Hi All,

 

Was stuck on the M6 today, not moving at all...so hot outside too..was looking at the Amb temp gauge on the Air Con panel, it was 37..38 39 - 45, i thought sh*t..but it wil be ok by this time i had my heating on High at 40deg (roof was off!!) then looked down again, and its was at 60! Pulled over just incase on to the hard shoulder, got the bonnet up and gave 10mins..it had dropped to about 44 and the traffic was moving a bit more, so all was fine.

 

My oil and coolant is fine got them both flushed abd changed the weekend (nice to meet you Paul!), so im just wondering if i would of carried on at 60deg would it of been ok?

 

I know this is just the outside amb temp gauuge - obvioulsy it increases when the engines hot because of where the thermometer its placed..

 

Anyone else had similar?

thanks

Ed

No, but I wouldn't be particularly worried, that said, stock water temp gauge is very poor, i recommend getting an aftermarket one to keep an eye on water temp, i'd say once it hits 95 its time to shut it off.

I have a water leak and got stuck in traffic the other day. My aftermarket gauge was at 95c (normally 75) before i pulled over and gave up trying to get to work. The stock gauge was still bang in the middle tho - just shows how crap they are!

Yep, my aftermarket guage showed 95 today but once again the stock lived upto its reputation of being sh#t!!

Why is 95 degrees so bad for a ZX engine?

 

I'm not questioning anyone's judgement here, I just want to know. The temp guage on my SLK is marked in degrees (up to 120) rather than just a red bit, yet in the hot weather it can regularly hit 100 without any problems???

 

ZX stock guage sits well below 1/2 way - although after a hard drive, when I turn the engine off for 10 minutes then switch the ignition back on (without starting) it shows 3/4. However when I start the engine it drops back to below 1/2 almost immediately........

 

Richard :)

I also don't know why it;s so bad for a modern car like a Zed to be seen as running very hot at 95 degrees, most cars the scale is from 90-120 with the car usually running somewhere in the middle highly safely.

ok thanks guys

95-110 is fine for most "non" performance passenger cars.

These cars generally run hotter on purpose...to improve fuel economy and keep emmision levels low.

 

performance cars (like the Zed) should be kept cooler (optimal range is between 85-90) and it's not such a good idea to run above 95, unless it's been done on purpose.

Octane requirements of an engine (especially the case for turbo charged cars) increase with coolant temperature and high temps can cause pinging/detonation.

 

..additional problem the Zed has, it can't get rid of the heat very easily and it tends to keep it in the engine bay for a long time (even with the engine off).

In some cases the temperature even increases with sometimes up to + 20C when the engine is turned off. The bubbling sound you sometimes hear when you turn off the engine, is the coolant that starts to boil..

In extreme cases it can even cause the overflow bottle to spit out lots of coolant...a clear sign that the engine has seriously overheated.

95-110 is fine for most "non" performance passenger cars.

These cars generally run hotter on purpose...to improve fuel economy and keep emmision levels low.

 

performance cars (like the Zed) should be kept cooler (optimal range is between 85-90) and it's not such a good idea to run above 95, unless it's been done on purpose.

Octane requirements of an engine (especially the case for turbo charged cars) increase with coolant temperature and high temps can cause pinging/detonation.

 

..additional problem the Zed has, it can't get rid of the heat very easily and it tends to keep it in the engine bay for a long time (even with the engine off).

In some cases the temperature even increases with sometimes up to + 20C when the engine is turned off. The bubbling sound you sometimes hear when you turn off the engine, is the coolant that starts to boil..

In extreme cases it can even cause the overflow bottle to spit out lots of coolant...a clear sign that the engine has seriously overheated.

 

lymon,your mentioning that our zeds have a hard time to get rid of all its heat,so what can we do to help lose some of it?i know perfomance rads and all that but what else can we do?

>> but what else can we do?

 

a vented bonnet helps very well, but is not to everyone's taste.

 

another option, which is done in Japan quite a lot, is to slightly tilt the bonnet on the back (by placing rings under the hinges) and by removing the rubber firewall seal and sound isolation material/blanket under the bonnet

This will allow some airflow under the bonnet and a gap at the back to let the hot air escape (while moving).

 

only negative effect of this is that the hot air from under the bonnet will be "sucked" up by the blower in the car...can be annoying (hot) in the summer, if you don't have a (working) aircon.

 

more "radical" options are:

-remove complete aircon system (esp. compressor/pipes/condensor)

-remove catalysts (these hold a lot of heat, which radiates back into the engine room)

-remove/relocate less important/unused items in the engine bay (HICAS actuator + pipes, Battery,Cruise control hardware, solenoids + piping/hoses, aircon items)

 

electronics:

-additional electronics to have the auxilary fan blow in fresh air when the engine is off and enginebay or coolant temperature above a certain point.

-ideally an electric waterpump, with afterrun option (as found on Audi S4's)

I was watching the Zed using Datascan the other day and the auxiliary engine fan didn't cut until 93 degrees (and I checked, it did work, air con on). I would let mine get to 100-105 without worrying.

 

Ian A.

I know this is just the outside amb temp gauuge - obvioulsy it increases when the engines hot because of where the thermometer its placed..

 

The ambient temp on your aircon has nothing to do with the coolant temp?? :confused:

The sensor is out on the inside of the front bumper, nowhere near anything warm.

If it's showing temperatures that high I'd say it's faulty or has a bad connection - when not working the aircon shows a high figure like you're getting.

 

It's the water temp gauge you should be looking at...

The ambient temp on your aircon has nothing to do with the coolant temp?? :confused:

The sensor is out on the inside of the front bumper, nowhere near anything warm.

If it's showing temperatures that high I'd say it's faulty or has a bad connection - when not working the aircon shows a high figure like you're getting.

 

It's the water temp gauge you should be looking at...

 

 

Yeah the water temp guage just stays in the middle, doesnt really move.

I know the amb temp is just the outside temp, but obviously the hotter the engine bay is getting the hotter temp that will display. It was just an observation really.

I didnt have the aircon on - i had the heater on full blast!! (on econ mode)

I know the amb temp is just the outside temp, but obviously the hotter the engine bay is getting the hotter temp that will display. It was just an observation really.

 

It doesn't though, the ambient sensor is placed there so the engine doesn't have any effect on it.

I've thrashed my car in hot weather (and it's far from standard) and the ambient temp never moves.

If yours is going up to 60 degrees there's something wrong with it unless you were driving across the surface of the sun at the time :rofl:

It doesn't though, the ambient sensor is placed there so the engine doesn't have any effect on it.

I've thrashed my car in hot weather (and it's far from standard) and the ambient temp never moves.

If yours is going up to 60 degrees there's something wrong with it unless you were driving across the surface of the sun at the time :rofl:

 

 

hmm strange..what could that be then...connectors?

I was watching the Zed using Datascan the other day and the auxiliary engine fan didn't cut until 93 degrees (and I checked, it did work, air con on). I would let mine get to 100-105 without worrying.

 

Ian A.

 

I think I'd agree with this too, having a relatively stock 300zx.

 

OK, many have said the OEM water temp guage is crap but I find it hard to believe any manufacturer, let alone a Japanese one with a reputation for reliability, would install one that worked so badly.

 

Here's a theory......

 

From memory (and someone jump in if I've missed it) but nowhere in the hand book does it state what the operating temperature of the coolant should be. It just shows a range on the temp guage. Now we all know aftermarket guages are super sensitive (not necessarily more accurate), hence the significant needle movement when coolant temp increases by a degree or 2. So if the engine coolant is still within Nissan's original recommended operating range then it stands to reason the OEM guage will not fluctuate by much, right?

 

So an aftermarket guage may show the exact coolant temp in degrees but unless you have a very highly modded engine is it really necessary - I think the slight increased running temps are normal for hot weather conditions and the extra guage makes many owners panic a little. Afterall if the engine was severly overheating then I think it would be noticable - performance would be down (detting?) etc.

 

Plus the addition of antifreeze plus the high coolant pressure ensure the boiling point of the coolant is well above 100 degrees C anyway. Like I said, my Merc SLK temp guage reads in degrees C, with the red line being the one above 120 degrees. I regularly see 100 degrees in very hot weather and the car behaves just fine. Being supercharged it is not an "ordinary" car either, although not the performance machine my 300ZX is.

 

Richard :)