pugface

Hi guys

Like many people here, my 944 seems to be running a little hotter than I'd like. This has been exacerbated by moving to Texas, and getting my A/C fixed

Just got back in from a run to town, and I noticed something I thought was odd. A increase in voltage load seems to make my temp gauge jump up. I'd thought I'd noticed this earlier, but I found an easy way to test it. Pressing the window close switch with the window already closed. When I do this, my temp gauge jumps up noticeably a few degrees. It's a quick and repeatable test.

I would have assumed the voltage to the gauges is regulated so they read consistently no matter the load on the system, but perhaps this is normal?

Now, I know the car runs hotter with A/C on, but perhaps some of what I am seeing is due to the gauge jumping with A/C and interior fans running full blast?

My time and skills are limited, but I did check that the gauge is reading accurate (without the car running) by disconnecting the sender and jumpering resistors.

I also removed the thermostat and filled with mostly distilled water, same issues.

Someone suggested on an earlier thread that running hotter is due to a cumulative effect of 30 year old parts not working as well, not a failure of one thing. I have a new water pump and t-stat (once I put back in) - I am thinking I should go ahead and replace the radiator and hoses. Good idea, or waste of time and money?

Last - Pelican is out of stock on radiators. I checked a few places, and couldn't find any at a reasonable price. Any recommendations?

Thanks
pf

odonnell

Clean all your grounds - lots of threads on the details. The voltage across the alternator is regulated with respect to its ground, but poor grounds elsewhere will cause issues like this.

gtroth

Yup, the grounds at the back of the engine are the most important to clean if your temp gauge is jumping when big electrical are engaged. Was the fix for me anyway. And my temp gauge read a bit lower too after that.

pugface

Thanks guys. That should have been the first thing I checked, sorry.

Now I've just got to find the time! Work is nuts, and family has priority over working on cars