Cooling issues

[DavidL]

Thoughts please - new (to me) red 952.
Temp gauge sat at first line quite happily but tended to creep up at the first opportunity, lights, slow traffic uphill etc. Going downhill or at speed the gauge would tend to drop a fraction under the line.
Fans (both work) would cut in at towards the 2nd line and bring it back to the first as I would expect it to but I felt it did this too often in normal traffic.
Had a word with local indie and we agreed thermostats would be a good start so this has been done but to no avail. In fact its almost worse as "normal" appears to be at about 90 so almost horizontal, and again the gauge creeps up sooner than I think it should. Certainly sooner than my S does - this actually doesn't move at all unless sat for a few minutes in traffic, not a minute.
So without wishing to give someone carte blanche with my cheque book what next?
I'm not loosing fluid - been pressure tested.
Car had major top end rebuild 4 years ago but only 3K ago following HG failure. Also new rad but not sure about the water pump's age - I'll check. ETA 6years 20K and 2 sets of belts.
I need this sorted as I hate driving watching the temp gauge all the time.
Just (a month ago) new belts.
So any ideas?

 

[George Elliott]

David, - get the "S" checked, your 952 sounds OK, mine is virtually the same - perhaps mine sits 3mm lower on the scale than yours. I replaced the main & turbo stat on my car, and it runs hotter since the change.
(I am assuming the fans cut in and the temp increase ceases to climb, and never comes close to the red area)
Congrat's on your investment
George
944T
964

 

[DavidL]

Thanks George.
It occured to me before I had the stats changed that maybe it was ok but surely a drag up a hill behind a lorry shouldn't cause the temp to rise enough to put the fans on?
I'm sure the S is fine. I've had it 3 years and never had any issues cooling wise, It sits in traffic merrily heating and cooling without any bother.
I'm sure the 952 would as well but I think it gets hotter faster. It doesn't overheat and crucially, at least in my mind, when the fans kick in the gauge drops back to the bottom mark and then gradually rises to almost horizontal for "normal" running.
I've been mulling this over since I drove the car home last night - would an iffy waterpump slow the flow of water to and from the rad so making the car run hotter and respond more quickly to "trying" conditions?

 

[Diver944]

Sounds normal.

A new stat always tends to make it run hotter than before as they gradually weaken and open sooner. The manual actually says something like 'normal temperature is in between the two centre lines'

 

[DavidL]

ORIGINAL: Diver944

Sounds normal.

A new stat always tends to make it run hotter than before as they gradually weaken and open sooner. The manual actually says something like 'normal temperature is in between the two centre lines'

I read that too but most people seem to run at about the 1st line. Does anyone have a car that normally runs closer to horizontal than the 1st line?
Actally rereading that's what George is saying but anyone else?
I didn't know that about the stats, thanks Paul.

 

[Fen]

Perhaps if I also say thats fine and normal you'll believe it [8D]

I'd also say change the 'stat in your S - if you've had it for 3 years and not changed it then it's at least that old which means it needs a new one. I know it isn't something done often, but I tend to change the 'stat in all my cars when I get them as I realised some time ago that most cars benefit from it.

On some modern cars with a good 'stat the needle never moves, but with the 944T normal behaviour is to get to the first mark quickly (the 'stat doing its job and staying closed to let the engine warm up as quickly as possible) and then it will move between that mark and the next. It will rise and fall at idle as the cooling system can't reject enough heat to maintain temperature without air flow. Similarly the fans can be needed to help the radiator after "exercise" as the amount of heat generated is high and it's best to get rid of it as quickly as possible. I imagine the S might be more stable as the NA engine generates less heat - sounds to me like yours never gets hot enough though.