VH temp problems

[mondy888]

got my VH commodore sl wagon vacationer, 3.3 blue 202, dual fuel atm. the thing is the engine temp needle doesnt really move when u drive the car, i took it out 4 a drive, about 40 minutes in that time the neddle just got off cold, i touched the boneet and it was hot as they do, ive tested the temp guage itself and its working fine so im thinking its the temp sensor, how do i go about finding it and checking it?

cheers

[DerekP]

Could also be the thermostsat not closing thus keeping the engine too cool - easy and cheap to fix.

Not sure where the temp sender is on a 202.

[mondy888]

yeh i thought about the thermostat, but the motor get pretty hot theres no chance its staying closed i dnt reckon but i will test it or replace it anyways

[DANNY8]

Thermostat's cost bugger all so ya may as well replace it anyways. My old 173 had the temp sensor on the driver side right at the back of the head.

[mondy888]

ahk cheers, yeh better to be safe than sorry especially with the weak pistons in the blus motors, how can i check the sensor?

[DANNY8]

Personally I'd just buy a new sensor as they also would be bugger all. Just to fully eliminate it as a problem.

[mondy888]

theres a sensor that goes onto the thermostat housin yeh?? through the top? and has three small black pipes coming out of it?

[VK SL 3800]

Thats a Thermal vacuum switch, im pretty sure it controls the dizzy and something else, i know it allows vacuum advance at idle the distributor when the engine is running hot, around 100 degrees C to help cool it down. There should be another TVS that opens when the engine is warm for ported vacuum advance to the distributor ( your normal advance line).
Gauge sensor is pretty small and is at the back of the head on the drivers side just below the tappet cover, and most likely will be covered in oil so may be hard to see.

[mondy888]

ahk cheers, ill give it a look over today see wat i can find

[mondy888]

just had a look at that sensor, the guage works fine when i earthed it at the needle on the temp went right up and came down fine to, so im thinking it could b that sensor, how much r they and where can i get one from??
Autobahn?
Supercheap?

[Darren_L]

yeah any of those stores (or Repco) will probably keep them, it's a fairly generic part used on various makes and models.
make sure you ask for a temperature 'sender' rather than a sensor though.

[mondy888]

just had another look at it today.....i noticed when i ran the car 4 a while and reved it up the temp neddle did really get past cold, but as soon as i turned it off and left the ignition on the temp gauge needle went up to wat looked to be a normal reading. wats going on? possible alturnator issue? and yes i spelt that wrong :P

[ari666]

sure your temp isnt connected to oil pressure?

(i dunno, just throwing it out there)

[DerekP]

Definitely a wiring problem.

[Darren_L]

just had another look at it today.....i noticed when i ran the car 4 a while and reved it up the temp neddle did really get past cold, but as soon as i turned it off and left the ignition on the temp gauge needle went up to wat looked to be a normal reading. wats going on? possible alturnator issue? and yes i spelt that wrong :P

the engine temp will naturally rise for the first few minutes when the engine is turned off, because there is no longer any airflow past the engine/radiator and the coolant circulation is greatly reduced without the water pump turning.

You can check the output of the sender by checking the resistance reading between the centre pin and the outer body. A certain resistance = a certain temp. I have the specs in my books at home - just away from home for the week so can't check for you. Problem is though, you need to know the temp of the water before checking the output of the sender

If it were me, I would just buy a cheap temp gauge from the likes of Supercheap (capillary wire type is cheap, accurate & takes the place of the sender unit doesn't need power), connect it up, dont even bother running it into the cabin, just leave it under the bonnet. Run the car and check what the actual temp reading is. You may be worried about nothing