M35 Low Temp Thermostat

[scotty nm35]

I recieved my Mishimoto low temp thermostat today from the states and plan to fit it tonight. Is there a special procedure for bleeding the system?

My informeter displays cruising temps of 93 degrees and up to 105 while stuck in traffic so hopefully the 62 degree thermostat will help lower the coolant temps substantially. I have also seen intake temps over 85 degrees while stationary too, which im trying to lower also.

I picked up some Nulon coolant and MoCool Motul additive, hopefully the standard radiator is up to the task.

[andy65b]

have a look at the G35 service manual. I think it shows all the details in there. Let me know if you need any of the pages.

[iamhe77]

Scott, just unscrew the air bleeder from the line at the rear drivers side of the engine (I also undid the overflow bottle and the radiator cap), then open up the bottom plug on the radiator.

Edited February 23, 2010 by iamhe77

[scotty nm35]

Ok, found the bleeder Thanks. I will give it a go.

May as well change the oil while im there, another lot of 300v going in. I cant believe its 5000ks already, comes up quick.

[iamhe77]

you could do 7.5-10k on 300V mate.... with a good filter of course

[scotty nm35]

I was told you need to change it at 5k and filter at 10k, of course I have a box of filters now so I will be changing them with the oil.

Ive been meaning to do it anyway as I still have a bit of smoke at startup and wanted to try slightly thicker oil. I have 3 liters of 10w and 2 liters of 15w so I will see how that mix goes.

[iamhe77]

.... you should always change your filter with your oil, man... Edited February 23, 2010 by iamhe77

[KiwiRS4T]

I should think the new thermostat will make no difference to your top temperatures - your stock one would have been wide open by then anyway.

If you use an expensive high quality synthetic oil it should be good for at leat 30,000km. If you change your filter at say every 10k (or more often if you like) the oil should be fine.

[iamhe77]

.... how the hell can you change the filter without draining the oil?

[KiwiRS4T]

On most cars sump level is below filter.

[andy65b]

On most cars sump level is below filter.

Not on the VQ25DET.

[scotty nm35]

I should think the new thermostat will make no difference to your top temperatures - your stock one would have been wide open by then anyway.

If you use an expensive high quality synthetic oil it should be good for at leat 30,000km. If you change your filter at say every 10k (or more often if you like) the oil should be fine.

Soon see if it makes a difference, im confident it will. Obviously the thermo fan kicks in quite high on these alloy blocks. The thermostat box stated 20 degrees cooler running temps, it can only help.

I will leave the oil for 10k if you all think that's fine...

[zei20l]

i change my oil every 10k. 5k on an SR20 as its always high up in the rpm, the VQ25DET performs pretty well (in fairly stuck form) under 3k. oil should be fine, but as cam said, id be doing the filter with the oil regardless of how often you change it.

[chuckie]

Soon see if it makes a difference, im confident it will. Obviously the thermo fan kicks in quite high on these alloy blocks. The thermostat box stated 20 degrees cooler running temps, it can only help.

I will leave the oil for 10k if you all think that's fine...

Hi Scotty,i have S2 stagea, i do 20,000 pre oil change + i have been SAMPLING my oil,WESTRAC here in Perth do sample kit`s at $26. great price as i set up trend & see what is happening with my oil,i change Filter at 10,000, Nissan Filter aswell,there is some detail`s on my OIL SAMPLING,+ if you go with relocation filter you can Move it so it will be easyer to remove ,good luck Cheer`s Chuckie.

[scotty nm35]

Hi Scotty,i have S2 stagea, i do 20,000 pre oil change + i have been SAMPLING my oil,WESTRAC here in Perth do sample kit`s at $26. great price as i set up trend & see what is happening with my oil,i change Filter at 10,000, Nissan Filter aswell,there is some detail`s on my OIL SAMPLING,+ if you go with relocation filter you can Move it so it will be easyer to remove ,good luck Cheer`s Chuckie.

I have a cooler/relocation kit here but I like where my filter is now is now, right beside the drain plug.

Probably no need for the oil cooler now that the water sits on 70 degrees.

[chook]

dont want to rain on your parade, but a lower thermostat, especially one this low will do a couple of things.

Firstly, if you are running a stock ECU, the engine will be constantly trying to warm itself by running rich until the proper temps are achieved...hence higher fuel consumption, lower performance and added engine wear on cold days (engine clearances are designed for the stock temps). Also it wont lower the temps on hot days, as the thermostat will be fully open on both standard and low temp thermos ay around 90, so no difference.

Your temps are not that high, consider a radiator upgrade first.

[scotty nm35]

dont want to rain on your parade, but a lower thermostat, especially one this low will do a couple of things.

Firstly, if you are running a stock ECU, the engine will be constantly trying to warm itself by running rich until the proper temps are achieved...hence higher fuel consumption, lower performance and added engine wear on cold days (engine clearances are designed for the stock temps). Also it wont lower the temps on hot days, as the thermostat will be fully open on both standard and low temp thermos ay around 90, so no difference.

Your temps are not that high, consider a radiator upgrade first.

If the mixtures are out I will adjust them with the emanage, but I doubt it will change much. The car runs like balls when its over 100c that was the priority. I will let the good M35 blokes know how things go.

Cam is running the Nismo thermostat without issue so I doubt it will be a problem.

Radiator, yes I would love one. Do you have a bolt in solution for me? I will be upgrading this next, after the ecu remap. (which will bring the thermos in at lower temp too.)

Edited February 23, 2010 by scotty nm35

[iamhe77]

If the mixtures are out I will adjust them with the emanage, but I doubt it will change much. The car runs like balls when its over 100c that was the priority. I will let the good M35 blokes know how things go.

Cam is running the Nismo thermostat without issue so I doubt it will be a problem.

Radiator, yes I would love one. Do you have a bolt in solution for me? I will be upgrading this next, after the ecu remap. (which will bring the thermos in at lower temp too.)

I have a bolt in solution for you.... but you can't have it

There IS a semi-bolt in solution if you want it.....

[scotty nm35]

Ok, I went for a cruise today to check out the temps and mixtures. It cruises on 75 to 80 degrees now so a 15 or more degree drop which is what I had hoped for. Intake temps seem down by 6 or 7 degrees and the mixtures are much better at 11.8-12, from a slightly rich 11.

Very happy with the result, the car definitely pulls harder and seems to shift better too, probably from lower trans fluid temps.

[Cephas]

Just for reference, where did you get the thermostat from?

And is it identicle to the part used on the VQ35?

Thanks.