. this connects to the radiator and heating matrix.

best thing to do is to look at the big rubber hoses near the cylinder head and you should see one that's bolted to the cylinder head with a black rubber hose coming out of it.

Answer 7

This is the BMW 2.5TD engine - very reliable!

When you disconnect the top hose from the radiator, there's a stub left bolted to the cylinder head - undo that, the thermostat is sat behind it on the front face of the cylinder head.