what water temps should i see on the PFC commander?

[richard cash]

I have a single turbo rex with fluidyne radiator and whilst ive been running it in ive noticed that the water temps are quite erratic. It can display between 85 and 95 C and go between these figures in a mater of 30 secs. It can go from 85 to 95 or the other way in this period of time. Most of the time it hovers about 90C.

I spoke to tim at rxmotors and he said that this seemed a little high at 90C but when i spoke to him i hadnt noticed the temps jumping around as much as they do.

This was best checked when i went to butlins this weekend and got my girlfriend to repeatedly check the figures. Whilst the inlet temps seem to do as i thought (go up slowly in traffic to around 55C and go down to 20C on the motorway) the water was doing what it liked. In a 17minute traffic jam going 500metres id have thought this would increase to well over 90 and stay there until i moved again but it still jumped around, sometimes being on 85.

Is this normal for the power FC to display this and im just worrying over nothing or should i be concerned?

[G@NDY]

Hmmmmm sounds like something amiss. My single is running a normal rad and my temp is pretty solid at 82, think the highest i have seen it is 85 but the rise/fall is very slow.:confused:
Maybe some more technical folk will help out matey:o :Thumbs-up

[BlitzBoy]

all depends on how your fans have been setup to cut in, as regards to water temp anything up to 100 is quite safe and not to worry about as standard  fans dont come in until 95 from what I can remember, my temps are around late 80\'s to early 90s, you can see over 100 when booting it on the track

[richard cash]

i thought the thermostat doesnt kick in until 83, so how do you get 82C consistantly?? If my temps are like this when im running in i wonder what they will be like once its been tuned again. Although saying that i never have seen above 95, even when i was booting it at times before i had the rebuild. if upto 100 is ok then i guess im ok.

[michaelb]

Hi

I recently had a water temp and oil pressure gauges fitted.  My car re cooling is standard and in traffic and on the motorway it deos go up to around 101C but it generally moves around 85C  I guess after reading the comments here it is standard, right ?  I must admit that since having does gauges fitted it has made me a bit paranoid when the water temp reaches 100C…after all it is the boiling point of water.  I know that with the coolant added the boiling point probably goes up to 120C but I still worry…

Any way, is 103C normal? Stock twins, HKS exhaust system but not decated,

Regards,
Michaelb

[Rx-7 turbz]

keep your a/c turned on and it will hover around 83c 84c all day long

[richard cash]

i havent got AC anymore.

michaelB, i thought the coolant actually drops the boiling point as the BP of th ecoolant is less than water. However as pressure increases so does the BP.

[michaelb]

..…it is actually the other way around, your water will start boiling at higher temperatures then 100C , pending how much coolant mixture you have, it will generally not boil till around 120C …if the coolant droped the boiling temp your water would boil at say 80C and the cooling system would be in trouble...

Regards,
Michaelb

i havent got AC anymore.

michaelB, i thought the coolant actually drops the boiling point as the BP of th ecoolant is less than water. However as pressure increases so does the BP.

[pete sparrow]

Hi
I\'m running a T78.I had problems with my temp as well.It was flucuating like yours.Turned out i had a tiny hole in the rad,so i was loosing water.Changed the rad sorted the problem.Are you loosing water? Have you got the under tray still on? Not having one causes the fan air to go under the engine rather than over it.Vented bonnets help too.
Cheers
Pete

[richard cash]

pete, i took my tray off when i changed the engine but will put it on straight away.

michael B, i understand that water temps boil over 100C as we\'d all be in trouble if the water temps went over that. However a big part of this is due to the pressure of the system and not the coolant i would have thought. If no coolant was added, and it was simply tap water then it still wouldnt boil at 100C.

[James B]

Defo put undertray back on.

My water temps for road use usually stay pretty steady at around 87 - 89 although the other evening they were going up to 95 then I imagine the fans were kicking in and dropped back down to 87 then crept back up to 95 and so on and so forth.

Unusual for my car ...... checked water levels and fine.

Not doing it at the moment.

J

[pete sparrow]

pete, i took my tray off when i changed the engine but will put it on straight away.

michael B, i understand that water temps boil over 100C as we\'d all be in trouble if the water temps went over that. However a big part of this is due to the pressure of the system and not the coolant i would have thought. If no coolant was added, and it was simply tap water then it still wouldnt boil at 100C.

The water in the system will never boil as it is pressurised.It\'ll only boil if you have a major leak. Check the seal on the water header cap. Summer coolant will help as well 50/50 mix should do.

[gsb876]

I believe water temps are dependant upon setup,

In the winter i will see as low as 73oC, and today driving about was on 74-77oC, in traffic it will jump slowly to a max of 90oC and then upon movement will start to drop down again.

Depends on what front end you have on the car too, more cold air feed to the intercooler will produce lower water temps naturally.

Gurj :cheers

[Smifta]

Depends on what front end you have on the car too, more cold air feed to the intercooler will produce lower water temps naturally.

Gurj :cheers

You mean, more cold air to feed the radiator right?

[mx1311]

i havent got AC anymore.

if the a/c is removed (pump, rad pipes etc) and you turn it on, the fans will still come on as long as the fuse(s) and relay are still in place  :yes

i see about 78 - 85 max with them running in traffic

colum