Thermostat on a supercharged 6

[Darren]

lol I never said it was easy, those stubby spanners for this job are worth their weight in gold that's for sure.

Even with them I was swearing and cursing, lots of patience is required.

 

[sixshooter]

Hey Darren what effects have you noticed running the cooler thermostat ?

Does the motor take longer to heat up ?

Does the motor run any cooler in Summer ?

 

[Scooter79]

Hey Darren what effects have you noticed running the cooler thermostat ?

Does the motor take longer to heat up ?

Does the motor run any cooler in Summer ?

I'd like to know more too. Is it worth going 10 degrees cooler and is there any possible problems in doing so? Keeping in mind we're talking about an L67.

 

[Darren]

I haven't noticed any difference or very little by using a cooler thermostat, engine seems to come up to temperature around the same time, as for the normal operating temperature it does seem slightly lower although this could be my imagination, mine has never hit the 1/2 way mark so I guess that's a good thing, it sits between 1/4 & 1/2 with or without the a/c on.

The whole purpose of the thermostat (I'm sure I'll be corrected on this one if incorrect) is to open up earlier say 81 degree and keep it around that same point give or take a few degree's instead of opening up and remaining around the 91 degree which from memory is the standard one.

In short, I don't think your going to notice 10 degree's too much on the temp gauge.

 

[sixshooter]

Cheers Darren !

Hey Scooter, what temp have you noticed yours sits at ?

Mine sits just a whisker under 1/4...and sometimes gets up to half way when standing still then the thermo's cut in and she drops back to 1/4...

I should do a trans service, backflush and change of coolant soon... I've only changed the plugs, aircleaner & oil & filter since acquiring the car.

 

[Scooter79]

Cheers Darren !

Hey Scooter, what temp have you noticed yours sits at ?

Mine sits just a whisker under 1/4...and sometimes gets up to half way when standing still then the thermo's cut in and she drops back to 1/4...

I should do a trans service, backflush and change of coolant soon... I've only changed the plugs, aircleaner & oil & filter since acquiring the car.

Hey sixshooter, mine is pretty much the same as yours. sits on a quarter. In heavy traffic it goes to 1/2 but never more. Thermos usually kicks in at just above 1/4. Have changed aircleaner, oil and filter (mobil1 10w/30) and coolant. I wanted to do the thermostat but is impossible to get too. Sixshooter, whats your method for a backflush? ...and what coolant you using? I've been using Nulon long life concentrate in the exec and now this one.

 

[sixshooter]

I haven't done the coolant in mine yet...it looks like it was flushed recently tho... but I want to make sure its done properly...
My method for flushing depends on the condition of the coolant to start with. If its putrid I'll add a tin of radiator cleaner to the radiator then go for a short drive before I start flushing...
Then when the motor is cool enough to work on I undo the top and bottom radiator hoses
remove thermostat... refit thermostat housing
refit bottom hose
put garden hose in top radiator tube
wait till over flowing then undo bottom hose
refit bottom hose repeat a few times
refit bottom hose
fill up with water turn heater on
start car and let run about 2 minutes....water goes in the radiator and exits out the unattached top hose
turn off
undo bottom hose drain again
reattach bottom hose fill up repeat flushing again
then flush once more with distilled water before
refitting thermostat
then add premixed coolant to the radiator or refill again with distilled water and add coolant concentrate
also dont forget to add the Holden coolant pellets in the top radiator hose.

 

[Scooter79]

Sixshooter, i reckon your flushing method might be a little different with the L67. You wanna flush as best as possible before you take out the thermostat because to get to it you need to remove the throttle body and supercharger u bend. Bit hard to stat the car without those and you done wanna reassemble it to start it then disassemble to fit new thermostat. I said it before and I'll say it again. it's a rediculous design!

 

[sixshooter]

Theres enough room to get a 10mm 1/4inch drive socket on the front bolt and a 10mm ring spanner on the back...and enough room to remove the thermostat housing without removing the u-bend...:drink:unless the rear bolt dosen't unscrew fully before hitting the u-bend... I'll find out when I have time to do it.

Just looking at Darren's photo...there's alot less room in the VT/X/Y/Z's with all those hoses...and the bulkhead looks alot closer to the motor compared to the VS...

 

[Hatchman76]

I joined this forum just because of this thread as it was very helpful, I've got a VX S2 S with a supercharger and I would have to say that replacing the thermostat is an absolute bastard of a thing to do.

I did it this way:
Removed the throttle body
Removed the vacuum diaphragm on the side of the supercharger next to the U-bend (no way I can get to the bleed screw with it on)
Removed the U-bend intake - ring spanners needed here
Removed and replaced the thermostat and gasket
Put it all back together in reverse order trying to remember where all the bloody vacuum hoses go! I also replaced the gaskets on each end of the u-bend while I was at it.

Ring spanners did the bulk of the work although I used a socket wrench for the thermostat housing. Removing the bolts for the U-bend at the back are ridiculously pain-staking, I could only move them about 2mm at a time so it took forever to get them off.

I'm a backyard hack at best when it comes to cars and this took a long time even by my standards. Why for the life of me Holden put the thermostat in such a ridiculous position is beyond me, surely it could have been done better, it shouldn't have to be that hard to replace a thermostat on a Commodore.