DIG-S Coolant swap

[SplanK]

I have searched high and low for a service manual that contains the HR12DDR (DIG-S) engine, but cant find one anywhere!

I am giving the wife's car a good old service at the end of the money and looking at doing the coolant as I cant remember when it was last done! I would like to know if there is a particular procedure or a bleed valve hidden away somewhere!

I see in the workshop manual for the HR12DE variant, the manual states to disconnect the top heater hose, fill slowly (to prevent air pockets forming) until water escapes,refit and continue filling until full, refit cap and heat cycle the car 3 times (keep repeating until water level stop dropping)....

Any tips/knowledge?

 

[NathanFul123]

I had no problems with mine, I just drained from the bottom of the rad, filled it up to the brim, ignition on, make sure full heat and full fan, started engine.

Topped it up when the level dropped and kept checking the hoses, eventually had red hot heater in car and and at rad cap, put cap on and been fine since.

 

[SplanK]

I had no problems with mine, I just drained from the bottom of the rad....

Did you pull the bottom rad hose, or did you use the drain plug?

Was under the car today doing the oil so I have a nosey at next weeks job of draining the rad. I happened to notice on the drain plug some sort of seal between the radiator end and the drain plug itself. Looks either worn/perished or corroded and will probably leak when I pop it back together. No notes in the workshop to say what it is - IE just a simple o-ring or a crush washer....?

Im thinking of playing it safe and pulling the bottom hose but the drain plug, but if I can get my hands on a new seal....

 

[SplanK]

I did this today..... pulled the bottom hose. Wasn't too bad but did start dripping from everywhere (bit of sand on the floor helps with that that and multiple buckets!).

Didnt bother pulling the heater core hose as suggested in the workshop manual, I had a look and thought sod that - to much of a PITA to get to!

Put back in around 3.5L including replacing the coolant in the overflow tank, so its around 65% of the overall coolant swapped - the old stuff didnt look horrific as I thought it was going to be so will leave it be now.

Using a funnel bucket made bleeding much easier which allowed the system to self bleed whilst running rather than going through the warming/cooling repeat cycle that Nissan suggest

For information:

Thermostat starts to open between 80/83c - lower pipe stayed cold until this temp as well.
Thermostat fully open at 95c
Thermostat closes at 77c
Fan turns on at 98c

I used an OBD reader and Torque to keep an eye on the water temperature to ensure that it was hot enough tha the thermostat had fully opened. It took some doing getting it up to temp. Its a cool running engine anyway but mix that with cool temps and a head wind didnt help!

 

[kptg]

In this colder half of the year, I observe the coolant temp stabilised around 84 C for road trips.
Since the aircon heating is pretty slow, I am thinking of partly covering the grill.

Maybe the fan only runs in summer time.

 

[nismo_400r]

Hi kptg,

On my model (HR12DE, so not supercharged) coolant temps do not vary between winter and summer (on long journeys of around 80 miles the temps vary between 78 and 85) so I think these cars are massively overcooled, presumably for the eastern markets it was designed and built in, and the operating temperatures are controlled by the thermostat restricting coolant flow

For reference, someone in Canada took a k13, which has the 1.6 litre HR16DE, and blocked most of the grille for an economy test, thought you might want to have a look as they have blocked roughly three quarters of the grille, as can be seen in this link: https://micra-forum.com/showthread....ire-PSI-10-better-fuel-consumption-at-90-km-h

From the workshop manual the cooling fan only runs if the coolant hits 98c, or if the air conditioning is running. I have only had my fan kick in once without the air con being on in two years, and that is because I have fitted an undertray to my car and I left the car idling with the air con off to help charge the battery during lockdown.

Hope this is useful

 

[SplanK]

Over cooled maybe, but it doesn't drop below what it should be....

On the supercharged versions, we should not be blocking off the grille as that would also impede air going to the intercooler, leading to increased air intake temps and thus lower performance/MPG.

Blocking off the radiator though, as long as you dont mind lower performance from the air con should be in theory ok, but I really dont see the need unless your climate is very cold, or your trip as very short and getting to temp sooner would be a benefit, but for most , the car seems to hold at the desired temp well enough!

The other problem is lack of temp gauge so unless you have a OBD reader, then you will have no idea whats happening!