Radiator temperature?

I've installed the Scangauge II and its all great but..

Now that I can read a digital temp, what is considered to be to hot?

I'm going to be towing a caravan and this is something I want to monitor.

Unloaded, it sits at around 93 degrees.

I dunno but I've got to go out soon and they reckon it's 35 out there so I'll see what mine is after about 40mins on the road.

According to the scangauge book a vehicle with a 50/50 mix of coolant and water will not boil over until about 256 degree F (about 130 C) at sea level and less at higher elevations so I guess you have a bit to go before it's too hot.

My guess and it's only a guess at this stage would be that 93 is reasonable

I've always been taught that 87 deg is optimum jacket cooling water temp for a diesel. This changes across engine manufacturers though.

Just spoke to a Nissan Service manager and he suggests that 102-103 should be the acceptable max. if it hits this, throw on the heater and drop the temp.
He also mentioned a secondary cooling fan cuts in around this level - anyone know of this?

Maybe its the air con condenser fan.

I ran my D40 for about 40 ks before and they reckoned it was 36.8 outside when I started (felt more like 35.3 but who can you argue with). My scangauge was reading between 87 and 93 degrees and given that the needle was only about a third of the way up the gauge I wasn't overly worried about that temp.

I know the difference in degrees between the top part of a temperature gauge and the next line down isnt usually much in degrees but mine was still miles off the second line so Nissan's figure of just over 100 might be ok as long as it doesn't creep much further.

According to the manual, the thermostat opens between 80.5C and 83.5C. It should start closing again at 77C. The thermostat's "full open lift amount" should occur at 95C.

The ECU is programmed to not operate the radiator fan below 97C. When the coolant temperature is between 98C and 104C, it operates the fan at "low" speed and at 105C or higher it operates the fan at "high" by sending the appropriate signal through the CAN to the relay control for the fan.

These change when driving and using the air conditioner. When aircon is on, the thermal fan is always on LOW unless the coolant temperature rises above 104C. When the aircon is off, if the temperature is in mid-range causing the fan to be run at low speed, once the vehicle exceeds 40km/h the fan is turned off. If the temp exceeds 104C, it runs the fan at high speed again (refer to p351 and p1120 in Engine -> Cooling System).

If the ECU detects an over-temp condition it sets P0217 (or P1217).

The really silly thing is it doesn't give a figure for what it considers "over temp". I've been through the 1300-odd pages and can't see it, I must be blind!

I'm going to take a stab that it doesn't like the coolant much over 105C, where it seems to whack the fan onto HIGH no matter what else is happening.

Good stuff Old Tony, I couldn't be bothered going out and getting my manual and was going to look tomorrow but you saved me the effort. I reckon by christmas you'll nearly have that manual memorised and most of it typed here.

The only vehicle I have had with a digital temp guage was my R1 motorbike. The thermo fan wouldnt even cut in until it got to 105 deg. Different engine though I know.

I know im going to eventually have to fit in a bigger radiator in my car, on hot days my car does not like climbing long hill climbs, im guessing its all the extra weight that has been added over standard. What i mean by that is, it does not overheat but the temp needle does creep up when sitting high revs in 4th gear going uphill on a freeway to keep it at 110km/h.

One of the things listed in the "Engine Over Temperature Diagnostics" is to check for fog lights.

I'm guessing that my own number plate is going to impede airflow. There's also the issue of the hot, compressed air passing through the intercooler and the air conditioning heat exchanger also adding its burden. Add to that the oil cooler and you're really cooking!

I can see that these things might be tempermental in summer. I wonder if there's some way to improve on that.

Thanks for the info. Fantastic.
Qld have a slim line plate. Something I may look at if the current one is impeding the flow.
We have a short 11% hill, about 2-3 kms, which I travel every day from work. The temp does creep up to 100 degrees on this (unloaded - though I am fat??). Maybe one day when I'm bored I'll hook on the van and check it out. Trouble is that the 2-3kms is to short to really test it.
I have an auto so it will be interesting what the temp is when towing the van (Jayco Hawk - about 1300kg). I'm off to Straddie in Febuary so guaranteed to be hot, humid and there are some long hill climbs on Straddie. Will keep all informed. Has nayone found it neccesary to fit an extra tranny cooler?

While rising temps aren't something to take lightly I prefer to take the naive approach. Car makers have been making cars for quite a long time and usually use more knowledgeable designers than me so when it comes to taking delivery of the finished product I pretty much figure they have done the testing to cover most things.

There is hundreds of Nav's in hotter parts of the world than our cities and many of them would have bull bars, nudge bars, lights and all sorts of stuff hanging of the front and while some might impede the air flow a little given that so many of these things are factory options I'd reckon they took a lot of them into account during testing.

It would be stupid not to be aware of your temps especially on hot days but I'd still reckon that in most cases unless there is other problems the standard cooling on the vehicle is adequate even for towing. Chances are anyone who's brought their Nav from a dealer told them they were going to be towing a van so surely if these things weren't made to tow such things the first thing the dealers would be suggesting is a factory mod added to the vehicle to fix it. With the mark ups dealers work on it would be stupid if they didn't, especially when they offer you such other meaningless things that only serve to make them profit.

As vehicles age there can obviously be issues with the cooling systems (I know I've seen the NATRAD ad) and they need to be addressed as they arise but I've never been worried about any of my cars in their first few years of life.

I'll let you guys know how it goes this weekend. We're taking another run to Broke, will be climbing Harpers Hill with 1.8 tonnes behind her. I'll keep a close eye on it - I won't be pushing it hard, or using cruise control, but given the heat this morning, I can't see this afternoon being too kind to cooling systems.

It ought to be a good test.

When my car was only a couple of years old i often and still do tow a tandem trailer about 800kg and my charger about 1450kg, thats way over 2tonnes and i never had a overheating prob even uphills, only after i started with all the barwork and such did i notice the temp needle slightly moving of its usual mark.

So you think the bar work impeded the airflow?

I just did the same trip as I did yesterday arvo however the outside temp was about 5 degrees lower but a howling head wind heading over and a little head wind heading home. The only difference in the water temp was tha it hovered between 88 and 90 rather than going up to 93 so I'm going to assume Mr Nissan is happy for mine to run at about 90

We're at Broke again, and not only did we conquer Harpers Hill without moving the needle (and while pouring on a little power too), we got through the next section of 100km/h climbs in the dual carriageway heading past Belford without a hint of movement of the temp guage.

I'm going to assume that I have no issues with heat, despite my number plate partially blocking the lower part of the air intake.

I've never had a car with a temperature gauge that fluctuated very much when things were running fine. All my cars have sat at or below the half way make under normal conditions and I've had bummer mounted driving lights on every car I've owned.

Driving a car regularly you get to know and expect where a temp gauge will sit under most circumstances and you should always keep an eye on it, we used to put a mark in the dashboard dust as a guide

rambada said:

So you think the bar work impeded the airflow?

Click to expand...

I dont think so, also the spotties are huge and cover most of the grill, i think it could have been the bigger tyres not helping but ultimately and most likely was a lot of mud build up on the radiator over time.