More help needed

[nbskyline]

Well there is no oil in coolant or coolant in oil :-) Only problem is timing belt is still a bit tight. Also my oil temp slowly raises the the mid point!! My coolant bubbles after shutdown. Air in the coolant system?? My coolant temp is not going above half??

[Skym]

Bubbling is normal for RB26 and can be fixed with a air separation bottle / breather tank -

http://www.nengun.com/arc/air-removal-tank-normal-set

Diagram of how the bubbling happens inside engine -

http://www.trust-power.com/04cooling/breather_tank.html

Breather tank helps by removing bubbles and creates a new high point (instead of radiator cap or top of engine as a highpoint). Also N1 water pump helps to reduce cavitation.

But thermostat could be stuck partly closed, as oil and water temp are taken from engine. Feel bottom radiator hose when engine is warm. If bottom radiator hose feels slightly cooler than top radiator hose, then it's not thermostat. If bottom radiator hose feels cold when engine is up to temperature, then it's a late opening thermostat problem. If thermostat stays fully closed while accelerating, can over pressurise and take out headgasket, etc. I think sometimes thermostat can stay fully open. I've experienced the late opening type of thermostat with my car, but not fully open.

When engine is cold, before warming up, check for low radiator coolant level in overflow and in radiator. It's another symptom of thermostat or leaking headgasket.

Also check coolant to water ratio.

[nbskyline]

Bottom hose is slightly cooler then the top. No oil in coolant or coolant in oil and no white smoke. Also my coolant temp stays dead center on the gauge. Oil temp raises to half or just above on stock gauge?? What is stock oil temp??

[Skym]

Centre or slighly above centre on stock water temp gauge is normal for stock thermostat (opens at 76.5 degrees). With Nismo lower temp thermostat it sits around 62.5 degrees at idle or just below halfway on stock water temp gauge. At factory I think around 80 degrees is normal at idle with stock thermostat.

I think oiltemp should be around 180 degrees (operating temp), as most thermostat's for oilcoolers open at that temp (some open higher, like 200degrees). Oiltemps can go higher if car is thrashed on a racetrack.

[nbskyline]

I was just taking a short 30 min. cruise nothing hard and the coolant temp stayed fine but the oil was around 95 when I shut it off. Could air in the coolant cause oil temp to raise?? I am also running 5w50 oil which I am going to change.

Thanks

[Skym]

I don't think 95 degrees is high for oil temp.

Being a coolant to oil oilcooler, the hot coolant helps to warm oil up. They run a similar coolant to oil oilcooler setup with radiator (bottom of radiator) for automatic transmission's and the radiator helps transmission to warmup in cold climates (snow, etc). When you modify a automatic engine, the gearbox oiltemps, coolant temps rise, so have to bypass the factory oilcooler in bottom of radiator and run transmission directly to aftermarket oilcooler core. It makes a big difference to coolant, oil temps. But is not recommended in cold climates, like where it snows.

[91blackgtr]

it wasn't around 95, it was just shy of the middle line on the oil temp which would be 110, or did it go over :S

[nbskyline]

Still don't know why?? Idea's

timing belt or a belt to tight??
Coolant not fully bleed?

I just want to drive my car once this summer!!!

[Skym]

Like I said above, coolant helps to warm the oil up. I wouldn't worry until oiltemps are over 180 degrees or operating temperature. If they do go over 180 degrees, engine, turbo's need a oil to air engine oilcooler. In some cases removing the stock water to oil oilcooler and running sandwich plate off the shortblock (like you do with auto transmission via bypassing stock oilcooler) can solve oil temp problems.

Can get a oilcooler core and sandwich plate, braided hoses from here (Setrab oilcooler core, Mocal sandwich plates, etc) -

http://www.racerpartswholesale.com/category/Setrab_Oil_Coolers2

They supposedly use the same brand of engine oilcooler on Ferrari's, etc. They can be ordered with proper mounting brackets, etc. Just need to fabricate ducting, which isnt hard to do out of sheets of aluminium with tabs that have bolts through them and nuts to hold the pieces together. Or if you prefer, weld them together.

I had high oiltemps on my car that damaged the stock turbo, so it's important to keep oiltemps under control with a engine oilcooler.

[nbskyline]

thanks Skym